U.S. patent application number 13/860173 was filed with the patent office on 2013-10-10 for fluid turbine with vortex generators.
This patent application is currently assigned to FLODESIGN WIND TURBINE CORP.. The applicant listed for this patent is FLODESIGN WIND TURBINE CORP.. Invention is credited to Soren Hjort, Rune Rubak, Carsten H. Westergaard.
Application Number | 20130266439 13/860173 |
Document ID | / |
Family ID | 48143647 |
Filed Date | 2013-10-10 |
United States Patent
Application |
20130266439 |
Kind Code |
A1 |
Rubak; Rune ; et
al. |
October 10, 2013 |
FLUID TURBINE WITH VORTEX GENERATORS
Abstract
The present disclosure relates to fluid turbines having a
turbine shroud assembly formed with mixing elements (e.g., both
inwardly and outwardly curving elements) having airfoil cross
sections. These airfoils form ringed airfoil shapes that provide a
means of controlling the flow of fluid over the rotor assembly or
over portions of the rotor assembly. The fluid dynamic performance
of the ringed airfoils directly affects the performance of the
turbine rotor assembly. The mass and surface area of the shrouds
result in load forces on support structures. By delaying or
eliminating the separation of the boundary layer over the ringed
airfoils, boundary layer energizing members (e.g., vortex
generators, flow control ports) on the ringed airfoils increase the
power output of the fluid turbine system and allow for relatively
shorter chord-length airfoil cross sections and therefore reduced
mass and surface area of the shroud assemblies.
Inventors: |
Rubak; Rune; (Silkeborg,
DK) ; Westergaard; Carsten H.; (Houston, TX) ;
Hjort; Soren; (Silkeborg, DK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FLODESIGN WIND TURBINE CORP. |
Waltham |
MA |
US |
|
|
Assignee: |
FLODESIGN WIND TURBINE
CORP.
Waltham
MA
|
Family ID: |
48143647 |
Appl. No.: |
13/860173 |
Filed: |
April 10, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61622294 |
Apr 10, 2012 |
|
|
|
Current U.S.
Class: |
415/208.1 |
Current CPC
Class: |
Y02E 10/72 20130101;
F05B 2250/182 20130101; F03D 1/04 20130101; F05B 2240/122 20130101;
F05B 2240/124 20130101; F01D 1/04 20130101; F05B 2240/133 20130101;
F05B 2240/1231 20130101; F05B 2240/123 20130101 |
Class at
Publication: |
415/208.1 |
International
Class: |
F01D 1/04 20060101
F01D001/04 |
Claims
1. A shrouded fluid turbine system comprising: a rotor assembly; a
turbine shroud assembly disposed about the rotor assembly, the
turbine shroud having a low pressure side and a high pressure side,
the low pressure side in fluid communication with the rotor
assembly; and at least one boundary layer energizing member
associated with the turbine shroud assembly, the at least one
boundary layer energizing member configured and dimensioned to
alter a fluid boundary layer over a surface of the turbine shroud
assembly to alter the performance of the fluid turbine system.
2. The system of claim 1, wherein the at least one boundary layer
energizing member is positioned proximal to a leading edge of the
turbine shroud assembly.
3. The system of claim 1 further comprising a first plurality of
boundary layer energizing members and a second plurality of
boundary layer energizing members; wherein the first plurality of
boundary layer energizing members are positioned proximal to a
leading edge of the turbine shroud assembly; and wherein the second
plurality of boundary layer energizing members are positioned
between the leading edge and a trailing edge of the turbine shroud
assembly.
4. The system of claim 3, wherein the first and second pluralities
of boundary layer energizing members are associated with the low
pressure side of the turbine shroud assembly.
5. The system of claim 1 further comprising a plurality of boundary
layer energizing members; wherein the turbine shroud assembly
includes a plurality of curving mixing elements; and wherein each
mixing element is associated with at least one boundary layer
energizing member.
6. The system of claim 5, wherein the plurality of curving mixing
elements includes a first plurality of inwardly curving mixing
elements and a second plurality of outwardly curving mixing
elements.
7. The system of claim 6, wherein at least one boundary layer
energizing member is positioned on the high pressure side of the
turbine shroud assembly and proximal to an inward curving mixing
element of the plurality of inward curving mixing elements.
8. The system of claim 1, wherein the turbine shroud assembly
defines an airfoil ring having an apex; and wherein the at least
one boundary layer energizing member is positioned proximal to the
apex of the airfoil ring.
9. The system of claim 1, wherein the at least one boundary layer
energizing member is a vortex generator, the vortex generator in
the form of a protruding member that protrudes from a surface of
the turbine shroud assembly.
10. The system of claim 9, wherein the vortex generator has a
length and a height; and wherein the length is about four times the
height of the vortex generator.
11. The system of claim 9, wherein the vortex generator has a
length and a height; wherein the vortex generator is fabricated
from a flexible material and includes a first un-flexed condition
and a second flexed condition; and wherein when the vortex
generator is in the second flexed condition, the length of the
vortex generator is about eight times the height.
12. The system of claim 5, wherein each curving mixing element
includes a voluminous leading edge that transitions to a curved
planar form at a trailing edge.
13. The system of claim 1 further comprising an ejector shroud
assembly positioned downstream from and coaxial with the turbine
shroud assembly; wherein at least one boundary layer energizing
member is associated with the ejector shroud assembly, the at least
one boundary layer energizing member associated with the ejector
shroud assembly configured and dimensioned to alter a fluid
boundary layer over a surface of the ejector shroud assembly to
alter the performance of the fluid turbine system.
14. The system of claim 13, wherein the at least one boundary layer
energizing member associated with the ejector shroud assembly is
positioned proximal to a leading edge of the ejector shroud
assembly.
15. The system of claim 13 further comprising a first plurality of
boundary layer energizing members and a second plurality of
boundary layer energizing members associated with the ejector
shroud assembly; wherein the first plurality of boundary layer
energizing members are positioned proximal to a leading edge of the
ejector shroud assembly; and wherein the second plurality of
boundary layer energizing members are positioned between the
leading edge and a trailing edge of the ejector shroud
assembly.
16. The system of claim 15, wherein the first and second
pluralities of boundary layer energizing members are associated
with the low pressure side of the ejector shroud assembly.
17. The system of claim 13, wherein the ejector shroud assembly
defines an airfoil ring having an apex; and wherein the at least
one boundary layer energizing member associated with the ejector
shroud assembly is positioned proximal to the apex of the airfoil
ring.
18. The system of claim 13, wherein the at least one boundary layer
energizing member associated with the ejector shroud assembly is a
vortex generator, the vortex generator in the form of a protruding
member that protrudes from a surface of the ejector shroud
assembly.
19. The system of claim 1, wherein the at least one boundary layer
energizing member is a flow control port, the flow control port
configured and dimensioned to employ high velocity flow through the
flow control port for flow control purposes and to alter a fluid
boundary layer over a surface of the turbine shroud assembly to
alter the performance of the fluid turbine system.
20. The system of claim 19, wherein the at least one flow control
port is positioned proximal to a leading edge of the turbine shroud
assembly.
21. The system of claim 19, wherein the at least one flow control
port is remotely energized with the high velocity flow.
22. The system of claim 19, wherein the at least one flow control
port is energized with the high velocity flow by harvesting fluid
energy from the fluid turbine system.
23. The system of claim 1, wherein the at least one boundary layer
energizing member is configured and dimensioned to prevent
separation of a fluid boundary layer over a surface of the turbine
shroud assembly to alter the performance of the fluid turbine
system.
24. The system of claim 1, wherein the at least one boundary layer
energizing member is configured and dimensioned to alter a fluid
boundary layer over a surface of the turbine shroud assembly to
reduce the performance of the fluid turbine system.
25. The system of claim 1, wherein the turbine shroud assembly
defines an annular airfoil having a leading edge that transitions
to a faceted trailing edge.
26. The system of claim 19, wherein the volume or angle of the high
velocity flow through the flow control port is variable.
27. The system of claim 1, wherein the at least one boundary layer
energizing member configured and dimensioned to alter a fluid
boundary layer over a surface of the turbine shroud assembly alters
the performance of the fluid turbine system.
28. A shrouded fluid turbine system comprising: a rotor assembly; a
turbine shroud assembly disposed about the rotor assembly, the
turbine shroud having a low pressure side and a high pressure side,
the low pressure side in fluid communication with the rotor
assembly, the turbine shroud assembly including a plurality of
curving mixing elements; and a first and second plurality of
boundary layer energizing members associated with the turbine
shroud assembly, each boundary layer energizing member configured
and dimensioned to alter a fluid boundary layer over a surface of
the turbine shroud assembly, the first plurality of boundary layer
energizing members positioned proximal to a leading edge of the
turbine shroud assembly and the second plurality of boundary layer
energizing members positioned between the leading edge and a
trailing edge of the turbine shroud assembly, at least a portion of
the first and second pluralities of boundary layer energizing
members associated with the low pressure side of the turbine shroud
assembly, and each mixing element associated with at least one
boundary layer energizing member.
29. A shrouded fluid turbine system comprising: a rotor assembly; a
turbine shroud assembly disposed about the rotor assembly, the
turbine shroud having a low pressure side and a high pressure side,
the low pressure side in fluid communication with the rotor
assembly; at least one first boundary layer energizing member
associated with the turbine shroud assembly, the at least one first
boundary layer energizing member configured and dimensioned to
alter a fluid boundary layer over a surface of the turbine shroud
assembly to alter the performance of the fluid turbine system; an
ejector shroud assembly positioned downstream from and coaxial with
the turbine shroud assembly; at least one second boundary layer
energizing member associated with the ejector shroud assembly, the
at least one second boundary layer energizing member configured and
dimensioned to alter a fluid boundary layer over a surface of the
ejector shroud assembly to alter the performance of the fluid
turbine system; wherein the turbine shroud assembly includes a
plurality of curving mixing elements; wherein the at least one
first boundary layer energizing member is positioned proximal to a
leading edge of the turbine shroud assembly; and wherein the at
least one second boundary layer energizing member is positioned
proximal to a leading edge of the ejector shroud assembly.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Application Ser. No. 61/622,294 filed Apr. 10, 2012, the contents
of which is herein incorporated by reference in its entirety.
BACKGROUND
[0002] 1. Technical Field
[0003] The present disclosure relates to fluid turbine systems
(e.g., wind or water turbines) and, more particularly to fluid
turbine systems having a rotor assembly in fluid communication with
a shroud assembly (e.g., turbine shroud assembly) having boundary
layer energizing members (e.g., vortex generators, flow control
ports). The present disclosure further relates to fluid turbine
systems having a shroud assembly with reduced surface area and or
mass.
[0004] 2. Background
[0005] In general, some conventional horizontal axis fluid turbines
used for power generation have blades (e.g., two to five open
blades) arranged like a propeller, the blades typically being
mounted to a horizontal shaft attached to a gear box which drives a
power generator. Attempts have been made to provide a means of
delaying or preventing flow separation between the flowing fluid
and the blade surfaces.
[0006] Example fluid turbines are described and disclosed in U.S.
Pat. Nos. 8,021,100; and 8,393,850, and U.S. Patent Pubs. Nos.
2011/0014038; 2010/0270802; 2010/0247289; 2011/0002781;
2011/0020107; 2011/0085901; 2011/0135460; 2010/0166547;
2010/0133853; and 2012/0070275, the entire contents of each being
hereby incorporated by reference in their entireties.
SUMMARY
[0007] An interest exists for advantageous fluid turbine systems
that provide an improved means of delaying or preventing flow
separation over a flow control surface (e.g., over the turbine
shroud assembly), for improving the performance of the turbine
system and or rotor assembly. These and other opportunities for
improvement are addressed and or overcome by the assemblies,
systems and methods of the present disclosure.
[0008] The present disclosure provides improved fluid turbine
systems. More particularly, the present disclosure provides
advantageous fluid turbine systems having a rotor assembly in fluid
communication with a shroud assembly (e.g., a turbine shroud
assembly in the shape of an airfoil or ringed airfoil), the shroud
assembly having boundary layer energizing members (e.g., vortex
generators, flow control ports). The present disclosure also
provides for improved fluid turbine systems having a shroud
assembly with reduced surface area and or mass. In example
embodiments, the reduction of surface area provides a means of
reducing load forces and or tower stress forces (e.g., in excessive
fluid flow conditions).
[0009] In general, the present disclosure provides fluid turbine
systems having boundary layer energizing members (e.g., vortex
generators, flow control devices or ports). The boundary layer
energizing members are advantageously configured and dimensioned to
prevent separation of a fluid boundary layer over the turbine
shroud assembly and or over the ejector shroud assembly to alter or
improve the performance of the fluid turbine system.
[0010] In general, there are many situations in which it can be
desirable to provide a means of delaying or preventing flow
separation between a flowing medium and a flow control surface. For
example, a fluid passing over an airfoil surface from the leading
edge to the trailing edge typically flows from a region with low
static pressure to a region with high static pressure. This can
result in forces which tend to retard the boundary layer and cause
the fluid to separate, resulting in increased separation-drag and
therefore reduced lift and reduced performance of the airfoil.
Boundary layer energizing members (e.g., vortex generators),
associated with the flow control surface, can be used to
substantially prevent and or minimize flow separation by mixing
free flow with the boundary layer. As used herein, the term
"boundary layer" refers to the layer of fluid flow in the immediate
vicinity of a flow control surface. One skilled in the art will
recognize that a boundary layer is involved or included in all
embodiments of the present disclosure where a flowing fluid or
medium is flowing over a flow control surface.
[0011] In general, a properly designed shroud or duct delivers
greater mass flow rate to the interior of the shroud or duct than
to the exterior. As such, improved performance over that of a
similar open-rotor system can be achieved from a rotor in fluid
communication with a properly designed shroud or duct. In example
embodiments of the present disclosure, boundary layer energizing
members provide a means of delaying or preventing flow separation
over a flow control surface (e.g., over the turbine shroud
assembly), thereby advantageously allowing for the reduction of
flow control surface area (e.g., turbine shroud assembly surface
area or airfoil surface area), while maintaining or increasing
performance characteristics similar to that of a relatively larger
flow control surface area (e.g., an airfoil with a larger chord).
Moreover, the reduction of surface area and mass also reduces loads
and tower stress forces (e.g., in high velocity fluid flow
conditions) of the turbine systems of the present disclosure.
[0012] In example embodiments, the present disclosure
advantageously provides for turbine systems that include vortex
generators or the like mounted with respect to shroud surfaces
(e.g., to the suction side of shroud assembly or ringed airfoil
surfaces), the vortex generators are configured and dimensioned to
generate vortices (vortexes) that energize or provide energy to the
boundary layer to delay or prevent flow separation before the fluid
has reached the trailing edge of the shroud assembly. In example
embodiments, a vortex generator is a device or member that is
configured and dimensioned to generate a vortex or vortices
(vortexes) or the like, thereby providing energy to or energizing
(via the generated vortex) a fluid boundary layer over a surface of
the turbine system (e.g., over the turbine shroud assembly), which
can alter the fluid boundary layer over a surface of the turbine
system (e.g., to delay or prevent flow separation before the fluid
has reached the trailing edge of the shroud assembly). In certain
embodiments and as discussed further below, the shroud assemblies
of the present disclosure take the form of ringed airfoils (e.g.,
substantially circular in form), although the present disclosure is
not limited thereto. Rather, the shroud assemblies of the present
disclosure can take a variety of forms (e.g., assemblies or
airfoils having a non-circular shape; assemblies or airfoils that
include gaps of sections along their circumference, periphery or
shape; etc.).
[0013] In certain embodiments, the lift-side airfoil cross-sections
of a shroud assembly or ringed airfoil are on the interior surface
of the shroud assembly or ring. In other embodiments, a majority or
plurality of the lift-side airfoil cross-sections of the shroud
assembly are on the interior surface, while portions of the
interior surface of the shroud assembly can also include
pressure-side airfoil cross-sections, and or portions of the outer
surface of the ringed airfoil or shroud assembly may include
lift-side airfoil cross-sections.
[0014] An airfoil assembly (e.g., ringed airfoil assembly) that
surrounds or is disposed about a rotor assembly is typically known
as a turbine shroud assembly. In general, the turbine shroud
assembly is generally cylindrical and is configured to generate
relatively lower pressure within the turbine shroud assembly (the
interior of the shroud) and relatively higher pressure outside the
turbine shroud (the exterior of the shroud). The shroud assembly or
ringed airfoil can be cambered, and have cross-sections shaped like
an aircraft wing airfoil. In example embodiments, the turbine
shroud assembly includes inward and outwardly curving mixing
elements that have airfoil cross sections.
[0015] In certain embodiments, boundary layer energizing members
(e.g., vortex generators) on the pressure side of the turbine
shroud assembly, proximal to the inward turning mixing elements,
prevent or minimize separation of the portion of the fluid stream
that provides mixing of bypass flow with flow that has passed
through the rotor assembly. The turbine shroud assembly can include
mixing elements such as, for example, mixing lobes or slots.
[0016] In some embodiments, a second shroud assembly may be located
proximal or adjacent to the trailing edge of the turbine shroud
assembly, and the second shroud assembly is typically known as an
ejector shroud assembly. For example, the ejector shroud assembly
can take the form or shape of a ringed airfoil that includes an
annular ring having members with airfoil cross sections, although
the present disclosure is not limited thereto. In example
embodiments, boundary layer energizing members (e.g., vortex
generators) mounted with respect to the suction side of the ejector
shroud assembly prevent flow separation until the fluid stream has
passed the trailing edge of the turbine system.
[0017] Load forces (e.g., originating from the shrouded system) on
support structures, such as tower and foundation components, of a
turbine system may be caused by drag and or side loads on
aerodynamic surfaces of the turbine system. Boundary layer
energizing members delay or substantially eliminate or minimize the
separation of the boundary layer over flow control surfaces (e.g.,
airfoils), providing a means of employing airfoil cross sections
with relatively shorter chord lengths than that of airfoils with
similar performance characteristics. It is noted that a reduction
in the chord length can provide a ringed airfoil with reduced
surface area and therefore, reduced loads, drag and or reduced
tower and foundation stress.
[0018] Some mixer-ejector turbines employ mixing elements such as
diverging and converging airfoil segments. In general, such mixing
elements provide controlled stream-wise vorticity in the area
downstream of the mixer-ejector turbine. It is noted that a faceted
trailing edge configuration of the turbine also provides similarly
controlled stream-wise vorticity. In example embodiments, the fluid
turbine systems having faceted segments with the substantially
annular airfoils provides appropriate surface area for load
mitigation by having a shorter turbine shroud and a longer ejector
shroud.
[0019] In general, reducing lift forces over turbine aerodynamic
surfaces, particularly when the turbine is in a parked
configuration, reduces loads on turbine structural components. In
certain embodiments, the aerodynamic augmentation provided by
vortex generators may also be achieved by flow control devices or
ports (e.g., active flow control devices). An advantage of flow
control devices is that they can either prevent or cause separation
over a flow control surface. In general, introducing fluid (e.g.,
air) normal to the airfoil surface can prevent flow separation.
Lift forces over the shroud surfaces when the turbine is in a
parked configuration can cause unintended yaw moment forces and
therefore, undue stress on structural components. In example
embodiments, by controlling the volume of airflow and or the angle
of flow to the airfoil surface, boundary layer separation can be
caused, effectively stalling the airfoil and reducing the lift
force and therefore the yaw moment. A reduced yaw moment reduces
the loads on turbine structural components.
[0020] The present disclosure provides for a shrouded fluid turbine
system including a rotor assembly; a turbine shroud assembly
disposed about the rotor assembly, the turbine shroud having a low
pressure side and a high pressure side, the low pressure side in
fluid communication with the rotor assembly; and at least one
boundary layer energizing member associated with the turbine shroud
assembly, the at least one boundary layer energizing member
configured and dimensioned to alter a fluid boundary layer over a
surface of the turbine shroud assembly to alter the performance of
the fluid turbine system.
[0021] The present disclosure also provides for a shrouded fluid
turbine system wherein the at least one boundary layer energizing
member is positioned proximal to a leading edge of the turbine
shroud assembly. The present disclosure provides for a shrouded
fluid turbine system further including a first plurality of
boundary layer energizing members and a second plurality of
boundary layer energizing members; wherein the first plurality of
boundary layer energizing members are positioned proximal to a
leading edge of the turbine shroud assembly; and wherein the second
plurality of boundary layer energizing members are positioned
between the leading edge and a trailing edge of the turbine shroud
assembly.
[0022] The present disclosure provides for a shrouded fluid turbine
system wherein the first and second pluralities of boundary layer
energizing members are associated with the low pressure side of the
turbine shroud assembly. The present disclosure provides for a
shrouded fluid turbine system further including a plurality of
boundary layer energizing members; wherein the turbine shroud
assembly includes a plurality of curving mixing elements; and
wherein each mixing element is associated with at least one
boundary layer energizing member. The present disclosure provides
for a shrouded fluid turbine system wherein the plurality of
curving mixing elements includes a first plurality of inwardly
curving mixing elements and a second plurality of outwardly curving
mixing elements. The present disclosure provides for a shrouded
fluid turbine system wherein at least one boundary layer energizing
member is positioned on the high pressure side of the turbine
shroud assembly and proximal to an inward curving mixing element of
the plurality of inward curving mixing elements.
[0023] The present disclosure provides for a shrouded fluid turbine
system wherein the turbine shroud assembly defines an airfoil ring
having an apex; and wherein the at least one boundary layer
energizing member is positioned proximal to the apex of the airfoil
ring. The present disclosure provides for a shrouded fluid turbine
system wherein the at least one boundary layer energizing member is
a vortex generator, the vortex generator in the form of a
protruding member that protrudes from a surface of the turbine
shroud assembly. The present disclosure provides for a shrouded
fluid turbine system wherein the vortex generator has a length and
a height; and wherein the length is about four times the height of
the vortex generator. The present disclosure provides for a
shrouded fluid turbine system wherein the vortex generator has a
length and a height; wherein the vortex generator is fabricated
from a flexible material and includes a first un-flexed condition
and a second flexed condition; and wherein when the vortex
generator is in the second flexed condition, the length of the
vortex generator is about eight times the height.
[0024] The present disclosure provides for a shrouded fluid turbine
system wherein each curving mixing element includes a voluminous
leading edge that transitions to a curved planar form at a trailing
edge. The present disclosure provides for a shrouded fluid turbine
system further including an ejector shroud assembly positioned
downstream from and coaxial with the turbine shroud assembly;
wherein at least one boundary layer energizing member is associated
with the ejector shroud assembly, the at least one boundary layer
energizing member associated with the ejector shroud assembly
configured and dimensioned to alter a fluid boundary layer over a
surface of the ejector shroud assembly to alter the performance of
the fluid turbine system.
[0025] The present disclosure provides for a shrouded fluid turbine
system wherein the at least one boundary layer energizing member
associated with the ejector shroud assembly is positioned proximal
to a leading edge of the ejector shroud assembly. The present
disclosure provides for a shrouded fluid turbine system further
including a first plurality of boundary layer energizing members
and a second plurality of boundary layer energizing members
associated with the ejector shroud assembly; wherein the first
plurality of boundary layer energizing members are positioned
proximal to a leading edge of the ejector shroud assembly; and
wherein the second plurality of boundary layer energizing members
are positioned between the leading edge and a trailing edge of the
ejector shroud assembly.
[0026] The present disclosure provides for a shrouded fluid turbine
system wherein the first and second pluralities of boundary layer
energizing members are associated with the low pressure side of the
ejector shroud assembly. The present disclosure provides for a
shrouded fluid turbine system wherein the ejector shroud assembly
defines an airfoil ring having an apex; and wherein the at least
one boundary layer energizing member associated with the ejector
shroud assembly is positioned proximal to the apex of the airfoil
ring. The present disclosure provides for a shrouded fluid turbine
system wherein the at least one boundary layer energizing member
associated with the ejector shroud assembly is a vortex generator,
the vortex generator in the form of a protruding member that
protrudes from a surface of the ejector shroud assembly.
[0027] The present disclosure provides for a shrouded fluid turbine
system wherein the at least one boundary layer energizing member is
a flow control port, the flow control port configured and
dimensioned to employ high velocity flow through the flow control
port for flow control purposes and to alter a fluid boundary layer
over a surface of the turbine shroud assembly to alter the
performance of the fluid turbine system. The present disclosure
provides for a shrouded fluid turbine system wherein the at least
one flow control port is positioned proximal to a leading edge of
the turbine shroud assembly. The present disclosure provides for a
shrouded fluid turbine system wherein the at least one flow control
port is remotely energized with the high velocity flow. The present
disclosure provides for a shrouded fluid turbine system wherein the
at least one flow control port is energized with the high velocity
flow by harvesting fluid energy from the fluid turbine system.
[0028] The present disclosure provides for a shrouded fluid turbine
system wherein the at least one boundary layer energizing member is
configured and dimensioned to prevent separation of a fluid
boundary layer over a surface of the turbine shroud assembly to
alter the performance of the fluid turbine system. The present
disclosure provides for a shrouded fluid turbine system wherein the
at least one boundary layer energizing member is configured and
dimensioned to alter a fluid boundary layer over a surface of the
turbine shroud assembly to reduce the performance of the fluid
turbine system.
[0029] The present disclosure provides for a shrouded fluid turbine
system wherein the turbine shroud assembly defines an annular
airfoil having a leading edge that transitions to a faceted
trailing edge. The present disclosure provides for a shrouded fluid
turbine system wherein the volume or angle of the high velocity
flow through the flow control port is variable. The present
disclosure provides for a shrouded fluid turbine system wherein the
at least one boundary layer energizing member configured and
dimensioned to alter a fluid boundary layer over a surface of the
turbine shroud assembly alters the performance of the fluid turbine
system.
[0030] The present disclosure provides for a shrouded fluid turbine
system including a rotor assembly; a turbine shroud assembly
disposed about the rotor assembly, the turbine shroud having a low
pressure side and a high pressure side, the low pressure side in
fluid communication with the rotor assembly, the turbine shroud
assembly including a plurality of curving mixing elements; and a
first and second plurality of boundary layer energizing members
associated with the turbine shroud assembly, each boundary layer
energizing member configured and dimensioned to alter a fluid
boundary layer over a surface of the turbine shroud assembly, the
first plurality of boundary layer energizing members positioned
proximal to a leading edge of the turbine shroud assembly and the
second plurality of boundary layer energizing members positioned
between the leading edge and a trailing edge of the turbine shroud
assembly, at least a portion of the first and second pluralities of
boundary layer energizing members associated with the low pressure
side of the turbine shroud assembly, and each mixing element
associated with at least one boundary layer energizing member.
[0031] The present disclosure provides for a shrouded fluid turbine
system including a rotor assembly; a turbine shroud assembly
disposed about the rotor assembly, the turbine shroud having a low
pressure side and a high pressure side, the low pressure side in
fluid communication with the rotor assembly; at least one first
boundary layer energizing member associated with the turbine shroud
assembly, the at least one first boundary layer energizing member
configured and dimensioned to alter a fluid boundary layer over a
surface of the turbine shroud assembly to alter the performance of
the fluid turbine system; an ejector shroud assembly positioned
downstream from and coaxial with the turbine shroud assembly; at
least one second boundary layer energizing member associated with
the ejector shroud assembly, the at least one second boundary layer
energizing member configured and dimensioned to alter a fluid
boundary layer over a surface of the ejector shroud assembly to
alter the performance of the fluid turbine system; wherein the
turbine shroud assembly includes a plurality of curving mixing
elements; wherein the at least one first boundary layer energizing
member is positioned proximal to a leading edge of the turbine
shroud assembly; and wherein the at least one second boundary layer
energizing member is positioned proximal to a leading edge of the
ejector shroud assembly.
[0032] These and other non-limiting features or characteristics of
the present disclosure will be further described below. Any
combination or permutation of embodiments is envisioned. Additional
advantageous features, functions and applications of the disclosed
assemblies, systems and methods of the present disclosure will be
apparent from the description which follows, particularly when read
in conjunction with the appended figures. All references listed in
this disclosure are hereby incorporated by reference in their
entireties.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The following is a brief description of the drawings, which
are presented for the purposes of illustrating the disclosure set
forth herein and not for the purposes of limiting the same. Example
embodiments of the present disclosure are further described with
reference to the appended figures. It is to be noted that the
various features and combinations of features described below and
illustrated in the figures can be arranged and organized
differently to result in embodiments which are still within the
spirit and scope of the present disclosure. To assist those of
ordinary skill in the art in making and using the disclosed
systems, assemblies and methods, reference is made to the appended
figures, wherein:
[0034] FIG. 1 is a front perspective view of an embodiment of a
fluid turbine system;
[0035] FIG. 2 is a rear perspective view of the system of FIG.
1;
[0036] FIGS. 3-4 are front, side perspective, detail views of the
system of FIG. 1;
[0037] FIG. 5 is a rear, side perspective, detail view of the
system of FIG. 1;
[0038] FIG. 6 is a side cross-sectional, detail view of the system
of FIG. 1 depicting the proportion between the length and height of
a vortex generator and the length and height of the airfoil member
that it is engaged with;
[0039] FIG. 7 is a side cross-sectional, detail view of the system
of FIG. 1 depicting the proportion between the length and height of
a vortex generator and the length and height of the airfoil member
that it is engaged with;
[0040] FIGS. 8-10 are side, cross section detail views of
embodiments of the system of FIG. 1;
[0041] FIGS. 11-12 are detailed, cross sectional views of
additional embodiments of a vortex generator of a shrouded fluid
turbine of the present disclosure;
[0042] FIG. 13 is a front perspective view of another embodiment of
a fluid turbine system of the present disclosure;
[0043] FIGS. 14-16 are detailed cross sectional views of the system
of FIG. 13;
[0044] FIG. 17 is a front perspective view of another embodiment of
a fluid turbine system of the present disclosure depicting boundary
layer energizing members;
[0045] FIG. 18 is a front, right-perspective, detailed cross
section of the system of FIG. 17;
[0046] FIG. 19 is a side detailed cross section of the system of
FIG. 17;
[0047] FIG. 20 is a front right, detailed cross section view of the
system of FIG. 17;
[0048] FIG. 21 is a front perspective view of another embodiment of
a fluid turbine system of the present disclosure depicting boundary
layer energizing members;
[0049] FIG. 22 is a front right perspective view of another
embodiment of a fluid turbine system of the present disclosure;
[0050] FIG. 23 is a front, right perspective, detailed cross
section view of the system of FIG. 22 depicting boundary layer
energizing members; and
[0051] FIG. 24 is a side, detailed cross section view of the system
of FIG. 22.
DETAILED DESCRIPTION
[0052] The example embodiments disclosed herein are illustrative of
advantageous fluid turbine systems, and assemblies of the present
disclosure and methods or techniques thereof. It should be
understood, however, that the disclosed embodiments are merely
examples of the present disclosure, which may be embodied in
various forms. Therefore, details disclosed herein with reference
to example fluid turbine systems or fabrication methods and
associated processes or techniques of assembly and or use are not
to be interpreted as limiting, but merely as the basis for teaching
one skilled in the art how to make and use the advantageous fluid
turbine systems of the present disclosure.
[0053] A more complete understanding of the components, processes,
and apparatuses disclosed herein can be obtained by reference to
the accompanying figures. These figures are intended to demonstrate
the present disclosure and are not intended to show relative sizes
and dimensions or to limit the scope of the example
embodiments.
[0054] Although specific terms are used in the following
description, these terms are intended to refer only to particular
structures in the drawings and are not intended to limit the scope
of the present disclosure. It is to be understood that like numeric
designations refer to components of like function.
[0055] The term "about" when used with a quantity includes the
stated value and also has the meaning dictated by the context. For
example, it includes at least the degree of error associated with
the measurement of the particular quantity. When used in the
context of a range, the term "about" should also be considered as
disclosing the range defined by the absolute values of the two
endpoints. For example, the range "from about 2 to about 4" also
discloses the range "from 2 to 4."
[0056] In certain embodiments, a mixer-ejector fluid turbine
provides an improved means of generating power from fluid currents.
A turbine shroud assembly can be disposed about a rotor assembly,
with the rotor assembly extracting power from a primary fluid
stream. A mixer-ejector pump can be included in some embodiments
that ingests flow from the primary fluid stream and secondary flow,
and promotes turbulent mixing of the two fluid streams. This
enhances the power system by increasing the amount of fluid flow
through the system, increasing the velocity at the rotor assembly
for more power availability, and reducing back pressure on turbine
blades.
[0057] The term "rotor assembly" is used herein to refer to any
assembly in which blades are attached to a shaft and able to
rotate, allowing for the generation of power or energy from fluid
rotating the blades. Rotor assemblies can include a propeller-like
rotor or a rotor or stator assembly. Any type of rotor assembly may
be utilized with the fluid turbines of the present disclosure.
[0058] In certain embodiments, the leading edge of a turbine shroud
assembly may be considered the front of the fluid turbine system,
and the trailing edge of a turbine shroud assembly or of an ejector
shroud assembly may be considered the rear of the fluid turbine
system. A first component of the fluid turbine system located
closer to the front of the turbine system may be considered
"upstream" of a second component located closer to the rear of the
turbine system. Put another way, the second component is
"downstream" of the first component.
[0059] The present disclosure provides advantageous fluid turbine
systems. More particularly, the present disclosure provides
improved fluid turbine systems having a rotor assembly in fluid
communication with a shroud assembly (e.g., turbine shroud
assembly) having boundary layer energizing members (e.g., vortex
generators, flow control ports). The present disclosure also
provides for improved fluid turbine systems having a shroud
assembly with reduced surface area and or mass. In general, the
reduction of surface area provides a means of reducing load forces
and tower stress forces in excessive fluid flow conditions.
[0060] In example embodiments, the present disclosure provides
shrouded fluid turbines (e.g., wind or water turbines) having a
shroud assembly formed with both inward and outwardly curving
elements having airfoil cross sections. These airfoils form ringed
airfoil shapes that provide a means of controlling the flow of
fluid over the rotor assembly and or over portions of the rotor
assembly. In general, the fluid dynamic performance of the ringed
airfoils directly affects the performance of the turbine rotor
assembly. The mass and surface area of the shroud assemblies result
in load forces on support structures. By delaying or eliminating
the separation of the boundary layer over the ringed airfoils,
boundary layer energizing members (e.g., vortex generators, flow
control ports) on the ringed airfoils increase the power output of
the fluid turbine system and allow for relatively shorter
chord-length airfoil cross sections and therefore reduced mass and
surface area of the shroud assemblies.
[0061] In certain embodiments, the present disclosure provides for
a fluid turbine system including a turbine shroud assembly (e.g.,
ringed turbine shroud) that surrounds a rotor assembly, and can
further include in some embodiments an ejector shroud assembly that
surrounds the exit of the turbine shroud assembly. It is noted that
the fluid turbine system of the present disclosure may or may not
include an ejector shroud assembly, as further discussed below. In
general, boundary layer energizing members (e.g., vortex
generators, flow control ports) are associated with the turbine
shroud assembly and or ejector shroud assembly for the purpose of
preventing flow separation of the boundary layer.
[0062] The term vortex generator is used to describe a range of
assemblies or devices mounted with respect to a turbine system. The
term vortex generator can mean, but is in no way limited to,
"device or member generating a vortex." For example, a vortex
generator can be a protruding member such as illustrated throughout
the figures. However, one skilled in the art will readily recognize
numerous suitable vortex generator forms or shapes may be utilized
in practicing the present disclosure, and therefore the recited
embodiments of the figures are not intended to be limiting in
scope.
[0063] Referring now to the drawings, like parts are marked
throughout the specification and drawings with the same reference
numerals, respectively. Drawing figures are not necessarily to
scale and in certain views, parts may have been exaggerated for
purposes of clarity.
[0064] FIG. 1 is a front perspective view of an example embodiment
of a fluid turbine system 100 (e.g., shrouded fluid turbine system)
of the present disclosure. FIG. 2 is a rear perspective view of the
fluid turbine system 100 of FIG. 1. In general, a system having a
rotor or impeller assembly 140 encircled in part or completely by
one or more shroud assemblies 110, 120 can be described as a
shrouded fluid turbine system 100.
[0065] Referring to FIGS. 1 and 2, the shrouded fluid turbine
system 100 includes a turbine shroud 110, a nacelle body or housing
150, a rotor assembly 140, and in some embodiments an ejector
shroud assembly 120. It is noted that the shrouded fluid turbine
system 100 may or may not include an ejector shroud assembly 120,
as further discussed below. In embodiments that include the ejector
shroud assembly 120, support members 106 (e.g., trusses, attachment
struts) connect the turbine shroud assembly 110 to the ejector
shroud assembly 120.
[0066] The turbine shroud assembly 110 includes a front end 112,
also known as an inlet end or a leading edge. The turbine shroud
assembly 110 also includes a rear end 116, also known as an exhaust
end or trailing edge. In some embodiments, the ejector shroud 120
includes a front end, inlet end or leading edge 122, and a rear
end, exhaust end, or trailing edge 124.
[0067] The rotor assembly 140 surrounds the nacelle body 150. The
rotor assembly 140 includes a central hub 141 at the proximal end
of the rotor blades. The central hub 141 is rotationally engaged
with the nacelle body 150. The nacelle body 150 and the turbine
shroud assembly 110 are supported by a tower 102. The rotor
assembly 140, turbine shroud assembly 110, and ejector shroud
assembly 120 can be coaxial with each other, i.e., they share a
common central axis 105 (FIG. 2). It is noted that the terms inward
or inwardly and outward or outwardly in regards to the mixing
elements 115, 117 discussed below are relative to the central axis
105.
[0068] Although turbine shroud assembly 110 is shown encompassing
or encircling the rotor assembly 140, in some embodiments, the
turbine shroud assembly 110 can partially encompass or encircle the
rotor assembly 140 (e.g., the turbine shroud assembly 110 may have
gaps, have slots, be discontinuous, segmented, and the like, or the
rotor assembly 140 may extend beyond the leading edge 122 or
trailing edge 124 of the turbine shroud assembly 110). See, e.g.,
U.S. Patent Pub. No. 2010/0247289 for example shrouds that are
segmented. Moreover, the ejector shroud assembly 120, if present,
may have gaps, have slots, be discontinuous, segmented, and the
like. In some embodiments, the turbine shroud assembly 110 may not
encircle the rotor assembly 140 (e.g., at least a portion of the
rotor assembly 140 may be positioned in front of the leading edge
122 or past the trailing edge 124 of the turbine shroud assembly
110).
[0069] As noted, rotor assembly 140 refers to any assembly in which
blades are attached to a shaft and able to rotate, allowing for the
generation of power or energy from fluid rotating the blades. Rotor
assemblies 140 can include a propeller-like rotor or a rotor or
stator assembly. Any type of rotor assembly 140 may be utilized
with fluid turbine system 100.
[0070] In example embodiments, the turbine shroud assembly 110 has
the cross-sectional shape of an airfoil, with the suction side
(i.e., low pressure side) on the interior of the shroud assembly
110. The rear end 116 of the turbine shroud assembly 110 has mixing
elements or lobes, including outwardly directed mixing elements 115
and inwardly directed mixing elements 117. The mixing elements 115,
117 extend downstream beyond the rotor blades and are directed
either outwardly or inwardly with respect to the central axis 105.
Put another way, the trailing edge 116 of the turbine shroud
assembly 110 is shaped to form two different sets of mixing
elements 115, 117. Inwardly directed mixing elements 117 extend
inwardly towards the central axis 105 of the mixer shroud.
Outwardly directed mixing elements 115 extend outwardly away from
the central axis 105. When viewed from the rear the mixing elements
or lobes 115, 117 form a general circular crenellated or
circumferential undulating in-and-out shape, as shown in FIG. 2. A
pressure drop occurs in the wake of the rotor assembly 140 as a
result of the energy taken out by the rotor assembly 140. Inwardly
and outwardly directed elements 115, 117 provide turbulent mixing
of high and low pressure streams, such that the fluid pressure in
the wake of the turbine rapidly returns to ambient pressure.
[0071] In certain embodiments, a mixer-ejector pump is formed by
the ejector shroud assembly 120 surrounding the ring of inwardly
directed mixing elements 117 and outwardly directed mixing elements
115 of the turbine shroud assembly 110. In example embodiments, the
airfoil defined by the ejector shroud assembly 120 can have a
generally cylindrical or ring-like configuration having a
circumferential body extending about the central axis 105.
[0072] The mixing elements 115, 117 can extend downstream and into
the inlet end 122 of the ejector shroud assembly 120. In certain
embodiments, the mixer-ejector pump provides turbulent mixing of
fluid that passes through the rotor assembly 140 with fluid that
bypasses the rotor assembly 140. A pressure drop occurs in the wake
of the rotor assembly 140 as a result of the energy taken out by
the rotor assembly 140. Inwardly and outwardly directed elements
115, 117 in combination with the ejector shroud assembly 120
provide turbulent mixing of high and low pressure streams, such
that the fluid pressure in the wake of the turbine rapidly returns
to ambient pressure.
[0073] In example embodiments, system 100 includes boundary layer
energizing members 130. As shown in FIGS. 1-10, boundary layer
energizing members 130 take the form of vortex generators 130
(e.g., protruding members, etc.) or the like. In general, boundary
layer energizing members 130 are configured and dimensioned to
prevent separation of a fluid boundary layer over flow control
surfaces (e.g., over the turbine shroud assembly 110 and or ejector
shroud assembly 120) to alter or improve the performance of the
fluid turbine system 100 (or over shrouds 310, 320 of system 300,
or over shrouds 410, 420 of system 400, as discussed below). Stated
another way, boundary layer energizing members 130 (e.g., vortex
generators), associated with flow control surface (e.g., assembly
110, 120) of system 100, can be used to substantially prevent and
or minimize flow separation by mixing free flow with the boundary
layer. In certain embodiments, boundary layer energizing members
130 (e.g., vortex generators) are configured and dimensioned to
energize the boundary layer to delay or prevent flow separation
before the fluid has reached the trailing edge of a flow control
surface (e.g., shroud assembly 110 and or 120) of system 100.
[0074] In example embodiments, a vortex generator 130 is a device
or member that is configured and dimensioned to generate a vortex
or vortices (vortexes) or the like, thereby providing energy to or
energizing (via the generated vortex) a fluid boundary layer over a
surface of the turbine shroud assembly 110, which can alter the
fluid boundary layer over a surface of the turbine shroud assembly
110 (e.g., to delay or prevent flow separation before the fluid has
reached the trailing edge of the shroud assembly). For example,
vortex generators 130 can take the form of protruding members or
the like, although the present disclosure is not limited thereto.
Rather, protruding members 130 can take a variety of suitable forms
or shapes. In example embodiments, the protruding members 130 are
designed so that they do not extend across the diameter of the
shrouds 110 and or 120, and are low profile having a limited aspect
ratio. The term "energizing" can mean, but is in no way limited to,
providing energy or fluid flow to a system or location (e.g., to a
fluid boundary layer over a surface of the turbine shroud assembly
110).
[0075] In general, at least one vortex generator 130 is mounted
with respect to a surface of system 100 (e.g., to a surface of
turbine shroud assembly 110, or assembly 120). In example
embodiments, a plurality of vortex generators 130 are mounted with
respect to a surface of turbine shroud assembly 110 (or assembly
120). In some embodiments, the vortex generators 130 are integrally
formed with assembly 110 (or assembly 120), although the present
disclosure is not limited thereto.
[0076] In certain embodiments and referring to FIGS. 3-4, vortex
generators 130 can be mounted with respect to the turbine shroud
assembly 110 approximately at or proximal to the leading edge 112
of the turbine shroud assembly 110. However, it is noted that
vortex generators 130 can be mounted with respect to assembly 110
(or assembly 120) at any suitable location or position. For
example, system 100 can include vortex generators 130 mounted with
respect to the suction side (e.g., low pressure side on the
interior of the shroud assembly) and or with respect to the
pressure side (higher pressure side on the outside or exterior of
the shroud assembly) of shroud assembly surfaces (assembly 110 and
or 120). As such, the vortex generators 130 can be configured and
dimensioned to energize the boundary layer to delay or prevent flow
separation before the fluid has reached the trailing edge of the
shroud assembly 110, 120.
[0077] As shown in FIGS. 3-4, vortex generators 130 can be mounted
with respect to the turbine shroud assembly 110 proximal to the
leading edge 112 of the turbine shroud assembly 110 on the suction
side (e.g., low pressure side on the interior of the shroud
assembly 110--FIG. 4), and or on the pressure side (higher pressure
side on the outside or exterior of the shroud assembly 110--FIG.
3). In example embodiments, the vortex generators 130 can be
positioned substantially equidistantly apart from one another
around the circumference or periphery (suction or pressure side) of
assembly 110 (or 120), although the present disclosure is not
limited thereto.
[0078] Additional vortex generators 130 can be mounted with respect
to the turbine shroud assembly 110 near or proximal to the apex 111
of the airfoil ring defined by the interior of assembly 110 (e.g.,
approximately at the thickest part of the cross sectional shape of
the airfoil ring defined by assembly 110--FIG. 4). In some
embodiments and as shown in FIG. 4, a plurality of vortex
generators 130 can be arranged or disposed in two or more
circumferential rows about the surface of the shroud assembly 110.
For example, the plurality of vortex generators 130 can be arranged
in a first downstream row (e.g, a row downstream of the blades of
the rotor assembly 140) and in a second upstream row (e.g, a row
upstream of the blades of the rotor assembly 140). In example
embodiments and as shown in FIG. 4, assembly 110 includes a
plurality of vortex generators 130 positioned near or proximal to
the apex 111 and disposed in a circumferential row downstream of
the blades of the rotor assembly 140. Assembly 110 also includes a
plurality of vortex generators 130 proximal to the leading edge 112
and disposed in a circumferential row upstream of the blades of the
rotor assembly 140. Again, it is noted that vortex generators 130
can be mounted with respect to system 100 at any suitable location.
Moreover, vortex generators 130 can be mounted with respect to the
pressure side of the assembly 110 and proximal to the leading edge
112 of the turbine shroud assembly 110, and or proximal to the
inward turning mixing elements 117 (FIG. 3).
[0079] As noted, vortex generators 130 can be mounted with respect
to ejector shroud assembly 120 at any suitable location. As shown
in FIG. 5, vortex generators 130 can be mounted with respect to
ejector shroud assembly 120 (e.g., on the suction or interior side)
near or proximal to the leading edge 122 of the ejector 120, and
additional vortex generators 130 can be mounted with respect to the
ejector shroud assembly 120 between the leading edge 122 and the
trailing edge 124 (e.g., approximately located or positioned at the
thickest part of the cross sectional shape of the airfoil ring
defined by assembly 120).
[0080] FIGS. 6-7 illustrate the relative proportion of an
embodiment of a vortex generator 130 mounted with respect to the
ejector shroud assembly 120. As shown in FIG. 7, the height 144 of
the vortex generator 130 is approximately equal to about 1% of the
chord length 140 of the airfoil cross-section defined by the
ejector shroud assembly 120. Moreover, the height 144 of the vortex
generator 130 is approximately 1/4th or 25% of the length 146 of
the vortex generator 130. Put another way, the length 146 of this
particular vortex generator 130 is about four times the height 144
of the vortex generator 130. It is important to note that the size
of the vortex generators are scaled to the physical properties of
the location on the surface relative to the thickness of the
boundary layer and the desired effect. As such, it is noted that
there are many possible combinations of height 144 and/or length
146 of vortex generators 130 to generate different effects. For
example and as shown in FIG. 7, in some embodiments the height 144
of the vortex generator 130 may be configured and dimensioned to
extend proximal to, above and/or past the boundary layer to
displace energy or flow from the free stream flow above the
boundary layer in order to prevent separation of the boundary layer
over the surface of ejector shroud assembly 120. In some
embodiments, the energy displaced from the free stream flow is
transferred or distributed to the boundary layer. In other
embodiments, the height 144 of the vortex generator 130 does not
extend above or past the boundary layer of a flow control surface
of system 100. Again, there are multiple permutations of height 144
and/or length 146 of vortex generators 130 to generate different
effects.
[0081] FIG. 8 illustrates the relative difference in chord length
between an airfoil cross section 160 without vortex generators, and
an airfoil cross-section defined by the ejector shroud assembly 120
having vortex generators 130. The airfoil cross section 160 with
chord length 152 is greater than the chord length 142 of the
airfoil cross-section defined by the ejector shroud assembly 120
having vortex generators 130. It has been found that a shorter
chord length 142, such as that of assembly 120 having vortex
generators 130 maintains and or improves upon the performance of an
airfoil cross section 160 that does not have vortex generators.
[0082] FIGS. 9-10 illustrate an example embodiment displaying the
relative difference in chord length between mixing element airfoil
cross sections 165, 167 without vortex generators, and with airfoil
cross-sections defined by mixing elements 115, 117 of assembly 110
having vortex generators 130. In certain embodiments, inward
turning mixing elements 117 introduce bypass flow (arrow 172) into
the fluid stream that is down-stream of the rotor assembly 140. The
bypass flow 172 progresses along the pressure side, or outer
surface of the airfoil cross-section defined by mixing element 117.
Thus, vortex generators 130 positioned on the outer surface of the
mixing element 117 (FIG. 9) prevent separation of the fluid stream
along the upper surface of the airfoil cross-section defined by
mixing element 117. The airfoil cross section 167 with chord length
168 is relatively greater than the chord length 119 of the airfoil
cross-section defined by mixing element 117. A shorter chord length
119, such as that of airfoil cross-section 117 having vortex
generators 130 maintains and or improves upon the performance of an
airfoil cross section 167 that does not have vortex generators.
[0083] In example embodiments and as shown in FIG. 10, outwardly
turning mixing elements 115 mix the flow (arrow 174) that has
passed through the rotor assembly 140, with bypass flow in the
fluid stream that is down-stream of the rotor assembly 140. The
flow 174 progresses along the lift-side, or inner surface of the
airfoil cross-section defined by mixing element 115. Thus, vortex
generators 130 positioned on the inner surface of the mixing
element 115 (FIG. 10) prevent separation of the fluid stream along
the inner surface of the airfoil cross-section defined by mixing
element 115. The airfoil cross section 165 with chord length 166 is
relatively greater than the chord length 186 of the airfoil
cross-section defined by mixing element 115. A shorter chord length
186, such as that of airfoil cross-section 115 having vortex
generators 130 maintains and or improves upon the performance of an
airfoil cross section 165 that does not have vortex generators.
[0084] FIG. 11 is a detail, cross section view of an additional
embodiment of a vortex generator 130' of the present disclosure.
FIG. 12 is a another detail cross sectional view of the vortex
generator 130' of FIG. 11.
[0085] FIGS. 11-12 illustrate a vortex generator 130' that is
fabricated at least in part from a flexible material designed to
change shape under set flow velocity conditions. For example, at
times it can be beneficial to reduce the performance of a ringed
airfoil (e.g., ringed airfoil defined by shroud assembly 110 or
120) proximal to a rotor assembly 140 in high fluid velocity
conditions. In one embodiment, the flexible vortex generator 130'
may be utilized in shedding load on the shrouded turbine system 100
during periods of high fluid velocity. For example, the vortex
generator 130' can be mounted with respect to the lift or interior
side 223 of the ringed airfoil defined by shroud assembly 120 (or
at any other suitable location). The height 244 of the un-flexed
vortex generator 130' is approximately equal to 1% of the chord
length 242 of the airfoil cross section defined by shroud assembly
120. The length 246 of the vortex generator 130' is, in this
un-flexed configuration, approximately four times the height
244.
[0086] FIG. 12 illustrates vortex generator 130' that is in a
collapsed or flexed configuration as it would be in a fluid stream
of a set velocity. The reduction of performance of the vortex
generator 130' causes separation along the interior side 223 of the
ringed airfoil defined by shroud assembly 120, and therefore
provides a reduced performance of the airfoil with the intent to
reduce the speed of the rotor assembly 140 in high velocity flow.
In example embodiments and in this collapsed or flexed
configuration as shown in FIG. 12, the length 247 of the vortex
generator 130' is approximately eight times the height 245.
[0087] FIG. 13 is a front perspective view of an additional
embodiment of a shrouded fluid turbine system 300 of the present
disclosure. FIGS. 14-15 are detailed cross section views of the
system 300 of FIG. 13.
[0088] Referring to FIGS. 13-15, the shrouded fluid turbine system
300 is a mixer ejector turbine with airfoils that include single
surface portions. The turbine system 300 includes a turbine shroud
assembly 310, a nacelle body 350, a rotor assembly 340, and in some
embodiments an ejector shroud assembly 320. The turbine shroud
assembly 310 includes a front end 312, also known as an inlet end
or a leading edge. The turbine shroud assembly 310 also includes a
rear end 316, also known as an exhaust end or trailing edge. The
ejector shroud assembly 320 includes a front end, inlet end or
leading edge 322, and a rear end, exhaust end, or trailing edge
324.
[0089] In example embodiments, the airfoil cross section defined by
the turbine shroud assembly 310 includes a voluminous leading edge
312 that transitions to a curved planar portion at the trailing
edge 316. The ejector shroud assembly 320 includes a voluminous
leading edge 322 that transitions to a curved planar portion at the
trailing edge 324.
[0090] The rotor assembly 340 surrounds the nacelle body 350. The
rotor assembly 340 includes a central hub 341 at the proximal end
of the rotor blades. The central hub 341 is rotationally engaged
with the nacelle body 350. The nacelle body 350 and the turbine
shroud assembly 310 are supported by a tower 302. The rotor
assembly 340, turbine shroud assembly 310, and ejector shroud
assembly 320 can be coaxial with each other, i.e. they share a
common central axis 305. Support members 306 connect the turbine
shroud assembly 310 to the nacelle body 350.
[0091] In certain embodiments, the turbine shroud assembly 310 has
the cross-sectional shape of an airfoil, with the suction side
(i.e. low pressure side) on the interior of the shroud assembly
310. The rear end 316 of the turbine shroud assembly 310 has mixing
elements, including outwardly directed mixing elements 315 and
inwardly directed mixing elements 317. The mixing elements 315, 317
extend downstream beyond the rotor blades and are directed either
outwardly or inwardly with respect to the central axis 305. Put
another way, the trailing edge 316 of the turbine shroud assembly
310 is shaped to form two different sets of mixing elements 315,
317. Inwardly directed mixing elements 317 extend inwardly towards
the central axis 305 of the mixer shroud. Outwardly directed mixing
elements 315 extend outwardly away from the central axis 305.
[0092] A mixer-ejector pump is formed by the ejector shroud
assembly 320 surrounding the ring of inwardly directed mixing
elements 317 and outwardly directed mixing elements 315 of the
turbine shroud assembly 310. The mixing elements 315, 317 extend
downstream and are proximate to the inlet end 322 of the ejector
shroud assembly 320. This mixer-ejector pump provides turbulent
mixing of fluid that passes through the rotor assembly 340 with
fluid that bypasses the rotor assembly 340. A pressure drop occurs
in the wake of the rotor assembly 340 as a result of the energy
taken out by the rotor assembly 340. Inward and outwardly directed
elements 315, 317, in combination with the ejector shroud assembly
320 provide turbulent mixing of high and low pressure streams, such
that the fluid pressure in the wake of the turbine rapidly returns
to ambient pressure.
[0093] In example embodiments, system 300 includes boundary layer
energizing members 330. Similar to members 130 discussed above,
boundary layer energizing members 330 take the form of vortex
generators 330 (e.g., protruding members, etc.) or the like,
although the present disclosure is not limited thereto. In general,
boundary layer energizing members 330 are configured and
dimensioned to prevent separation of a fluid boundary layer over
flow control surfaces (e.g., over the turbine shroud assembly 310
and or ejector shroud assembly 320) to alter or improve the
performance of the fluid turbine system 300 (or over shrouds 110,
120 of system 100, or shrouds 410, 420 of system 400, as discussed
above and below). Stated another way, boundary layer energizing
members 330 associated with flow control surface (e.g., assembly
310, 320) of system 300, can be used to substantially prevent and
or minimize flow separation by mixing free flow with the boundary
layer. In certain embodiments, boundary layer energizing members
330 (e.g., vortex generators) are configured and dimensioned to
energize the boundary layer to delay or prevent flow separation
before the fluid has reached the trailing edge of a flow control
surface (e.g., shroud assembly 310 and or 320) of system 300.
[0094] FIGS. 14-15 illustrate vortex generators 330 mounted with
respect to the outwardly turning mixing elements 315, and with
respect to the airfoil defined by the ejector shroud assembly 320.
It is noted that an airfoil with a voluminous leading edge that
transitions to a curved planar trailing edge provides a reduction
in the mass of the airfoil while maintaining performance. The
introduction of vortex generators 330 on such an airfoil (e.g.,
mixing elements 315 and or airfoil defined by the ejector shroud
assembly 320) further reduces the material and therefore surface
area and mass of the airfoil while maintaining performance
characteristics.
[0095] Vortex generators 330 energize the boundary layer over the
inner surface of the outwardly turning mixing elements 315, to
prevent separation over the boundary layer. Outwardly turning
mixing elements 315 mix the flow that has passed through the rotor
assembly 340, with bypass flow in the fluid stream down-stream of
the rotor assembly 340. The flow 374 progresses along the lift
side, or inner surface of the airfoil, hence, vortex generators 330
prevent separation of the fluid stream along the inner surface of
the airfoil defined by mixing elements 315.
[0096] FIG. 16 illustrates vortex generators 330 mounted with
respect to the inward turning mixing element 317. Inward turning
mixing elements 317 introduce bypass flow (arrow 372) into the
fluid stream down-stream of the rotor assembly 340. The bypass flow
372 progresses along the pressure side, or outer surface of the
airfoil defined by the mixing elements 317, hence, vortex
generators 330 prevent separation of the fluid stream along the
upper surface of the airfoil defined by the mixing elements
317.
[0097] In example embodiments, the airfoil defined by the mixing
elements 317 includes a voluminous leading edge 312 that
transitions to a curved planar form at the trailing edge 316. The
airfoil design coupled with vortex generators 330 provides an
airfoil with the performance characteristics of a substantially
larger and more massive airfoil.
[0098] Turning now to FIGS. 17-20, another example embodiment of a
shrouded fluid turbine system is depicted in accordance with
embodiments of the present disclosure. The fluid turbine system 400
includes a turbine shroud assembly 310, a nacelle body 350, a rotor
assembly 340, and in some embodiments an ejector shroud assembly
320. The turbine shroud assembly 310 includes a front end 312 and a
rear end 316, and the ejector shroud assembly 320 includes a
leading edge 322, and trailing edge 324.
[0099] The rotor assembly 340 includes a central hub 341, and the
nacelle body 350 and the turbine shroud assembly 310 are supported
by a tower 302. The rotor assembly 340, turbine shroud assembly
310, and ejector shroud assembly 320 can be coaxial with each
other, i.e. they share a common central axis 305. Support members
306 connect the turbine shroud assembly 310 to the nacelle body
350. The rear end 316 of the turbine shroud assembly 310 has mixing
elements, including outwardly directed mixing elements 315 and
inwardly directed mixing elements 317. It is noted that like
reference numbers refer to like components.
[0100] In certain embodiments and as shown in FIGS. 17-20, system
400 includes boundary layer energizing members 430. Certain
boundary layer energizing members 430 take the form of flow control
devices (e.g., active flow control devices) or ports or apertures
430 or the like. In example embodiments, boundary layer energizing
members 430 are configured and dimensioned to alter (e.g., cause or
prevent separation of) a fluid boundary layer over a flow control
surface (e.g., over the turbine shroud assembly 310 and or ejector
shroud assembly 320) to alter the performance of the fluid turbine
system 400 (or shrouds 110, 120 of system 100, or shrouds 310, 320
of system 300, etc.). In example embodiments, the flow control
ports or devices 430 employ high velocity flow through or via the
ports 430 on aerodynamic surfaces of the system 400 for flow
control purposes (e.g., for the purpose of preventing or causing
separation of the boundary layer). In example embodiments, fluid
delivered to the flow control ports 430 can be provided by a
suitable external pumping or actuation means or assembly or the
like, and or can be provided by harvesting fluid energy from within
the shrouded fluid turbine system 400.
[0101] In general, at least one flow control port 430 is associated
with and or is mounted with respect to a surface of system 400
(e.g., with a surface of turbine shroud assembly 310, or assembly
320). In example embodiments, a plurality of flow control ports 430
are associated with a surface of turbine shroud assembly 310 (or
assembly 320). In some embodiments, the flow control ports 430 are
integrally formed with assembly 310 (or assembly 320), although the
present disclosure is not limited thereto.
[0102] In certain embodiments, flow control ports 430 can be
associated with and or positioned on the turbine shroud assembly
310 approximately at or proximal to the leading edge 312 of the
turbine shroud assembly 310. However, it is noted that flow control
ports 430 can be associated with or positioned on assembly 310 (or
assembly 320) at any suitable location. For example, system 400 can
include flow control ports 430 on the suction side (e.g., low
pressure side on the interior of the shroud assembly) and or on the
pressure side (higher pressure side on the outside or exterior of
the shroud assembly) of shroud assembly surfaces (assembly 310 and
or 320). As such, the flow control ports 430 can be configured and
dimensioned to energize or provide fluid flow to the boundary layer
to alter fluid flow (e.g., delay, cause or prevent flow separation
before the fluid has reached the trailing edge of the shroud
assembly 310, 320).
[0103] It is noted that the flow control ports 430 can be utilized
in lieu of or in addition to the vortex generators 330 (or 130,
etc.) in the fluid turbine systems of the present disclosure.
[0104] In example embodiments, the flow control ports or devices
430 employ high velocity flow through or via the ports 430 on
aerodynamic surfaces of the system 400 for preventing or causing
separation of the boundary layer. FIGS. 17-20 illustrate
embodiments of the system 400 having flow control ports 430
associated with the ringed airfoil surfaces (e.g., assemblies 310,
320). It is noted that in excessive fluid velocity conditions, the
flow devices or ports 430 can be disengaged so as to reduce the
performance of the airfoils and therefore reduce the overall
performance of the turbine system 400. The flow devices or ports
430 may be disengaged using a variety of means including active
pneumatic or electromechanical actuation, passive actuation due to
velocity or pressure profile, or some combination thereof. One
skilled in the art will readily recognize that the above noted
actuation means are merely illustrative of sample embodiments and
are not intended to be limiting in scope.
[0105] In example embodiments and as shown in FIG. 18, the flow
control ports 430 are associated with the inner surface of the
turbine shroud 310 proximal to the outwardly turning mixing
elements 315. Again, it is noted that ports 430 can be associated
with or positioned on assembly 310 (or assembly 320) at any
suitable location. For example and as shown in FIGS. 19 and 20,
flow control ports 430 can be associated with the outer surface of
the turbine shroud 310 proximal to the inward turning mixing
elements 317. Moreover and as shown in FIG. 19, flow control ports
430 can be associated with the inner surface of the ejector shroud
assembly 320. As noted, fluid delivered to the flow control ports
430 can be provided by a suitable external pumping or actuation
means or assembly, and or can be provided by harvesting fluid
energy from within the shrouded fluid turbine system 400.
[0106] FIG. 21 depicts another example embodiment of a shrouded
fluid turbine system 500. The system 500 is a single shroud system
free of an ejector shroud. As such, an example embodiment of the
fluid turbine system 500 in accordance with the present disclosure
is shown in FIG. 21. The fluid turbine system 500 includes a
turbine shroud assembly 510, a nacelle body 550 and a rotor
assembly 540. The turbine shroud assembly 510 includes a front end
512 and a rear end 516. Support members 506 connect the turbine
shroud assembly 510 to the nacelle body 550.
[0107] The rotor assembly 540 includes a central hub 541, and the
nacelle body 550 and the turbine shroud assembly 510 are supported
by a tower 502. The rotor assembly 540 and turbine shroud assembly
510 can be coaxial with each other, i.e. they share a common
central axis 505. The rear end 516 of the turbine shroud assembly
510 has mixing elements, including outwardly directed mixing
elements 515 and inwardly directed mixing elements 517.
[0108] In example embodiments and as shown in FIG. 21, system 500
includes boundary layer energizing members 530. Boundary layer
energizing members 530 can take the form of vortex generators and
or flow control devices or ports 530 or the like, as similarly
discussed and described above in conjunction with FIGS. 1-20.
[0109] As noted above, boundary layer energizing members 530 are
configured and dimensioned to alter a fluid boundary layer (e.g.,
prevent separation of a fluid boundary layer) over a flow control
surface (e.g., over the turbine shroud assembly 510) to alter the
performance of the fluid turbine system 500. In general, at least
one boundary layer energizing member 530 is associated with and or
is mounted with respect to a surface of system 500 (e.g., with a
surface of turbine shroud assembly 510). In example embodiments, a
plurality of boundary layer energizing members 530 are associated
with a surface of turbine shroud assembly 510.
[0110] As discussed above in conjunction with FIGS. 1-20, it is
noted that boundary layer energizing member 530 can be associated
with or positioned on assembly 510 at any suitable location. For
example, system 500 can include members 530 on the suction side
(e.g., low pressure side on the interior of the shroud assembly)
and or on the pressure side (higher pressure side on the outside or
exterior of the shroud assembly) of shroud assembly surfaces
(assembly 510). As such, members 530 can be configured and
dimensioned to energize or provide fluid flow to the boundary layer
to alter a fluid boundary layer (e.g., delay or prevent flow
separation before the fluid has reached the trailing edge of the
shroud assembly 510).
[0111] Turning now to FIGS. 22-24, another example embodiment of a
fluid turbine system 1500 in accordance with the present disclosure
is shown. As discussed further below, FIGS. 22-24 illustrate a
fluid turbine system 1500 having boundary layer energizing members
1530 (e.g., flow control ports 1530) engaged with substantially
faceted annular airfoil surfaces. Boundary layer energizing members
1530 can take the form of flow control devices (e.g., active flow
control devices) or ports 1530 or the like, although the present
disclosure is not limited thereto. Rather, it is noted that the
boundary layer energizing members 1530 can take other forms, e.g.,
vortex generators.
[0112] In example embodiments and as shown in FIG. 22, the turbine
shroud assembly 1510 takes the form of an annular airfoil that
includes a leading edge portion 1512 (also known as the inlet end).
In certain embodiments, the leading edge 1512 is substantially
annular, thus providing a relatively narrow gap between the rotor
blade tips of rotor assembly 1540 and the interior surface of the
leading edge 1512. The leading edge 1512 is engaged with a series
of substantially linear segments with constant cross sections 1515,
also known as turbine shroud facets, that transition from the
annular leading edge 1512. Turbine shroud facets 1515 enjoin at
nodes 1517, and further include rear ends 1516, also known as the
exit or trailing edge of the turbine shroud assembly 1510.
[0113] In some embodiments, a secondary shroud assembly 1520 (e.g.,
a shroud assembly in the shape of an annular airfoil) includes
substantially linear segments with constant cross sections 1535,
otherwise referred to as ejector shroud facets, and include leading
edges 1522 and trailing edges 1524 that are in fluid communication
with the trailing edge 1516 of the turbine shroud assembly 1510.
Facets 1535 enjoin at nodes 1537. Facets 1535 also enjoin at struts
1513 that support the nodes 1517, 1537 of both shroud assemblies
1510, 1520. The shroud assemblies 1510, 1520 are co-axial with the
rotor assembly 1540, rotor hub 1541 and nacelle body 1550 about the
central axis 1505. The rotor assembly 1540 and shroud assemblies
1510, 1520 are supported by a tower structure 1502.
[0114] In certain embodiments and as shown in FIGS. 22-24, system
1500 includes boundary layer energizing members 1530. Boundary
layer energizing members 1530 take the form of flow control devices
or ports or apertures 1530 or the like. In general, boundary layer
energizing members 1530 are configured and dimensioned to alter a
fluid boundary layer (e.g., prevent separation of a fluid boundary
layer) over a flow control surface (e.g., over the turbine shroud
assembly 1510 and or ejector shroud assembly 1520) to alter the
performance of the fluid turbine system 1500. In general, the flow
control ports or devices 1530 employ high velocity flow through or
via the ports 1530 on aerodynamic surfaces of the system 1500 for
flow control purposes. In example embodiments, fluid delivered to
the flow control ports 1530 can be provided by a suitable external
pumping or actuation means or assembly, and or can be provided by
harvesting fluid energy from within the shrouded fluid turbine
system 1500.
[0115] In general, at least one flow control port 1530 is
associated with and or is mounted with respect to a surface of
system 1500 (e.g., with a surface of turbine shroud assembly 1510,
or assembly 1520). A plurality of flow control ports 1530 can be
associated with a surface of turbine shroud assembly 1510 (or
assembly 1520).
[0116] Flow control ports 1530 can be associated with and or
positioned on the turbine shroud assembly 1510 approximately at or
proximal to the leading edge 1512 of the turbine shroud assembly
1510. However, it is noted that flow control ports 1530 can be
associated with or positioned on assembly 1510 (or assembly 1520)
at any suitable location (e.g., on the suction side of a shroud
assembly, on the pressure side 1538 of a shroud assembly, etc.). As
such, the flow control ports 1530 can be configured and dimensioned
for flow control purposes (e.g., to energize or provide fluid flow
to the boundary layer to delay or prevent flow separation before
the fluid has reached the trailing edge of the shroud assembly
1510, 1520).
[0117] As shown in FIGS. 23-24, flow control ports 1530 are
associated with the inner surface of the turbine shroud assembly
1510 proximal to the outward leading edge 1512. Flow control ports
1530 are also associated with the inner surface of the ejector
shroud assembly 1520. By providing fluid flow through the ports
1530, boundary layer attachment over the aerodynamic surfaces may
be maintained or disrupted by varying volume and or angle of flow
through ports 1530, and in so doing providing a means of increasing
or decreasing performance of turbine system 1500 (e.g., airfoil
performance). As noted, fluid delivered to the flow control ports
1530 can be provided by a suitable external pumping or actuation
means or assembly, and or can be provided by harvesting fluid
energy from within the shrouded fluid turbine system 1500.
[0118] Although the systems and methods of the present disclosure
have been described with reference to example embodiments thereof,
the present disclosure is not limited to such example embodiments
and or implementations. Rather, the systems and methods of the
present disclosure are susceptible to many implementations and
applications, as will be readily apparent to persons skilled in the
art from the disclosure hereof. The present disclosure expressly
encompasses such modifications, enhancements and or variations of
the disclosed embodiments. Since many changes could be made in the
above construction and many widely different embodiments of this
disclosure could be made without departing from the scope thereof,
it is intended that all matter contained in the drawings and
specification shall be interpreted as illustrative and not in a
limiting sense. Additional modifications, changes, and
substitutions are intended in the foregoing disclosure.
Accordingly, it is appropriate that the appended claims be
construed broadly and in a manner consistent with the scope of the
disclosure.
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