U.S. patent application number 13/078382 was filed with the patent office on 2011-10-13 for fluid turbines.
Invention is credited to William Scott Keeley, Thomas J. Kennedy, III, Walter M . Presz, JR., Michael J. Werle.
Application Number | 20110250053 13/078382 |
Document ID | / |
Family ID | 45094279 |
Filed Date | 2011-10-13 |
United States Patent
Application |
20110250053 |
Kind Code |
A1 |
Presz, JR.; Walter M . ; et
al. |
October 13, 2011 |
FLUID TURBINES
Abstract
Shrouded fluid turbines of various configurations are disclosed.
The shrouded fluid turbines include an impeller, a turbine shroud
surrounding the impeller, and an ejector shroud around the turbine
shroud. The ejector shroud may completely surround the turbine
shroud. The turbine shroud may have a plurality of mixing lobes
that form a crenellated trailing edge. Alternatively, the turbine
shroud may have a plurality of open slots. Means for directing
fluid flow into the plurality of open slots may include an ejector
shroud that seals with the turbine shroud downstream of the open
slots. A plurality of fluid ducts may also connect individually to
each open slot. An external stator may be connected to an exterior
surface of the ejector shroud.
Inventors: |
Presz, JR.; Walter M .;
(Wilbraham, MA) ; Werle; Michael J.; (West
Hartford, CT) ; Kennedy, III; Thomas J.; (Wilbraham,
MA) ; Keeley; William Scott; (Charleston,
RI) |
Family ID: |
45094279 |
Appl. No.: |
13/078382 |
Filed: |
April 1, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12054050 |
Mar 24, 2008 |
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13078382 |
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61415626 |
Nov 19, 2010 |
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60919588 |
Mar 23, 2007 |
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Current U.S.
Class: |
415/115 |
Current CPC
Class: |
F05B 2260/601 20130101;
Y02E 10/72 20130101; F05B 2240/13 20130101; F03D 1/04 20130101;
F05B 2240/133 20130101; F05B 2260/96 20130101; F05B 2210/16
20130101; F05C 2225/06 20130101; F05B 2280/4006 20130101 |
Class at
Publication: |
415/115 |
International
Class: |
F01D 1/02 20060101
F01D001/02 |
Claims
1. A fluid turbine comprising: an impeller; a turbine shroud
surrounding the impeller, the turbine shroud comprising a leading
edge and a plurality of mixing lobes that form a crenellated
trailing edge, the trailing edge having a first diameter; and an
ejector shroud coaxial with the turbine shroud, the ejector shroud
comprising a leading edge and a trailing edge, the leading edge
having a second diameter, wherein the second diameter is greater
than the first diameter.
2. The fluid turbine of claim 1, wherein the leading edge of the
turbine shroud is coplanar with the leading edge of the ejector
shroud.
3. The fluid turbine of claim 1, wherein the leading edge of the
turbine shroud is downstream of the leading edge of the ejector
shroud.
4. The fluid turbine of claim 1, wherein the leading edge of the
turbine shroud has a substantially circular shape.
5. The fluid turbine of claim 1, wherein the leading edge of the
ejector shroud has a substantially circular shape.
6. The fluid turbine of claim 1, wherein the ejector shroud has a
ring airfoil shape.
7. The fluid turbine of claim 1, further comprising a nacelle body,
the impeller surrounding the nacelle body, the nacelle body having
a trailing edge, wherein the nacelle body, turbine shroud, and
ejector shroud are coaxial to each other.
8. The fluid turbine of claim 7, wherein the trailing edge of the
nacelle body is upstream of the trailing edge of the ejector
shroud.
9. The fluid turbine of claim 7, wherein the trailing edge of the
nacelle body is downstream of the trailing edge of the ejector
shroud.
10. The fluid turbine of claim 1, wherein the impeller is a
rotor/stator assembly.
11. A fluid turbine comprising: an impeller; a turbine shroud
surrounding the impeller, the turbine shroud comprising a plurality
of open slots downstream of the impeller; and an exterior structure
for directing fluid flow from outside the turbine shroud through
the plurality of open slots.
12. The fluid turbine of claim 11, wherein the exterior structure
for directing fluid flow is an ejector shroud disposed about the
turbine shroud, the turbine shroud and the ejector shroud being
sealed to each other downstream of the plurality of open slots.
13. The fluid turbine of claim 11, wherein the exterior structure
for directing fluid flow is a plurality of fluid ducts located
along an exterior surface of the turbine shroud, each fluid duct
comprising an inlet and an outlet, the outlet being connected to
one of the opens slot in the turbine shroud.
14. The fluid turbine of claim 13, wherein each fluid duct further
comprises a fluid duct impeller.
15. The fluid turbine of claim 13, wherein the inlets of the
plurality of fluid ducts are downstream of an inlet end of the
turbine shroud and are parallel to the inlet end of the turbine
shroud.
16. The fluid turbine of claim 11, wherein a leading edge of the
turbine shroud has a substantially circular shape.
17. A fluid turbine comprising: an impeller; a turbine shroud
surrounding the impeller; an ejector shroud downstream of the
turbine shroud, a trailing edge of the turbine shroud extending
into an inlet end of the ejector shroud; and a stator connected to
an exterior surface of the ejector shroud.
18. The fluid turbine of claim 17, wherein the turbine shroud
comprises a substantially circular leading edge and a plurality of
mixing lobes that form a crenellated trailing edge.
19. The fluid turbine of claim 17, wherein the stator has a ring
airfoil shape.
20. The fluid turbine of claim 17, wherein the ejector shroud has a
ring airfoil shape.
21. A fluid turbine comprising: an impeller; a turbine shroud
surrounding the impeller, the turbine shroud comprising a leading
edge and a plurality of mixing lobes that form a crenellated
trailing edge; and an ejector shroud completely surrounding the
turbine shroud, the ejector shroud comprising a leading edge and a
trailing edge.
Description
BACKGROUND
[0001] This application claims priority to U.S. Provisional Patent
Application Ser. No. 61/415,626, filed Nov. 19, 2010. This
application is also a continuation-in-part from U.S. patent
application Ser. No. 12/054,050, filed Mar. 24, 2008, which claimed
priority from U.S. Provisional Patent Application Ser. No.
60/919,588, filed Mar. 23, 2007. The disclosures of these
applications are hereby fully incorporated by reference in their
entirety.
[0002] The present disclosure relates to shrouded fluid turbines
having various configurations. The shrouded fluid turbines include
an impeller, a turbine shroud, and an ejector shroud.
[0003] Conventional horizontal axis wind turbines (HAWTs) used for
power generation have two to five open blades arranged like a
propeller, the blades being mounted to a horizontal shaft attached
to a gear box which drives a power generator. HAWTs will not exceed
the Betz limit of 59.3% efficiency in capturing the potential
energy of the wind passing through it. HAWTs are also heavy,
requiring substantial support and increasing transport costs of the
components. It would be desirable to increase the efficiency of a
fluid turbine by collecting additional energy from the fluid.
BRIEF DESCRIPTION
[0004] The present disclosure relates to shrouded fluid turbines of
various configurations. The fluid turbines include an impeller, a
turbine shroud, and an ejector shroud in various configurations. In
some configurations, a plurality of fluid ducts is used in lieu of
an ejector shroud. In others, an external stator extends radially
from the ejector shroud. The fluid turbines may be used as, for
example, wind turbines or water turbines.
[0005] Disclosed in embodiments is a fluid turbine comprising: an
impeller; a turbine shroud surrounding the impeller, the turbine
shroud comprising a leading edge and a plurality of mixing lobes
that form a crenellated trailing edge; and an ejector shroud
completely surrounding the turbine shroud, the ejector shroud
comprising a leading edge and a trailing edge.
[0006] In some embodiments, the leading edge of the turbine shroud
is coplanar with the leading edge of the ejector shroud. In others,
the leading edge of the turbine shroud is downstream of the leading
edge of the ejector shroud.
[0007] In particular versions, the leading edge of the turbine
shroud has a substantially circular shape. In others, the leading
edge of the ejector shroud has a substantially circular shape. The
ejector shroud may have a ring airfoil shape.
[0008] The fluid turbine may further comprise a nacelle body, the
impeller surrounding the nacelle body, the nacelle body having a
trailing edge, wherein the nacelle body, turbine shroud, and
ejector shroud are coaxial to each other. The trailing edge of the
nacelle body can be upstream or downstream of the trailing edge of
the ejector shroud.
[0009] The impeller may be a rotor/stator assembly.
[0010] Also disclosed is a fluid turbine comprising: an impeller; a
turbine shroud surrounding the impeller, the turbine shroud
comprising a plurality of open slots downstream of the impeller;
and an exterior structure for directing fluid flow from outside the
turbine shroud through the plurality of open slots.
[0011] In some embodiments, the exterior structure for directing
fluid flow is an ejector shroud disposed about the turbine shroud,
the turbine shroud and the ejector shroud being sealed to each
other downstream of the plurality of open slots.
[0012] In other embodiments, the exterior structure for directing
fluid flow is a plurality of fluid ducts located along an exterior
surface of the turbine shroud, each fluid duct comprising an inlet
and an outlet, the outlet being connected to one of the opens slot
in the turbine shroud.
[0013] Each fluid duct may further comprise a fluid duct
impeller.
[0014] The inlets of the plurality of fluid ducts are downstream of
an inlet end of the turbine shroud and are parallel to the inlet
end of the turbine shroud.
[0015] Also disclosed is a fluid turbine comprising: an impeller; a
turbine shroud surrounding the impeller; an ejector shroud
downstream of the turbine shroud, a trailing edge of the turbine
shroud extending into an inlet end of the ejector shroud; and a
stator connected to an exterior surface of the ejector shroud.
[0016] In embodiments, the turbine shroud comprises a substantially
circular leading edge and a plurality of mixing lobes that form a
crenellated trailing edge.
[0017] The stator may have a ring airfoil shape. The ejector shroud
may have a ring airfoil shape.
[0018] These and other non-limiting features or characteristics of
the present disclosure will be further described below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] 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.
[0020] FIG. 1 is a front left perspective view of a shrouded fluid
turbine.
[0021] FIG. 2 is a rear right perspective view of the shrouded
fluid turbine of FIG. 1.
[0022] FIG. 3 is a front perspective view of a first exemplary
shrouded fluid turbine.
[0023] FIG. 4 is a first right side perspective cross-sectional
view of the fluid turbine of FIG. 3.
[0024] FIG. 5 is a second right side perspective cross-sectional
view of the fluid turbine of FIG. 3.
[0025] FIG. 6 is a side cross-sectional view of the fluid turbine
of FIG. 3.
[0026] FIG. 7 is a front perspective view of a second exemplary
shrouded fluid turbine.
[0027] FIG. 8 is a right side perspective cross-sectional view of
the fluid turbine of FIG. 7.
[0028] FIG. 9 is a side cross-sectional view of the fluid turbine
of FIG. 7.
[0029] FIG. 10 is a left front perspective view of a third
exemplary shrouded fluid turbine.
[0030] FIG. 11 is a front view of the shrouded fluid turbine of
FIG. 10.
[0031] FIG. 12 is a left cross-sectional view of the shrouded fluid
turbine of FIG. 10.
[0032] FIG. 13 is a left front perspective view of a third
exemplary shrouded fluid turbine, having fluid ducts.
[0033] FIG. 14 is a front view of the shrouded fluid turbine of
FIG. 13.
[0034] FIG. 15 is a left cross-sectional view of the shrouded fluid
turbine of FIG. 13. The nacelle body is removed so that aspects of
the turbine shroud are visible.
[0035] FIG. 16 is a left front perspective view of a third
exemplary shrouded fluid turbine, having impellers in the fluid
ducts.
[0036] FIG. 17 is a front view of the shrouded fluid turbine of
FIG. 16.
[0037] FIG. 18 is a left cross-sectional view of the shrouded fluid
turbine of FIG. 16. The nacelle body is removed so that aspects of
the turbine shroud are visible.
[0038] FIG. 19 is a perspective view of a shrouded fluid turbine
with an external stator
[0039] FIG. 20 is a cross-sectional view of the shrouded fluid
turbine of FIG. 2.
[0040] FIG. 21 is a smaller view of FIG. 20.
[0041] FIG. 21A and FIG. 21B are magnified views of the mixing
lobes of the fluid turbine of FIG. 21.
[0042] FIG. 22 is a rear view of the shrouded fluid turbine of FIG.
2. The impeller is removed from this figure so that other aspects
of the fluid turbine can be more clearly seen and explained.
DETAILED DESCRIPTION
[0043] 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 exemplary
embodiments.
[0044] 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.
[0045] 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."
[0046] A Mixer-Ejector Power System (MEPS) provides an improved
means of generating power from wind currents. A primary shroud
contains an impeller which extracts power from a primary wind
stream. A mixer-ejector pump is included that ingests flow from the
primary wind stream and secondary flow, and promotes turbulent
mixing. This enhances the power system by increasing the amount of
air flow through the system, reducing back pressure on turbine
blades, and reducing noise propagating from the system.
[0047] The term "impeller" 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. Exemplary impellers include a propeller or a
rotor/stator assembly. Any type of impeller may be enclosed within
the turbine shroud in the fluid turbine of the present
disclosure.
[0048] The end of the fluid turbine wherein fluid enters to rotate
the impeller may be considered the front of the fluid turbine, and
the end of the fluid turbine where fluid exits after passing
through the impeller may be considered the rear of the fluid
turbine. A first component of the fluid turbine located closer to
the front of the turbine may be considered "upstream" of a second
component located closer to the rear of the turbine. Put another
way, the second component is "downstream" of the first
component.
[0049] The present disclosure relates to different configurations
of a shrouded fluid turbine. The fluid turbines may be used as a
wind turbine or a water turbine. FIG. 1 and FIG. 2 initially
present some details of the shrouded fluid turbine which will help
in discussing various aspects of the different configurations.
[0050] The shrouded fluid turbine 100 comprises an aerodynamically
contoured turbine shroud 110, an aerodynamically contoured nacelle
body 150, an impeller 140, and an aerodynamically contoured ejector
shroud 120. Support members 106 connect the turbine shroud 110 to
the ejector shroud 120. The impeller 140 surrounds the nacelle body
150. The nacelle body 150 is connected to the turbine shroud 110
through the impeller 140, or by other means.
[0051] The turbine shroud has the cross-sectional shape of an
airfoil with the suction side (i.e. low pressure side) on the
interior of the shroud. The rear end 114 of the turbine shroud also
has mixing lobes 116. The mixing lobes extend downstream beyond the
rotor blades. Put another way, the trailing edge 118 of the turbine
shroud is formed from a plurality of mixing lobes 116. The rear or
downstream end of the turbine shroud is shaped to form two
different sets of mixing lobes 116. High energy mixing lobes 117
extend inwardly towards the central axis 105 of the mixer shroud.
Low energy mixing lobes 119 extend outwardly away from the central
axis 105. These mixing lobes are more easily seen in FIG. 2.
[0052] A mixer-ejector pump (indicated by reference numeral 101)
comprises an ejector shroud 120 surrounding the ring of mixing
lobes 116 on the turbine shroud 110. The mixing lobes 116 extend
downstream and into an inlet end 122 of the ejector shroud 120.
This mixer/ejector pump provides the means for consistently
exceeding the Betz limit for operational efficiency of the fluid
turbine.
[0053] In additional embodiments of the present disclosure, the
ejector shroud completely surrounds the turbine shroud. Generally,
the turbine shroud is located between the leading and trailing
edges of the ejector shroud.
[0054] FIGS. 3-6 are different views of one exemplary embodiment
where the ejector shroud completely surrounds the turbine shroud.
Here, the shrouded fluid turbine 300 comprises an impeller 340
which surrounds a nacelle body 350. The impeller is depicted here
as a rotor/stator assembly. The nacelle body 350 has a trailing
edge 352, which in this embodiment appears to be a tapered point.
The impeller 340 is surrounded by turbine shroud 310. Ejector
shroud 320 in turn completely surrounds the turbine shroud 310. The
leading edge 314 of the turbine shroud 310 has a substantially
circular shape. The leading edge 324 of the ejector shroud 320 also
has a substantially circular shape. The nacelle body 350, impeller
340, turbine shroud 310, and ejector shroud 320 are coaxial with
each other, i.e. share a common axis.
[0055] As seen in FIG. 4 and FIG. 5, a plurality of mixing lobes
316 is present on the rear end of the turbine shroud, resulting in
a crenellated trailing edge 318.
[0056] As seen in FIG. 6, the turbine shroud has a leading edge 314
and a trailing edge 318. Similarly, the ejector shroud has a
leading edge 324 and a trailing edge 328. The leading edge 314 of
the turbine shroud is coplanar with the leading edge 324 of the
ejector shroud. In addition, the trailing edge 328 of the ejector
shroud is downstream of the trailing edge 318 of the turbine
shroud. The trailing edge 318 of the turbine shroud is downstream
of the impeller 340. The ejector shroud 320 has a ring airfoil
shape, i.e. has the cross-sectional shape of an airfoil with the
suction side (i.e. low pressure side) on the interior of the
ejector shroud.
[0057] FIGS. 7-9 are different views of a second exemplary
embodiment where the ejector shroud completely surrounds the
turbine shroud. Here, the shrouded fluid turbine 400 comprises an
impeller 440 which surrounds a nacelle body 450. The impeller is
depicted here as a rotor/stator assembly. The nacelle body 450 has
a trailing edge 452, which in this embodiment appears to be a
tapered point. The impeller 440 is surrounded by turbine shroud
410. Ejector shroud 420 in turn completely surrounds the turbine
shroud 410. The leading edge 414 of the turbine shroud 410 has a
substantially circular shape. The leading edge 424 of the ejector
shroud 420 also has a substantially circular shape. The nacelle
body 450, impeller 440, turbine shroud 410, and ejector shroud 420
are coaxial with each other, i.e. share a common axis.
[0058] As seen in FIG. 8, a plurality of mixing lobes 416 is
present on the rear end of the turbine shroud, resulting in a
crenellated trailing edge 418.
[0059] As seen in FIG. 9, the turbine shroud has a leading edge 414
and a trailing edge 418. Similarly, the ejector shroud has a
leading edge 424 and a trailing edge 428. The leading edge 414 of
the turbine shroud is downstream of the leading edge 424 of the
ejector shroud. In addition, the trailing edge 428 of the ejector
shroud is downstream of the trailing edge 418 of the turbine
shroud. The trailing edge 418 of the turbine shroud is downstream
of the impeller 440. The ejector shroud 420 has a ring airfoil
shape, i.e. has the cross-sectional shape of an airfoil with the
suction side (i.e. low pressure side) on the interior of the
ejector shroud.
[0060] It should be noted that in FIG. 6, the trailing edge 352 of
the nacelle body 350 is upstream of the trailing edge 328 of the
ejector shroud 320. In FIG. 9, the trailing edge 452 of the nacelle
body 450 is downstream of the trailing edge 428 of the ejector
shroud 420. The location of the trailing edge of the nacelle body
may vary.
[0061] In other additional embodiments of the present disclosure,
the fluid turbine includes a turbine shroud that comprises a
plurality of open slots downstream of the impeller. An "open slot"
allows fluid flowing along an exterior surface of the turbine
shroud to pass radially from the exterior to the interior of the
turbine shroud. The fluid turbine also includes an exterior
structure which directs fluid flow from outside the turbine shroud
through the plurality of open slots.
[0062] FIGS. 10-12 show different views of one exemplary embodiment
of such a fluid turbine. The shrouded fluid turbine 500 comprises
an impeller 540 which surrounds a nacelle body 550. The impeller is
depicted here as a rotor/stator assembly. The nacelle body 550 has
a trailing edge 552, which in this embodiment appears to be a
tapered point. The impeller 540 is surrounded by turbine shroud
510. In this embodiment, ejector shroud 520 acts as the exterior
structure for directing fluid flow. The leading edge 514 of the
turbine shroud 510 has a substantially circular shape. The leading
edge 524 of the ejector shroud 520 also has a substantially
circular shape. The nacelle body 550, impeller 540, turbine shroud
510, and ejector shroud 520 are coaxial with each other, i.e. share
a common axis.
[0063] As seen in FIG. 12, the turbine shroud 510 has a ring
airfoil shape, with the suction side on the interior of the turbine
shroud. A plurality of open slots 560 are located downstream of
impeller 540. The open slots here are located along a trailing edge
504 of the fluid turbine. The turbine shroud 510 and ejector shroud
520 are sealed to each other downstream of the open slots 560. Put
another way, the fluid turbine has only one trailing edge, rather
than the turbine shroud and ejector shroud having separate trailing
edges, as seen for example in the embodiment of FIG. 2. High energy
fluid 568 flowing along an exterior surface 517 of the turbine
shroud 510 is directed by the ejector shroud 520 through the open
slots 560.
[0064] As drawn in FIG. 12, the leading edge 514 of the turbine
shroud is coplanar with the leading edge 524 of the ejector shroud.
The leading edge 524 of the ejector shroud may be upstream of the
leading edge 514 of the turbine shroud (see FIG. 9) or downstream
of the leading edge of the turbine shroud (see FIG. 1), as desired.
Similarly, the open slots 560 are shown as being located along the
trailing edge 504 of the fluid turbine. This aspect is not
required. Rather, the open slots 560 must be located downstream of
impeller 540.
[0065] FIGS. 13-15 show different views of another exemplary
embodiment of a fluid turbine with open slots. The shrouded fluid
turbine 600 comprises an impeller 640 which surrounds a nacelle
body 650. The impeller is depicted here as a rotor/stator assembly.
The impeller 640 is surrounded by turbine shroud 610. The leading
edge 614 of the turbine shroud 610 has a substantially circular
shape. The nacelle body 650, impeller 640, and turbine shroud 610
are coaxial with each other, i.e. share a common axis.
[0066] As seen in FIG. 15, the turbine shroud 610 has a ring
airfoil shape, with the suction side on the interior of the turbine
shroud. A plurality of open slots 660 are located downstream of
impeller 640. In contrast with the embodiment of FIG. 12, the open
slots 660 here are separated from the trailing edge 604 of the
turbine shroud. The open slots are seen here as having an
elliptical shape, although in principle any shape may be used.
[0067] A plurality of fluid ducts 670 is located along the exterior
surface 617 of the turbine shroud. Each fluid duct 670 comprises an
inlet 672 and an outlet 674. The outlet 674 of a fluid duct is
connected to an open slot 660 in the turbine shroud. The inlet 672
is downstream of the inlet end 611 of the turbine shroud, and is
parallel to the inlet end as well.
[0068] FIGS. 16-18 show different views of another exemplary
embodiment of a fluid turbine similar to that of FIGS. 13-15. This
embodiment differs in that each fluid duct 670 has a fluid duct
impeller 675. The fluid duct impeller 675 is powered, so that fluid
is forced into the exhaust stream of the turbine shroud through the
open slots 660.
[0069] FIG. 19 shows another configuration of a fluid turbine 800
similar to that of FIG. 1, but having an external stator. The
shrouded fluid turbine 800 comprises an impeller 840 which
surrounds a nacelle body 850. The impeller is depicted here as a
rotor/stator assembly. Stator vanes 844 and rotor blades 848 are
visible. The impeller 840 is surrounded by turbine shroud 810. The
turbine shroud has a plurality of mixing lobes 816 that form a
crenellated trailing edge 818. The leading edge 814 of the turbine
shroud 810 has a substantially circular shape.
[0070] An ejector shroud 820 is downstream of the turbine shroud
810. The mixing lobes 816 of the turbine shroud extend downstream
and into an inlet end 822 of the ejector shroud 820. The leading
edge 824 of the ejector shroud 820 also has a substantially
circular shape. The nacelle body 850, impeller 840, turbine shroud
810, and ejector shroud 820 are coaxial with each other, i.e. share
a common axis. The ejector shroud 820 has a ring airfoil shape,
i.e. has the cross-sectional shape of an airfoil with the suction
side (i.e. low pressure side) on the interior of the ejector
shroud.
[0071] A stator 880 is connected to an exterior surface 827 of the
ejector shroud. The stator may also have a ring airfoil shape.
[0072] The turbine shroud and the ejector shroud may be formed to
be lightweight. For example, they can be formed by covering a rigid
frame or skeleton with a skin. The shrouds may comprise the same or
different materials. The material for the shroud skins may include
polymeric films. Exemplary polymeric films include high density
polyethylene (HDPE); polyesters such as polyethylene terephthalate
(PET), polybutylene terephthalate (PBT), or polytrimethylene
terephthalate (PTT); and polyurethane films. Both aliphatic and
aromatic polyurethane along with polyether and polyester polyols
may be utilized. Peroxide cured unsaturated polyester polymers in a
glass matrix may also be used. The glass may be E or S glass. A
composite matrix may also contain epoxy systems to improve the
strength of the composite.
[0073] Other exemplary materials include polyvinyl chloride (PVC),
polyurethane, polyfluoropolymers, and multi-layer films of similar
composition. Stretchable fabrics, such as spandex-type fabrics or
polyurethane-polyurea copolymer containing fabrics, may also be
employed.
[0074] Polyurethane films are tough and have good weatherability.
The polyester-type polyurethane films tend to be more sensitive to
hydrophilic degradation than polyether-type polyurethane films.
Aliphatic versions of these polyurethane films are generally
ultraviolet resistant as well.
[0075] Exemplary polyfluoropolymers include polyvinyldidene
fluoride (PVDF) and polyvinyl fluoride (PVF). Commercial versions
are available under the trade names KYNAR.RTM. and TEDLAR.RTM..
Polyfluoropolymers generally have very low surface energy, which
allow their surface to remain somewhat free of dirt and debris, as
well as shed ice more readily as compared to materials having a
higher surface energy.
[0076] The skin may be reinforced with a reinforcing material.
Examples of reinforcing materials include but are not limited to
highly crystalline polyethylene fibers, paramid fibers, and
polyaramides.
[0077] The skin may independently be multi-layer, comprising one,
two, three, or more layers. Multi-layer constructions may add
strength, water resistance, UV stability, and other functionality.
However, multi-layer constructions may also be more expensive and
add weight to the overall fluid turbine.
[0078] Film/fabric composites are also contemplated along with a
backing, such as foam.
[0079] FIGS. 1-2 and FIGS. 20-22 illustrate various additional
aspects of the different configurations of the shrouded fluid
turbines of the present disclosure. Again, the shrouded fluid
turbine 100 comprises an aerodynamically contoured turbine shroud
110, an aerodynamically contoured nacelle body 150, an impeller
140, and an aerodynamically contoured ejector shroud 120. The
turbine shroud 110 includes a front end 112 and a rear end 114. The
ejector shroud 120 includes an inlet end 122 and an exhaust end
124. Support members 106 connect the turbine shroud 110 to the
ejector shroud 120.
[0080] The impeller 140 surrounds the nacelle body 150. Here, the
impeller is a rotor/stator assembly comprising a stator 142 having
stator vanes 144 and a rotor 146 having rotor blades 148. The rotor
146 is downstream and "in-line" with the stator vanes 144. Put
another way, the leading edges of the rotor blades are
substantially aligned with the trailing edges of the stator vanes.
The rotor blades are held together by an inner ring and an outer
ring (not visible), and the rotor 146 is mounted on the nacelle
body 150. The nacelle body 150 is connected to the turbine shroud
110 through the stator 142, or by other means. In some embodiments,
a central passageway 152 may also extend through the nacelle body
150.
[0081] The turbine shroud's entrance area and exit area will be
equal to or greater than that of the annulus occupied by the
impeller. The internal flow path cross-sectional area formed by the
annulus between the nacelle body and the interior surface of the
turbine shroud is aerodynamically shaped to have a minimum
cross-sectional area at the plane of the turbine and to otherwise
vary smoothly from their respective entrance planes to their exit
planes. The ejector shroud entrance area is greater than the exit
plane area of the turbine shroud.
[0082] Several optional features may be included in the shrouded
fluid turbine. A power take-off, in the form of a wheel-like
structure, can be mechanically linked at an outer rim of the
impeller to a power generator. Sound absorbing material can affixed
to the inner surface of the shrouds, and to absorb and prevent
propagation of the relatively high frequency sound waves produced
by the turbine. The fluid turbine can also contain blade
containment structures for added safety. The shrouds will have an
aerodynamic contour in order to enhance the amount of flow into and
through the system. The inlet and outlet areas of the shrouds may
be non-circular in cross section such that shroud installation is
easily accommodated by aligning the two shrouds. A swivel joint may
be included on a lower outer surface of the turbine for mounting on
a vertical stand/pylon, allowing the turbine to be turned into the
fluid in order to maximize power extraction. Vertical aerodynamic
stabilizer vanes may be mounted on the exterior of the shrouds to
assist in keeping the turbine pointed into the fluid.
[0083] The area ratio of the ejector pump, as defined by the
ejector shroud 120 exit area over the turbine shroud 110 exit area,
will be in the range of 1.5-3.0. The number of mixing lobes can be
between 6 and 28. The height-to-width ratio of the lobe channels
will be between 0.5 and 4.5. The mixing lobe penetration will be
between 50% and 80%. The nacelle body 150 plug trailing edge angles
will be thirty degrees or less. The length to diameter (L/D) of the
overall fluid turbine will be between 0.5 and 1.25.
[0084] Referring now to FIG. 22, the turbine shroud 110 has a set
of nine high energy mixing lobes 117 that extend inwards toward the
central axis 105 of the turbine. The turbine shroud also has a set
of nine low energy mixing lobes 119 that extend outwards away from
the central axis. The high energy mixing lobes alternate with the
low energy mixing lobes around the trailing edge 118 of the turbine
shroud. The impeller 140, turbine shroud 110, and ejector shroud
120 are coaxial with each other, i.e. they share a common central
axis 105.
[0085] As seen in FIG. 2, the leading edge 112 of the turbine
shroud 110 has a substantially circular shape. As seen in FIG. 22,
the trailing edge 118 of the turbine shroud 110 has a circular
crenellated shape. The trailing edge can be described as including
several inner circumferentially spaced arcuate portions 181 which
each have the same radius of curvature. Those inner arcuate
portions 181 are evenly spaced apart from each other. Between
portions are several outer arcuate portions 183, which each have
the same radius of curvature. The radius of curvature for the inner
arcuate portions 181 is different from the radius of curvature for
the outer arcuate portions 183, but the inner arcuate portions and
outer arcuate portions have the same center (i.e. along the central
axis). The inner arcuate portions 181 and the outer arcuate
portions 183 are then connected to each other by radially extending
portions 185. This results in a circular crenellated shape. The
term "crenellated" as used herein does not require the inner
arcuate portions, outer arcuate portions, and radially extending
portions to be straight lines, but instead refers to the general
up-and-down or in-and-out shape of the trailing edge. This
crenellated structure forms two sets of mixing lobes, high energy
mixing lobes 117 and low energy mixing lobes 119.
[0086] The outer arcuate portions 183 are located in an outer
plane, which is indicated here with reference numeral 190. The
inner arcuate portions 181 are located in an inner plane indicated
here with reference numeral 192. As seen from this perspective, the
outer plane 190 and inner plane 192 are generally cylindrical, with
their axis being the central axis 105. The outer plane 190 and
inner plane 192 are also coaxial.
[0087] The leading edge of the turbine shroud, indicated here as
dotted circle 194, has a front radius of curvature 199. The outer
radius of curvature 195 of the outer arcuate portions is greater
than the inner radius of curvature 197 for the inner arcuate
portions. The front radius of curvature 199 of the leading edge of
the turbine shroud can be greater than, substantially equal to, or
less than the outer radius of curvature 195.
[0088] Referring now to FIG. 20, free stream fluid (indicated
generally by arrow 160, which may be, for example, wind or water)
passing through the stator 142 has its energy extracted by the
rotor 146. High energy fluid indicated by arrow 162 bypasses the
turbine shroud 110 and stator 142, flows over the exterior of the
turbine shroud 110, and is directed inwardly by the high energy
mixing lobes 117. The low energy mixing lobes 119 cause the low
energy fluid exiting downstream from the rotor 146 to be mixed with
the high energy fluid 162.
[0089] Referring now to FIG. 21A, a tangent line 171 is drawn along
the interior trailing edge indicated generally at 172 of the high
energy mixing lobe 117. A rear plane 173 of the turbine shroud 110
is present. A line 174 is formed normal to the rear plane 173 and
tangent to the point 171 where a low energy mixing lobe 119 and a
high energy mixing lobe 117 meet. An angle O.sub.2 is formed by the
intersection of tangent line 171 and line 174. This angle O.sub.2
is between 5 and 65 degrees. Put another way, a high energy mixing
lobe 117 forms an angle O.sub.2 between 5 and 65 degrees relative
to a longitudinal axis of the turbine shroud 110. In particular
embodiments, the angle O.sub.2 is from about 35.degree. to about
50.degree..
[0090] In FIG. 21B, a tangent line 176 is drawn along the interior
trailing edge indicated generally at 177 of the low energy mixing
lobe 119. An angle O is formed by the intersection of tangent line
176 and line 174. This angle O is between 5 and 65 degrees. Put
another way, a low energy mixing lobe 119 forms an angle O between
5 and 65 degrees relative to a longitudinal axis of the turbine
shroud 110. In particular embodiments, the angle O is from about
35.degree. to about 50.degree..
[0091] Mixing lobes are present on the turbine shroud. If desired,
though, mixing lobes may also be formed on a trailing edge 128 of
the ejector shroud.
[0092] The present disclosure has been described with reference to
exemplary embodiments. Obviously, modifications and alterations
will occur to others upon reading and understanding the preceding
detailed description. It is intended that the present disclosure be
construed as including all such modifications and alterations
insofar as they come within the scope of the appended claims or the
equivalents thereof.
* * * * *