U.S. patent application number 14/105809 was filed with the patent office on 2014-07-24 for methods of manufacturing turbomachines blades with shaped channels by additive manufacturing, turbomachine blades and turbomachines.
This patent application is currently assigned to Nuovo Pignone Srl. The applicant listed for this patent is Nuovo Pignone Srl. Invention is credited to Lorenzo Cosi, Iacopo Giovannetti, Mirco Innocenti, Frencesco Piraccini, Pierluigi Tozzi.
Application Number | 20140205454 14/105809 |
Document ID | / |
Family ID | 47683832 |
Filed Date | 2014-07-24 |
United States Patent
Application |
20140205454 |
Kind Code |
A1 |
Giovannetti; Iacopo ; et
al. |
July 24, 2014 |
METHODS OF MANUFACTURING TURBOMACHINES BLADES WITH SHAPED CHANNELS
BY ADDITIVE MANUFACTURING, TURBOMACHINE BLADES AND
TURBOMACHINES
Abstract
A hollow blade for a turbomachine comprises an airfoil portion;
the airfoil portion extends longitudinally for a length; the
airfoil portion is defined laterally by an external surface; the
airfoil portion has at least one internal cavity extending along
said length and defined laterally by an internal surface; the
airfoil portion has a set of channels extending from the external
surface to the internal surface; the openings of said channels on
said external surface are aligned along a curved line that reflects
an isobar on said external surface.
Inventors: |
Giovannetti; Iacopo;
(Florence, IT) ; Cosi; Lorenzo; (Florence, IT)
; Innocenti; Mirco; (Florence, IT) ; Piraccini;
Frencesco; (Florence, IT) ; Tozzi; Pierluigi;
(Florence, IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nuovo Pignone Srl |
Florence |
|
IT |
|
|
Assignee: |
Nuovo Pignone Srl
Florence
IT
|
Family ID: |
47683832 |
Appl. No.: |
14/105809 |
Filed: |
December 13, 2013 |
Current U.S.
Class: |
416/95 ;
29/889.72 |
Current CPC
Class: |
B22F 3/1055 20130101;
Y10T 29/49339 20150115; Y02P 10/25 20151101; B22F 5/04 20130101;
F05D 2230/30 20130101; F01D 5/187 20130101; F01D 5/186 20130101;
Y02P 10/295 20151101; F01D 5/185 20130101; F01D 5/18 20130101; F01D
5/181 20130101; F05D 2230/22 20130101; F05D 2230/31 20130101 |
Class at
Publication: |
416/95 ;
29/889.72 |
International
Class: |
F01D 5/18 20060101
F01D005/18 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 13, 2012 |
IT |
CO2012A000061 |
Claims
1. A hollow blade for a turbomachine, the hollow blade comprising:
an airfoil portion, wherein the airfoil portion extends
longitudinally for a length, wherein the airfoil portion is defined
laterally by an external surface, wherein the airfoil portion has
at least one internal cavity extending along the length and defined
laterally by an internal surface, wherein the airfoil portion
comprises a set of channels extending from the external surface to
the internal surface, and wherein the openings of the channels on
the external surface are aligned along a curved line that reflects
an isobar on the external surface.
2. The hollow blade of claim 1, wherein the airfoil portion
comprises two internal cavities extending along the length and
defined laterally by internal surfaces, and two corresponding sets
of channels extending from the external surface to the internal
surfaces, and wherein the openings of the channels on the external
surface are aligned along two corresponding curved lines that
reflect isobars on the external surface.
3. The hollow blade of claim 2, wherein a first curved line of the
two curved lines is on a pressure side of the airfoil portion, and
wherein a second curved line of the two curved lines is on a
suction side of the airfoil portion.
4. The hollow blade of claim 1, wherein at least some of the
channels are straight and inclined or straight and curved, with
respect to the external surface.
5. The hollow blade of claim 2, wherein at least some of the
channels are straight and inclined or straight and curved, with
respect to the external surface.
6. The hollow blade of claim 3, wherein at least some of the
channels are straight and inclined or straight and curved, with
respect to the external surface.
7. The hollow blade of claim 1, wherein the channels start in a
leading edge region of the hollow blade.
8. The hollow blade of claim 1, wherein the channels start in a
trailing edge region of the hollow blade.
9. The hollow blade of claim 1, wherein the channels are shaped to
facilitate flow of fluid from the external surface to the internal
surface.
10. The hollow blade of claim 1, wherein the channels are shaped to
facilitate flow of fluid from the internal surface to the external
surface.
11. The hollow blade of claim 1, wherein the hollow blade is
arranged as a stator blade of a steam turbine.
12. The hollow blade of claim 1, wherein the hollow blade is in a
single piece.
13. A turbomachine, comprising: a plurality of hollow blades,
wherein each of the plurality of hollow blade comprises an airfoil
portion, wherein the airfoil portion extends longitudinally for a
length, wherein the airfoil portion is defined laterally by an
external surface, wherein the airfoil portion has at least one
internal cavity extending along the length and defined laterally by
an internal surface, wherein the airfoil portion comprises a set of
channels extending from the external surface to the internal
surface, and wherein the openings of the channels on the external
surface are aligned along a curved line that reflects an isobar on
the external surface.
14. The turbomachine of claim 13, wherein the airfoil portion
comprises two internal cavities extending along the length and
defined laterally by internal surfaces, and two corresponding sets
of channels extending from the external surface to the internal
surfaces, and wherein the openings of the channels on the external
surface are aligned along two corresponding curved lines that
reflect isobars on the external surface.
15. The turbomachine of claim 14, wherein a first curved line of
the two curved lines is on a pressure side of the airfoil portion,
and wherein a second curved line of the two curved lines is on a
suction side of the airfoil portion.
16. The turbomachine of claim 15, wherein at least some of the
channels are straight and inclined or straight and curved, with
respect to the external surface.
17. A method of manufacturing a hollow blade for a turbomachine,
the hollow blade comprising an airfoil portion, wherein the airfoil
portion extends longitudinally for a length, wherein the airfoil
portion is defined laterally by an external surface, wherein the
airfoil portion has at least one internal cavity extending along
the length and defined laterally by an internal surface, wherein
the airfoil portion comprises a set of channels extending from the
external surface to the internal surface, and wherein the openings
of the channels on the external surface are aligned along a curved
line that reflects an isobar on the external surface, the method
comprising: obtaining the airfoil portion by additive
manufacturing.
18. The method of claim 17, wherein obtaining the airfoil portion
by additive manufacturing comprises a single additive manufacturing
process for the whole airfoil portion starting from a first end of
the airfoil portion and ending at a second end of the airfoil
portion.
Description
TECHNICAL FIELD
[0001] Embodiments of the present invention disclosed herein relate
to methods of manufacturing turbomachines blades with shaped
channels, turbomachines blades so manufactured and turbomachines
using such blades.
BACKGROUND ART
[0002] In steam turbines, partial condensation of the steam occurs
at their last stage or stages.
[0003] In particular condensation occurs on the airfoil portion of
the stator blades of a so-called "condensing stage", typically the
last stage of the turbine.
[0004] If droplets are generated as a consequence of condensation,
they leave the static stator blades and they hit the rotating rotor
blades; therefore, damages to the rotor blades may occur.
[0005] In order to reduce the damages caused by the droplets, the
rotation speed of the rotor blades may be reduced; but in this way,
the efficiency of the turbine is also reduced.
[0006] Alternatively, in order to reduce any damage on the rotor
blades, solutions exist for collecting the condensation before the
generation of droplets.
[0007] The most typical of these solutions consists in using hollow
stator blades where condensation is likely to occur, providing
holes or slots through the airfoil portion of the blades extending
from the airfoil surface to the internal cavity, and sucking from
the internal cavity so to that any condensation leaves the airfoil
surface and enters the internal cavity. In this way, droplets on
the airfoil surface of the stator blades are not generated and
released.
[0008] These hollow blades are typically obtained through milling
two metal bars, welding them together and mill finishing the
assembled component, in order to produce the blades with a
reasonable precision while avoiding the high cost of casting.
[0009] In gas turbines, hollow blades are sometime used for rotor
blades in order to reduce weight of the rotating element.
[0010] These hollow blades are typically obtained through casting,
particularly "investment casting", in order to obtain a rotating
element having an extremely precise shape and size.
SUMMARY
[0011] Therefore, there is a general need for improving the blades
of turbomachines to be used in "Oil & Gas" applications.
[0012] Improvements may relate not only functional aspects, for
example the shape and size of the airfoil portion, but also
mounting, maintenance and especially manufacturing.
[0013] As far as manufacturing is concerned, it must be considered
that in the field of "Oil & Gas" small-lot production is common
also because solutions are studied (or at least customized) for a
specific client.
[0014] In general, it is always desirable to have a high precision
and a low production cost.
[0015] Ideally, in order to achieve high performances, the shape,
size and material(s) of the blade should be freely selectable along
its whole length.
[0016] Such general need is particularly felt for the hollow stator
blades of steam turbines; these blades are generally located at the
last stage or stages of a multistage steam turbine; these blades
are very often made of metal.
[0017] According to an embodiment of the present invention, the
manufacturing method may be positively influenced by the specific
configuration of the blade to be manufactured.
[0018] A first aspect of the present invention is a hollow blade
for a turbomachine.
[0019] According to embodiments thereof, a hollow blade for a
turbomachine comprises an airfoil portion; the airfoil portion
extends longitudinally for a length; the airfoil portion is defined
laterally by an external surface; the airfoil portion has at least
one internal cavity extending along said length and defined
laterally by an internal surface; the airfoil portion has a set of
channels extending from the external surface to the internal
surface; the openings of said channels on said external surface are
aligned along a curved line that reflects an isobar on said
external surface.
[0020] In this case, additive manufacturing is particularly
effective and advantageous.
[0021] A second aspect of the present invention is a
turbomachine.
[0022] According to embodiments thereof, a turbomachine comprises a
plurality of hollow blades; each of the hollow blades comprises an
airfoil portion; the airfoil portion extends longitudinally for a
length; the airfoil portion is defined laterally by an external
surface; the airfoil portion has at least one internal cavity
extending along said length and defined laterally by an internal
surface; the airfoil portion has a set of channels extending from
the external surface to the internal surface; the openings of said
channels on said external surface are aligned along a curved line
that reflects an isobar on said external surface.
[0023] A third aspect of the present invention is a method of
manufacturing a turbomachine hollow blade.
[0024] According to embodiments thereof, a method of manufacturing
a turbomachine hollow blade comprising an airfoil portion, the
airfoil portion extends longitudinally for a length; the airfoil
portion is defined laterally by an external surface; the airfoil
portion has at least one internal cavity extending along said
length and defined laterally by an internal surface; the airfoil
portion has a set of channels extending from the external surface
to the internal surface; the openings of said channels on said
external surface are aligned along a curved line that reflects an
isobar on said external surface; the airfoil portion is obtained by
additive manufacturing.
[0025] Technical features of the blade, the turbomachine and the
manufacturing method are set out in the detailed description.
BRIEF DESCRIPTION OF DRAWINGS
[0026] The accompanying drawings, which are incorporated herein and
constitute a part of the specification, illustrate embodiments of
the present invention and, together with the description, explain
these embodiments. In the drawings:
[0027] FIG. 1 shows a transversal cross-section of an airfoil
portion of a first embodiment of a blade according to the present
invention,
[0028] FIG. 2 shows a transversal cross-section of an airfoil
portion of a second embodiment of a blade according to the present
invention,
[0029] FIG. 3 shows a first tridimensional view of a length of an
airfoil portion of a third embodiment of a blade according to the
present invention--the third embodiment combines the features of
the first and second embodiments,
[0030] FIG. 4 shows a second tridimensional view of a length of an
airfoil portion of the embodiment of FIG. 3, the length being
partially sectioned,
[0031] FIG. 5 shows a transversal cross-section of an airfoil
portion of a fourth embodiment of a blade according to the present
invention,
[0032] FIG. 6A shows a first lateral view of an airfoil portion of
the embodiment of FIG. 5,
[0033] FIG. 6B shows a second lateral view of an airfoil portion of
the embodiment of FIG. 5,
[0034] FIG. 7 shows a transversal cross-section of an airfoil
portion of a fifth embodiment of a blade according to the present
invention.
DETAILED DESCRIPTION
[0035] The following description of embodiments refers to the
accompanying drawings. The same reference numbers in different
drawings identify the same or similar elements. The following
detailed description does not limit the present invention. Instead,
the scope of the present invention is defined by the appended
claims.
[0036] Reference throughout the specification to "one embodiment"
or "an embodiment" means that a particular feature, structure, or
characteristic described in connection with an embodiment is
included in at least one embodiment of the subject matter
disclosed. Thus, the appearance of the phrases "in one embodiment"
or "in an embodiment" in various places throughout the
specification is not necessarily referring to the same embodiment.
Further, the particular features, structures or characteristics may
be combined in any suitable manner in one or more embodiments.
[0037] In order to understand the basic idea behind the present
invention, reference may be made to the embodiment FIG. 5 and FIG.
6.
[0038] The blade 50 of FIG. 5 and FIG. 6, is for a turbomachine
and, during operation of the turbomachine is surrounded by an
external fluid flow (as shown in FIG. 5) that moves from the
leading edge 58 of the airfoil 1 to the trailing edge 59 of the
airfoil on both sides of the airfoil 1, i.e. the "suction side" and
the "pressure side" (as shown in FIG. 5).
[0039] The blade 50 of FIG. 5 and FIG. 6 is hollow in the sense
that it has at least one internal cavity; this blade has two
internal cavities 54 and 55, each of the shapes of these cavities
being different from the shape of the airfoil of the blade. This
blade comprises an airfoil portion 1 that extends longitudinally
for a length and has a first end region 2 and a second end region 3
(see FIG. 6); the airfoil portion 1 is defined laterally by an
external surface (also called "airfoil surface").
[0040] The internal cavity or cavities 54 and 55 extend partially
or entirely along said length and are defined laterally by an
internal surface. In the embodiment of FIG. 5 and FIG. 6, the
airfoil portion 1 has two sets of channels: a first set 56 for the
cavity 54 on the pressure side and a second set 57 for cavity 55 on
the suction side; each of these channels extends from the external
surface of the airfoil to the internal surface of an internal
cavity; these channels are straight and inclined with respect to
the external surface of the airfoil (i.e. are not perpendicular to
the tangential plane) or are curved; in the embodiment of FIG. 5
and FIG. 6, they are both straight and inclined.
[0041] The arrangement, shape, orientation, inclination of the
channels takes into account the direction of flow on the suction
side of the airfoil portion or the pressure side of the airfoil
portion that strongly depends on the external shape of the airfoil
portion; in the embodiment of FIG. 5 and FIG. 6, the flow in the
channels of the set 56 is inward and flow in the channels of the
set 57 is outward.
[0042] It is clear that, even if only one channel may carry out the
function of sucking or ejecting a fluid, typical embodiments of the
present invention will use a plurality of channels. The channels of
the plurality extends between the external surface and the internal
surface, and may be differently shaped and/or sized and/or
oriented.
[0043] The channels used for sucking condensation from the airfoil
surface of steam turbine blades are, typically, holes or, even more
typically, slots.
[0044] The channels may have a non-uniform cross-section (this is
not shown in the figures).
[0045] In the embodiment 10 of FIG. 1, there is only one internal
cavity 4; channels 6 are inclined and lead to the laterally
displaced internal cavity 4; the cavity 4 is use to suck
condensation and the channels 6 are inclined so to facilitate the
movement of the fluid from the external surface of the airfoil
portion 1, along the channels 6 and into the internal cavity 4
(considering also the fluid flow around the airfoil portion during
operation of the machine). In this embodiment, the channels 6
correspond to a plurality of long slots arranged in two rows (as
shown in FIG. 3 on the right) and correspondingly one short conduit
is shown in FIG. 1. The shape of the chamber 4 and the arrangement
of the channels 6 allow to locate the sucking area very close to
the trailing edge of the airfoil portion 1 of the blade 10.
[0046] In the embodiment 20 of FIG. 2, there is only one internal
cavity 5; the channels 7 are inclined and lead to the laterally
displaced internal cavity 5; the cavity 5 is used to eject a fluid
(typically a hot fluid) and the channels 7 are inclined so to
facilitate the movement of the fluid from the internal cavity 5,
along the channels 7, to the external surface of the airfoil
portion 1 (considering also the fluid flow around the airfoil
portion during operation of the machine). In this embodiment, the
channels 7 correspond to a plurality of short slots arranged in one
rows (as shown in FIG. 3 on the left) and correspondingly one short
conduit is shown in FIG. 2. The shape of the chamber 5 and the
arrangement of the channels 7 allow to locate the ejection area
very close to the leading edge of the airfoil portion 1 of the
blade 20.
[0047] In the embodiment 30 of FIG. 3 and FIG. 4, the technical
features of both embodiments 10 and 20 of FIG. 1 and FIG. 2 are
combined, i.e. there is sucking of a fluid into the airfoil portion
of the blade and there is ejection of fluid out of the airfoil
portion of the blade; both sucking and ejection take place on the
pressure side of the airfoil; on the contrary, in the embodiment of
FIG. 5, sucking takes place on the pressure side while ejection
takes place on the suction side; it is two be noted that a variant
of the embodiment of FIG. 5 may provide to have sucking from both
sides (i.e. two corresponding sets of channels) and ejection on
both sides (i.e. two corresponding sets of channels).
[0048] The channels may lie in a plane perpendicular to the axis of
the blade.
[0049] Alternatively, the channel may extend across a plurality of
planes perpendicular to the axis of the blade; this is the case of
channels 6 and 7 in FIG. 4.
[0050] Depending on the function of the internal cavity, the
channels may start advantageously in a leading edge region of the
blade (see e.g. FIG. 2) or a trailing edge region of the blade (see
e.g. FIG. 1).
[0051] Depending on the function of the internal cavity, the
channels may be shaped so that to facilitate flow of fluid from
said external surface to said internal surface (see e.g. FIG. 1) or
from said internal surface to said external surface (see e.g. FIG.
2).
[0052] In the embodiment of FIG. 5 and FIG. 6, the set 56 of
channels extend between the external surface (pressure side) and
the internal surface (cavity 54); the openings of the channels 56
on the external surface are aligned along a curved line (see FIG.
6B); in this way, they reflect approximately an isobar on the
airfoil surface due to the external flow. The same is true for
channels 57.
[0053] In the embodiment of FIG. 3 and FIG. 4, the set 6 of
channels extend between the external surface of the airfoil to the
internal surface (cavity); the openings of the channels 6 on the
external surface are aligned along two distinct and remote (even if
close to each other) lines (see FIG. 3 on the right). On the
contrary, the openings of the channels 7 on the external surface
are aligned along only one line (see FIG. 3 on the left).
[0054] For the same of clarity, it is worth noting that cavity 4
and cavity 5 may comprise internal reinforcing elements (for
example in the shape of short cylinders as shown in FIG. 4) in
order to avoid collapse of the cavity.
[0055] The embodiment 70 of FIG. 7 comprises a plurality of
internal cavities 71, 72, 73, 74; cavities 74 are located in the
area of the trailing edge of blade and are not connected to the
external surface of the airfoil portion of the blade; they may be
used for example for controlling the temperature of the trailing of
the airfoil; cavities 71, 72 and 73 are all used for ejecting
fluid, for example a hot fluid; cavity 71 is separated from
cavities 72 and 73 and ejects from a plurality of channels 75
differently oriented; cavities 72 and 73 are in communication
between each other and only cavity 73 ejects from a plurality of
channels 76 similarly oriented; in this way cavity 71 and cavities
72 and 73 may be at different pressures and/or temperatures. Its is
clear that the embodiment 70 of FIG. 7 may have a very high number
of variants.
[0056] The solutions described above are particularly effective for
stator blades of steam turbines used in turbomachine for "Oil &
Gas" applications; in this case, the blades are preferably made of
metallic material in a single piece.
[0057] More in general, the blade design according to the present
invention may be used as (static or moving) phase separator device
for a turbomachine (e.g. a turbine, a compressor, a pump) that gets
in contact with a multiphase fluid, typically a combination of
liquid and gas.
[0058] It is to be noted that the holes or slots may be used for
sucking condensation and, alternatively, for ejecting a fluid,
typically a hot fluid. It is to be noted that the internal cavities
may be more than one and may have the same function or different
functions (lightening the blade, cooling the blade, heating the
blade, sucking fluid, ejecting fluid).
[0059] The realistic manufacturing methods of the blades according
to the present invention are based on additive manufacturing; in
this case and if there is a completely closed internal cavity, at
least two holes (even very small) are associated to the cavity in
order to evacuate the powder that remains in the cavity after the
additive process is completed.
[0060] Considering for example the embodiment of FIG. 5 and FIG. 6,
the airfoil portion 1 of the blade is obtained by additive
manufacturing.
[0061] The additive manufacturing starts preferably from a first
end 2 or 3 of the airfoil portion 1 and ends at a second end 3 or 2
of the airfoil portion 1.
[0062] Considering for example the embodiment of FIG. 5 and FIG. 6,
the additive manufacturing proceeds perpendicularly to the axis of
the blade; alternatively, the additive manufacturing may proceed
inclinedly to the axis of the blade, preferably according to a
fixed predetermined angle with respect to the axis of the
blade.
[0063] The manufacturing of the blade comprising preferably a
single additive manufacturing process at least for the whole
airfoil portion.
[0064] Additive manufacturing is a very powerful and flexible
technique; in this way, it is possible to bind a single granular
material or a plurality of granular materials. Typically, materials
used for stator blades of steam turbines used in turbomachine for
"Oil & Gas" applications are metallic.
[0065] Additive manufacturing has many advantages with respect to
the traditional technologies used for turbomachines blades, in
particular for stator blades of steam turbines, as it allows a
great design flexibility for the external shape of the blade as
well as for the internal shape of the blade (in particular its
internal cavity or cavities), as it allows to realize even small
details in a shape (this includes the production of small blades),
as it allows to realize graded materials in a blade (for example
the material may vary along the length or height of a blade
according to the mechanical and/or chemical requirements of the
various specific points of the blade), as it allows a simpler
manufacturing process and a lower manufacturing cost.
[0066] As far as manufacturing is concerned, it must be considered
that in the field of "Oil & Gas" small-lot production is common
also because solutions are studied (or at least customized) for a
specific client. In general, it is always desirable to have a high
precision and a low production cost.
[0067] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any computing system or systems and performing any
incorporated methods. The patentable scope of the invention is
defined by the claims, and may include other examples that occur to
those skilled in the art. Such other examples are intended to be
within the scope of the claims if they have structural elements
that do not differ from the literal language of the claims, or if
they include equivalent structural elements with insubstantial
differences from the literal language of the claims.
* * * * *