TURBINE VANE
A plurality of film cooling holes are formed, so as to communicate with a front cooling passage, in a vane surface on the front-edge side of a stator vane body of a turbine stator vane. The hole cross-section of each of the film cooling holes has a rectangular long-hole shape extending in a direction parallel to the cross-section along the span direction and having a rounded corner. The hole-center line of each of the film cooling holes is inclined with respect to the thickness direction in the cross-section along the span direction. The exit-side portion of the hole wall surface of each of the film cooling holes is inclined with respect to the thickness direction by a greater degree than that of the hole-center line.
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This application is a continuation application of International Application No. PCT/JP2012/059459, filed on Apr. 6, 2012, which claims priority to Japanese Patent Application No. 2011-085580, filed on Apr. 7, 2011, the entire contents of which are incorporated by references herein.
BACKGROUND OF THE INVENTION1. Field of the Invention
The present invention relates to a turbine vane used in a turbine for gas turbine engines such as an aircraft engine and an industrial gas turbine engine.
2. Description of the Related Art
In general, turbine vanes to be exposed to a combustion gas while a gas turbine engine is in operation can be cooled by use of cooling air (part of compressed air) extracted from a compressor or a fan of the gas turbine engine.
To put it specifically, a cooling passage into which the cooling air can flow is formed inside the turbine vane, and multiple film cooling holes through which the cooling air can jet out are formed in a vane surface of the turbine vane in such a way as to communicate with the cooling passage. For this reason, while the gas turbine engine is in operation, the cooling air flowing into the cooling passage is jetted out through the multiple film cooling holes, thus forms a film cooling layer which covers the vane surface of the turbine vane, and can perform film cooling on the turbine vane.
Conventional techniques related to the present invention have been disclosed in JP 2009-162224 A and JP 07-063002 A.
SUMMARY OF THE INVENTIONIn recent years, there has been increasing demand for higher output from gas turbine engines. To meet the demand, the temperature of a combustion gas tends to become very high at an entrance-side portion of a turbine. Against this background, it is imperative to increase the cooling performance of the turbine vane to a higher level by increasing film efficiency on the vane surface of the turbine vane, particularly around a front edge-side vane surface of the turbine vane (including the front edge-side vane surface) where the temperature of the component is apt to rise due to collisions of the combustion gas.
With this taken into consideration, an object of the present invention is to provide a turbine vane having a novel configuration which is capable of fully cooling a front edge-side vane surface and its vicinity.
An aspect of the present invention is a turbine vane for a turbine of a gas turbine engine, and capable of being cooled by cooling air, the turbine vane comprising: a vane body including: a vane surface; a cooling passage allowing the cooling air to flow into the vane body; and a plurality of film cooling holes formed in the vane surface on a front edge side of the vane body so as to communicate with the cooling passage to jet out the cooling air through the plurality of film cooling holes, a hole cross section of each film cooling hole having a long-hole shape extending in a direction parallel to a cross section along a span direction of the vane body, a hole-center line of each film cooling hole tilting from a thickness direction of the vane body on a cross section of the vane surface along the span direction, and an exit-side and obtuse angle-side portion of a hole wall surface of each film cooling hole tilting further from the thickness direction than the hole-center line on the cross section along the span direction.
In the description and scope of claims of this application, the “turbine vane” represents a turbine rotor vane and a turbine stator vane, and the “hole cross section” means a cross section perpendicular to the hole-center line. Furthermore, the “exit side” represents the exit side viewed in the flowing direction of the cooling air, and the “obtuse angle side” represents a side (region) having an obtuse angle defined with the vane surface.
The present invention makes it possible to fully diffuse the cooling air, which is jetted out through each film cooling hole, on the front edge-side vane surface of the turbine vane in the span direction while inhibiting the cooling air from coming up away from the front edge-side vane surface of the turbine vane. For this reason, it is possible to increase the film efficiency around the front edge-side vane surface of the turbine vane, and accordingly to increase the cooling performance of the turbine vane to a higher level.
Descriptions will be provided for an embodiment of the present invention by referring to
As shown in
The turbine stator vane 1 is produced (cast) by lost wax precision casting, for example. As shown in
As shown in
The stator vane body 3 has a vane surface 3v in its flank portion. Multiple film cooling holes 13 are formed in the vane surface 3v so as to communicate with the front cooling passage 7 or the rear cooling passage 9. The cooling air CA which flows into the front cooling passage 7 or the rear cooling passage 9 is jetted out through the film cooling holes 13.
The stator vane body 3 further has a vane surface 3p in its rear edge-side portion. Multiple film cooling holes 15 are formed in the vane surface 3p so as to communicate with the rear cooling passage 9. The cooling air CA which flows into the rear cooling passage 9 is jetted out through the film cooling holes 15.
The stator vane body 3 has a vane surface 3b in its back portion. Multiple film cooling holes (not shown) similar to the film cooling holes 11, the film cooling holes 13 and the film cooling holes 15 may be formed in the vane surface 3b. In this case, too, the film cooling holes are formed communicating with the front cooling passage 7 or the rear cooling passage 9 in the same way that has been described. The cooling air which flows into the front cooling passage 7 or the rear cooling passage 9 is jetted out through the film cooling holes (not shown).
As shown in
A pipe-shaped front insert 25 is arranged in the front cooling passage 7 of the stator vane body 3. The upper portion of the front insert 25 is inserted into the front insertion hole 21 of the outer band 19. Multiple front impingement cooling holes 27 are formed in the outer peripheral surface of the front insert 25. The cooling air CA is jetted out to the inner wall surface of the front cooling passage 7 through the front impingement cooling holes 27.
A pipe-shaped rear insert 29 is arranged in the rear cooling passage 9 of the stator vane body 3. The upper portion of the rear insert 29 is inserted into the rear insertion hole 23 of the outer band 19. Multiple rear impingement cooling holes 31 are formed in the outer peripheral surface of the rear insert 29. The cooling air CA is jetted out to the inner wall surface of the rear cooling passage 9 of the stator vane body 3 through the rear impingement cooling holes 31.
Descriptions will be subsequently provided for a main part of the embodiment of the present invention.
As shown in
As shown in
An exit-side and obtuse angle-side portion (predetermined exit-side portion) lie on the hole wall surface of each film cooling hole 11 tilts further to the span direction SD (or the vane surface 3c) than the hole-center line 11c of the film cooling hole 11 on the cross section along the span direction SD. In addition, a tilt angle θe of the predetermined exit-side portion 11e of the hole wall surface of each film cooling hole 11 to the span direction SD (or the vane surface 3a) is in a range of 5° to 20° or preferably in a range of 5° to 10°. The reason for this is that: if the tilt angle θe is less than 5°, it is not possible to fully diffuse the cooling air CA in the span direction SD; and if the tilt angle θe is greater than 20°, the stream is more likely to separate inside the hole wall surface of the film cooling hole 11, and the cooling performance accordingly deteriorates.
Descriptions will be subsequently provided for how the embodiment of the present invention works and for effects of the embodiment.
While the gas turbine engine is in operation, the cooling air CA flowing into the front insert 25 is jetted out to the inner wall surface of the front cooling passage 7 of the stator vane body 3 through the multiple front impingement cooling holes 27, and the cooling air CA flowing into the rear insert 29 is jetted out to the inner wall surface of the rear cooling passage 9 of the stator vane body 3 through the multiple rear impingement cooling holes 31. Thereby, the impingement cooling (inner cooling) can be performed on the turbine stator vane 1 (the stator vane body 3).
Furthermore, the cooling air CA contributing to the impingement cooling of the turbine stator vane 1, in other words, the cooling air CA flowing into the front cooling passage 7 and the rear cooling passage 9 of the stator vane body 3 is jetted out through the multiple film cooling holes 11, the multiple film cooling holes 13 and the multiple film cooling holes 15. Thereby, the cooling air CA forms a film cooling layer (not shown) covering the front edge-side vane surface 3a, the flank-side vane surface 3v, and the like of the stator vane body 3 of the turbine stator vane 1, and can perform the film cooling on the turbine stator vane 1.
In this respect, descriptions will be provided for a result of an analysis using a three-dimensional steady-state viscosity CFD (Computational Fluid Dynamics) on how the turbine vane is cooled by the film cooling holes of the embodiment.
As shown in
As shown in
As shown in
Next, descriptions will be provided for conditions for the analysis. As shown in
In
It is learned that the area M and the area L shown in
Moreover,
In
In the embodiment, as described above, the hole cross section of each film cooling hole 11 is shaped like a long hole extending in the direction PD parallel to the cross section along the span direction SD. In addition, the hole-center line 11c of each film cooling hole 11 tilts from the thickness direction TD on the cross section along the span direction SD. Moreover, the predetermined exit-side portion 11e of the hole wall surface of each film cooling hole 11 tilts further from the thickness direction TD than the hole-center line 11c on the cross section along the span direction SD. For this reason, each film cooling hole 11 is capable of more fully diffusing the cooling air CA, which is jetted out through the film cooling hole 11, on the vane surface 3a of the stator vane body 3 in the span direction SD while inhibiting the cooling air CA from coming up (separating) away from the vane surface 3a than the case where the cross-sectional of the film cooling hole 11 would be shaped like a circle or an ellipse.
In addition, the embodiment makes it possible to increase the film efficiency around the vane surface 3a of the stator vane body 3 of the turbine stator vane 1, and accordingly to increase the cooling performance of the turbine stator vane 1 to a higher level.
It should be noted that the present invention is not limited to what has been described for the embodiment. The present invention can be carried out in other various modes including, for example, a mode where the technical idea applied to the turbine stator vane 1 is applied to a turbine rotor vane. What is more, the scope of the right included in the present invention is not limited to these embodiments.
Claims
1. A turbine vane for a turbine of a gas turbine engine, and capable of being cooled by cooling air, the turbine vane comprising:
- a vane body including: a vane surface; a cooling passage allowing the cooling air to flow into the vane body, and a plurality of film cooling holes formed in the vane surface on a front edge side of the vane body so as to communicate with the cooling passage to jet out the cooling air through the plurality of film cooling holes, a hole cross section of each film cooling hole having a long-hole shape extending in a direction parallel to a cross section along a span direction of the vane body, a hole-center line of each film cooling hole tilting from a thickness direction of the vane body on a cross section of the vane surface along the span direction, and an exit-side and obtuse angle-side portion of a hole wall surface of each film cooling hole tilting further from the thickness direction than the hole-center line on the cross section along the span direction.
2. The turbine vane according to claim 1, wherein
- an aspect ratio of the hole cross section of each film cooling hole is set in a range of 1.1 to 3.0.
3. The turbine vane according to claim 1, wherein
- a tilt angle of the hole-center line of each film cooling hole to the thickness direction is set in a range of 20° to 60°.
4. The turbine vane according to claim 1, wherein
- a tilt angle of the exit-side and obtuse angle-side portion of the wall surface of each film cooling hole to the thickness direction is set in a range of 5° to 20°.
5. The turbine vane according to claim 1, wherein
- a plurality of other film cooling holes through which to jet out the cooling air are formed in a vane surface other than the vane surface on the front-edge side so as to communicate with the cooling passage.
Type: Application
Filed: Oct 4, 2013
Publication Date: Feb 6, 2014
Applicants: The Society of Japanese Aerospace Companies, Inc. (Minato-ku), IHI Corporation (Koto-ku)
Inventor: Yoji OKITA (Tokyo)
Application Number: 14/046,191
International Classification: F01D 5/18 (20060101);