JP3592744B2 - Gas turbine air-cooled blade - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a gas turbine air-cooled blade to which convection cooling is applied inside the blade.
[0002]
[Prior art]
A conventional gas turbine air-cooling blade will be described with reference to FIGS. 5 is a cross-sectional view of the air-cooled blade, FIG. 6 is a cross-sectional view taken along line BB, FIG. 7 is a distribution diagram of local heat transfer coefficient on the blade inner surface, and FIG. . 5 and 6, a first cooling passage 6, a second cooling passage 7, and a third cooling passage 8 are provided inside the air cooling blade 1 of the gas turbine, and these are communicated with each other, and the cooling air 20 passes through these passages. , And comes out behind the air-cooled wing 1. In these passages, a plurality of oblique fins 2 are attached to the ventral side 21 of the air-cooling wing 1, and the oblique fins 3 have an inclination in a direction opposite to the inclination of the fin 2 and are provided on the back side 22 of the air-cooling wing 1. Installed. Reference numerals 4 and 5 denote internal ribs, which partition the inside and form first to third cooling passages, respectively. With such a configuration, the blades are cooled by the cooling air passing through the first to third passages 6, 7, and 8.
[0003]
The oblique fins 2 and 3 cause turbulence in the air flow inside the air-cooling wing 1 to generate a swirling flow along the fins, thereby improving the heat transfer coefficient of the cooling passage and improving the cooling performance. . Also, it is well known that the average heat transfer coefficient is improved by making the fins 2 and 3 oblique to the flow as compared with the case where the flow is orthogonal.
[0004]
However, in the conventional cooling blade 1, as shown in FIG. 5, the oblique fins 2 and 3 have the same inclination direction on the ventral side 21 together with the first, second and third cooling passages 6, 7 and 8. The oblique fins 3 also incline in the same direction in the opposite direction to the first, second, and third cooling passages 6, 7, and 8 on the back side 22 as well. The fins 2 and 3 may be both inclined in the same direction. In this case, as shown in FIG. 8, the regions 10 and 11 having a high local heat conductivity are concentrated on the ribs 4 as shown. This is not preferable from the viewpoint of uniformly cooling the whole.
[0005]
[Problems to be solved by the invention]
FIG. 4 is an explanatory diagram of the distribution of the local heat transfer coefficient of the wings in which the oblique fins are inclined in the opposite directions. As shown in the figure, the distribution is biased, and the local heat transfer coefficient The high region 11 is also offset on the inner surface of the ventral side 21. The reason for this is that when oblique fins are used, a secondary flow occurs along the fins, and the secondary flow has a large local heat transfer coefficient when flowing toward the heat transfer surface, and a local heat transfer coefficient when flowing away from the heat transfer surface. Since the heat transfer coefficient is small, the distribution is offset.
[0006]
For this reason, regions with a high local heat transfer coefficient on the inner surface of the air-cooling blade 1 are distributed as shown by 10 and 11 in FIG. In this figure, in particular, an undercooled area 12a is formed on the back side 22 of the rib 4, and an undercooled area 12b is similarly formed on the ventral side 21 of the rib 5, and this part is undercooled. Therefore, it is necessary to dispose the oblique fins so that such a region of insufficient cooling is not offset.
[0007]
[Means for Solving the Problems]
In order to solve such a problem, the present invention sets the oblique fins provided on the ventral side and the back side of the inner surface of the cooling passage in the air-cooling blade to have the same inclination of the oblique fins on the same side of each passage, and to adjoin each other. The configuration is such that the fins on the same side of the passage have alternately opposite inclinations, and the abdominal side and the back side have opposite inclinations in the same passage.
[0008]
That is, according to the present invention, the inside of the gas turbine air cooling blade is separated by a rib, a plurality of passages are provided, and the passages of the plurality of passages are formed as cooling passages through which cooling air flows, and the ventral side and the back side of the cooling passage. Gas turbine air cooling provided with a plurality of oblique fins on both inner surfaces of which are inclined in the same direction in the same passage on the ventral side and the rear side with respect to the flow direction of the cooling air for improving the heat transfer coefficient. In the blade, the inclined directions of the oblique fins on the same side of the inner surface of the cooling passage are made to have the same direction in the same passage, and are alternately opposite in inclination to the oblique fins on the same side of the adjacent passage. The gas turbine air-cooling blade is characterized in that it is inclined in the opposite direction to the oblique fins on the back side and the ventral side.
[0009]
[Action]
According to the present invention, by the above-described means, the cooling air flows in the cooling passages communicating with each other, and the ventral side and the dorsal side are inclined in the same direction in the same passage, and the oblique fins on the ventral side and the dorsal side in the same passage. Since they are arranged so as to cross each other in the opposite direction, a secondary flow along the oblique fins occurs, and this secondary flow has a large local heat transfer coefficient in the flow toward the heat transfer surface, and moves away from the heat transfer surface. It becomes smaller in the flow. Therefore, regions with high local heat transfer rates are offset on the ventral and dorsal sides, respectively, and similar high regions occur on each passage, and regions with high local heat transfer rates due to oblique fins are on the ventral and dorsal sides of the wing. Since the distribution is uniform over the entire surface, the distribution is more uniform than in the conventional example, and the insufficient cooling on the back side of the front edge side rib and the ventral side of the rear edge side rib, which has conventionally occurred, is solved.
[0010]
【Example】
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. FIG. 1 is a cross-sectional view of a gas turbine air-cooling blade according to one embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line AA, and FIG. 3 is an explanatory diagram of a local heat transfer coefficient distribution on the blade inner surface according to the present invention. In FIG. 1, the air-cooling blade 1 is provided with first, second, and third cooling passages 6, 7, and 8 by ribs 4, 5 as in the conventional case, and the cooling air 20 communicates with the first and second cooling passages from the lower part of the blade. It is configured to pass through the second and third cooling passages 6, 7, 8 and flow out of the trailing edge fin 9.
[0011]
23 (1) is an oblique fin (1) provided on the ventral side 21 of the first cooling passage 6, and 23 (2) is provided on the ventral side 21 of the second cooling passage 7 as well. The oblique fins (2) and 23 (3) having the opposite inclination are provided on the ventral side 21 of the third cooling passage 8, and are opposite to the fins 23 (2) and are the same as the fins 23 (1). The inclined fins (3) are inclined. Similarly, the oblique fins (1) and 24 (2) are provided on the back 22 of the first cooling chamber 6 and are inclined in opposite directions to the fins 23 (1) on the ventral side 21. The oblique fins (2) and 24 (3) which are provided on the back side 22 of the second cooling chamber 7 and which are also opposite to the fins 24 (1) and the fins 23 (2) in the same passage 7 are also provided in the third cooling chamber. The diagonal fins (3) provided on the back side 22 of the fin 8 and having the fins 24 (2) and the fins 23 (3) in the same passage 8 having mutually opposite inclinations.
[0012]
As described above, the oblique fins 23 (1), 23 (2), and 23 (3) are alternately inclined at the first, second, and third cooling passages 6, 7, and 8 on the ventral side 21 so as to be provided to each cooling passage. The oblique fins 24 (1), 24 (2), and 24 (3) are similarly arranged on the back side 22 in the first, second, and third cooling passages 6, 7, and 8, and the inclination is alternately reversed. And the cooling passages are arranged in a plurality of stages, and the fins 23 and 24 on the ventral side 21 and the back side 22 are arranged so that the inclinations thereof are opposite to each other.
[0013]
With the arrangement of the oblique fins, as shown in FIG. 3, in the first cooling passage 6, the region 10 having a high local heat conductivity is located on the rib 4 side of the ventral side 21, and 11 is located on the back side 22. At a distance from the ribs 4. Similarly, in the second cooling passage 7, the cooling air 20 flows in the opposite direction to the first cooling passage 6, and the oblique fins (2) also have a slope opposite to that of the passage 7, as shown in FIG. 10 is near the rib 5, and on the back side 22, the high region 11 is farther from the rib 5 and occurs near the rib 4. Similarly, in the third cooling passage 8, as shown in the figure, 10 on the ventral side 21 is separated from the rib 5, and on the dorsal side 22, 11 is formed near the rib 5.
[0014]
Therefore, the distribution of the region having a high local heat transfer coefficient in the present embodiment is more uniform than that of the conventional example of FIG. 7, and the region with insufficient inner surface cooling in the conventional distribution of FIG. 22 and 12b on the ventral side 21, but such a non-uniform distribution is provided and the ventral side 21 and the dorsal side 22 are uniformly cooled.
[0015]
【The invention's effect】
As described above in detail, according to the present invention, the inclination of the oblique fins in the cooling passage of the gas turbine air-cooling blade is different from that of the conventional one, and the inside of the gas turbine air-cooling blade is divided by the ribs to form a plurality of passages. A plurality of rows are provided, and the passages of the plurality of rows are formed as cooling passages through which cooling air flows in communication with each other, and the inner surfaces of the cooling passage on the ventral side and the back side are formed in the flow direction of the cooling air for improving the heat transfer coefficient. On the other hand, in a gas turbine air-cooling blade provided with a plurality of oblique fins that are inclined in the same direction in the same passage on the ventral side and the back side, the inclination directions of the oblique fins on the same side of the cooling passage inner surface are the same. as the inverse of the slope alternately oblique fins on the same side of the adjacent channel with the same direction in the inner and the back side, each other in the reverse inclined obliquely to the respective oblique fins ventral side of the cooling passage Gas turbine air cooling Becomes uniform local heat transfer coefficient distribution inside by the cooling air, results the metal temperature distribution of the blade it becomes uniform than conventionally as the thermal stress is reduced, in which blade life is increased.
[Brief description of the drawings]
FIG. 1 is a sectional view of a gas turbine air-cooling blade according to an embodiment of the present invention.
FIG. 2 is a sectional view taken along the line AA in FIG.
FIG. 3 is an explanatory diagram of a local heat transfer coefficient distribution on an inner surface of a blade according to an embodiment of the present invention.
FIG. 4 is an explanatory diagram of a local heat transfer coefficient distribution by a conventional oblique fin.
FIG. 5 is a cross-sectional view of a conventional gas turbine air-cooling blade.
FIG. 6 is a sectional view taken along line BB in FIG.
FIG. 7 is an explanatory diagram of a conventional local heat transfer coefficient distribution on the inner surface of a blade.
FIG. 8 is an explanatory diagram of a local heat transfer coefficient distribution on the inner surface of another type of conventional air-cooled blade.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Air-cooling blade 4 Rib 5 Rib 6 First cooling passage 7 Second cooling passage 8 Third cooling passage 20 Cooling air 21 Vent side 22 Back side 23 Oblique fin 24 Oblique fin

Claims (1)

The interior of the gas turbine air-cooling blade is separated by ribs, a plurality of rows of passages are provided, and the plurality of rows of passages are used as cooling passages through which cooling air flows, and heat is applied to both the inner surface on the ventral side and the back side of the cooling passage. In the gas turbine air-cooling blade provided with a plurality of oblique fins each of which is inclined in the same direction in the same passage on the ventral side and the rear side with respect to the flow direction of the cooling air for improving the transmission rate, the cooling passage The inclined directions of the oblique fins on the same side of the inner surface are the same in the same passage, and the slanted fins on the same side of the adjacent passage are alternately inclined in the opposite direction. A gas turbine air-cooling blade characterized by being inclined in the opposite direction to each of the oblique fins on the side.

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