JP2012002228A - Member including cooling passage therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a member including a cooling passage therein and enabling efficient cooling by reducing a peeling circulation region.SOLUTION: Inside the member including the cooling passage therein, the cooling passage having a wall face 23 on which cooling ribs 31a, 31b are arranged is provided, and cooling is performed by making a cooling medium flow along the wall face 23. The cooling ribs 31a, 31b are arranged so that part of the cooling medium made to flow in a portion 51 in the vicinity of the center of the wall face 23 of the cooling passage is made to flow to sides of both lateral ends 6b, 6c of the wall face 23, and are installed so that part 58 of the cooling medium made to flow on the surfaces of the cooling ribs 31a, 31b is made to move along the surfaces of the cooling ribs 31a, 31b and flow to the wall face 23.

Description

  The present invention relates to a member having a cooling passage therein, and particularly to a member having a cooling rib on a wall surface of the cooling passage.

  With respect to the member having the cooling passage inside, for example, as described in Patent Document 1, the generation of turbulent flow and the flow from the center of the wall surface to the side edge of the wall surface are promoted with respect to the cooling medium that runs over the wall surface of the cooling passage Therefore, a technique including cooling ribs that are inclined with respect to the flow direction of the cooling medium has been proposed.

Japanese Patent No. 3006174

  In the cooling passage having ribs disclosed in Patent Document 1, there is a large separation circulation region that does not contribute to heat transfer relatively downstream of the rib in the coolant flow direction, and this region has the heat transfer performance of the entire cooling passage. It is lowered.

  An object of the present invention is to provide a member having a cooling passage in the inside thereof that can create an effective flow for cooling the member, reduce the separation circulation region, and efficiently cool with a small amount of cooling medium.

  In order to achieve the above object, the present invention comprises a cooling passage having a wall surface provided with cooling ribs therein, and a cooling medium is circulated through the wall surface to cool the member. The cooling rib is disposed so that a part of the cooling medium flowing near the center of the wall surface of the cooling flow path flows to both ends of the wall surface, and the cooling medium flowing on the surface of the cooling rib. A part of the cooling rib is installed on the surface of the cooling rib so as to flow to the wall surface, and the rib front surface of the cooling rib has a streamline shape in a cross section in the cooling passage forming direction. The length of the cooling rib in the flow direction becomes longer from the center of the wall toward the both ends of the wall surface, and the height of the cooling rib is reduced in the direction of the cooling air flow. Bed height is characterized by comprising a zero.

  According to the present invention, it is possible to generate an effective turbulent flow in the cooling medium flow in the cooling flow path inside the member, obtain a high cooling heat transfer coefficient, and efficiently cool the member with a small amount of cooling medium. .

The perspective view of the cooling structure which is one of the embodiments of the present invention is shown. The longitudinal cross-sectional view of a gas turbine blade is shown. The cross-sectional view of a gas turbine blade is shown. The cross-sectional enlarged view of the cooling channel | path which is one of the embodiment of this invention is shown. The comparison figure of the Nusselt number of embodiment of this invention and a comparative example is shown. The cross-sectional enlarged view of the cooling channel | path which is one of the embodiment of this invention is shown. The perspective view of the cooling structure which is one of the embodiments of the present invention is shown. The perspective view of the cooling structure which is one of the embodiments of the present invention is shown. The cross-sectional enlarged view of the cooling passage of a comparative example is shown. The perspective view of the cooling structure of a comparative example is shown.

  A gas turbine blade, which is an example of a member having a cooling passage inside, will be described as an example.

  In the gas turbine equipment, compressed air and fuel compressed by a compressor are mixed and burned by a combustor, and the turbine is driven by the generated high-temperature and high-pressure working gas to convert it into energy such as electric power.

  The working gas temperature of a gas turbine is limited by the ability of the turbine blade material to withstand thermal stresses due to the gas temperature. In order to satisfy the service temperature of the turbine blade, a hollow portion, that is, a cooling passage is provided in the turbine blade, and a cooling medium such as air or steam is circulated in the passage to cool the blade. Specifically, one or more passages are formed inside the turbine blade, and the turbine blade is cooled from the inside by passing a cooling medium. Further, there is a method in which the cooling medium is discharged from the cooling holes provided on the surface, leading edge or trailing edge of the turbine blade to cool it.

  In this embodiment, a case where air is used as a cooling medium will be described. As the cooling air, for example, a part of the air extracted from the middle stage or the outlet of the compressor is used. If a large amount of cooling air is consumed at this time, the combustion air is reduced, resulting in a decrease in the output of the gas turbine. There is also a cooling system called an open cycle in which the cooled air after cooling is discharged into the mainstream gas. In a gas turbine that employs this cooling method, an increase in the amount of cooling air leads to a decrease in the mainstream gas temperature, thereby reducing the thermal efficiency of the gas turbine. Therefore, it is desired to cool efficiently with a smaller amount of cooling air.

  In a gas turbine, it is desirable to obtain as much power energy as possible with respect to the consumed fuel. From this point, an improvement in the efficiency of the gas turbine is expected. As one of the means, the working gas is being heated up. On the other hand, in a combined plant with a steam system that uses the exhaust gas of a gas turbine, great expectations are placed on improving the overall energy conversion efficiency including the gas turbine and the steam turbine. In order to improve this efficiency, it is very effective to raise the temperature of the working gas of the gas turbine. In order to realize a gas turbine having a higher working gas temperature, it is effective to improve the heat transfer performance inside the blades and improve the cooling effect on the amount of cooling air to be supplied, that is, the cooling efficiency. For this reason, various heat transfer promotion measures are taken on the cooling surface.

  In order to promote heat transfer in the blade internal passage, there is a method of suppressing the development of the boundary layer by making the air flow on the surface of the heat transfer surface an effective turbulent flow. For this purpose, it is effective to provide a large number of protrusions on the surface to be cooled inside the blade. For example, there is a method of improving heat transfer by arranging the cooling ribs alternately in a reverse C shape with respect to the flow direction of the cooling air, that is, in a staggered manner.

  FIG. 9 shows an example of a cooling passage having cooling ribs. Cooling ribs 60a and 60b that are inclined with respect to the flow direction 15 of the cooling air are provided on the rib installation surface 23, which is the wall surface of the internal cooling passage 7c of the member 6 having a cooling flow path therein. In this specification, a cooling rib having an angle 66 formed by the front surface of the cooling rib and the partition wall that is greater than 0 ° and smaller than 90 ° is referred to as an inclined cooling rib. However, the front surface of the cooling rib is assumed to be the upstream surface of the cooling rib in the flow direction of the cooling medium. Further, the formed angle 66 is an angle on the upstream side in the cooling medium flow direction among the angles formed by the front surface of the cooling rib and the partition plate in a plane parallel to the rib installation surface. For example, if the angle 66a formed by the front surface of the cooling rib 60a and the partition wall 6c is larger than 0 ° and smaller than 90 °, it can be said that the cooling rib 60a is inclined.

  The flow of the cooling medium around the cooling ribs 60a and 60b is shown in FIG. For simplicity, it is assumed here that the cooling passage 7c has a substantially columnar shape surrounded by four surfaces. Two pairs of secondary flows 52 and 53 are formed in the direction away from the rib installation surface 23 in the vicinity of the partition wall 6b, which is a side wall, and in the direction toward the rib installation surface 23 in the vicinity of the flow path center 51 of the cooling medium. The flow path center 51 of the cooling medium indicates a point on a line connecting the central points in the cross section perpendicular to the cooling medium flow direction of the cooling passage. In the vicinity of the rib installation surface 23, a meandering flow 55 is formed so as to crawl the rib opening portion 80 that is a gap between the ribs, and a flow 56 is formed along the rib toward the partition wall 6 b that is a side wall. However, there is a relatively large separation circulation region 57 that does not contribute to heat transfer behind the rib, and the heat transfer performance of the entire cooling passage is lowered.

  The purpose of arranging the cooling ribs in an inclined manner is to guide a part of the meandering flow 55 of the cooling medium toward the side wall of the cooling passage by the ribs. This flow 56 toward the rib installation surface side end is an effective turbulent flow, which contributes to an improvement in cooling efficiency. Therefore, as long as the above object can be achieved, the front surfaces of the inclined cooling ribs are not necessarily flat. Even if a part or all of the front surface of the cooling rib is a curved surface, a concave surface, or a convex surface, and even if the front surface of the cooling rib is composed of a plurality of surfaces, the surface that can promote the flow 56 can be obtained. If it is a cooling rib which has this, the same kind of effect as the cooling rib arranged in the above-mentioned inclination can be acquired. Moreover, even if there is a portion where the angle between the front surface of the cooling rib and the partition wall is 90 ° or more, if it is local, the same kind of effect as the above-described inclined cooling rib can be obtained. it can. For this reason, in the present specification, the inclined cooling rib is not only a cooling rib having an angle 66 between the front surface of the cooling rib and the partition wall that is greater than 0 ° and smaller than 90 °, but also a flow. Suppose that all the cooling ribs which can acquire the effect which accelerates | stimulates 56 are shown.

  In each of the embodiments of the present invention, the cooling medium flowing on the cooling rib surface is installed so that the cooling medium flows over the cooling rib surface to the rib installation surface, and / or the cooling air separated by the cooling rib Ribs are installed so as to reduce the distance to reattachment to the rib installation surface. The reattachment means that the medium peeled from the ribs flows again so as to craw on the ribs or the rib installation surface. By simultaneously performing this and a part of the cooling medium flowing near the center of the rib installation surface to both ends of the rib installation surface, the separation circulation region can be reduced. As a result, a high cooling heat transfer coefficient can be obtained, and the member can be efficiently cooled with a small amount of cooling medium. The side end of the rib installation surface is an end in the partition plate direction on the wall surface on which the rib is installed.

  Embodiment 1 of the present invention will be specifically described with reference to FIG. FIG. 2 is a view showing a cross-sectional structure of a gas turbine blade embodying the present invention.

  In the gas turbine blade 1 shown in FIG. 2, internal passages 4 and 5 are provided inside the shank portion 2 and the blade portion 3. The internal passages 4 and 5 are partitioned by the partition walls 6a, 6b, 6c, 6d, and 6e in the wing portion 3 to form cooling passages 7a, 7b, 7c, 7d, 7e, and 7f. And a folding flow path is formed with the front curved parts 8a and 8b and the lower curved parts 9a and 9b. That is, in the present embodiment, the first passage 4 is a return flow type cooling passage constituted by the cooling passage 7a, the tip curved portion 8a, the cooling passage 7b, the lower curved portion 9a, the cooling passage 7c, and the blowout hole 11. The internal passage 5 that is the second passage is composed of a cooling passage 7d, a tip curved portion 8b, a cooling passage 7e, a lower curved portion 9b, a cooling passage 7f, and a blowout portion 13 provided at the blade trailing edge 12. It is a return flow type cooling passage.

  Air as a cooling medium is supplied to the supply unit 14 from, for example, a rotor disk that holds the turbine blades 1, and cools the blades from the inside while passing through the passages 4 and 5 that are serpentine passages. The air deprived of heat from the blade is blown into the working gas from the blow hole 11 provided in the blade tip wall 10 and the blow portion 13 of the blade trailing edge 12.

  Cooling ribs that promote turbulent flow are inclined on the cooling wall surfaces of the cooling passages 7b, 7c, 7d, and 7e. With this arrangement, effective turbulence can be generated to promote heat transfer, and the blade cooling effect can be enhanced.

  FIG. 3 shows a section of the turbine blade 1 along the line AA in FIG. In FIG. 3, reference numerals 20 and 21 denote blade back side walls and blade side walls constituting the blade portion of the turbine blade 1, and cooling passages 7 a, 7 b, 7 c, 7 d, 7 e, and 7 f denote the blade back side wall 20, blade front side wall. 21 and the partition walls 6a, 6b, 6c, 6d, 6e. For example, the cooling passage 7c includes a blade back side wall 20, a blade belly side wall 21, and partition walls 6b and 6c. The rib installation surface 23 that is the back side cooling surface of the cooling passage 7c is provided with cooling ribs 25a and 25b that are integrally formed with the blade back side wall 20, and the rib installation surface 24 that is the opposite abdominal side cooling surface is provided on the rib installation surface 24. Cooling ribs 26 a and 26 b that are integral with the side wall 21 are provided. As for the cooling passages 7b, 7d, and 7e, cooling ribs for promoting heat transfer are provided on the abdomen cooling surface of the blade abdominal side wall 21 and the back side cooling surface of the wing back side wall 20, respectively.

  FIG. 4 shows a cross section of the cooling passage 7c along the line BB in FIG. FIG. 4 is a longitudinal sectional view of the cooling passage. Here, the blade back side wall 20 side will be described as an example. The cooling ribs that are integrally installed on the rib installation surface 23 that is the back cooling surface of the blade back side wall 20 extend from the vicinity of the middle between the opposing partition walls 6b and 6c to the one partition wall 6c side while being on the partition wall 6c side. A cooling rib 25a positioned on the downstream side in the flow direction of the cooling medium relative to the other end, and a partition wall extending from the vicinity of the middle between the opposite partition walls 6b and 6c to the other partition wall 6b side A plurality of cooling ribs 25b are alternately arranged at the end on the 6b side on the downstream side in the flow direction of the cooling medium with respect to the other end. In other words, the cooling ribs are arranged in a zigzag pattern in an inverted C shape alternately with respect to the cooling air flow direction from the substantially center of the rib installation surface 23 which is the back side cooling surface. The planar shape of these cooling passages is substantially rectangular, trapezoidal, rhombus and the like.

  In the cooling ribs 25a and 25b of the present embodiment, the cross-sectional shape of the cooling rib at the boundary with the partition walls 6c and 6b is a straight line whose front surface is perpendicular to the wall surface with respect to the cooling passage formation direction. The position reaching the rib installation surface 23 from the highest position to the rear, that is, the upper surface and the rear surface of the cooling rib are streamlined. Here, the streamline shape means that the cross-sectional shape of the rib cut by a plane perpendicular to the cooling air flow direction has a continuous inclination by a curve defined by a plurality of straight lines and / or functions. The front surface of the cooling rib is a portion mainly having an effect of promoting the formation of the flow 56, and the rear surface is a portion downstream of the cooling medium in the flow direction and hidden behind the flow of the cooling medium. is there. The top surface is a surface that includes a surface that is parallel or nearly parallel to the rib installation surface and connects the front surface and the back surface. Some cooling ribs do not have an upper surface.

  FIG. 4 shows the cooling passage 7c in which the cooling medium flow is an upward flow in FIG. For example, even in the case of a cooling passage in which the flow of the cooling medium is a downward flow, such as 7b and 7d, the cooling ribs are alternately arranged in a reverse letter C shape with respect to the cooling air flow direction, and the upper and rear surfaces of the cooling ribs The streamline shape is the same as in the cooling passage 7c.

  Next, the flow of cooling air around the cooling ribs 25a and 25b in the cooling passage 7c will be described with reference to FIG. In FIG. 1, illustration of the rib installation surface 24 that is a wall surface facing the rib installation surface 23 having the cooling ribs 25a and 25b, the cooling ribs 26a and 26b, and the partition wall 6c existing therein is omitted. Yes.

  In the cooling passage 7c, there are two pairs of secondary flows 52 and 53 in a direction away from the cooling surface in the vicinity of the partition walls 6b and 6c corresponding to the flow path side walls and toward the rib installation surface in the vicinity of the flow path center 51. It is formed. Further, in the vicinity of the cooling ribs 25 a and 25 b that promote heat transfer, from the meandering flow 55 that crawls the rib opening portion 80 that is a portion of the rib installation surface 23 where the cooling rib is not installed, and the meandering flow 55. A flow 56 is formed which branches and flows along the rib toward the partition walls 6b and 6c.

  When the cooling air flows in the vicinity of the flow path center 51, it does not contribute much to the cooling of the member. On the other hand, the cooling medium flowing in the vicinity of the rib installation surface 23 that is the back side cooling surface and the rib installation surface 24 that is the abdominal side cooling surface exchanges heat with the high temperature member to cool the member. Therefore, the temperature of the cooling medium in the vicinity of the flow path center 51 is relatively lower than that of the cooling medium outside the cooling passage 7c.

  In the present embodiment, cooling ribs 25a and 25b that promote heat transfer are arranged so as to cause a flow 56 from the center of the rib installation surface 23 toward the boundary with the partition walls 6c and 6b that are the side ends of the rib installation surface 23. . Further, cooling ribs that cause a similar flow are also arranged on the rib installation surface 24 that is the ventral cooling surface. As a result, formation of two pairs of secondary flows 52 and 53 is promoted. By the two pairs of secondary flows 52 and 53, a low-temperature cooling medium near the flow path center 51 and a high-temperature cooling medium near the rib installation surfaces 23 and 24 can be circulated. Therefore, it is possible to supply a cooling medium having a lower temperature to the vicinity of the rib installation surface 23 that is a back side cooling surface that requires a low-temperature cooling medium and the vicinity of the rib installation surface 24 that is a ventral side cooling surface.

  For the above reason, the meandering flow 55 has a turbulent flow structure in which the cold air 15b having a low temperature at the flow path center 51 is provided by the secondary flow 52. Therefore, the cooling effect on the rib installation surface 23 in particular, the center portion of the flow path, and further the flow path center side portion of the cooling ribs 25a and 25b is enhanced.

  On the other hand, a separation circulation region 57 that hardly contributes to heat transfer may be formed behind the cooling ribs 25a and 25b in the flow direction of the cooling medium. When the fluid passes over the rib, the flow is easily separated from the rib, and the fluid does not easily reach a portion that is shaded by the fluid flow, that is, a region behind the rib. This area is called a peeling circulation area. In the separation circulation region, there is almost no inflow of fluid from outside the region, and most of the fluid in the region continues to circulate within the region. In addition, when a fluid peels from a rib installation surface, a big pressure loss generate | occur | produces.

  In this embodiment, the upper surface and the rear surface of the cooling rib are streamlined. For this reason, the flow 58 including the part of the flow 56 that is guided to the ribs and goes to the partition plate and exceeds the cooling rib flows to the rear of the rib over the rib upper surface and the rear surface. Thereby, peeling of the cooling medium on the rib can be suppressed, and the pressure circulation loss 57 can be reduced at the same time as the pressure loss of the cooling air is reduced.

  In the separation circulation region 57, air heated by removing heat from the member circulates. Therefore, reducing this region greatly contributes to increasing the cooling efficiency of the member. Further, in the portion where the circulation region is reduced as compared with the conventional case, the air 15b having a low temperature in the flow path center 51 along the secondary flow 52 is supplied as a meandering flow 55 and a flow 56 toward the partition plate to cool the member. To do.

  In other words, in this embodiment, the separation circulation region 57 is reduced by smoothing the upper and rear surfaces of the cooling ribs 25a and 25b, and the low-temperature air in the flow path center 51 is guided to the meandering flow 55 by the secondary flow 52. Three effects of reducing the pressure loss of the cooling medium due to peeling can be obtained. By these synergistic effects, the gas turbine blade of the present embodiment can be efficiently cooled.

In the present embodiment, a part of the description of the cooling ribs 26a and 26b is omitted, but the cooling ribs 26a and 26b are the heat transfer promotion ribs 25a and 25b installed on the rib installation surface 23 which is the back cooling surface. Similarly, it goes without saying that it is installed on the rib installation surface 24 which is the ventral cooling surface and has the same effect.

  In the present embodiment, an example in which the shape of the upper surface and the rear surface of the rib is a streamline shape is shown in order to suppress separation of the cooling medium on the rib, but the effect obtained in this embodiment is limited to the streamline shape. It is not what was done. Compared with a conventional rectangular parallelepiped rib or the like, the same kind of effect can be obtained as long as the cooling medium can extend the distance over the upper surface and the rear surface of the rib, or can reduce the degree of peeling of the cooling medium. That is, any shape that promotes the cooling medium flowing on the surface of the cooling rib to flow over the rib surface to the rib installation surface may be used. Examples of the shape conforming to the streamline shape include those obtained by combining a plurality of strip-shaped planes along the streamline shape.

  In FIG. 5, the tendency of the heat transfer characteristic in a present Example is shown. In FIG. 5, the vertical axis represents the ratio between the dimensionless average Nusselt number indicating the heat flow state and the Nusselt number of the rib installation surface using the ribs of FIGS. 9 and 10 used as a comparative example. Is a dimensionless Reynolds number indicating the flow of cooling air. In this figure, the larger the value on the vertical axis, the better the cooling performance. As shown in the figure, the heat transfer performance of the structure of this example tends to be higher than the structure of the comparative example.

  Next, a second embodiment of the present invention will be described with reference to FIGS. 6 and 7, the same symbols are assigned to portions common to FIGS. 3 and 4, and the description thereof is omitted.

  FIG. 6 is a longitudinal sectional view of the cooling passage. Here, the blade back side wall 20 side will be described as an example. The heat transfer promotion ribs 30a and 30b of the rib installation surface 23 which is the back cooling surface are alternately left and right from the vicinity of the equidistant line from the boundary with the partition walls 6b and 6c which are the rib non-installation surfaces on the rib installation surface 23. And at different angles to the cooling air flow direction. In other words, the cooling ribs 30a and 30b that promote turbulent flow are arranged in an inverted cross-section and staggered with respect to the flow. In conventional turbulent flow promoting ribs, the cross-section of the cooling rib is often the same in any cross-section in the cooling air flow direction. However, in the cooling rib 30a in the present embodiment, the back surface 70b of the rib 30a gradually increases in length in the flow direction of the rib from the center of the flow path toward the partition wall 6c that is the side wall, and in the cooling air flow direction. The height of the rib decreases as it goes, and the rib height is zero in front of the rear partition wall 6b.

  FIG. 7 shows the flow around the ribs in the cooling passage 7c where the cooling ribs are arranged. In the present embodiment, the cross section of the rib is changed in a direction perpendicular to the cooling air flow, and a slope is formed on the rib back surface 70b on the downstream side of the rib. This accelerates the reattachment of the flow 58 that is a part of the flow 56 toward the partition walls 6b and 6c along the ribs to the heat transfer surface beyond the ribs. That is, the distance that the cooling air is peeled from the rib can be shortened. Therefore, the circulation area 57 can be reduced.

  In other words, in this embodiment, the back surface of the cooling ribs 30a and 30b has a shape in which the cooling air that has passed through the upper surface of the rib is easily reattached to the rib installation surface 23, and the separation circulation region is obtained by reducing the distance until reattachment The effect of 57 reduction is obtained. Further, the effect of guiding the low-temperature air in the flow path center 51 to the meandering flow 55 by the secondary flow 52 can also be obtained. Due to these synergistic effects, the gas turbine blade of this embodiment can be cooled more efficiently than the conventional one as in the first embodiment.

  The characteristic configuration of the present embodiment is that the rear surface of the rib is an inclined surface, whereby the reattachment of the separated cooling medium to the rib is promoted, and the separation circulation region 57 can be reduced. Therefore, the cooling rib having a shape that promotes the reattachment of the cooling medium may not be the one shown in the present embodiment.

  FIG. 8 shows a third embodiment of the present invention. FIG. 8 shows the flow around the ribs in the cooling passage 7c where the cooling promotion rib structure is arranged, as in FIGS. Here, the blade back side wall 20 side will be described as an example. The cooling ribs 31a and 31b of the rib installation surface 23 are alternately arranged on the left and right from the center of the rib installation surface 23 and at different angles with respect to the cooling air flow direction. That is, the cooling ribs 31a and 31b are arranged in an inverted C shape and alternately with respect to the flow. However, in the present embodiment, the cooling rib 31a has a streamlined front surface in the cooling passage formation direction, and the rib back surface 71b of the rib 31a moves from the center of the flow path toward the partition wall 6c as a side wall. The length in the flow direction gradually increases, the rib height decreases as it goes in the cooling air flow direction, and the rib height is zero before the rear rib. That is, it can be said that the cooling rib of the present embodiment is obtained by applying the shape of the rib of the second embodiment to the streamlined rib of the first embodiment.

  By forming the cooling promotion rib in this way, the effect of Example 1, that is, the effect of reducing the circulation region by suppressing the separation on the rib upper surface, the effect of reducing the pressure loss, and the effect of Example 2, That is, it is possible to synergize with the effect of shortening the circulation region by speeding the reattachment. This, combined with the configuration in which the low-temperature air in the center 51 of the flow path is guided to the meandering flow 55 by the secondary flow 52, can further reduce or eliminate the circulation region and obtain a high heat transfer effect.

  In the present embodiment, the cooling rib is formed with a gentle slope on the back surface while the cross section of the rib cut by a plane parallel to the partition plate surface is streamlined. However, any other shape may be used as long as the cooling medium is prevented from being peeled off by the cooling ribs and the reattachment of the cooling medium peeled off by the ribs is promoted. This is because the cooling rib having such a shape can obtain the same type of effect as the cooling rib of the present embodiment.

  Each embodiment describes the basic configuration of the present invention, but it goes without saying that various embodiments, modifications, and application examples can be considered.

  As mentioned above, although the Example of this invention was described, the shape of a rib is not limited to one with respect to each rib, Even if it has multiple, there exists the same effect and it does not specifically limit. In addition, about the installation position of the cooling rib, it was installed so that it might extend toward the side edge from the center vicinity of a rib installation surface. However, as long as the meandering flow is formed on the rib installation surface, it may be longer or shorter than that of the present embodiment in the direction perpendicular to the flow of the cooling medium.

  Further, it is desirable in terms of strength that the temperature of the gas turbine blade is as uniform as possible. On the other hand, the external thermal conditions of the turbine blade are different around the blade. Therefore, in order to cool the blade to a uniform temperature, it is appropriate to make the cooling rib structure on the back side, the ventral side, and the partition wall of the blade match the external thermal conditions. Specifically, the structure, shape, and arrangement specifications of the cooling rib shown in each of the above-described embodiments or considered elsewhere are adopted according to the requirements of each cooling surface.

  In the above description, the gas turbine has been described as an example. However, as described above, the present invention is not limited to the gas turbine, and can be applied to any member having a cooling passage inside. In the embodiments, a return flow type structure having two internal structures is shown as an example. However, the application of the present invention is not limited to the number of cooling passages. Further, although the cooling medium has been described as air, other medium such as steam may be used. The gas turbine blade adopting the structure of the present invention has a simple configuration and can be manufactured by the current precision casting method.

  DESCRIPTION OF SYMBOLS 1 ... Gas turbine blade, 2 ... Shank part, 3 ... Blade part, 4, 5 ... Passage, 6 ... Member, 6a, 6b, 6c, 6d, 6e ... Partition wall, 7a, 7b, 7c, 7d, 7e, 7f ... Cooling passages, 8a, 8b ... curved tip, 9a, 9b ... lower curved part, 10 ... tip wall, 11 ... blow hole, 12 ... blade trailing edge, 13 ... blown part, 14 ... supply part, 15 ... cooling air 15b ... air, 20 ... blade back side wall, 21 ... blade ventral side wall, 23,24 ... rib installation surface, 25a, 25b, 26a, 26b, 30a, 30b, 31a, 32b, 60a, 60b ... rib, 51 ... Center of flow path, 52, 53 ... Secondary flow, 55 ... Meandering flow, 56, 58 ... Flow, 57 ... Circulation region, 66 ... Corner, 70a, 71a ... Front of rib, 70b, 71b ... Back of rib, 80 ... Rib opening.

Claims (1)

In a member having a cooling passage inside, provided with a cooling passage having a wall surface provided with cooling ribs inside, for cooling by circulating a cooling medium on the wall surface,
The cooling rib is disposed so that a part of the cooling medium flowing near the center of the wall surface of the cooling flow path flows to both ends of the wall surface, and the cooling medium flowing on the surface of the cooling rib. Some are installed on the cooling rib surface to flow to the wall surface,
The rib front surface of the cooling rib has a streamline shape in the cooling passage forming direction cross section,
The rib back surface of the cooling rib has a longer length in the flow direction of the cooling rib as it goes from the center of the wall surface to both ends of the wall surface, and the height of the cooling rib becomes lower as it goes in the direction of cooling air flow, A member having a cooling passage inside, wherein the cooling rib height becomes zero before the rear rib.

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