阅读说明：本技术 一种具有收缩型端壁气膜孔冷却结构的涡轮转子叶片 (Turbine rotor blade with shrinkage type end wall film hole cooling structure ) 是由 张魏 张鹏 刘松 王鹏飞 郭文 李广超 查海勇 赵长宇 何洪斌 于 2021-09-18 设计创作，主要内容包括：一种具有收缩型端壁气膜孔冷却结构的涡轮转子叶片,属于燃气涡轮发动机技术领域,涡轮转子叶片包括叶身、端壁、中间叶根、榫头、供气通道和多个第一气膜孔；叶身设置为流线型,包括前缘、尾缘、吸力面、压力面、尾缘劈缝和蜿蜒通道；蜿蜒通道设置在叶身内部引导冷气沿不同的方向流动,叶身与端壁连接,第一气膜孔设置在端壁、前缘和压力面上；供气通道设置在榫头和中间叶根的内部,供气通道与蜿蜒通道相通；第二气膜孔设置在端壁上,端壁气膜孔与供气通道相通,第二气膜孔的入口面积大于出口面积,呈逐渐收缩状。第二气膜孔布置在端壁上,既保证了叶片原来的结构强度,又能对叶片尾缘进行冷却。(A turbine rotor blade with a contraction type end wall air film hole cooling structure belongs to the technical field of gas turbine engines, and comprises a blade body, an end wall, a middle blade root, a tenon, an air supply channel and a plurality of first air film holes; the blade body is streamlined and comprises a front edge, a tail edge, a suction surface, a pressure surface, a tail edge split seam and a serpentine channel; the serpentine channel is arranged in the blade body to guide cold air to flow in different directions, the blade body is connected with the end wall, and the first air film hole is arranged on the end wall, the front edge and the pressure surface; the air supply channel is arranged inside the tenon and the middle blade root and is communicated with the winding channel; the second air film hole is arranged on the end wall, the air film hole of the end wall is communicated with the air supply channel, and the area of the inlet of the second air film hole is larger than that of the outlet and gradually shrinks. The second air film holes are arranged on the end wall, so that the original structural strength of the blade is guaranteed, and the tail edge of the blade can be cooled.)

1. A turbine rotor blade having a convergent endwall film hole cooling configuration, said turbine rotor blade comprising a body, an endwall, a midblade root, a dovetail, a supply air passage, and a plurality of first film holes;

the blade body is streamlined and comprises a front edge, a tail edge, a suction surface, a pressure surface, a tail edge split seam and a serpentine channel; the suction surface and the pressure surface extend from the front edge to the tail edge, the suction surface is of a convex type, and the pressure surface is of a concave type; the serpentine channel is arranged inside the blade body and used for guiding cold air to flow in different directions;

the blade body is connected with the end wall, the air supply channel is arranged inside the tenon and the middle blade root, the air supply channel is communicated with the serpentine channel, a second air film hole is formed in the end wall and is communicated with the air supply channel, the inlet area of the second air film hole is larger than the outlet area, and the second air film hole is gradually contracted and used for cooling the blade body of the turbine rotor blade;

first film holes are provided in the leading edge, pressure face and endwall, the first film holes provided in the leading edge and pressure face of the airfoil communicating with the serpentine passageway for cooling the airfoil; a first film hole provided in the end wall communicates with the gas supply passage for cooling the end wall.

2. The turbine rotor blade with a converging endwall film hole cooling configuration of claim 1, wherein said second film holes are provided in the endwall adjacent the trailing edge segment on the suction side and in a minimum of one row.

3. The turbine rotor blade with converging endwall film hole cooling of claim 1, wherein the second film hole is tapered converging or round slot converging.

4. The turbine rotor blade with a converging endwall film hole cooling configuration of claim 3, wherein the second film hole has a ratio of the inlet area to the outlet area of the second film hole converging, decreasing from the leading edge to the trailing edge; the included angle between the second film hole and the end wall gradually increases from the leading edge to the trailing edge.

5. The turbine rotor blade with convergent endwall film hole cooling features of claim 4 wherein the parameters of said second film hole are first modified by Newton's second law

f₂＝m₂a₂＝ρ₂V₂a₂ (1)

In the formula (f)₂The aerodynamic force per unit area of the cold air at the outlet of the second air film hole; m is₂Cold air mass per unit area; a is₂The cold air acceleration of the outlet of the second air film hole; determining the momentum of the cold air sprayed out of the second air film hole as

Then using the continuity equation from the second gas film hole inlet to the outlet

ρ_iV_iA_i＝C (3)

In the formula, ρ_iThe density of the cold air at the inlet or the outlet of the second air film hole; v_iThe speed of the cold air at the inlet or the outlet of the second air film hole; a. the_iThe area of the inlet or the outlet of the second gas film hole; c is a constant; i is 1 and 2 are parameters of an inlet or an outlet of the second gas film hole; a second film hole shrinkage ratio of

Inlet and outlet areas of

The aperture of the inlet and the outlet is

In the formula (d)_iThe aperture of the inlet and the outlet of the second air film hole;

the hole interval is

l＝5d₂ (7)

The distance from the center of the second air film hole to the blade root is

k＝2d₂ (8)

The number of the second air film holes is

In the formula, y is the chord length of the blade;

the blowing ratio is

In the formula, ρ_cThe air-cooling density in the second air film hole 10; rho_mThe density of the fuel gas in the blade grid channel;

u_cthe cold air speed in the second air film hole 10; u. of_mThe velocity of the gas in the blade grid channel;

at a temperature ratio of

In the formula, T_mThe temperature of the fuel gas in the blade grid channel; t is_cIs the cold gas temperature in the end wall film hole 10.

6. The turbine rotor blade with the converging endwall film hole cooling structure of claim 1, wherein the serpentine channel is longitudinally arranged along the blade height and comprises a plurality of jet impingement holes, a multi-pass serpentine ribbed channel, and a plurality of trailing edge region turbulator posts.

Technical Field

The invention relates to the technical field of gas turbine engines, in particular to a turbine rotor blade with a contraction type end wall air film hole cooling structure.

Background

Gas turbine engines convert thermal energy into mechanical energy through the rotation of turbine rotor blades, which operate in high temperature, high pressure, high rotational speed environments, which place very high demands on their structural strength and cooling performance. Turbine rotor blades typically employ a combination of internal serpentine path cooling and external film cooling. However, when the air film sprayed from the leading edge region flows to the trailing edge region, the air film drifts to the blade top under the vortex action of the cascade channel, so that the cooling effect of the blade root region of the suction surface of the trailing edge is very poor, cracks can gradually appear in the operation process of the gas turbine engine, the structural strength of the blade root region of the suction surface of the trailing edge is gradually reduced, and the service life of a turbine rotor blade is shortened. Because the trailing edge of the turbine rotor blade is thin, the film holes are difficult to arrange in the blade body area for cooling, and even if the film holes can be arranged, the strength of the trailing edge of the blade can be obviously reduced. In the prior art, for example, a turbine air cooling blade disclosed in patent No. CN201210578874.6, an end wall film hole arrangement structure disclosed in patent No. CN202010611065.5, a turbine blade structure with irregular micro-group film cooling holes disclosed in patent No. CN202011513089.3, a manufacturing method thereof, a gas turbine, a cooled blade for a gas turbine disclosed in patent No. 201310273761.X, a concave-film hole cooling structure for a cooled blade and a film cooling device disclosed in patent No. CN201710571467.5, mainly a film hole is longitudinally formed on a suction surface of a turbine rotor blade, and even if the end wall is provided with a film hole, the film hole is only used for cooling the end wall; the air film holes are arranged near the tail edge of the suction surface, so that the strength of the turbine rotor blade is reduced, the air film coverage of the blade root area of the suction surface at the tail edge is poor, and the cooling effect is poor. Therefore, how to improve the cooling effect of the turbine rotor blade without affecting the structural strength of the turbine rotor blade is an urgent technical problem to be solved.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a turbine rotor blade with a contraction type end wall air film hole cooling structure, which comprises a blade body, an end wall, a middle blade root, a tenon, an air supply channel and a plurality of first air film holes;

the blade body is streamlined and comprises a front edge, a tail edge, a suction surface, a pressure surface, a tail edge split seam and a serpentine channel; the suction surface and the pressure surface extend from the front edge to the tail edge, the suction surface is of a convex type, and the pressure surface is of a concave type; the serpentine channel is arranged inside the blade body and used for guiding cold air to flow in different directions;

the blade body is connected with the end wall, the air supply channel is arranged inside the tenon and the middle blade root, the air supply channel is communicated with the serpentine channel, a second air film hole is formed in the end wall and is communicated with the air supply channel, the inlet area of the second air film hole is larger than the outlet area, and the second air film hole is gradually contracted and used for cooling the blade body of the turbine rotor blade;

first film holes are provided in the leading edge, pressure face and endwall, the first film holes provided in the leading edge and pressure face of the airfoil communicating with the serpentine passageway for cooling the airfoil; a first film hole provided in the end wall communicates with the gas supply passage for cooling the end wall.

The second air film holes are formed in the end wall, close to the tail edge section, of one side of the suction surface, and at least one row of the second air film holes is formed.

The second air film hole is in conical shrinkage or circular seam-changing shrinkage.

The contraction ratio of the inlet area to the outlet area of the second air film hole is the contraction ratio of the second air film hole and gradually decreases from the front edge to the tail edge; the included angle between the second film hole and the end wall gradually increases from the leading edge to the trailing edge.

The parameters of the second gas film hole firstly pass through Newton's second law

f₂＝m₂a₂＝ρ₂V₂a₂ (1)

In the formula (f)₂The aerodynamic force per unit area of the cold air at the outlet of the second air film hole; m is₂Cold air mass per unit area; a is₂The cold air acceleration of the outlet of the second air film hole; determining the momentum of the cold air sprayed out of the second air film hole as

Then using the continuity equation from the second gas film hole inlet to the outlet

ρ_iV_iA_i＝C (3)

In the formula, ρ_iThe density of the cold air at the inlet or the outlet of the second air film hole; v_iThe speed of the cold air at the inlet or the outlet of the second air film hole; a. the_iThe area of the inlet or the outlet of the second gas film hole; c is a constant; i is 1 and 2 are parameters of an inlet or an outlet of the second gas film hole; a second film hole shrinkage ratio of

Inlet and outlet areas of

The aperture of the inlet and the outlet is

In the formula (d)_iThe aperture of the inlet and the outlet of the second air film hole;

the hole interval is

l＝5d₂ (7)

The distance from the center of the second air film hole to the blade root is

k＝2d₂ (8)

The number of the second air film holes is

In the formula, y is the chord length of the blade;

the blowing ratio is

In the formula, ρ_cThe air-cooling density in the second air film hole 10; rho_mThe density of the fuel gas in the blade grid channel;

u_cthe cold air speed in the second air film hole 10; u. of_mThe velocity of the gas in the blade grid channel;

at a temperature ratio of

In the formula, T_mThe temperature of the fuel gas in the blade grid channel; t is_cIs the cold air temperature in the second film hole 10.

The serpentine channel is longitudinally arranged along the blade height and includes a plurality of jet impingement holes, a multi-pass serpentine ribbed channel, and a plurality of trailing edge region turbulator posts.

The invention provides a turbine rotor blade, wherein a second air film hole is arranged on the end wall of a suction surface, and cold air sprayed out from the second air film hole is not used for cooling the end wall but used for cooling the tail edge area of the suction surface of the blade. And cold air sprayed out of the second air film hole is sucked to flow to the suction surface of the tail edge of the blade by using the grid channel vortex to cool the part, so that the technical problem that the suction surface of the tail edge of the blade is difficult to cool is solved. The conventional design idea is to spray cool air to cool the blade through the first film holes on the surface of the blade, and the second film holes are not arranged on the end wall. The second air film hole is formed in the end wall of the blade, and the design can effectively solve the problem of strength reduction of the blade caused by hole opening of the blade body. Meanwhile, the cold air sprayed out of the row of second air film holes by using the cascade channel vortex can be just sucked to the trailing edge of the suction surface of the blade body. In the prior cooling design, the cascade channel vortexes are disadvantageous, and the cooling structure design of the invention just utilizes the cascade channel vortexes.

The existing first air film hole design is to cool the wall surface where the first air film hole is located by utilizing the cold air sprayed from the first air film hole, so that the included angle between the first air film hole and the wall surface is as small as possible on the premise of meeting the technological requirements, and the outlet of the first air film hole is expanded to reduce the injection momentum of the cold air at the outlet of the first air film hole, so that the distance of the cold air separated from the wall surface is as short as possible, and the purpose of improving the cooling effect is achieved. The invention utilizes the cold air sprayed by the second air film hole to cool the blade, namely the cooled wall surface and the wall surface where the second air film hole is positioned are two wall surfaces which are basically vertical. This results in a fundamental change in the arrangement of the second film holes. In order to make the cold air sprayed from the second film hole flow to the blades more easily, the included angle between the second film hole and the end wall is larger.

The second film holes arranged on the end wall gradually shrink from the inlet to the outlet, namely the outlet area of the second film holes is smaller than the inlet area of the second film holes. The design of the first air film hole in the past is that the air film hole gradually expands from the inlet to the outlet, and the momentum of cold air at the outlet of the first air film hole is reduced, so that the cold air is better attached to the wall surface where the first air film hole is located. The second air film hole in the invention can be shrunk according to a conical shape or a round seam changing shape. The conical contraction is easy to process, and the circular seam-changing contraction can form better air film cooling performance. And the included angle between the second film hole and the end wall is relatively large, so that the cold air sprayed out of the second film hole has larger spraying momentum and is easier to separate from the end wall and flow to the tail edge of the blade. The second air film hole structure is completely different from the design idea of the existing first air film hole.

And projecting the tip region of the trailing edge of the cooling blade by using a second film hole close to the leading edge. When the second film hole contraction ratio is set, the closer to the front edge, the larger the contraction ratio of the second film hole is, the larger the cold air has the jet momentum, and the cold air can reach the top end of the blade more easily. Meanwhile, when cold air flows from the second air film hole to the top end of the blade, the cold air can flow to the trailing edge, and therefore the cold air can be guaranteed not to flow out of the trailing edge of the blade when flowing to the top end of the blade. The contraction ratio of the second film hole close to the trailing edge is relatively smaller, the spraying momentum of the cold air is relatively smaller, and the sprayed cold air is mainly used for cooling the area of the trailing edge of the blade close to the blade root. The second film hole is designed according to the non-uniform contraction ratio, so that the aim of uniformly cooling the tail edge of the blade is fulfilled.

Compared with the prior art, the turbine rotor blade with the shrinkage type end wall film hole cooling structure has the beneficial effects that:

on the basis of a common turbine rotor blade structure, the second air film hole is arranged on the end wall of one side of the suction surface close to the tail edge section, and the thrown cold air can be just turned from the bottom to the top by using the cascade channel vortex, so that the coverage range of the air film of the tail edge suction surface is increased. The original structural strength of the blade is guaranteed, and the suction surface of the tail edge of the blade can be cooled. The cold air led out from the internal channel of the middle blade root has lower temperature and covers the area with weak air film on the suction surface of the trailing edge, so that the cooling effect of the area is better. The second air film hole is of a contraction structure, so that cold air in the second air film hole can obtain larger jet momentum, the cold air can be separated from the end wall more easily, and the cold air is thrown to the surface of the blade under the vortex action of the blade cascade channel. The contraction ratio of the row of second air film holes arranged on the end wall is changed, the closer to the front edge, the larger the contraction ratio of the second air film holes is, and the design can ensure that cold air is sucked to the blade top by the main flow before flowing out of the tail edge of the suction surface; the shrinkage of the second air film hole close to the tail edge is small, and the sprayed cold air mainly forms an air film near the root of the tail edge, so that the full air film covering near the tail edge of the suction surface is realized. Therefore, the cooling effect of the trailing edge of the blade is improved by 20-35% under the condition of not changing the amount of cold air.

Drawings

FIG. 1 is a schematic view of a turbine rotor blade configuration provided by the present invention;

FIG. 2 is a diagram of a second gas film hole location provided by the present invention;

FIG. 3 is a diagram of a second gas film hole provided by the present invention;

FIG. 4 is a schematic view of a cold air flow line of the second film hole for spraying cold air on the blade surface;

FIG. 5 is a schematic illustration of cascade channel vortices provided by the present invention;

FIG. 6 is a schematic illustration of an internal structure of a turbine rotor blade body provided by the present invention.

Wherein the content of the first and second substances,

1. the blade comprises a tenon, 2 parts of a middle blade root, 3 parts of an end wall, 4 parts of a blade body, 5 parts of a first air film hole, 6 parts of a pressure surface, 7 parts of a front edge, 8 parts of a suction surface, 9 parts of a tail edge, 10 parts of a second air film hole, 11 parts of a blade chord, 12 parts of a blade root, 13 parts of a blade top, 14 parts of a tail edge split joint, 15 parts of a turbulence column, 17 parts of an impact hole, 18 parts of a rib, 19 parts of a serpentine channel, 20 parts of a blade profile, 22 parts of an inlet, 23 parts of an outlet, 24 parts of an axis, 25 parts of a cold air flow line and 26 parts of a blade grid channel vortex.

Detailed Description

In order to solve the problems of the prior art, as shown in fig. 1 to 6, the present invention provides a turbine rotor blade having a contraction-type end wall film hole cooling structure, which includes a blade body 4, an end wall 3, an intermediate blade root 2, a rabbet 1, a gas supply passage and a plurality of first film holes 5; the function of the rabbet 1 is to connect the blade and the disk and to transfer the work on the blade to the disk. The middle blade root 2 can obviously reduce the temperature of the tenon 1, and effectively reduces the heat transfer quantity of the blade to the wheel disc.

The blade body 4 is provided with a streamline shape and comprises a front edge 7, a tail edge 9, a suction surface 8, a pressure surface 6, a tail edge cleft 14 and a serpentine channel 19; the suction surface 8 and the pressure surface 6 extend from the front edge 7 to the tail edge 9, the suction surface 8 is of an external convex type, and the pressure surface 6 is of an internal concave type; the serpentine channel 19 is arranged inside the blade body 4 to guide the cold air to flow in different directions;

blade 4 is connected with end wall 3, the air feed passageway sets up in tenon 1 and the inside of middle blade root 2, the air feed passageway communicates with each other with sinuous passageway 19, be provided with second air film hole 10 on the end wall 3, second air film hole 10 communicates with each other with the air feed passageway, the air conditioning in the air feed passageway can directly be discharged from second air film hole 10, the entry area in second air film hole 10 is greater than the exit area, be the form of contracting gradually, make the air conditioning of end wall air film hole 10 spun have a bigger injection momentum, break away from end wall 3 more easily and flow to blade trailing edge 9, a blade 4 for cooling turbine rotor blade.

The first film holes 5 are arranged on the leading edge 7, the pressure surface 6 and the end wall 3, the first film holes 5 arranged on the leading edge 7 and the pressure surface 6 of the blade body are communicated with the serpentine channel 19, and can discharge cold air for cooling the blade body 4; a first film hole 5 provided in the end wall 3 communicates with the air supply channel and enables discharge of cold air for cooling the end wall 3.

The second film holes 10 are arranged in the end wall 3 on the suction side 8 side near the section of the trailing edge 9 in a row at a minimum. The second gas film hole 10 is tapered or round slit-changed. The second air film hole 10 is arranged on the end wall 3 close to the tail edge 9 section of the root of the suction surface 8, the cold air is led out from the air supply channel and is thrown to the position close to the surface of the blade body 4, and the thrown cold air is sucked to the blade root 12 of the tail edge 9 of the suction surface 8 under the action of the cascade channel vortex 26. The area covered by the cold air is just located at the weak position of the previous air film cooling, and the temperature of the cold air sprayed out from the second air film hole 10 is lower, so that more heat can be taken away, and the cooling effect of the surface of the blade body 4 is better. Compared with the previous first air film holes 5, the second air film holes 10 arranged on the end wall 3 can better cover the root tail edge 9 section of the suction surface 8 of the blade body 4 by cold air sprayed out of the second air film holes 10 on the basis of not changing the strength of the blade. The invention breaks the convention, uses the cascade channel vortex 26 to suck the cold air sprayed from the end wall 3 to the tail edge 9 area of the suction surface 8 with poor cooling effect, and improves the air film cooling efficiency and obtains wider air film cooling range.

The ratio of the area of the inlet 22 to the area of the outlet 23 of the second film hole 10 (the contraction ratio of the second film hole 10) decreases from the leading edge 7 to the trailing edge 9, and the angle between the second film hole 10 and the end wall 3 increases from the leading edge 7 to the trailing edge 9. The second film holes 10 provided in the end wall 3 converge from the inlet 22 to the outlet 23 and have a higher contraction ratio closer to the leading edge 7. The cold air enters from the inlet 22 with the larger area of the second air film hole 10, is accelerated to obtain larger momentum, and then is sprayed out through the outlet 23 with the smaller area, and the included angle between the end wall 3 surface and the second air film hole 10 is larger, so that the cold air can be more easily separated from the end wall 3 and flows to the tail edge 9. Meanwhile, the temperature of cold air sprayed by the second air film holes 10 is lower than that of cold air in the blade body 4, and the temperature of an air film formed on the surface of the blade body 4 is relatively lower, so that the cooling efficiency of the surface of the blade is obviously improved.

The serpentine channel 19 is arranged longitudinally along the blade height and comprises a plurality of jet impingement holes 17, a multi-pass serpentine ribbed 18 channel and a plurality of wake 9 area turbulence columns 15. The cooling air flows into the blade through the bottom end of the tenon 1, through the tenon 1, the intermediate blade root 2 and the end wall 3 and thereafter into the meandering channel 19. The serpentine channel 19 guides the cold air to flow in different directions. A flow of cold air reaches the front end (close to the leading edge 7) of the blade body 4 through a winding channel 19 arranged longitudinally along the blade height, impacts the inner wall of the turbine rotor blade through a jet hole, and then flows out of the blade body 4 from a first film hole 5 to form film cooling on the surface of the blade. The other stream of cold air reaches the rear end of the blade body 4 (near the trailing edge 9) through a serpentine channel 19 arranged longitudinally along the blade height, and then flows out of the blade body 4 from the trailing edge slit 14 and the first film holes 5.

The principle according to which the second film holes 10 are provided is as shown in fig. 4 and 5, and the cascade passage vortices 26 are a pair of vortices which are formed when the main flow passes through the cascade passage and flows toward the suction surface 8 of the blade, and which can turn the cold air ejected from the second film holes 10 to a weak cooling place at the trailing edge 9 of the suction surface 8. The cold air ejected from the second film hole 10 flows to the blade trailing edge 9 and the blade top 13 to form a cold air film to cool the surface of the blade body 4. The cold air flow line 25 formed by the cold air sprayed from the second film holes 10 close to the front edge 7 flows along the direction of the end wall 3, and then is sucked to the surface of the blade body 4 by the main flow to flow along the direction of the blade height. The second film holes 10 near the trailing edge 9 spray cool air near the trailing edge 9 and the root 12 of the suction surface 8, and then flow out of the trailing edge 9 along the surface of the blade body 4 with the combustion gas. And a second air film hole 10 is formed in the end wall 3, and sprayed cold air covers the region of the tail edge 9 of the suction surface 8 of the blade, so that the air film is completely covered from the tail edge 9 of the suction surface 8, the blade root 12 to the blade top 13, and the cooling efficiency of the region of the tail edge 9 of the suction surface 8 is greatly improved.

The turbine rotor blade provided by the invention does not influence the structural strength of the blade, and can improve the cooling efficiency of the region of the tail edge 9 of the suction surface 8 of the turbine rotor blade. The cold air temperature sprayed out from the second air film holes 10 is lower than that of the inside of the blade body 4, and generates a larger temperature difference with the surface of the blade body 4, so that the cooling effect is better. The second air film holes 10 formed in the end wall 3 close to the tail edge 9 and the blade root 12 of the suction surface 8 are compared with the original first air film holes 5 of the suction surface 8, the row of second air film holes 10 formed in the end wall 3 are of a contraction type, the contraction mode is mainly conical contraction, the contraction ratio of the row of second air film holes 10 is changed, the injection momentum of each second air film hole 10 is different, the cold air is injected to the surface of the blade body 4 in a gradient distribution mode, and the cold air injected by the second air film holes 10 close to the front edge 7 is sucked to the blade top 13 through the action of the blade grid channel vortex 26, so that the performance and the range of cooling of the external air film of the suction surface 8 are greatly improved. According to the invention, under the conditions that the blade profile (blade profile 20) is not changed and the amount of cold air is increased, the cooling efficiency of the external air film is improved through the position and the structural arrangement of the second air film hole 10, so that the cooling condition of the poor cooling area at the rear half section of the root part of the suction surface 8 is obviously improved, and the comprehensive cold effect distribution of the whole suction surface 8 is more reasonable. In actual use, the size parameters of the second air film hole 10 have certain difference, but the structure is not changed.

Determining the parameters of the second gas film hole 10 by first Newton's second law

f₂＝m₂a₂＝ρ₂V₂a₂ (1)

In the formula (f)₂The aerodynamic force per unit area of the cold air at the outlet of the second air film hole; m is₂Cold air mass per unit area; a is₂The cold air acceleration of the outlet of the second air film hole; the momentum of the cold air sprayed from the second film hole 10 is determined as

The continuity equation is then used from the inlet 22 to the outlet 23 of the second gas film hole 10

ρ_iV_iA_i＝C (3)

In the formula, ρ_iIs a second gas filmThe density of the hole inlet or outlet cold gas; v_iThe speed of the cold air at the inlet or the outlet of the second air film hole; a. the_iThe area of the inlet or the outlet of the second gas film hole; c is a constant; i is 1 and 2 are parameters of an inlet or an outlet of the second gas film hole; a second gas film hole 10 shrinkage ratio of

The area of the inlet and the outlet 23 is

The aperture of the inlet and the outlet 23 is

In the formula (d)_iThe aperture of the inlet and the outlet of the second air film hole;

the hole interval is

l＝5d₂ (7)

The distance from the center of the outlet 23 of the second air film hole 10 to the blade root 12 is

k＝2d₂ (8)

The number of the second air film holes 10 is

In the formula, y is the chord length of the blade;

the blowing ratio is

In the formula, ρ_cThe air-cooling density in the second air film hole 10; rho_mThe density of the fuel gas in the blade grid channel;

u_cthe cold air speed in the second air film hole 10; u. of_mThe velocity of the gas in the blade grid channel;

at a temperature ratio of

In the formula, T_mThe temperature of the fuel gas in the blade grid channel; t is_cIs the cold air temperature in the second film hole 10.

Wherein the content of the first and second substances,

mean camber line: the curve passing through the center of all inscribed circles of the airfoil 20.

Blade chord 11: the mean camber line is connected with the intersection point of the front edge and the rear edge of the blade profile 20. The blade chord length is the length of the blade chord 11.

Leaf height: the height of the blade body 4.

Hole spacing: the distance between the centers of the outlets 23 of the adjacent second air film holes 10.

Second air film hole 10 shrinkage ratio: the ratio of the area of the inlet 22 of the second gas film hole 10 to the area of the outlet 23 of the second gas film hole 10.

Jet angle: the angle between the axis 24 of the second film hole 10 and the face of the end wall 3.

And (3) circular seam changing shrinkage: the circular transition from the inlet 22 of the second air film hole 10 to the narrow slit contraction mode of the outlet 23.

The blowing ratio is as follows: the ratio of the mass of cold air passing per unit time in the second film hole 10 to the mass of fuel gas passing per unit time in the cascade channel.

Temperature ratio: the ratio of the temperature of the combustion gas in the cascade channel to the temperature of the cold gas in the second film holes 10.

The first embodiment is as follows:

the end wall 3 sets up a row of second air film hole 10 quantity and is 9, can increase and decrease second air film hole 10 quantity according to the actual application condition. The blowing ratio is 2-4, the higher the blade body 4, the larger the blowing ratio is, and therefore the second film hole 10 jets the cold air farther from the end wall 3 surface, so that the cold air has enough momentum to flow to the blade tip. The temperature ratio is 1.5-2.5, the temperature of the cold air in the second air film hole 10 is kept unchanged, the temperature of the main flow is increased, and the heat exchange characteristic of the cold air projected to the tail edge 9 area of the suction surface 8 is enhanced. The aperture of the second air film holes 10 is 0.5-0.8mm, the distance between the second air film holes 10 is 2.5-4mm, the structure of each second air film hole 10 on the end wall 3 gradually shrinks from the area of the inlet 22 to the area of the outlet 23, the shrinking mode is conical shrinking or circular seam-changing shrinking, the shrinking ratio range is 1.39-2.22, and the specific size can be optimized according to air flow distribution. Compared with the common second air film hole in the prior art, the included angle between the second air film hole 10 and the end wall 3 surface is larger and ranges from 50 degrees to 80 degrees, so that cold air sprayed by the second air film hole 10 easily leaves the end wall 3 and flows to the tail edge 9 of the suction surface 8. The included angle between the second air film hole 10 close to the tail edge 9 and the end wall 3 surface is maximum 80 degrees, but the contraction ratio of the second air film hole 10 is minimum 1.39, and the sprayed cold air mainly covers the root area of the tail edge 9 of the suction surface 8 and is just at the position of air film cooling weakness, so that the structural advantage of the second air film hole 10 arranged in the invention is exerted. The angle between the second film holes 10 close to the leading edge 7 and the end wall 3 is 50 degrees at the minimum, but the contraction ratio of the second film holes 10 is 2.22 degrees at the maximum, the injected cold air has larger momentum, is less mixed with the main flow and can flow to a region far away from the end wall 3 along the blade height, and the action of the cascade channel vortex 26 enables the cold air to be sucked to the blade top 13 by the channel vortex, so that the coverage of the cold air on the suction surface 8 of the blade is greatly increased.

Example two:

when the chord length of the turbine rotor blade is 36mm and the blade height is 42mm, the second air film holes 10 arranged on the end wall 3 of the root part of the suction surface 8 have the blowing ratio of 2, the temperature ratio of 1.5, the hole diameter of the outlet 23 of 0.50mm, the hole pattern of a circle, the hole spacing of 2.50mm and the area of the outlet 23 of the second air film holes 10 of 0.7850mm²The distance from the center of the circle 23 of the outlet 23 of the second air film hole 10 to the blade root 12 is 1.0mm, and the number of the second air film holes 10 is 9. From the second air film hole 10 close to the tail edge 9, the contraction ratios of the second air film hole 10 are 1.39, 1.45, 1.56, 1.64, 1.75, 1.81, 1.89 and 1.95 in sequence, the jet angles are reduced in sequence, the reduction amplitude of the adjacent jet angles is 5-10 degrees, and the variation range is 50-80 degrees.

Example three:

the chord length of the turbine rotor blade is 44mm, the height of the turbine rotor blade is 53mm, the second air film hole 10 arranged on the end wall 3 of the root part of the suction surface 8,the blowing ratio is 3, the temperature ratio is 2, the aperture of the outlet 23 is 0.65mm, the hole pattern is circular, the hole distance is 3.25mm, the area of the outlet 23 of the second air film hole 10 is 1.3266mm²The distance from the center of the circle 23 of the outlet 23 of the second air film hole 10 to the blade root 12 is 1.3mm, and the number of the second air film holes 10 is 11. From the second film hole 10 close to the trailing edge 9, the contraction ratios of the second film hole 10 are 1.42, 1.49, 1.58, 1.67, 1.79, 1.88, 1.94 and 2.12 in sequence, the jet angles are reduced in sequence, the reduction amplitude of the adjacent jet angles is 5-10 degrees, and the variation range is 50-80 degrees.

Example four:

when the chord length of the turbine rotor blade is 48mm and the blade height is 66mm, the second air film holes 10 are arranged on the end wall 3 of the root part of the suction surface 8, the blowing ratio is 4, the temperature ratio is 2.5, the hole diameter of the outlet 23 is 0.70mm, the hole pattern is circular, the hole distance is 3.50mm, and the area of the outlet 23 of the second air film hole 10 is 2.0096mm²The distance from the center of the circle 23 of the outlet 23 of the second air film hole 10 to the blade root 12 is 1.6mm, and the number of the second air film holes 10 is 12. From the second air film hole 10 close to the tail edge 9, the contraction ratios of the second air film hole 10 are 1.45, 1.53, 1.63, 1.72, 1.81, 1.92, 2.11 and 2.22 in sequence, the jet angles are reduced in sequence, the reduction amplitude of the adjacent jet angles is 5-10 degrees, and the variation range is 50-80 degrees.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.