Cooling structure provided with vertical groove-shaped air film holes and turbine blade

Abstract

The invention provides a cooling structure provided with vertical groove-shaped air film holes and a turbine blade. The cooling structure comprises a base body, and the air film holes extending in the first direction inclined to the thickness direction of the base body are formed in the base body; an air inlet of the air film hole is formed in a first surface of the base body, an air outlet of the air film hole is formed in a second surface, opposite to the first surface, of the base body, and a straight section and an expansion section are sequentially arranged between the air inlet and the air outlet; wherein in the orthographic projection in the second direction orthogonal to the first direction, the straight section forms a long-strip-shaped hole structure, the length of the straight section extending in the air flow direction is configured to be larger than the width of the straight section extending in the air flow spanwise direction, and the expansion section is configured to expand towards the two sides in the width direction of the straight section in a gradually widening mode to form an air outlet. The injection effect of the air inlet is restrained, and the range of the low momentum area near the downstream wall of the air outlet is weakened.

Description

Technical Field

[0001] At least one embodiment of the present disclosure relates to the technical field of gas turbines, and more specifically, to a cooling structure and a turbine blade equipped with air film holes. Background Art

[0002] One of the effective ways to improve the efficiency of gas turbines is to increase the turbine inlet temperature. With the development of gas turbine technology, the turbine inlet temperature of advanced gas turbines has far exceeded the temperature resistance limit of high-temperature alloy materials. The development of high-temperature alloy technology alone cannot meet the demand for increasing turbine inlet temperature, and advanced cooling technology is urgently needed. Gas turbine cooling can be divided into internal cooling and external cooling. External cooling is film cooling. Its basic principle is to extract low-temperature air from the compressor as cooling air and transport it to the high-temperature part of the turbine that needs to be cooled. The cooling air flows out through discrete film holes and covers the wall surface, isolating the wall surface from the high-temperature mainstream while taking away some heat, thereby achieving the purpose of reducing the wall temperature and realizing the safe operation of the gas turbine.

[0003] The most widely used and mature hole type in engineering is the cylindrical hole. The cylindrical hole has the advantages of simple structure, low thermal stress, and easy processing. However, it also has a series of obvious disadvantages, such as small air film coverage area, high jet outlet velocity under high blowing, easy to detach from the wall, low air film cooling effect, large mixing loss, etc. With the continuous development of gas turbine technology, the turbine inlet temperature continues to increase, and the cooling effect provided by the cylindrical hole can no longer meet the gradually increasing cooling needs. In response to the above problems, domestic and foreign scholars have carried out a large number of studies on the hole types of film cooling holes and proposed a large number of novel air film cooling structures or hole types. At present, advanced gas turbine blades have widely used special-shaped air film holes instead of cylindrical holes. Among the many novel air film cooling structures, the outlet expansion hole is the most representative and practical. Among them, the fan-shaped hole and the straight hole have been widely used on the turbine blades of actual gas turbines.

[0004] Although fan-shaped holes and straight holes have improved the film cooling effect to a certain extent, there are still problems such as the deviation of the film trajectory and the reduction of the film coverage under high blowing ratio. In order to improve the film cooling effect of turbine blades, a more suitable film hole structure needs to be developed to meet the cooling needs. Summary of the invention

[0005] In order to solve at least one of the above-mentioned and other technical problems in the prior art, the present disclosure provides a cooling structure and a turbine blade equipped with air film holes. By reasonably configuring the aspect ratio of the straight section and the expansion section of the air film holes, the injection effect of the air inlet of the air film holes is suppressed, the range of the low momentum zone near the downstream wall of the air film hole outlet is weakened, the adhesion of the air film is improved, and the coverage range of the air film is expanded.

[0006] On the one hand, an embodiment of the present disclosure provides a cooling structure equipped with air film holes, including a substrate, wherein the substrate is provided with air film holes extending along a first direction inclined to the thickness direction of the substrate; an air inlet of the air film hole is formed on a first surface of the substrate, and an air outlet of the air film hole is formed on a second surface of the substrate opposite to the first surface, and a straight section and an expansion section are sequentially arranged between the air inlet and the air outlet; wherein, in the orthographic projection along a second direction orthogonal to the first direction, the straight section forms a long strip-shaped hole structure, the length of the straight section extending along the flow direction of the air flow is constructed to be greater than the width of the straight section extending along the extension direction of the air flow, and the expansion section is constructed to gradually expand toward both sides along the width direction of the straight section to form the air outlet, so as to suppress the injection effect of the air inlet and weaken the range of the low momentum zone near the downstream wall of the air outlet.

[0007] According to an embodiment of the present disclosure, the two side walls of the straight section arranged along the width direction are configured to be parallel to each other, and the upstream wall and the downstream wall arranged between the two side walls are configured to form a smooth transition with the side walls.

[0008] According to an embodiment of the present disclosure, in the orthographic projection along the second direction, the upstream wall of the straight section and / or the downstream wall of the straight section are configured as a semicircular arc structure.

[0009] According to an embodiment of the present disclosure, the width of the upstream wall of the air outlet is smaller than the width of the downstream wall of the air outlet.

[0010] According to an embodiment of the present disclosure, four corners of the air outlet are configured to be rounded.

[0011] According to an embodiment of the present disclosure, the extension direction of the center line of the above-mentioned expansion section is configured to coincide with the extension direction of the center line of the above-mentioned straight section.

[0012] According to an embodiment of the present disclosure, in the orthographic projection of the second direction, the length of the straight section is configured to be 3 to 6 times the width of the straight section.

[0013] According to an embodiment of the present disclosure, the length of the straight section along the first direction is configured to be 1 / 3 to 1 / 2 of the total length of the air film hole.

[0014] On the other hand, an embodiment of the present disclosure also provides a turbine blade having a cooling structure as described in the above embodiment, including a blade formed by a substrate, a gas flow channel for accommodating the passage of cooling gas is provided in the blade, a plurality of air film holes are provided in the blade, an air inlet of the air film hole is connected to the gas flow channel to guide the cooling gas to pass through the air film holes, and flow out through the air outlet of the air film hole to form an air film on at least a portion of the surface of the blade.

[0015] According to an embodiment of the present disclosure, the plurality of film holes are arranged at intervals on the blade along the airflow direction and / or airflow span direction of the cooling air to form an air film hole array.

[0016] According to the cooling structure and turbine blade provided by the present disclosure and equipped with air film holes, the straight section of the air film hole is constructed into a long strip hole structure, the length of the straight section extending along the air flow direction is constructed to be greater than the width of the straight section extending along the air flow direction, the vertical distance between the upstream wall and the downstream wall of the straight section of the air film hole is relatively large, the injection effect of the inlet is weakened, and the low momentum area caused by the inlet injection effect near the downstream wall is reduced, so that the cooling gas is concentrated near the upstream wall, the strength of the outlet anti-kidney vortex pair is significantly weakened, and the lateral deflection of the cooling gas to the side of the air film hole outlet under high blowing ratio is suppressed, and the width of the air film coverage is increased; in addition, by constructing the expansion section to expand gradually along the width direction of the straight section to form an air outlet, the outlet area is significantly increased, the injection momentum of the cooling gas is reduced, and the air film adhesion is enhanced. Further, due to the weakening of the strength of the anti-kidney vortex pair, combined with the cooling gas being concentrated near the upstream wall, the outlet lateral expansion angle can be greatly increased to obtain a wide and uniform downstream air film coverage. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of a cooling structure with fan-shaped air film holes in the prior art, wherein: Figure 1 A shows a top view of a cooling structure equipped with fan-shaped air film holes. Figure 1 B shows a cross-sectional view of a cooling structure provided with fan-shaped air film holes;

[0018] Figure 2 Schematic diagram of a cooling structure with a straight-line air film hole in the prior art, wherein: Figure 2 A shows a top view of a cooling structure equipped with a straight-line air film hole. Figure 2 B shows a cross-sectional view of a cooling structure provided with a straight-line air film hole; Figure 2 C shows a schematic diagram of a cooling structure provided with a straight-line air film hole from the perspective of A;

[0019] Figure 3 is a schematic diagram of a cooling structure equipped with air film holes according to an exemplary embodiment of the present disclosure, wherein: Figure 3 A shows a top view of a cooling structure equipped with vertical slot-shaped air film holes. Figure 3 B shows a cross-sectional view of a cooling structure provided with vertical slot-shaped air film holes; Figure 3 C shows a schematic diagram of a cooling structure provided with vertical slot-shaped air film holes from the perspective of A;

[0020] Figure 4 yes Figure 3 A comparison diagram of the flow field in the hole formed by the cooling structure with vertical slot-shaped air film holes in the exemplary embodiment shown and the existing cooling structure with air film holes in the flow field, wherein the Figure 1 The fan-shaped air film hole shown, Figure 2 The straight-line air film hole and Figure 3 A comparison diagram of the vertical slot-shaped air film holes of the exemplary embodiment shown;

[0021] Figure 5 yes Figure 3 A three-dimensional view of an air film hole array formed by a plurality of air film holes is shown in the exemplary embodiment;

[0022] Figure 6 yes Figure 4 A comparison diagram of the average lateral cooling efficiency of fan-shaped film holes, straight-line film holes and vertical slot-shaped film holes arranged on the suction surface shown; and

[0023] In the drawings, the meanings of the reference numerals are as follows:

[0024] 1. Air film hole;

[0025] 11. Straight section;

[0026] 111, upstream wall of the straight section;

[0027] 112, downstream wall of the straight section;

[0028] 12. expansion section; and

[0029] 2. Matrix. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0031] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0032] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0033] When using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, and C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc. When using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, or C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.

[0034] In air film cooling technology, fan-shaped air film holes and straight-line air film holes are widely used.

[0035] Figure 1 Schematic diagram of a cooling structure with fan-shaped air film holes in the prior art, wherein: Figure 1 A shows a top view of a cooling structure equipped with fan-shaped air film holes. Figure 1 B shows a cross-sectional view of a cooling structure provided with fan-shaped air film holes; Figure 2 Schematic diagram of a cooling structure with a straight-line air film hole in the prior art, wherein: Figure 2 A shows a top view of a cooling structure equipped with a straight-line air film hole. Figure 2 B shows a cross-sectional view of a cooling structure provided with a straight-line air film hole; Figure 2 C shows a schematic diagram of a cooling structure provided with a straight-line air film hole from the perspective of A.

[0036] In the prior art, fan-shaped film holes and straight-line film holes are the most common hole shapes used in gas turbine film cooling structures, such as Figure 1 and Figure 2 As shown in the figure, the fan-shaped hole expands the rear half of the air film hole laterally on the basis of the cylindrical hole. The fan-shaped hole can be divided into a straight section and an expansion section along the flow direction of the cooling gas. The total length of the air film hole is L, of which the length of the straight section is Lt. The cross-sectional shape of the straight section of the fan-shaped hole is circular with a diameter of D. The lateral expansion angle of the expansion section is γ. The outlet expansion structure of the fan-shaped hole provides a wider air film coverage downstream, which improves the air film cooling effect to a certain extent. Although the fan-shaped hole improves the air film cooling effect to a certain extent, there are still problems such as the deviation of the air film trajectory and the reduction of the air film coverage range under high blowing ratio.

[0037] The straight film hole can be divided into a straight section and an expansion section along the cold air flow direction. The total length of the film hole is L, of which the length of the straight section is Lt, and the lateral expansion angle of the expansion section is γ. The cross-sectional shape of the straight section of the straight film hole is a runway shape, and its cross-sectional width is recorded as W, and its cross-sectional height is recorded as H. Compared with the fan-shaped hole, at the same expansion angle, the straight film hole has a larger outlet width and a wider air film coverage width, which further improves the air film cooling performance. However, it should be considered that the outlet area of ​​the horizontal slot cross-section hole is reduced, the cold air jet velocity increases, and the vertical distance between the upstream wall and the downstream wall is reduced, the injection effect at the inlet is enhanced, and the low momentum area near the downstream wall is large. Under high blowing ratios, the cold air deviates laterally to the outlet side of the hole, and the air film coverage becomes narrower, and the expected air film coverage width cannot be achieved. The lateral coverage width of the air film will not always increase with the increase of the lateral expansion width of the outlet. Under the influence of the injection effect at the air inlet and the flow separation in the expansion section, the lateral outlet width of the air film hole is often not fully utilized. This phenomenon is more obvious in high mainstream flow velocity areas such as the suction surface of the turbine blade.

[0038] To this end, based on the above-mentioned deficiencies in the prior art, how to design the air film holes, reasonably design the geometric structure and aspect ratio of the straight section and the expansion section, suppress the injection effect at the air inlet and the deviation of the air film trajectory at the air outlet, and ensure the air film coverage range has become a technical problem that needs to be solved urgently.

[0039] In view of this, the embodiments of the present disclosure provide a cooling structure and a turbine blade equipped with air film holes based on the same inventive concept.

[0040] Figure 3 is a schematic diagram of a cooling structure equipped with air film holes according to an exemplary embodiment of the present disclosure, wherein: Figure 3 A shows a top view of a cooling structure equipped with vertical slot-shaped air film holes. Figure 3 B shows a cross-sectional view of a cooling structure provided with vertical slot-shaped air film holes; Figure 3 C shows a schematic diagram of a cooling structure provided with vertical slot-shaped air film holes from the perspective of A.

[0041] According to a cooling structure provided by the present disclosure and provided with air film holes, Figure 3As shown in A, it includes a substrate 2, in which an air film hole 1 extending along a first direction inclined to the thickness direction of the substrate 2 is arranged. The air inlet of the air film hole 1 is formed on the first surface of the substrate 2, and the air outlet of the air film hole 1 is formed on the second surface of the substrate opposite to the first surface. A straight section 11 and an expansion section 12 are sequentially arranged between the air inlet and the air outlet. Among them, in the orthographic projection along the second direction orthogonal to the first direction, the straight section 11 forms a long strip hole structure, the length of the straight section 11 extending along the air flow direction is configured to be greater than the width of the straight section 11 extending along the air flow direction, and the expansion section 12 is configured to expand gradually to both sides along the width direction of the straight section 11 to form an air outlet, so as to suppress the injection effect of the air inlet and weaken the range of the low momentum zone near the downstream wall of the air outlet.

[0042] According to the above-mentioned setting, since the length of the air inlet along the air flow direction is greater than the width, the vertical distance H between the upstream wall 111 and the downstream wall 112 of the straight section of the air film hole 1 is relatively large, which can effectively reduce the flow velocity gradient caused by the inlet jet effect, thereby suppressing the jet effect at the air inlet, and further reducing the range of the low momentum zone caused by the inlet jet effect near the downstream wall. The range of the low momentum zone in the air film hole 1 is reduced, which actually increases the range of the high momentum zone in the hole, thereby reducing the velocity gradient with the high-temperature gas at the air outlet of the air film hole 1, and further weakening the anti-kidney vortex pair at the air outlet. Under high blowing ratios, an overly strong anti-kidney vortex pair may cause the cooling gas to be blown away from the wall surface, resulting in a decrease in cooling efficiency. Through the above-mentioned setting, it is ensured that the anti-kidney vortex pair can be within a reasonable strength range, effectively suppress the lateral deviation of the cooling gas to the side of the air outlet under high blowing ratios, obtain a large width and uniform downstream air film coverage, and ensure the efficiency of air film cooling. Since the expansion section 12 widens toward both sides along the narrow width direction of the straight section 11, and since the vertical distance H between the upstream wall and the downstream wall is relatively large, the corresponding length W1 of the air outlet flow direction is also relatively large, so that the air outlet has a larger area, thereby reducing the momentum of the cooling air at the air outlet, improving the adhesion of the cooling air, and expanding the coverage of the air film.

[0043] In this embodiment, the air film hole 1 is suitable for transporting cooling air to the high-temperature part of the turbine that needs to be cooled.

[0044] In this embodiment, the base 2 is the suction surface, pressure surface or end wall of a turbine blade.

[0045] In this embodiment, the cooling gas is air or compressor guide air.

[0046] In this embodiment, the air film holes are obtained by laser drilling, electric spark drilling, etc.

[0047] In an illustrative embodiment, two side walls of the straight section 11 arranged along the width direction are configured to be parallel to each other, and the upstream wall 111 and the downstream wall 112 arranged between the two side walls are configured to form a smooth transition with the side walls.

[0048] According to the above arrangement, the flow resistance of the cooling airflow in the straight section 11 can be reduced and the generation of eddies can be prevented, thereby improving the stability of the airflow. In addition, since the upstream and downstream walls are parallel to each other and have a smooth transition with the side wall surface, the cooling airflow can be distributed as evenly as possible in the straight section 11, which helps to avoid local airflow separation.

[0049] In an exemplary embodiment, in the orthographic projection along the second direction, Figure 5 As shown, the upstream wall 111 of the straight section and / or the downstream wall 112 of the straight section are configured as a semicircular arc structure.

[0050] According to the above arrangement, the flow resistance of the cooling airflow in the straight section 11 can be reduced and the generation of vortices can be prevented, thereby improving the stability of the airflow. In addition, since the upstream wall 111 of the straight section and / or the downstream wall 112 of the straight section are configured as a semicircular arc structure, the cooling airflow can be evenly distributed in the straight section as much as possible, which helps to avoid local airflow separation.

[0051] In an illustrative embodiment, Figure 3 As shown in C, the width of the upstream wall of the air outlet is smaller than the width of the downstream wall of the air outlet.

[0052] According to the above arrangement, since the width of the downstream wall is larger than that of the upstream wall, the speed of the cooling air in the high momentum area close to the upstream wall can be guaranteed, which helps to weaken the strength of the anti-kidney vortex pair and expand the coverage of the air film.

[0053] In an illustrative embodiment, Figure 3 As shown in C, the four corners of the air outlet are configured to be rounded.

[0054] According to the above arrangement, it is possible to prevent eddy currents from being generated at the air outlet, thereby avoiding the influence of the uneven wall surface on the stability of the air film.

[0055] In an illustrative embodiment, Figure 3 As shown in B, the extension direction of the center line of the expansion section 12 is configured to coincide with the extension direction of the center line of the straight section 11.

[0056] According to the above arrangement, the stable flow of the cooling airflow in the air film holes can be ensured, thereby avoiding energy loss or turbulence caused by the change of the axis of the airflow channel.

[0057] In an illustrative embodiment, Figure 3 As shown in C, in the orthographic projection in the second direction, the length of the straight section 11 is configured to be 3 to 6 times the width of the straight section 11.

[0058] According to the above-mentioned arrangement, the straight section can have a larger aspect ratio in the orthographic projection in the second direction. On the one hand, the air film hole has a larger vertical distance from the upstream and downstream walls, thereby suppressing the occurrence of the inlet injection effect. On the other hand, it also prevents the situation in which the cooling gas stalls and the air film cooling cannot be effectively carried out due to the large distance between the upstream and downstream walls.

[0059] In an illustrative embodiment, Figure 3 As shown in B, the length of the straight section 11 along the first direction is constructed to be 1 / 3 to 1 / 2 of the total length of the air film hole 1.

[0060] According to the above-mentioned setting method, it can be ensured that the cooling gas passing through the air film hole has sufficient momentum in the straight section 11 so that it can effectively form an air film at the air outlet. By reasonably setting the length of the extension section 12, it is ensured that the momentum of the cooling gas at the air outlet is reduced to a reasonable range, so as to expand the coverage of the air film, improve the adhesion of the air film, prevent the air film from detaching, and ensure the efficiency of the air film cooling.

[0061] In an illustrative embodiment, Figure 3 As shown in A, the lateral expansion angle of the expansion section 12 is γ, which can be adjusted within a range of 10° to 30° to form a suitable air outlet size.

[0062] In an illustrative embodiment, Figure 3 As shown in B, the injection angle α of the air film hole 1 can be adjusted according to specific needs, and the range of α is between 30° and 60°.

[0063] According to the above arrangement, it is helpful to enhance the adhesion and stability of the air film, and because the cooling air jet forms a certain angle with the substrate 2, its flow path is longer, which increases the contact area with the high-temperature airflow, thereby improving the cooling effect.

[0064] Figure 4 yes Figure 3 A comparison diagram of the flow field in the hole formed by the cooling structure with air film holes in the exemplary embodiment and the existing cooling structure with air film holes in the flow field, wherein the Figure 1 The fan-shaped air film hole shown, Figure 2 The straight-line air film hole and Figure 1 A comparison diagram of the vertical slot-shaped air film holes of the exemplary embodiment shown.

[0065] In order to more intuitively illustrate the problem that can be solved by the cooling structure provided by the present disclosure with air film holes, Figure 4 The flow conditions of cooling air in the fan-shaped air film holes, the straight-line air film holes commonly used in the prior art, and the vertical groove-shaped air film holes in the embodiments of the present disclosure are given in the specification.

[0066] like Figure 4 As shown, the cooling air flow will separate at the hole entrance, which is the "jet effect". Under the influence of the jet effect, there are obvious differences in the distribution of cooling air in different film holes. For fan-shaped film holes and straight-line film holes, due to the small distance between the upstream and downstream walls of the hole, under the influence of the jet effect, the range of the low momentum area near the downstream wall is relatively large, and the cooling air is mainly distributed near the two side walls of the film hole. The intensity of the anti-kidney vortex pair downstream of the air outlet is relatively large, and the lower air film with a high blowing ratio is deflected toward the hole outlet. The distance H between the upstream and downstream walls of the vertical groove-shaped film hole structure in the embodiment of the present disclosure is significantly increased, the range of the low momentum area near the lower wall is reduced, and the main cooling air is concentrated near the upstream wall. From the flow conditions of the air outlet cross section, it can be seen that the high momentum areas of the fan-shaped air film holes and the straight air film holes are distributed on both sides of the holes, with a relatively small range; while the high momentum areas of the vertical slot-shaped air film holes in the disclosed embodiment are concentrated near the upstream wall, with a relatively large range, and the strength of the anti-kidney vortex pair is relatively weak, which effectively suppresses the lateral deflection of the cold air to the side of the hole outlet under high blowing ratios, and obtains a wide and uniform downstream air film coverage. In addition, the air outlet area of ​​the vertical slot-shaped air film holes in the disclosed embodiment is significantly increased, the injection momentum of the cold air outlet is significantly reduced, and the air film has strong adhesion.

[0067] It should also be pointed out that if Figure 2 C and Figure 3 As shown in C, it can be seen that the air film hole structure of the present invention is similar to the projection of the straight air film hole in the second direction. The air inlet is a structure with a large aspect ratio, but the directions of the two are different. The straight air film hole aims to improve the air film cooling effect by increasing the lateral width of the air film, so it expands the side wall with a short length laterally to achieve the largest possible outlet lateral width; while the air film hole of the present invention expands laterally with a large expansion angle based on the side wall with a long length. Compared with the fan-shaped air film hole and the straight air film hole, the vertical distance H between the upstream wall and the downstream wall of the air film cooling hole of the present invention is significantly increased, and the corresponding cold air outlet flow length W1 is also significantly increased, the cold air outlet area is greatly increased, and the cold air outlet momentum is significantly reduced.

[0068] The present disclosure also provides a turbine blade with the above-mentioned cooling structure, including a blade formed by a substrate, a gas flow channel for accommodating the passage of cooling gas is arranged in the blade, and a plurality of air film holes 1 are arranged in the blade, and the air inlet of the air film hole 1 is connected to the gas flow channel to guide the cooling gas to pass through the air film hole 1, and flow out through the air outlet of the air film hole 1 and form an air film on at least a part of the surface of the blade.

[0069] According to the above-mentioned setting method, the cooling gas forms an air film on at least a part of the surface of the turbine blade through the air film holes, which can prevent problems such as material damage caused by excessive temperature, thereby improving the performance and life of the turbine and reducing operating costs.

[0070] Figure 5 yes Figure 3 The illustrated exemplary embodiment is a three-dimensional view of an air film hole array formed by a plurality of air film holes.

[0071] In an illustrative embodiment, Figure 5 As shown, a plurality of film holes 1 are arranged at intervals on the blade along the airflow direction and / or airflow span direction of the cooling air to form an array of film holes 1.

[0072] According to the above-mentioned arrangement, by arranging an array of air film holes on the upper edge of the turbine blade, the high-temperature area on the turbine blade that needs to be cooled can be effectively covered to prevent the turbine blade from being overheated.

[0073] In this embodiment, the lateral spacing between two adjacent film cooling holes is P, and the hole spacing P is not less than 6D.

[0074] In order to illustrate the cooling effect of the vertical slot-shaped air film holes in the embodiment of the present disclosure, the air film cooling efficiency of the fan-shaped air film holes, the straight-line air film holes and the vertical slot-shaped air film hole array were tested respectively.

[0075] The parameters of the film cooling holes used in the test are as follows: D is 1mm, and the hole spacing P is 7.5D. The lateral expansion angle γ of the fan-shaped hole Fan-S and the straight film hole 1.7H is 14°, and the expansion angle of the vertical slot-shaped film hole 1.7V in the embodiment of the present disclosure is 20°. The vertical distance between the upstream wall and the downstream wall of the straight film hole is H, which is 0.5D, and the lateral width between the side walls is W, which is 1.7D; the vertical distance between the upstream wall and the downstream wall of the vertical slot-shaped film hole is H, which is 1.7D, and the lateral width between the side walls is W, which is 0.5D. The total length L of the three types of film holes is 6D, and the ratio of the straight section length to the total length of the film hole Lt / L is 1 / 3. The test operating parameters are as follows: the local mainstream velocity of the film hole is 115m / s, the cold air to mainstream density ratio is DR=1.5, and the blowing ratio is M=2.0.

[0076] Figure 6 yes Figure 4 The figure shows a comparison of the average lateral cooling efficiency of fan-shaped film holes, straight-line film holes and vertical slot-shaped film holes arranged on the suction surface.

[0077] like Figure 6 As shown, its horizontal coordinate S / D is the relative distance from the outlet to the downstream direction of the cooling air, and its vertical coordinate η Lis the average cooling efficiency of the air film in the span direction. From the comparison results, it can be seen that the air film cooling efficiency of the fan-shaped holes and the horizontal slot cross-section air film holes decays rapidly near the downstream of the hole outlet, while the vertical slot cross-section air film holes of the present invention maintain a high level of cooling efficiency throughout the downstream range, greatly improving the air film cooling effect. Compared with the fan-shaped hole Fan-S, the air film cooling effect of the vertical slot cross-section air film hole 1.7V in the embodiment of the present invention is improved by about 277.6% as a whole; compared with the horizontal slot cross-section air film hole 1.7H, the air film cooling effect of the vertical slot cross-section air film hole 1.7V in the embodiment of the present invention is improved by about 38.2% as a whole.

[0078] The air film cooling efficiency of the fan-shaped holes and the straight air film holes decays rapidly near the downstream of the hole outlet, while the vertical slot-shaped air film holes of the embodiment of the present disclosure maintain a high level of cooling efficiency throughout the downstream range, greatly improving the air film cooling effect. Compared with the fan-shaped hole Fan-S, the air film cooling effect of the vertical slot-shaped air film hole 1.7V of the embodiment of the present disclosure is improved by about 277.6% overall; compared with the straight air film hole 1.7H, the air film cooling effect of the vertical slot-shaped air film hole 1.7V of the embodiment of the present disclosure is improved by about 38.2% overall.

[0079] Based on the above technical solution, the cooling structure and turbine blade equipped with air film holes of the present invention have one or part of the following beneficial effects:

[0080] 1. Since the vertical distance between the upstream wall and the downstream wall is significantly enlarged, the inlet jet effect can be effectively weakened and the range of the low momentum area near the downstream wall caused by the inlet jet effect can be reduced.

[0081] 2. Due to the reduction of the low momentum zone near the downstream wall and the increase of the vertical distance between the upstream wall and the downstream wall, the main cold air is concentrated near the upstream wall, and the intensity of the anti-kidney vortex pair at the outlet is significantly weakened, which can effectively suppress the lateral deflection of the cold air to the side of the hole outlet under high blowing ratio.

[0082] 3. Due to the weakening of the inlet injection effect, the inlet flow blockage is weakened, the flow resistance is reduced, and the outflow coefficient is significantly increased.

[0083] 4. Due to the lateral expansion of the side wall due to its long length, the outlet area is significantly increased, the injection momentum of the cold air outlet is significantly reduced, and the air film has strong adhesion.

[0084] 5. As the strength of the anti-kidney vortex pair is weakened and the main fluid is concentrated near the upstream wall, the outlet lateral expansion angle can be greatly increased to obtain a wide and uniform downstream air film coverage.

[0085] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only reference directions of the drawings and are not intended to limit the scope of protection of the present disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted when they may cause confusion in the understanding of the present disclosure.

[0086] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present disclosure is defined by the attached claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A cooling structure with vertical slot-shaped air film holes, characterized in that: It comprises a substrate, wherein the substrate is provided with air film holes (1) extending along a first direction inclined with respect to the thickness direction of the substrate; The air inlet of the air film hole (1) is formed on the first surface of the base, and the air outlet of the air film hole (1) is formed on the second surface of the base opposite to the first surface, and a straight section (11) and an expansion section (12) are sequentially arranged between the air inlet and the air outlet; In the orthographic projection along a second direction orthogonal to the first direction, the straight section (11) forms a long strip-shaped hole structure, the length of the straight section (11) extending along the airflow direction is configured to be greater than the width of the straight section (11) extending along the airflow direction, and the expansion section (12) is configured to gradually expand toward both sides along the width direction of the straight section (11) to form the air outlet, so as to suppress the injection effect of the air inlet and weaken the range of the low momentum zone near the downstream wall of the air outlet.

2. The cooling structure according to claim 1, characterized in that: The two side walls of the straight section (11) arranged along the width direction are configured to be parallel to each other, and the upstream wall and the downstream wall arranged between the two side walls are configured to form a smooth transition with the side walls.

3. The cooling structure according to claim 2, characterized in that: In the orthographic projection along the second direction, the upstream wall (111) of the straight section and / or the downstream wall (112) of the straight section are configured as a semicircular arc structure.

4. The cooling structure according to claim 1, characterized in that: The width of the upstream wall of the air outlet is smaller than the width of the downstream wall of the air outlet.

5. The cooling structure according to claim 4, characterized in that: The four corners of the air outlet are configured to be rounded.

6. The cooling structure according to any one of claims 1 to 5, characterized in that: The extension direction of the center line of the expansion section (12) is configured to coincide with the extension direction of the center line of the straight section (11).

7. The cooling structure according to any one of claims 1 to 5, characterized in that: In the orthographic projection of the first direction, the length of the straight section (11) is configured to be 3 to 6 times the width of the straight section (11).

8. The cooling structure according to any one of claims 1 to 5, characterized in that: The length of the straight section (11) along the first direction is configured to be 1 / 3 to 1 / 2 of the total length of the air film hole (1).

9. A turbine blade having a cooling structure as claimed in any one of claims 1 to 8, characterized in that: The invention comprises a blade formed by a substrate, wherein a gas flow channel for accommodating cooling gas is arranged in the blade, and a plurality of air film holes (1) are arranged in the blade, and an air inlet of the air film hole (1) is connected to the gas flow channel to guide the cooling gas to pass through the air film hole (1), and to flow out through the air outlet of the air film hole (1) and form an air film on at least a part of the surface of the blade.

10. The turbine blade according to claim 9, characterized in that The plurality of film holes (1) are arranged at intervals on the blade along the airflow direction and / or airflow span direction of the cooling air to form an array of film holes (1).

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