Turbine variable stator vane and stator vane cooling method with water-drop shaped film holes

Abstract

The application discloses a turbine adjustable guide vane with water-drop-shaped air film holes, which comprises an adjustable guide vane and matrix-arranged air film holes on the front edge of the guide vane, wherein the air film holes are water-drop-shaped holes formed by a water-drop-shaped circular part and a water-drop-shaped sharp corner part connected by a circular streamline; and the application also provides a guide vane cooling method for the turbine guide vane. The water-drop-shaped air film holes have additional forward tilting expansion, which makes the outlet length of the water-drop-shaped air film holes longer than that of a cylindrical hole with the same tilting angle, increases the direct contact range between the main flow and the jet flow, can guide the air flow to form a stable air film, effectively isolates the direct contact between the high-temperature air flow and the front edge of the guide vane, and encrypts the number of the air film hole rows in the moving range of the aerodynamic stagnation point, so as to ensure that the arrangement of the air film holes can cover the peak area of the thermal load of the front edge of the guide vane in different working states, and improve the thermal fatigue resistance and thermal damage resistance of the adjustable guide vane.

Description

Technical Field

[0001] This invention relates to the field of high-temperature airflow turbine engines, and particularly to a thermal protection and cooling structure and cooling method for turbine guide vanes. Background Technology

[0002] Variable geometry turbines (VGTs) are core components of variable cycle engines. By adjusting their flow capacity, they alter output power, effectively improving engine economy and transient response characteristics. In 1971, Rolls-Royce, through extensive experimental research, discovered that adjustable guide vanes were the optimal method for implementing variable geometry turbines. Adjustable guide vanes change the turbine throat area by adjusting the vane installation angle, matching the engine's flow requirements to achieve a predetermined thrust. This allows the engine to maintain high thermal efficiency, resulting in better economic performance than conventional engines with fixed geometry. Therefore, the application of adjustable turbine guide vane technology is an important development trend for future aero-engines.

[0003] Film cooling is one of the most important and effective methods for cooling hot-end components of aero engines. However, the application of adjustable turbine guide vane technology has brought new challenges to turbine film cooling design: (1) Within the wide flow range of adjustable turbine guide vanes, changes in the guide vane opening not only alter the mainstream flow, but also the pressure load distribution on the blade surface and the airflow around it, resulting in significant differences in the aerodynamic environment of the blade surface under different guide vane openings; (2) Changes in the installation angle of adjustable turbine guide vanes can affect the adaptability of some film cooling structures. Traditional film cooling designs may produce cooling blind spots or even local high-temperature backflow, threatening the reliability and service life of the engine. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a turbine adjustable guide vane with teardrop-shaped film cooling holes and a guide vane cooling method that can maintain good cooling efficiency on the blade surface under different guide vane opening conditions and achieve good thermal protection effect under different engine operating conditions throughout the entire flight envelope.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a turbine adjustable guide vane with teardrop-shaped film perforations, comprising an adjustable guide vane and film perforations arranged in a matrix on the leading edge of the guide vane;

[0006] The aforementioned film pore is a teardrop-shaped hole formed by a circular portion of the teardrop and a transition from a circular streamline to a pointed tip. The diameter of the circular portion of the teardrop is D, the expansion angle formed by the axial direction of the teardrop and the apex of the pointed tip is α, the flow length from the circular portion to the apex of the pointed tip is L, and the depth of the hole is H. Therefore:

[0007] 2mm≥D≥0.5mm, to ensure sufficient cooling airflow while avoiding airflow separation and vortex phenomena caused by excessively large diameter;

[0008] 45°≥α≥20°, used to guide the cold air jet to form a stable air film;

[0009] 2≤H / D≤4, to ensure sufficient cooling airflow;

[0010] 5mm≥L≥1mm. If the flow length L is too long, the airflow will separate prematurely, while if it is too short, a stable air film cannot be formed.

[0011] Furthermore, the leading edge of the guide vane is mapped as a plane and divided into multiple identical area units. The air film pores are set within the area units. The longitudinal unit length Sy of the area unit is along the blade height span of the leading edge of the guide vane, and the transverse unit length Sx of the area unit is along the leading edge arc length span of the leading edge of the guide vane. Thus, the opening rate of the air film pores on the area unit of the leading edge of the guide vane is 5~15%.

[0012] Furthermore, the matrix arrangement of the air film pores specifically means that the air film pores are evenly arranged in rows on the leading edge of the guide vane from the root to the tip of the adjustable guide vane, and at least four rows are arranged to form a uniformly distributed air film layer on the leading edge of the guide vane, thereby improving the thermal protection effect.

[0013] Furthermore, the air film holes are evenly arranged in rows on the leading edge of the guide vane from the root to the tip, with at least two rows. Among them, at least four rows of air film holes are arranged within the aerodynamic stagnation point movement range of the leading edge of the guide vane, in order to improve the stability of the air film layer and enable the adjustable guide vane to adapt to the heat load under different working conditions.

[0014] Furthermore, the pneumatic stagnation point movement range is the movement range of the pneumatic stagnation line on the leading edge of the guide vane. The air film holes are asymmetrically arranged on both sides of the pneumatic stagnation line at the middle axial position of the leading edge of the guide vane, that is, the number of air film holes near the pressure surface of the guide vane is greater than the number of air film holes near the suction surface of the guide vane, and the ratio is (1.5~2):1.

[0015] Furthermore, the adjustable guide vane has an adjustment angle θ of 10° to -10°. When the adjustable guide vane opening is +10 degrees, the aerodynamic stagnation line is located at the midpoint of the leading edge arc. When the adjustable guide vane opening is -10 degrees, the aerodynamic stagnation line is located on the leading edge pressure surface side. As the adjustable guide vane closes, the aerodynamic stagnation line continuously moves towards the pressure surface side.

[0016] Furthermore, if the spacing of the film air holes in the blade height direction is P1, the spacing of the film air holes in the non-stagnant line movement range leading edge arc length direction is P2, the spacing of the film air holes in the stagnant line movement range direction is P3, and the diameter of the cylindrical section of the teardrop hole is D, then:

[0017] P2 > P3;

[0018] 2D≤P2≤4D;

[0019] 2D≤P3≤4D.

[0020] Furthermore, the matrix arrangement of the air film pores is specifically as follows: the air film pores are evenly arranged in rows on the leading edge of the guide vane from the root to the tip of the adjustable guide vane, and adjacent rows of air film pores are staggered in the flow direction, and at least four rows are arranged to reduce interference between the air film pores and enhance the adhesion of the air film.

[0021] Furthermore, the water droplet tip of the air film pore points towards the leaf root.

[0022] The present invention also provides a method for cooling the turbine guide vane, comprising the following steps:

[0023] The cold airflow C1 in the adjustable guide vane cavity is ejected through the film gas holes. Each film gas hole causes the cold airflow C1 to form an airflow with a width matching the flow direction length of the film gas hole on the surface of the adjustable guide vane, allowing sufficient cold airflow C1 to pass close to the film gas hole and forming a stable cold air covering layer C3 that completely covers the surface of the adjustable guide vane. The cold air covering layer C3 mixes with the mainstream C4, reducing the temperature of the adjustable guide vane wall. On the other hand, the formed cold air covering layer C3 blocks the high-temperature airflow from scouring the wall of the adjustable guide vane, thereby reducing heat transfer.

[0024] Meanwhile, as the adjustable guide vanes close, the aerodynamic stagnation line moves continuously toward the pressure surface of the adjustable guide vanes, and more of the cold air at the leading edge of the adjustable guide vanes flows toward the back of the blades. At this time, since the number of air film holes near the pressure surface of the guide vanes on both sides of the aerodynamic stagnation line is greater than the number of air film holes near the suction surface of the guide vanes, a large amount of cold air flow C1 is discharged from the pressure surface, effectively suppressing the tendency of cold air to deflect, making the cold air at the leading edge flow more evenly toward the blade base and the back of the blades, and reducing the unevenness of the air film distribution.

[0025] The beneficial effects of this invention are as follows: The adjustable guide vane provided by this invention has multiple teardrop-shaped film cooling holes arranged on its leading edge, which densifies the number of film cooling holes within the aerodynamic stagnation point movement range to optimize the film cooling effect. The teardrop-shaped film cooling holes have an additional forward-inclined expansion at the outlet, which makes their outlet length longer than that of cylindrical holes with the same inclination angle. This increases the direct contact range between the mainstream and the jet, guides the airflow to form a stable film cooling system, and effectively isolates the high-temperature airflow from direct contact with the guide vane leading edge, thereby reducing the thermal load on the guide vane.

[0026] Compared to conventional cylindrical film cooling orifices, its geometry optimizes the flow structure of the cold air jet, helping to guide the cold air to form a stable attached film and enhancing the cooling effect. Simultaneously, the teardrop-shaped design optimizes the flow field structure of the film cooling orifice, reducing airflow resistance and improving overall aerodynamic efficiency.

[0027] Meanwhile, by increasing the number of film cooling holes within the aerodynamic stagnation point movement range, the arrangement of the film cooling holes can cover the peak heat load area of ​​the guide vane leading edge under different operating conditions. Through this refined arrangement strategy, the reasonable diameter and arrangement of the film cooling holes ensure the uniform distribution and efficient flow of the cooling airflow, achieving efficient cooling of the guide vane leading edge, improving the inlet temperature limit of the adjustable turbine guide vane, increasing the Brayton cycle efficiency of the variable cycle engine, and also improving its resistance to thermal fatigue and thermal damage. This helps to reduce problems such as material performance degradation and component deformation caused by high temperatures, thereby significantly improving the performance, reliability, and operating efficiency of the aero-engine.

[0028] Furthermore, this invention extends the service life of aero engines. By reducing the thermal load on the leading edge of the guide vanes and minimizing thermal damage, this invention slows down the fatigue and aging process of components, thereby extending the engine's service life. This is of great significance for reducing maintenance costs, improving engine reliability, and lowering operating costs. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a film cooling hole layout suitable for adjustable low-pressure turbine guide vanes according to the present invention.

[0030] Figure 2 This is a schematic diagram of the structure of the air film pore of the present invention;

[0031] Figure 3 Comparison of the air film perforation layout in the leading edge region of the adjustable low-pressure turbine guide vane;

[0032] in, Figure 3 a is a schematic diagram of the traditional leading edge film air hole layout structure. Figure 3 b is a schematic diagram of the leading edge air film pore layout structure of the present invention;

[0033] Figure 4 This is a schematic diagram of the air film cooling effect of the present invention;

[0034] Figure 5 This is a streamline comparison diagram of the air film cooling effect of the present invention;

[0035] in, Figure 5 a is a streamline diagram of the film cooling effect on the pressure surface of a traditional cylindrical film cooling guide vane. Figure 5 b is a streamline diagram of the air film cooling effect on the pressure surface of the air film perforated guide vane of the present invention. Figure 5c is a streamline diagram of the film cooling effect on the suction surface of a traditional cylindrical film cooling guide vane. Figure 5 d is a streamline diagram of the air film cooling effect on the suction surface of the air film guide vane of the present invention;

[0036] Figure 6 This is a cloud map comparing the cooling efficiency of the air film of the present invention. Detailed Implementation

[0037] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0038] To achieve the above objectives, the present invention provides the following specific embodiments:

[0039] Example 1: As Figure 1 As shown in Figure 2, a turbine adjustable guide vane with teardrop-shaped film perforations includes an adjustable guide vane 1 and film perforations 2 arranged in a matrix on the leading edge 11 of the guide vane.

[0040] The air film pore 2 is a teardrop-shaped hole formed by the circular part of the water droplet and the transition from the circular streamline to the tip of the water droplet. The diameter of the circle mapped by the circular part of the water droplet in the air film pore 2 is D. The expansion angle formed by the axial direction of the hole in the circular part of the water droplet and the apex position of the tip of the water droplet is α. The tip of the water droplet in the air film pore 2 points towards the leaf root. The flow length from the circular part of the water droplet to the apex of the tip of the water droplet is L. The depth of the hole is H. Then:

[0041] 2mm≥D≥0.5mm, to ensure sufficient cooling airflow while avoiding airflow separation and vortex phenomena caused by excessively large diameter;

[0042] 45°≥α≥20°, used to guide the cold air jet to form a stable air film;

[0043] 2≤H / D≤4, to ensure sufficient cooling airflow;

[0044] 5mm≥L≥1mm. When the flow length L is too long, the airflow will separate prematurely, while if it is too short, a stable air film cannot be formed.

[0045] The guide vane leading edge 11 is mapped onto a plane and divided into multiple identical area units. The film pores 2 are set in the area units. The longitudinal unit length Sy of the area unit is along the blade height span of the guide vane leading edge 11, and the transverse unit length Sx of the area unit is along the leading edge arc length span of the guide vane leading edge 11. Thus, the opening rate of the film pores 2 on the area units of the guide vane leading edge 11 is 5~15%.

[0046] The matrix arrangement of the air film holes 2 is as follows: the air film holes 2 are evenly arranged in rows on the leading edge of the guide vane from the root to the tip of the adjustable guide vane, and at least four rows are arranged to form a uniformly distributed air film layer on the leading edge of the guide vane, thereby improving the thermal protection effect.

[0047] like Figure 1 , Figure 2 As shown, the geometric parameters of the teardrop-shaped film cooling orifice include the orifice diameter D, expansion angle α, orifice length H, and flow direction length L. The range of values ​​for these parameters has a significant impact on the performance of the film cooling orifice. The diameter D of the teardrop-shaped film cooling orifice ensures sufficient cooling airflow while avoiding airflow separation and vortex phenomena caused by an excessively large diameter.

[0048] The diameter D of the teardrop-shaped film cooling orifice still needs to be finely adjusted according to the actual situation to ensure optimal cooling effect. The expansion angle α determines the degree of expansion of the film cooling orifice. An appropriate expansion angle helps guide the cold air jet to form a stable film cooling effect. In this embodiment, the expansion angle α is 45°.

[0049] The orifice length H determines the size of the film cooling orifice perpendicular to the flow direction, and its value should be determined based on the curvature of the guide vane leading edge and cooling requirements. Generally, the orifice length H should be slightly larger than the film cooling orifice diameter D to ensure sufficient cooling airflow. The flow length L determines the size of the film cooling orifice in the flow direction, and its value should comprehensively consider both cooling effect and airflow stability. An excessively long flow length may cause premature airflow separation, while an excessively short flow length may prevent the formation of a stable film cooling effect. Therefore, the value of the flow length L should be finely adjusted according to the actual situation.

[0050] Example 2: Figure 1 , Figure 3 As shown, similar to Example 1, except that the air film holes 2 are evenly arranged in rows on the leading edge of the guide vane from the root to the tip of the adjustable guide vane 1, with at least two rows. Among them, at least four rows of air film holes 2 are arranged within the aerodynamic stagnation point movement range of the leading edge 11 of the guide vane, in order to improve the stability of the air film layer and enable the adjustable guide vane to adapt to the heat load under different working conditions.

[0051] The range of movement of the pneumatic stagnation point is the range of movement of the pneumatic stagnation line 12 on the leading edge 11 of the guide vane. The air film holes 2 are asymmetrically arranged on both sides of the pneumatic stagnation line 12 at the middle axial position of the leading edge 11 of the guide vane. That is, the number of air film holes near the pressure surface of the guide vane is greater than the number of air film holes near the suction surface of the guide vane, and the ratio is 1.5~2:1.

[0052] The adjustable guide vane 1 has an adjustment angle θ of 10° to -10°. When the opening of the adjustable guide vane 1 is +10 degrees, the aerodynamic stagnation line 12 is located at the midpoint of the leading edge arc. When the opening of the adjustable guide vane 1 is -10 degrees, the aerodynamic stagnation line 12 is located on the leading edge pressure surface side. As the adjustable guide vane 1 closes, the aerodynamic stagnation line 12 continuously moves towards the pressure surface side.

[0053] The spacing of the air film holes 2 arranged in the leaf height direction is P1, the spacing of the air film holes 2 arranged in the non-stagnant line movement range leading edge arc length direction is P2, the spacing of the air film holes 2 arranged in the stagnant line movement range direction is P3, and the diameter of the cylindrical section of the water droplet is D. Then:

[0054] P2 > P3;

[0055] 2D≤P2≤4D;

[0056] 2D≤P3≤4D.

[0057] like Figure 1 and Figure 3 As shown, with the increase in the number of air film holes within the aerodynamic stagnation point movement range, the uniformity of temperature distribution in the leading edge region under different guide vane openings is improved, the thermal stress of the blades in the leading edge region is reduced, and the reliability and service life of the adjustable low-pressure turbine guide vane are improved.

[0058] Example 3: Similar to Example 1, except that the matrix arrangement of the air film holes is as follows: the air film holes are evenly arranged in rows on the leading edge of the guide vane from the root to the tip of the adjustable guide vane. The adjacent rows of air film holes are staggered in the flow direction, and at least four rows are arranged to reduce the interference between the air film holes and enhance the adhesion of the air film.

[0059] The adjacent air film vents are arranged in a staggered pattern in the flow direction to reduce interference between the vents and enhance the adhesion of the air film. Simultaneously, this arrangement ensures that the cooling airflow forms a uniformly distributed air film layer at the leading edge of the guide vane, improving thermal protection.

[0060] Example 4: Figure 4 , Figure 5 , Figure 6 As shown, the present invention also provides a method for cooling turbine guide vanes, comprising the following steps:

[0061] The cold airflow C1 inside the adjustable guide vane 1 cavity is ejected from the film air hole 2. Each film air hole 2 causes the cold airflow C1 to form an airflow on the surface of the adjustable guide vane 1 with a width matching the flow length of the film air hole 2. This allows sufficient cold airflow C1 to pass close to the film air hole 2 and forms a stable cold air covering layer C3 that completely covers the surface of the adjustable guide vane 1. The cold air covering layer C3 mixes with the mainstream C4, reducing the temperature of the wall surface of the adjustable guide vane 1. On the other hand, the formed cold air covering layer C3 blocks the high-temperature airflow from scouring the wall surface of the adjustable guide vane 1, thereby reducing heat transfer.

[0062] Meanwhile, as the adjustable guide vane 1 closes, the aerodynamic stagnation line 12 continuously moves towards the pressure surface side of the adjustable guide vane 1, and more of the cold air at the leading edge of the adjustable guide vane 1 flows towards the back of the blade. At this time, since the number of air film holes near the pressure surface of the guide vane on both sides of the aerodynamic stagnation line 12 is greater than the number of air film holes near the suction surface of the guide vane, a large amount of cold air flow C1 is discharged from the pressure surface, effectively suppressing the cold air deviation trend, making the cold air at the leading edge flow more evenly towards the blade base and the back of the blade, and reducing the unevenness of the air film distribution.

[0063] like Figure 4 As shown, it displays the streamline diagrams of the traditional cylindrical film air hole layout and the optimized teardrop-shaped air hole layout. Based on the same inlet and outlet boundary conditions, the streamline diagrams of the cold air jets of the optimized teardrop-shaped film air hole layout model and the traditional leading edge layout model are compared. The jet of the cylindrical film air hole is concentrated in the downstream region of the film air hole, while the teardrop-shaped film air hole has an additional forward tilt expansion, which makes its outlet length longer than that of the cylindrical hole with the same tilt angle. This helps to guide the cold air jet to form a stable film air, and the distribution of the cold air jet is more uniform in the radial direction.

[0064] like Figure 5 As shown, the diagram illustrates the film cooling efficiency contour maps of a traditional cylindrical film cooling orifice and an optimized teardrop-shaped orifice. With the traditional cylindrical orifice, the cold air jet, due to its strong normal momentum, often penetrates the main high-temperature airflow after leaving the orifice. Only after reaching a considerable distance in the flow path does the cold air jet gradually adhere to the wall, forming a relatively efficient film cooling effect. However, the optimized teardrop-shaped orifice exhibits different flow characteristics. Due to the teardrop shape, the normal momentum of the jet is relatively small. This design allows the cold air jet to diffuse and mix with the surrounding fluid more quickly after leaving the orifice, thus forming a more uniform and efficient cooling film closer to the orifice. This optimized layout not only improves cooling efficiency but also makes the cooling effect more uniform and covers a wider area.

[0065] like Figure 6 As shown, the distribution of spanwise average film cooling efficiency (FSH) for three models is illustrated. S represents the arc length, and C represents the blade chord length. S / C > 0 indicates the pressure surface region, and S / C < 0 indicates the suction surface region. The figure reveals that the optimized layout of cylindrical FSH orifices effectively improves the spanwise average FSH efficiency at the front of both the suction and pressure surfaces, with a slight decrease at the rear of the pressure surface. Overall, the FSH efficiency on the blade surface is improved by 6.97%. Compared to the traditional cylindrical FSH orifice layout, the teardrop-shaped FSH orifice layout improves the overall FSH effect on the blade surface, increasing the overall FSH efficiency by 25.1%.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A turbine variable stator vane having a water droplet shaped air film hole, characterized by, Includes adjustable guide vanes (1) and a matrix of air film pores (2) on the leading edge (11) of the guide vanes; The aforementioned air film pore (2) is a teardrop-shaped pore formed by the circular part of the water droplet and the transition from the circular streamline to the pointed corner of the water droplet. The circular diameter mapped by the circular part of the air film pore (2) is D, the expansion angle formed by the hole axis of the circular part of the water droplet and the apex position of the pointed corner of the water droplet is α, the flow length from the circular part of the water droplet to the apex of the pointed corner of the water droplet is L, and the pore depth is H. Then: 2mm≥D≥0.5mm, to ensure sufficient cooling airflow while avoiding airflow separation and vortex phenomena caused by excessively large diameter; 45°≥α≥20°, used to guide the cold air jet to form a stable air film; 2≤H / D≤4, to ensure sufficient cooling airflow; 5mm≥L≥1mm, when the flow length L is too long, the airflow will separate prematurely, while if it is too short, a stable air film cannot be formed; The air film holes (2) are evenly arranged in rows on the leading edge of the guide vane from the root to the tip of the adjustable guide vane (1), with at least two rows. Among them, at least four rows of air film holes (2) are arranged within the aerodynamic stagnation point movement range of the leading edge (11) of the guide vane, in order to improve the stability of the air film layer and enable the adjustable guide vane to adapt to the heat load under different working conditions. The pneumatic stagnation point movement range is the movement range of the pneumatic stagnation line (12) on the leading edge (11) of the guide vane. The air film holes (2) are asymmetrically arranged on both sides of the pneumatic stagnation line (12) at the middle axial position of the leading edge (11) of the guide vane. That is, the number of air film holes near the pressure surface of the guide vane is greater than the number of air film holes near the suction surface of the guide vane, and the ratio is (1.5~2):

1. The adjustable guide vane (1) has an adjustment angle θ of 10° to -10°. When the opening of the adjustable guide vane (1) is +10 degrees, the pneumatic stagnation line (12) is located at the midpoint of the leading edge arc line. When the opening of the adjustable guide vane (1) is -10 degrees, the pneumatic stagnation line (12) is located on the leading edge pressure surface side. As the adjustable guide vane (1) closes, the pneumatic stagnation line (12) moves continuously towards the pressure surface side. The spacing of the air film holes (2) arranged in the blade height direction is P1, the spacing of the air film holes (2) arranged in the aerodynamic stagnation line movement range leading edge arc length direction is P2, the spacing of the air film holes (2) arranged in the aerodynamic stagnation line movement range in the aerodynamic stagnation line movement range is P3, and the diameter of the cylindrical section of the water droplet hole is D, then: P2 > P3; 2D≤P2≤4D; 2D≤P3≤4D.

2. The turbine adjustable guide vane with teardrop-shaped film gas holes as described in claim 1, characterized in that, The guide vane leading edge (11) is mapped as a plane and divided into multiple identical area units. The air film hole (2) is set in the area unit. The longitudinal unit length Sy of the area unit is along the blade height span of the guide vane leading edge (11), and the transverse unit length Sx of the area unit is along the leading edge arc length span of the guide vane leading edge (11). Then the opening rate of the air film hole (2) on the area unit of the guide vane leading edge (11) is 5~15%.

3. The turbine adjustable guide vane with teardrop-shaped film gas holes as described in claim 1, characterized in that, The matrix arrangement of the air film holes (2) is specifically as follows: the air film holes (2) are evenly arranged in rows on the leading edge of the guide vane from the root to the tip of the adjustable guide vane, and at least four rows are arranged to form a uniformly distributed air film layer on the leading edge of the guide vane, thereby improving the thermal protection effect.

4. The turbine adjustable guide vane with teardrop-shaped film gas holes as described in claim 1, characterized in that, The matrix arrangement of the air film pores is specifically as follows: the air film pores are evenly arranged in rows on the leading edge of the guide vane from the root to the tip of the adjustable guide vane, and adjacent rows of air film pores are staggered in the flow direction, and at least four rows are arranged to reduce interference between the air film pores and enhance the adhesion of the air film.

5. The turbine adjustable guide vane with teardrop-shaped film gas holes as described in any one of claims 1-4, characterized in that, The water droplet tip of the air film pore (2) points towards the leaf root.

6. The method for cooling turbine guide vanes as described in any one of claims 1-4, characterized in that, Includes the following steps: The cold airflow C1 in the cavity of the adjustable guide vane (1) is ejected from the film air hole (2). Each film air hole (2) causes the cold airflow C1 to form an airflow on the surface of the adjustable guide vane (1) with a width matching the flow length of the film air hole (2), allowing sufficient cold airflow C1 to pass close to the film air hole (2) and forming a stable cold air covering layer C3 that completely covers the surface of the adjustable guide vane (1). On the one hand, the cold air covering layer C3 mixes with the mainstream C4 to reduce the temperature of the wall of the adjustable guide vane (1); on the other hand, the formed cold air covering layer C3 blocks the high temperature airflow from scouring the wall of the adjustable guide vane (1), thereby reducing heat transfer. At the same time, as the adjustable guide vane (1) closes, the aerodynamic stagnation line (12) moves continuously toward the pressure surface side of the adjustable guide vane (1), and more cold air flows toward the back of the blade. At this time, since the number of air film holes near the pressure surface of the guide vane on both sides of the aerodynamic stagnation line (12) is greater than the number of air film holes near the suction surface of the guide vane, a large amount of cold air flow C1 is discharged from the pressure surface, which effectively suppresses the cold air deviation trend, and makes the cold air at the leading edge flow more evenly toward the blade basin and the back of the blade, reducing the unevenness of the air film distribution.

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