Turbine shroud blade for a gas turbine

Abstract

The application provides a turbine shroud blade of a gas turbine. The turbine shroud blade comprises a blade body and a shroud, the blade body has a blade top, the shroud is arranged on the blade top, the shroud is provided with a baffle, the baffle comprises a front row of baffles and a rear row of baffles, the front row of baffles is close to a front edge of the shroud, the rear row of baffles is close to a rear edge of the shroud, the shroud extends to outside of the blade body from front to rear, and upper surfaces of the front edge and the rear edge of the shroud are connected with side walls through smooth curved surfaces; slope angles of both sides of the baffle are between 30° and 60°, a top of the baffle is connected through a smooth curved surface, a bottom of the baffle is connected with an upper surface of the shroud through a smooth curved surface; a cooling channel is arranged inside the blade body, and the shroud is provided with a plurality of film holes penetrating through upper and lower surfaces. The application changes the shape of the shroud and the baffle, fully utilizes cold air to cool the blade, combines with the structure to improve the flow and heat exchange characteristics in the shroud gap, and weakens local high heat exchange.

Description

Technical Field

[0001] This invention relates to the field of gas turbine blade technology, and particularly to a crowned turbine blade for a gas turbine. Background Technology

[0002] A gas turbine is a thermodynamic mechanical device that uses air as its working medium, converting the chemical energy of fuel into mechanical energy. It is widely used in aircraft propulsion, power generation, and various industrial applications. Its core components are the compressor, combustion chamber, and turbine. The turbine rotor's work is the primary means of generating thrust. Within the turbine components, the blades are directly subjected to the high-temperature, high-pressure combustion gases, with operating temperatures far exceeding the temperature resistance limits of the materials used in their construction. Designing the blades for safe, stable, and long-life operation, considering internal flow characteristics and additional cooling structures, is crucial. Especially during rotor rotation, the pressure difference across the blades causes leakage flow at the blade tips, flowing from the pressure side to the suction side, resulting in significant flow losses and heat transfer effects. In severe cases, this can lead to blade ablation and chipping. To improve component performance, crowns are typically used at the tips of the moving blades to enhance sealing, working in conjunction with the casing. This concentrates the airflow in the main flow path, enhancing the aerodynamic efficiency of the rotor in a single turbine stage, achieving better work output, and also providing better blade vibration damping.

[0003] like Figure 1 As shown, A represents the blade crown, and B represents the blade section. Besides the blade crown, the blade crown typically employs multiple rows of serrations (C) to impede rearward airflow and enhance sealing, forming an "I"-shaped structure, which also improves the blade crown stiffness. Traditional serration structures are mostly trapezoidal in cross-section, offering good sealing performance, such as... Figure 1 The shown is the grating C. Turbines operate in high-temperature environments, and various cooling structures are incorporated into the blades to mitigate the impact of the high-temperature combustion gases. Considering the cooling effect of the cold gas on the blades is also essential; for hooded blades, cooling can further enhance blade performance and expand the operating environment of the blades.

[0004] While this type of grating structure provides a good seal, it also leads to complex flow patterns within the cavity, potentially causing heat transfer issues. For example, complex vortex flows can form in the angled dead zone, and sharp edges can create scraping vortex flow structures, affecting flow and heat transfer around the walls. Such flow patterns can easily lead to enhanced localized heat transfer, further impacting the structure and performance of the component. Summary of the Invention

[0005] The purpose of this invention is to provide a crowned turbine blade for a gas turbine. The design of the blade crown and ferrules is modified to further improve the performance of the crowned turbine blade. It also fully utilizes cool air to cool the blade, and the structural design improves the flow and heat transfer characteristics within the blade crown gap, reducing localized high heat transfer. Furthermore, compared to other designs, the cutting and rounding scheme of this invention increases the overall stiffness of the blade, reduces localized stress, and is easier to manufacture.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] A turbine blade with a crown for a gas turbine includes a blade body and a blade crown. The blade body has a blade tip, and the blade crown is disposed at the blade tip. The blade crown is provided with grating teeth, which include a front row of grating teeth and a rear row of grating teeth. The front row of grating teeth is close to the leading edge of the blade crown, and the rear row of grating teeth is close to the trailing edge of the blade crown.

[0008] The leaf crown extends both forward and backward outside the leaf blade, and the upper surfaces of the leading and trailing edges of the leaf crown are connected to the sidewalls by smooth arc surfaces.

[0009] The slope angle of the inclined surfaces on both sides of the grating teeth is between 30° and 60°. The top of the grating teeth is connected by a smooth arc surface, and the bottom of the grating teeth is connected to the upper surface of the leaf crown by a smooth arc surface.

[0010] The blade body has a cooling channel inside, and the blade crown has several air film holes that penetrate the upper and lower surfaces.

[0011] Optionally, the leading and trailing edges of the leaf crown are rounded, and the top and bottom of the ferrules are rounded.

[0012] Optionally, the axial width of the leaf crown inlet and outlet channels is L, the rounding radius of the leading and trailing edges of the leaf crown and the rounding radius of the top and bottom of the grating teeth are all r, and r and L satisfy: 20% ≤ r / L ≤ 50%.

[0013] Optionally, the thickness of the main body of the leaf crown is σ, and the height of the comb teeth is θ, where θ and σ satisfy: 1≤θ / σ≤3.

[0014] Optionally, the distance between the front row of grates and the leading edge of the leaf crown is D / 3, the distance between the rear row of grates and the trailing edge of the leaf crown is D / 3, and the spacing between the grates is D / 3, where D is the axial length of the leaf crown.

[0015] Optionally, the air film pores are located on the leaf crown surface corresponding to the inlet cavity and the leaf crown surface corresponding to the central cavity.

[0016] Optionally, all the air film pores are arranged on the same circumference.

[0017] Optionally, the pore size s of the air film is 0.4 mm to 1 mm.

[0018] Optionally, the axial spacing of the air film pores on the blade surface corresponding to the inlet cavity is greater than the pore diameter s.

[0019] Optionally, the distance from the air film hole closest to the tooth to the tooth is greater than the distance from the arc surface boundary to the tooth.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] This invention uses a turbine double-crate crowned blade as a reference. The upper surface and sidewall of the leading and trailing edges of the blade crown are connected by a smooth arc surface to reduce weight and guide airflow. The shape of the crate teeth is improved to reduce the slope angle on both sides and the transition is made by using an arc surface. A film cooling hole is added to the blade tip cavity, and the modified blade crown and crate teeth shape are combined to achieve better cooling. Attached Figure Description

[0022] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the drawings described below are one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort:

[0023] Figure 1 This is a schematic diagram of the structure of a crowned blade;

[0024] Figure 2 A schematic cross-sectional view of the turbine blade with a crown provided by the present invention;

[0025] Figure 3 for Figure 2 A schematic diagram of the apex portion of the middle leaflet;

[0026] Figure 4 A detailed structural diagram of the turbine crowned blade provided by this invention;

[0027] Figure 5 A cross-sectional parameter diagram of the turbine crowned blade provided for this invention;

[0028] Figure 6 A top view of the crowned turbine blade provided by the present invention;

[0029] Figure 7 for Figure 6 Enlarged view of point A in the middle;

[0030] Figure 8 , Figure 9 The images show the 2D streamlines of the leaf crown cross-section corresponding to the control leaf crown structure in the first embodiment and the improved leaf crown structure of the present invention, respectively.

[0031] Figure 10 , Figure 11 These are graphs showing the temperature and flow rate changes at different locations along the gap cross section;

[0032] Figure 12 , Figure 13 The images show the 2D streamlines of the leaf crown cross-section corresponding to the control leaf crown structure in the second embodiment and the improved leaf crown structure of the present invention, respectively.

[0033] Figure 14 , Figure 15 The images show the surface temperature cloud diagrams of the control leaf crown structure in the second embodiment and the improved leaf crown structure of the present invention at a rotation speed of 4000 rpm, respectively.

[0034] Figure 16 , Figure 17 The images show the surface temperature cloud diagrams of the control leaf crown structure in the second embodiment and the improved leaf crown structure of the present invention at a rotation speed of 8000 rpm. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0036] This invention is based on the double-crate crowned blade of a gas turbine. The leading and trailing edges of the blade crown are cut to create a smooth arc connection between the upper surface and the sidewall, reducing weight and guiding flow at the inlet and outlet. The shape of the cleavers is improved by reducing the slope angles on both sides, increasing the width of the cleaver root, and using a smooth arc transition at the turning points. Figure 2 As shown; axially equidistant film cooling holes are added to the concave cavity at the top of the crown blade, which, combined with the modified crown and serrated shape, achieves better cooling, such as... Figure 3 As shown. This invention belongs to the field of gas turbine blade structure design, specifically, it addresses the local styling of the tip of a crowned blade, specifically a blade tip structure form with modified serrations and crown edges. Based on improvements to the flow and heat transfer performance of the turbine rotor, particularly the performance improvement of the blade tip wall, this invention can be applied to some low-pressure turbine rotors and some high-pressure turbine rotors, and its application scope can be expanded to a wider range.

[0037] The realization of this invention is first based on the design, processing, and manufacturing benchmarks of the crowned blade, followed by the determination of the shape of the crown and the serrations. The small slope angle and curvature of the serrations, as well as the arc surfaces of the leading and trailing edges of the crown, are then manipulated to achieve the desired effect. Finally, the design of the film cooling system and its compatibility with the modified serrations and crown structure must be considered. This is the basic idea behind the realization of this invention.

[0038] like Figures 2-7 As shown, the present invention provides a crowned turbine blade for a gas turbine, comprising a blade body 10 and a crown 20. The blade body 10 has a blade tip 11, and the crown 20 is disposed at the blade tip 11. The crown 20 is provided with fangs 21, the fangs 21 including a front row of fangs 21a and a rear row of fangs 21b. The front row of fangs 21a is close to the leading edge 20a of the crown, and the rear row of fangs 21b is close to the trailing edge 20b of the crown. The crown 20 extends beyond the blade body 10 at both ends. The upper surfaces of the leading edge 20a and the trailing edge 20b of the crown are connected to the sidewalls by a flat... For ease of study, the leading edge 20a and trailing edge 20b of the blade crown can be rounded using a cutting process to achieve a smooth transition connection; the slope angle of the inclined surfaces on both sides of the grating teeth 21 is between 30° and 60°, the top of the grating teeth 21 is connected by a smooth arc surface, and the bottom of the grating teeth is connected to the upper surface of the blade crown by a smooth arc surface. Preferably, the top and bottom of the grating teeth can be rounded to achieve a smooth transition connection; the blade body 10 is provided with a cooling channel inside, and the blade crown 20 is provided with a plurality of air film holes 22 penetrating the upper and lower surfaces.

[0039] This invention employs a design that incorporates internal direct-flow cooling of turbine blades, blade tip film cooling, blade crown edge cutting and rounding of grates, and a small side slope angle to improve the inlet and outlet flow structure and heat exchange performance.

[0040] The specific technical solution and parameter settings for the structure are as follows, such as... Figure 5 , 6 As shown in Figure 7: Taking a blade channel with a canopy as an example, the surface width of the canopy 20 must cover the top of the blade body 10, and the axial length of the canopy 20 is D; the blade body 10 has a certain radial twist angle, a blade height of h, and a wall thickness greater than a certain value to ensure the structural strength of the blade; a cooling channel is set inside the blade body 10. Regarding the cooling airflow, this invention mainly focuses on the influence of film cooling at the blade tip, and does not specifically limit the design and requirements of internal cooling, which can be referred to the existing technology; the axial width of the inlet and outlet channels of the canopy 20 is L; the main body thickness σ of the canopy 20 is 1% to 2%h. An excessively thick canopy will increase the centrifugal stress of rotation, which is not conducive to improving efficiency;

[0041] The leaf crown 20 extends outwards from the blade body 10. The upper surfaces of the leading edge 20a and trailing edge 20b are both rounded to cut the leaf crown 20. The rounding radius r is 20% to 50%L. If it is too small, it will not be enough to improve the edge flow or reduce the mass. If it is too large, it will affect the structure and may increase leakage. The slope angle of the inclined surfaces on both sides of the grate 21 is about 60°. It should not be less than 30° even with a high grate height. If the root width is too large, it will also affect the arrangement of the air film pores at the top of the blade and increase the mass of the leaf crown. The rounding radius of the top and bottom of the grate 21 is also r.

[0042] The grates 21 are distributed in one row at the front and one row at the rear edge of the blade crown 20, with a height θ of 1 to 3σ. The distance between the front row of grates 21a and the front edge 20a is D / 3, and the distance between the rear row of grates 21b and the rear edge 20b is D / 3. The spacing between the grates is D / 3. In other embodiments, the distance between the rear row of grates 21b and the rear edge 20b can be appropriately reduced. This part of the blade tip surface is not in the main cooling range, and the two rows of grates have formed a good sealing effect.

[0043] The surface of the blade crown 20 corresponding to the inlet cavity a is distributed with several film cooling holes 22, which extend from the inner surface of the cooling channel below the blade crown 20 to the upper surface. Due to the limitation of the relative position of the blade body 10, the number of film cooling holes 22 should not be too large, the hole diameter s is 0.4mm to 1mm, and the axial spacing of the holes can be 1.6s and 2.4s, with a spacing at least greater than s. The film cooling holes 22 can be arranged equidistantly or unequally in the axial direction. The surface of the blade crown 20 corresponding to the central cavity b is distributed with more film cooling holes 22, which extend from the inner surface of the blade crown 20 to the upper surface. The aperture s of the air film holes 22 extends to the upper surface and is 0.4 mm to 1 mm. The axial spacing of the holes can be appropriately increased, for example, to 2.4 s. The air film holes 22 can be arranged equidistantly or unequally in the axial direction. All air film holes 22 are arranged on the same circumference. The surface of the blade crown 20 corresponding to the outlet cavity c does not have air film cooling holes. The distance from the air film hole 22 closest to the grate tooth 21 to the grate tooth 21 is generally greater than the distance from the arc surface boundary to the grate tooth 21. For example, the distance from the air film hole 22 closest to the grate tooth 21 to the grate tooth 21 is 6 s. The cross-sectional shape of the air film holes 22 can be cylindrical or other suitable cross-sectional shapes.

[0044] The parameters determined above are for maintaining the basic shape characteristics of the present invention. The parameters within the range of variation can only be used as a reference, provided that the basic forms of the leaf crown and the fang teeth are kept close.

[0045] It is understandable that this invention simultaneously improves the blade tip and ferrule, achieving several positive effects without significantly altering the leakage rate of the crowned blade: eliminating excessive local stress; guiding the airflow entering the corner of the blade tip gap, improving corner flow; considering the comprehensive impact of film cooling on the large rounded blade tip structure; the rounded cutting scheme at the leading and trailing edges of the blade tip reduces the surrounding complex flow structure, weakens heat exchange between the blade tip edge and the high-temperature gas, reduces local impact, and extends service life; the rounded ferrule also reduces local heat exchange, decreases local stress, and increases blade stiffness. Simultaneously, the small slope and rounded shape allow for widespread propagation of the nearby film cooling airflow, extending the film cooling effect. These improved characteristics broaden the applicability of the invention's structure. This invention provides a flow and cooling structure for the blade tip of a crowned gas turbine blade, specifically for the turbine rotor, improving flow and heat transfer at the blade tip while maintaining good sealing performance.

[0046] Specifically, the blade crown structure enhances the sealing of the single-row blade flow path. Airflow primarily passes through the main flow channel, with a small amount of leakage entering the gap between the blade crown and the casing. Compared to the right-angled blade crown edge, the rounded cut creates a gradually contracting channel after the airflow enters the gap, reducing edge obstruction and mitigating the scraping and impact of high-temperature combustion gases on the leading edge surface of the blade crown. This also reduces heat exchange between the high-temperature combustion gases and the leading edge surface, providing a degree of protection for the leading edge. Compared to the inlet width, the radius of the rounded cut is within a certain range and does not increase leakage losses.

[0047] As the high-temperature airflow reaches the front of the grate teeth, the improved vortex structure in front of the teeth results in a more orderly airflow. Guided by the gently sloping wall, the airflow flows more smoothly into the grate tooth gaps through the constriction channel, alleviating the stagnant flow in the right-angle dead zone. From the bottom to the top of the grate tooth gap, the channel first constricts and then expands, allowing the airflow to flow smoothly near the wall. From the moment the airflow enters the blade crown gap to its passage through the grate tooth gaps, the complex flow structure near the wall is alleviated and improved, reducing heat exchange between the high-temperature combustion gas and the wall. With the grate tooth height remaining constant, although the resistance to fluid inflow into the grate tooth gaps is reduced, the inflow cross-sectional area remains unchanged, resulting in minimal change in leakage.

[0048] Both rows of grates have a different number of film cooling holes in front of them. Under the impact of a suitable proportion of cooling airflow, the blade surface and the high-temperature combustion gas are blocked by the cold air. The axially equidistant cooling holes can also better cover the circumference with cold air during the rotor's rotation. When the blade edge and the grate surface are smoothly rounded, the cooling airflow covers a wider area as it flows along the wall, resulting in a better cooling effect.

[0049] The rounded blade tip edge reduces local stress, increases structural strength, reduces blade crown mass, and shifts the center of gravity towards the blade tip, mitigating adverse blade vibrations. It also reduces corrosion and breakage under the impact of high-temperature exhaust gases. The simple cooling holes facilitate design, processing, and manufacturing. The comprehensive design benefits enable this invention to improve blade performance, ensure work efficiency, mitigate excessive local heat transfer, and adapt to a wider range of operating conditions.

[0050] This invention is best suited for use in gas turbine rotors where blade temperature resistance and structural strength are critical, and is particularly well-suited for operating environments with internal cooling. The crowned rotor blades, combined with the casing cavity, concentrate airflow in the main flow path, significantly reducing leakage. The grating on the blade crown further enhances sealing and improves efficiency. The blade crown cutting scheme, along with the grating slope angle and rounded design, comprehensively alters the flow near the wall surface, improving the heat transfer characteristics of the wall. Combined with film cooling, this further enhances blade performance, enabling it to adapt to more demanding environments. The effects of this invention are described in detail below with two embodiments.

[0051] Example 1:

[0052] Numerical simulations were performed on traditional right-angled trapezoidal cross-section double-crate crowned blades applied to low-pressure turbine blades with cooling structures. A comparative example was then applied to low-pressure turbine blades with the same cooling structure, featuring a cut crown, low-slope cleavage, and rounded design, as described in this invention. Specific parameters were: axial width at the inlet and outlet of the crown was 5 mm, crown thickness was 1.5 mm, cleavage height was 2.5 mm, cleavage gap was 0.5 mm, and rounding radius was 1 mm. The crown gap was used as the sole research object, and the same inlet flow conditions were set.

[0053] Figure 8 , Figure 9 This is a schematic diagram of the 2D streamlines of the circumferential cross-section within the blade crown gap. A small portion of the leakage flow enters the blade crown from the main flow channel. Under the scraping action of the blade crown leading edge, a large-scale vortex flow is formed in the direction towards the rear wall, forming a second corner vortex near the right-angled grate wall. The remaining fluid accelerates across the vortex structure and passes through the upper gap, forming a large vortex structure in the central cavity. Smaller vortex structures are also generated at the corner behind the first grate. These vortex structures near the wall significantly affect the heat transfer of the wall surface, forming high heat transfer regions in areas with complex flow near the wall surface, where frequent heat exchange occurs with the high-temperature combustion gas.

[0054] Compared to right-angled ferrules, the rounded leading and trailing edges of the blade crown essentially eliminate the large vortex structure behind it, and the vortex structure in the original ferrule corner area becomes smaller, allowing the fluid within the gaps to pass through more neatly. The flow after the first ferrule is also improved, with a gentler flow near the wall. Apart from the changes in the flow structure near the wall, the overall flow rate and velocity from the blade crown inlet to outlet change little. This indicates that the present invention effectively improves the flow and heat transfer performance near the blade tip wall while ensuring the sealing effect of the crowned blade.

[0055] like Figure 10 , Figure 11 The figures show a comparison of temperature and flow rate at various cross-sections in the gap between the double-toothed blades with right-angled trapezoidal cross-sections (dashed lines) and rounded cross-sections (solid lines). The x-axis represents the four cross-sectional positions from the inlet to the outlet of the blade gap. As can be seen from these two figures, although the results may differ to some extent with different tooth shapes, the flow rate and other parameters are very close at key node positions, ensuring the sealing effect of the teeth.

[0056] Example 2:

[0057] Taking a single-row blade channel as the research object, considering the effect of rotation, and setting the same inlet total temperature, total pressure, and outlet static pressure conditions, the study was conducted under multiple operating conditions. The pressure of the cold air was slightly higher than the gas pressure within the gaps between the grates. Specific parameters were: axial width of the blade inlet and outlet of 5 mm, blade thickness of 1.5 mm, grate height of 2.5 mm, grate gap of 0.5 mm, and rounding radius of 1 mm. Figure 12 , Figure 13 The figures show the 2D streamlines at different cross-sections of the blade tip structure at the blade crown gap. It is evident that the streamline distribution differs across cross-sections, with the most significant differences lying in the vortex structure near the inlet blade crown surface and the presence and morphology of complex flow structures in the corner region near the ferrules. For the improved blade tip structure, the flow structure near the smooth transition at the rounded corners of the blade crown and ferrules is simpler, thus improving heat transfer. Especially above the film cooling holes, the mainstream flow in the gap is significantly influenced by the cooling airflow. The combination of the film cooling airflow and the flow in the gap affects the flow pattern near the wall, causing the film cooling airflow to flow closer to the wall, providing better protection and positively impacting the heat transfer coefficient and temperature distribution on the blade crown surface.

[0058] like Figures 14-17 This is a cloud map showing the temperature distribution on the blade surface at different rotational speeds. (Comparison) Figure 14 , Figure 15As can be seen in this embodiment, under low-speed operating conditions, the distribution of the film cooling airflow is relatively similar under different structures. When using the blade tip structure of this invention, the low-temperature area near the film cooling holes in the inlet cavity is larger. This is especially evident in the central cavity, where the low-temperature coverage area is larger, and the lower-temperature region spreads more widely along the circumference. Under this condition, the average surface temperature of the blade tip is relatively similar for both structural forms.

[0059] contrast Figure 16 , Figure 17 It can be seen that under high-speed conditions, the relative temperature distribution patterns of the two structural forms tend to be consistent due to the influence of high speed, with low temperature mainly concentrated on the wall surface affected by the circumferential influence of the film cooling gas. However, the average temperature difference between the two is as high as 15K, indicating that the combined effect of structural changes and cooling gas results in a significant temperature reduction.

[0060] Under low-speed conditions, the overall flow leakage rate at the inlet of the crown gap of the right-angled blade tip structure is 0.0758%, while the leakage rate at the inlet of the improved blade tip structure of this invention is 0.0976%. The leakage flow rate is significantly smaller than the total inlet flow rate, and the difference in leakage rates between the two structures does not exceed 3%. Under high-speed conditions, the overall flow leakage rate at the inlet of the crown gap of the right-angled blade tip structure is 0.082%, while the leakage rate at the inlet of the improved blade tip structure of this invention is 0.0947%. The leakage flow rate is significantly smaller than the total inlet flow rate, and the difference in leakage rates between the two structures does not exceed 1.5%. Furthermore, it can be calculated that in this embodiment, the difference in leakage rates at the outlet of the crown gap under low and high speed conditions does not exceed 2% and 1.2%, respectively. Therefore, the single-row blades exhibit good overall sealing performance, the crowned blades themselves have low leakage rates, and the modification does not significantly alter the leakage rate, thus not affecting blade efficiency. This indicates that this invention can improve the overall heat exchange and film cooling effect at the blade tip without significantly affecting aerodynamic efficiency.

[0061] Based on the verification of the above examples and the shape characteristics of the rounded and cut structure, the present invention can produce certain positive effects in terms of blade flow, heat transfer, stress and other aspects.

[0062] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A crowned turbine blade for a gas turbine, comprising a blade body and a crown, wherein the blade body has a blade tip, the crown is disposed at the blade tip, and the crown is provided with serrations, the serrations comprising a front row of serrations and a rear row of serrations, the front row of serrations being close to the leading edge of the crown, and the rear row of serrations being close to the trailing edge of the crown; characterized in that: The leaf crown extends both forward and backward outside the leaf blade, and the upper surfaces of the leading and trailing edges of the leaf crown are connected to the sidewalls by smooth arc surfaces. The slope angle of the inclined surfaces on both sides of the grating teeth is between 30° and 60°. The top of the grating teeth is connected by a smooth arc surface, and the bottom of the grating teeth is connected to the upper surface of the leaf crown by a smooth arc surface. The blade body has a cooling channel inside, and the blade crown has several air film holes that penetrate the upper and lower surfaces.

2. The turbine crowned blade of the gas turbine as described in claim 1, characterized in that, The leading and trailing edges of the leaf crown are rounded, and the top and bottom of the ferrule are rounded.

3. The turbine crowned blade of the gas turbine as described in claim 2, characterized in that, The axial width of the leaf crown inlet and outlet channels is L, the rounding radius of the leading and trailing edges of the leaf crown and the rounding radius of the top and bottom of the grating teeth are all r, and r and L satisfy: 20% ≤ r / L ≤ 50%.

4. The crowned turbine blade of the gas turbine as described in claim 1, characterized in that, The thickness of the main body of the leaf crown is σ, and the height of the comb teeth is θ, where θ and σ satisfy: 1≤θ / σ≤3.

5. The crowned turbine blade of the gas turbine as described in claim 1, characterized in that, The distance between the front row of grates and the leading edge of the leaf crown is D / 3, the distance between the rear row of grates and the trailing edge of the leaf crown is D / 3, and the spacing between the grates is D / 3, where D is the axial length of the leaf crown.

6. The crowned turbine blade of the gas turbine as described in claim 1, characterized in that, The air film pores are located on the leaf crown surface corresponding to the inlet cavity and the leaf crown surface corresponding to the central cavity.

7. The crowned turbine blade of the gas turbine as described in claim 6, characterized in that, All the air film pores are arranged on the same circumference.

8. The crowned turbine blade of the gas turbine as described in claim 6, characterized in that, The pore diameter s of the air film pore is 0.4 mm to 1 mm.

9. The turbine crowned blade of the gas turbine as described in claim 8, characterized in that, The axial spacing of the air film pores on the blade crown surface corresponding to the inlet cavity is greater than the pore diameter s.

10. The turbine crowned blade of the gas turbine as described in claim 6, characterized in that, The distance from the air film hole closest to the tooth to the tooth is greater than the distance from the arc surface boundary to the tooth.

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