Power turbine with interstage integrated transition section

Abstract

The invention relates to the field of turboprop engine power turbines, in particular to a power turbine with an interstage integrated transition section, the end wall of the power turbine comprises an inner end wall and an outer end wall, the inner end wall is arranged in the outer end wall, and an annular channel is formed between the inner end wall and the outer end wall; the height between the inner end wall and the outer end wall of the annular channel at the integrated transition section is firstly increased and then decreased in the airflow direction; the integrated transition section, the first-stage turbine rotor section and the second-stage turbine guider section jointly form a channel with the inner end wall and the outer end wall expanding and extending upwards in a positive slope mode, and the second-stage turbine rotor section, the third-stage turbine guider section and the third-stage turbine rotor section form a channel with the inner end wall expanding and extending downwards in a negative slope mode and the outer end wall expanding and extending upwards in a positive slope mode. According to the power turbine, channel airflow separation and too high or too low local flow velocity can be avoided, the size and the weight of the power turbine can be reduced, the loss of an interstage integrated transition section can be controlled, and the turbine efficiency can be improved.

Description

Technical Field

[0001] The present invention relates to the field of power turbines of turboprop engines, and specifically to a power turbine with an integrated inter-stage transition section. Background Art

[0002] Most of the power turbines of high-power turboprop engines are arranged in a multi-stage axial flow manner. The turbine pressure ratio drop is high, and the area difference from the inlet to the outlet is large. Moreover, due to the different rotational speeds of the power turbine and the upstream gas turbine, there are often obvious differences in the turbine radius height between the power turbine and the gas turbine. To meet the air flow circulation requirements and ensure uniform expansion of the power turbine area, a transition section needs to be arranged between the power turbine and the gas turbine to meet the air flow circulation requirements. This makes the axial length of the power turbine long, and the size and weight are large, which affects the improvement of the engine power-to-weight ratio. To reduce the axial length of the power turbine, currently, an integrated inter-stage transition section structure in which the first-stage guide vane of the power turbine is integrated with the transition section is adopted on advanced engines. However, this structure cannot reduce the radial dimension difference between the power turbine and the gas turbine. Moreover, after adopting the integrated inter-stage transition section, the axial length of the power turbine is shortened, which causes a significant increase in the expansion angle of the turbine passage and an increase in the loss of the integrated inter-stage transition section, seriously affecting the aerodynamic performance of the power turbine. The larger the area ratio between the inlet and outlet of the power turbine, the more difficult it is to control the loss of the power turbine with the integrated inter-stage transition section structure. The contradiction between high aerodynamic performance and compact structure becomes more prominent.

[0003] Due to the different rotational speed differences between the power turbine and the gas turbine, there are obvious differences in the channel heights between the power turbine and the gas turbine. Moreover, for high-power multi-stage turboprop engines, due to the large turbine expansion ratio, the area difference between the inlet and outlet of the turbine is large. The turbine needs to adopt a longer axial length to balance the area difference between the inlet and outlet, so that the air flow acceleration is uniform. The traditional power turbine flow passage is as attached Figure 1 , the rear section of the inner end wall is arranged with an equal inner diameter, the outer end wall of the transition section does not have a turning structure, the annular channel does not have a converging structure and a corresponding appropriate inclination angle. For multi-stage power turbines with a relatively large expansion ratio, it will cause a relatively large height of the outlet last-stage turbine blades, and an excessive inclination angle on the outer end wall, which brings greater adverse factors to the aerodynamic performance, size, weight and strength life of the turbine. To take into account the height requirements of the flow passages of each stage of the power turbine, it will cause an excessive climbing angle or an excessive length of the transition section, increasing the difficulty of the aerodynamic design of the transition section. The design of the transition section needs to take into account the design of the turbine section, and the relevant design parameters of the two need to be designed in an associated manner to further improve the aerodynamic performance of the entire power turbine. Poor design is likely to lead to a relatively high pressure loss, affecting the aerodynamic performance of the power turbine. Summary of the Invention

[0004] The object of the present invention is to provide a power turbine with an integrated inter-stage transition section, which can avoid channel air flow separation and local flow velocity being too high or too low, that is, it can reduce the size and weight of the power turbine, and at the same time control the loss of the integrated inter-stage transition section and improve the turbine efficiency.

[0005] The object of the present invention can be achieved by the following technical solutions:

[0006] A power turbine with an integrated inter-stage transition section, the end wall of the power turbine includes an inner end wall and an outer end wall, the inner end wall is arranged inside the outer end wall, and an annular channel is formed between the inner end wall and the outer end wall. The annular channel includes an integrated transition section and a turbine section connected in sequence. The turbine section includes a first-stage turbine rotor section, a second-stage turbine guide vane section, a second-stage turbine rotor section, a third-stage turbine guide vane section, and a third-stage turbine rotor section connected in sequence. Blades are evenly distributed in each section of the integrated transition section and the turbine section. The height between the inner and outer end walls of the annular channel at the integrated transition section first increases and then decreases along the air flow direction; the integrated transition section, the first-stage turbine rotor section, and the second-stage turbine guide vane section together form a channel with both the inner and outer end walls extending upward with a positive slope, and the second-stage turbine rotor section, the third-stage turbine guide vane section, and the third-stage turbine rotor section form a channel with the inner end wall extending downward with a negative slope and the outer end wall extending upward with a positive slope.

[0007] In a further aspect, the area ratio of the outlet to the inlet of the annular channel is 3.5 - 4.5, and the height ratio of the outlet to the inlet of the annular channel is 2.5 - 3.5.

[0008] In a further aspect, the area ratio of the outlet to the inlet of the integrated transition section is 1 - 1.6.

[0009] In a further aspect, when the calculation formula for the average inclination angle of the end wall is θave = atan / L, where θave is the average inclination angle, R2 is the radius height at the intersection of the end wall outlet section and the end wall of the section to be calculated, R1 is the radius height at the intersection of the end wall inlet section and the end wall of the section to be calculated, and L is the axial distance between the two intersections, the average inclination angle of the outer end wall of the transition section is 20 - 23°, and the average inclination angle of the inner end wall of the transition section is 15 - 17°.

[0010] In a further aspect, the channel formed by the second-stage turbine rotor section, the third-stage turbine guide vane section, and the third-stage turbine rotor section is in a flared shape.

[0011] In a further embodiment, the arc-shaped channel in the integrated transition section is an arc-shaped air flow channel. The angle between the tangent direction of the axial cross-sectional line of the inner end wall of the integrated transition section and the engine axis first decreases and then increases along the air flow direction, and the angle between the tangent direction of the axial cross-sectional line of the outer end wall of the transition section and the engine axis first increases and then decreases along the air flow direction.

[0012] In a further embodiment, the change and turning positions of the angles are determined according to the position of the maximum curvature of the suction surface of the blade profile of the integrated transition section; the change and turning positions of the angles are located at the 12-20% relative chord length position of the blade of the integrated transition section.

[0013] In a further embodiment, the angle between the tangent direction of the axial cross-sectional line of the inner end wall of the integrated transition section and the engine axis is 0-15° in the decreasing stage and 15-20° in the increasing stage; the angle between the tangent direction of the axial cross-sectional line of the outer end wall of the integrated transition section and the engine axis is 25-40° in the increasing stage and 18-25° in the decreasing stage.

[0014] In a further embodiment, the average inclination angle of the outer end wall of the first-stage turbine rotor section is 22-27°, and the average inclination angle of the inner end wall of the first-stage turbine rotor section is 14-20°; the average inclination angle of the outer end wall of the second-stage turbine guide vane section is 22-27°, and the average inclination angle of the inner end wall of the second-stage turbine guide vane section is 4-8°; the average inclination angle of the outer end wall of the second-stage turbine rotor section is 22°-27°, and the average inclination angle of the inner end wall of the second-stage turbine rotor section is -6°-0°; the average inclination angle of the outer end wall of the third-stage turbine guide vane section is 20-24°, and the average inclination angle of the inner end wall of the third-stage turbine guide vane section is -8° to -4°; the average inclination angle of the outer end wall of the third-stage turbine rotor section is 0°-16°, and the average inclination angle of the inner end wall of the third-stage turbine rotor section is -8° to -4°.

[0015] Advantages of the present invention:

[0016] In the arc-shaped annular flow channel of the transition section of the present invention, the height between the inner and outer end walls of the annular channel first increases and then decreases along the air flow direction, which can reduce the air flow velocity at the blade inlet section and reduce the flow loss in the transition section.

[0017] The first three stages of the power turbine adopt a coordinated upward-expanding flow channel layout, reducing the axial length of the power turbine.

[0018] The last three stages of the power turbine adopt a coordinated upward and downward expanding channel layout structure. The annular channel at the last three stages is in the shape of a flared mouth, which can meet the flow area requirements of the subsequent stages of the high-expansion ratio power turbine while reducing the size and weight.

[0019] By optimizing the climbing angles of each section of the channel and reasonably controlling the change of the blade channel area along the way, it is possible to avoid the separation of the channel air flow and the excessive or too low local flow velocity, that is, it can reduce the size and weight of the power turbine, and also control the loss of the inter-stage integrated transition section and improve the turbine efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 is a schematic diagram of the layout of a power turbine with a medium inner diameter structure in the related art;

[0022] Figure 2 is a schematic diagram of the layout of the power turbine with an inter-stage integrated transition section in this embodiment;

[0023] Figure 3 is a marked diagram of the power turbine transition section in the embodiment of the present invention;

[0024] Figure 4 is a schematic diagram of the position with the maximum curvature of the blade profile surface of the transition section in the embodiment of the present invention;

[0025] In the figure: 1. Transition section; 2. First-stage turbine rotor section; 3. Second-stage turbine guide vane section; 4. Second-stage turbine rotor section; 5. Third-stage turbine guide vane section; 6. Third-stage turbine rotor section; 7. Inner end wall; 8. Outer end wall; 9. Blade. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0027] Such as Figure 2As shown in the figure, a power turbine with an integrated inter-stage transition section. The end wall of the power turbine includes an inner end wall 7 and an outer end wall 8. The inner end wall 7 is arranged inside the outer end wall 8, and an annular channel is formed between the inner end wall 7 and the outer end wall 8. The annular channel includes an integrated transition section 1 and a turbine section connected in sequence. The turbine section includes a first-stage turbine rotor section 2, a second-stage turbine guide vane section 3, a second-stage turbine rotor section 4, a third-stage turbine guide vane section 5, and a third-stage turbine rotor section 6 connected in sequence. Blades 9 are evenly distributed in each section of the integrated transition section 1 and the turbine section. In the figure, it is the position indicated by the cross-hatching. The height between the inner and outer end walls of the annular channel at the integrated transition section 1 first increases and then decreases along the air flow direction; the integrated transition section 1, the first-stage turbine rotor section 2, and the second-stage turbine guide vane section 3 together form a channel in which both the inner and outer end walls expand and extend with a positive slope upward, and the second-stage turbine rotor section 4, the third-stage turbine guide vane section 5, and the third-stage turbine rotor section 6 form a channel in which the inner end wall expands and extends with a negative slope downward and the outer end wall expands and extends with a positive slope upward.

[0028] This power turbine, together with the upstream gas turbine and the downstream exhaust frame structure, constitutes the turbine component of a turboprop engine to meet the gas expansion work demand. The projection contour lines of the inner end wall and the outer end wall in the axial section are integrally continuous. As Figure 2 The height of the annular channel is matched with the height of the blades. Therefore, the blade height changes in the same way as the height of the annular channel. The integrated transition section 1 adopts an integrated structure of the transition section and the first-stage turbine guide vane section, which can not only realize the connection between the upstream gas turbine and the power turbine, but also provide guidance and acceleration for the air flow flowing into the first-stage turbine rotor section 2 in the power turbine.

[0029] In some embodiments, the value range of the area ratio of the outlet to the inlet of the annular channel can be 3.5 - 4.5, and the value range of the height ratio of the outlet to the inlet of the annular channel can be 2.5 - 3.5.

[0030] In some embodiments, the value range of the area ratio of the outlet to the inlet of the integrated transition section 1 can be 1 - 1.6.

[0031] In some embodiments, when the calculation formula for the average inclination angle of each section of the annular channel is defined as θ ave = atan(R2 - R1) / L, where θ ave is the average inclination angle, R2 is the radius height at the intersection of the outlet section of the end wall of the section to be calculated and the end wall of this section, R1 is the radius height at the intersection of the inlet section of the end wall of the section to be calculated and the end wall of this section, and L is the axial distance between the two intersections. As Figure 3 shown, the radius height R at the intersection of the outlet section of the outer end wall of the integrated transition section 1 and the outer end wall of the integrated transition section 1 is calculated t2Substitute R2, the radius height R of the intersection point between the inlet section of the outer end wall of the integrated transition section 1 and the outer end wall of the integrated transition section 1 t1 Substitute R1, L is R t2 and R t1 For the distance value corresponding to the two intersection points, the average inclination angle of the outer end wall of the integrated transition section 1 can be obtained. Similarly, substitute the radius height R of the intersection point between the outlet section of the inner end wall of the integrated transition section 1 and the outer end wall of the integrated transition section 1 h2 Substitute R2, the radius height R of the intersection point between the inlet section of the inner end wall of the integrated transition section 1 and the outer end wall of the integrated transition section 1 h1 Substitute R1, L is the distance value corresponding to the two intersection points of Rh2 and Rh1, and the average inclination angle of the inner end wall of the integrated transition section 1 can be obtained. Through experiments, it can be obtained that when the range of the average inclination angle of the outer end wall of the integrated transition section 1 can be 20 - 23°, and the range of the average inclination angle of the inner end wall of the integrated transition section 1 can be 15 - 17°, the air extraction requirement of the integrated transition section 1 can be met.

[0032] Through this arrangement of the inner and outer end walls, on the one hand, by controlling the flow area expansion ratio of the integrated transition section 1, the climbing angle of the integrated transition section 1 can be reduced, thereby reducing the axial length of the integrated transition section 1. And due to the required smaller expansion angle of the integrated transition section 1, the integrated transition section 1 can operate in a region with better performance; further, through the optimized arrangement of the inner and outer end profiles, the increase in the flow area of the front section of the integrated transition section 1 is relatively large, and the fluid velocity at the inlet of the inner blade flowing through this section can be reduced as much as possible. And through the area change in the rear section of the integrated transition section 1 and the convergence of the blade channels of the integrated transition section 1, the outlet air flow can be accelerated to the design speed, so that the flow loss in the integrated transition section 1 can be reduced and the performance of the power turbine can be improved.

[0033] In some embodiments, the average inclination angle of the outer end wall of the first-stage turbine rotor section 2 can range from 22-27°, and the average inclination angle of the inner end wall of the first-stage turbine rotor section 2 can range from 14-20°, so that the inner and outer end walls of the first-stage turbine rotor section 2 can be arranged to be tilted upward and have a suitable average inclination angle; the average inclination angle of the outer end wall of the second-stage turbine guide vane section 3 can range from 22-27°, and the average inclination angle of the inner end wall of the second-stage turbine guide vane section 3 can range from 4-8°, so that the inner and outer end walls of the second-stage turbine guide vane section 3 can be arranged to be tilted upward and have a suitable average inclination angle; the average inclination angle of the outer end wall of the second-stage turbine rotor section 4 can range from 22°-27°, so that the outer end wall of the second-stage turbine rotor section 4 can be arranged to be tilted upward and have a suitable average inclination angle, and the second The average inclination angle of the inner end wall of the turbine rotor section 4 can range from -6° to 0°, so that the inner end wall of the second-stage turbine rotor section 4 can be kept straight or tilted downward, and can have a suitable average inclination angle; the average inclination angle of the outer end wall of the third-stage turbine guide vane section 5 can range from 20-24°, so that the outer end wall of the third-stage turbine guide vane section 5 can be arranged to be tilted upward, and can have a suitable average inclination angle, the average inclination angle of the inner end wall of the third-stage turbine guide vane section 5 can range from -8° to -4°, so that the inner end wall of the third-stage turbine guide vane can be arranged to be tilted downward and have a suitable average inclination angle, the outer end wall of the third-stage turbine rotor section 6 is arranged to be tilted upward or straight, the average inclination angle of the outer end wall can range from 0° to 16°, the inner end wall is arranged to be tilted downward, and the average inclination angle can range from -8° to -4°.

[0034] In some embodiments, Figure 3 As shown, the arc-shaped passage at the integrated transition section 1 is an arc-shaped airflow passage, and the angle between the tangent direction of the axial cross-section line of the inner end wall of the integrated transition section 1 and the engine axis first decreases and then increases along the airflow direction. Figure 3 The diagram is not very clear, and those skilled in the art should be able to imagine that the inner end wall angle first decreases from zero to a certain negative value, and then gradually increases. Through this structure, the inner end wall first expands toward the engine axis and then climbs away from the axis. The angle between the tangent direction of the axial cross-section line of the outer end wall of the integrated transition section 1 and the engine axis first increases and then decreases along the airflow direction, that is, there is an angle turning point on the inner and outer end walls of the integrated transition section 1. The end wall angle is defined as the local inclination angle and is marked as θ t When the local inclination angle is positive, it means that the radius height of the end wall profile increases from the inlet to the outlet. When the local inclination angle is negative, it means that the radius height of the end wall profile decreases from the inlet to the outlet.

[0035] The local inclination angle of the inner end wall first decreases and then increases, while the local inclination angle of the outer end wall first increases and then decreases, so that the blade height between the inner and outer end walls first increases and then decreases along the flow direction. The turning position of the change in the local inclination angles of the inner and outer end walls can be determined according to the position of the maximum curvature of the suction surface of the blade profile of the integrated transition section 1. Refer to Figure 3 the turning position of the change in the included angle shown, which is theoretically the position of the maximum curvature on the blade profile at the blade tip and blade root as shown in Figure 4 The connection line of the maximum positions is the connection line of the points with the maximum curvature on the blade profiles at the blade root and blade tip. The specific position of the point with the maximum blade profile curvature can be determined according to the transition section load. In this embodiment, the turning point of the local inclination angle of the end wall is located at the position of 12-20% of the relative chord length of the blade of the integrated transition section 1. According to the different blade profile loads at the blade root and blade tip positions of the integrated transition section 1 blade, the turning position is different; before the turning point of the local inclination angle, the range of the local inclination angle of the outer end wall can be between 25-40°, and the range of the local inclination angle of the inner end wall can be between 0-15°; after the turning point of the inclination angle, the range of the local inclination angle on the outer end wall can be between 18-25°, and the range of the local inclination angle on the inner end wall can be between 15-20°. Thus, through this arrangement, the annular passage area in front of the integrated transition section blade is increased as much as possible, the flow velocity in front of the blade is reduced, and the flow loss in the integrated transition section is reduced.

[0036] The blades of the integrated transition section 1 can be composed of a combination of large and small blades with different outer shapes or blades with the same outer shape of the integrated transition section 1. A convergent cascade passage is formed between two adjacent blades of the integrated transition section 1.

[0037] In this way, through the relay upward inclination and climb of the inner and outer end walls of the first-stage rotor section 2 and the second-stage guide vane section 3, the lack of insufficient area expansion of the integrated transition section 1 between stages is supplemented. Under the limited axial dimension, the radial height difference requirements of the gas turbine and the power turbine can be met, the overall axial length of the power turbine is reduced, and the weight of the turbine is reduced.

[0038] Aiming at the characteristics of the large flow area demand and strong work capacity of the third-stage turbine. By keeping the outer end walls of the last three turbine sections, namely the second-stage turbine rotor section 4, the third-stage turbine guide vane section 5 and the third-stage turbine rotor section 6, continue to tilt upward, but the inclination angle gradually decreases, and the inner end part tilts downward, and by constructing a "horn"-shaped channel, while ensuring the high flow area and high work capacity requirements of the last-stage turbine of the power turbine, the maximum outer diameter dimension of the third-stage turbine rotor section 6 of the power turbine can be reduced, the size of the turbine disk is reduced, and the weight of the power turbine casing and the turbine disk is greatly reduced.

[0039] Thus, through the above methods, the requirement for the expansion of the airflow area of the power turbine is met, ensuring the aerodynamic performance of the turbine while reducing the size and weight of the turbine.

[0040] In addition to reducing the axial and radial dimensions, the weight of the power turbine can be reduced by replacing the blade material with a lightweight material, such as titanium aluminide. In addition, the weight can be reduced by increasing the rotational speed of the power turbine and reducing the height of the power turbine flow path. Or the axial length can be adjusted by adjusting the axial clearance between the rotor blades and the stator blades.

[0041] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0042] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A power turbine with an integrated inter-stage transition section, the end wall of the power turbine comprising an inner end wall (7) and an outer end wall (8), the inner end wall (7) being disposed within the outer end wall (8), an annular channel being formed between the inner end wall (7) and the outer end wall (8), the annular channel comprising an integrated transition section (1) and a turbine section connected in sequence, the turbine section comprising a first-stage turbine rotor section (2), a second-stage turbine stator section (3), a second-stage turbine rotor section (4), a third-stage turbine stator section (5), and a third-stage turbine rotor section (6) connected in sequence, blades (9) being evenly distributed within each of the integrated transition section (1) and the turbine section, characterized in that, The height between the inner and outer end walls of the annular passage at the integrated transition section (1) first increases and then decreases along the air flow direction. The integrated transition section (1), the first-stage turbine rotor section (2), and the second-stage turbine guide vane section (3) together form a passage with both the inner and outer end walls expanding and extending with a positive slope upwards. The second-stage turbine rotor section (4), the third-stage turbine guide vane section (5), and the third-stage turbine rotor section (6) form a passage with the inner end wall expanding and extending with a negative slope downwards and the outer end wall expanding and extending with a positive slope upwards.

2. A power turbine with an integrated inter-stage transition section according to claim 1, characterized in that, The area ratio of the outlet to the inlet of the annular passage is 3.5 - 4.5, and the height ratio of the outlet to the inlet of the annular passage is 2.5 - 3.

5.

3. The power turbine with an integrated inter-stage transition section according to claim 1, characterized in that The area ratio of the outlet to the inlet of the integrated transition section (1) is 1 - 1.

6.

4. A power turbine with an integrated inter-stage transition section according to claim 1, characterized in that, When the calculation formula for the average inclination angle of the end wall is θ ave = atan(R2 - R1) / L, where θ ave is the average inclination angle, R2 is the radius height at the intersection of the end wall outlet section of the section to be calculated and the end wall of this section, R1 is the radius height at the intersection of the end wall inlet section of the section to be calculated and the end wall of this section, and L is the axial distance between the two intersections, the average inclination angle of the outer end wall of the transition section (1) is 20 - 23°, and the average inclination angle of the inner end wall of the transition section (1) is 15 - 17°.

5. A power turbine with an integrated inter-stage transition section according to claim 1, characterized in that The passage formed by the second-stage turbine rotor section (4), the third-stage turbine guide vane section (5), and the third-stage turbine rotor section (6) is in the shape of a flared opening.

6. A power turbine with an integrated inter-stage transition section according to claim 1, characterized in that, The arc-shaped passage at the integrated transition section (1) is an arc-type air flow passage. The angle between the tangent direction of the axial section line of the inner end wall of the integrated transition section (1) and the engine axis first decreases and then increases along the air flow direction, and the angle between the tangent direction of the axial section line of the outer end wall of the transition section (1) and the engine axis first increases and then decreases along the air flow direction.

7. A power turbine with an integrated inter-stage transition section according to claim 6, characterized in that, The change and turning positions of the angles are determined according to the position of the maximum curvature of the suction surface of the blade profile of the integrated transition section (1); the change and turning positions of the angles are located at the 12 - 20% relative chord length position of the integrated transition section blade.

8. A power turbine with an integrated inter-stage transition section according to claim 7, characterized in that, The angle between the tangent direction of the axial section line of the inner end wall of the integrated transition section (1) and the engine axis is 0 - 15° in the decreasing stage and 15 - 20° in the increasing stage; the angle between the tangent direction of the axial section line of the outer end wall of the integrated transition section (1) and the engine axis is 25 - 40° in the increasing stage and 18 - 25° in the decreasing stage.

9. A power turbine with an integrated inter-stage transition section according to claim 1, characterized in that The average inclination angle of the outer end wall of the first-stage turbine rotor section (2) is 22 - 27°, and the average inclination angle of the inner end wall of the first-stage turbine rotor section (2) is 14 - 20°; the average inclination angle of the outer end wall of the second-stage turbine guide vane section (3) is 22 - 27°, and the average inclination angle of the inner end wall of the second-stage turbine guide vane section (3) is 4 - 8°; the average inclination angle of the outer end wall of the second-stage turbine rotor section (4) is 22° - 27°, and the average inclination angle of the inner end wall of the second-stage turbine rotor section (4) is -6° - 0°; the average inclination angle of the outer end wall of the third-stage turbine guide vane section (5) is 20 - 24°, and the average inclination angle of the inner end wall of the third-stage turbine guide vane section (5) is -8° to -4°; the average inclination angle of the outer end wall of the third-stage turbine rotor section (6) is 0° - 16°, and the average inclination angle of the inner end wall of the third-stage turbine rotor section (6) is -8° to -4°.

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