Turbine and guide vane design method

Abstract

The application provides a turbine guide vane design method for adjusting temperature distribution of high-temperature gas flow along the height direction of the turbine guide vane, which comprises the following steps: selecting a plurality of blade profiles in the root area, the middle area and the tip area of the turbine guide vane respectively; adjusting the outlet effective angle of each blade profile, and then adjusting the throat width at the height of the blade profile, so that the throat width of the tip area is greater than that of the middle area. The above method can adjust the temperature distribution of the high-temperature gas flow along the height direction, especially reduce the temperature of the high-temperature gas flow at the root. The application also provides a turbine.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aero-engines, in particular to the field of turbines. BACKGROUND

[0002] With the development of aero-engine technology, the temperature at the outlet of the combustion chamber is continuously increased to achieve higher engine performance. The high-temperature and high-pressure gas discharged from the combustion chamber enters the high-pressure turbine, is deflected and accelerated by the guide vanes, and then impacts the rotor blades, causing them to rotate and output power. The working characteristics of high temperature, high pressure and high speed impose higher requirements on turbine design. The high-pressure turbine rotor blades are subjected to both high-temperature gas erosion and centrifugal tensile force caused by high speed, and the tensile stress is the largest at the blade root region, so the blade root region becomes the key position that restricts the improvement of the service life of the rotor blades.

[0003] The strength and service life of the turbine rotor blades mainly depend on two aspects: one is the temperature of the upstream gas flow, and the other is the cooling scheme of the rotor blades. To improve the service life of the rotor blades, by improving the cooling scheme of the rotor blades, by increasing the cooling gas flow, optimizing the internal cooling channel, optimizing the shape and arrangement of the film holes, etc., the metal temperature of the blades is reduced, the temperature gradient and thermal stress are improved, which is the main solution measure in the current engineering. However, increasing the cooling gas flow of the rotor blades will reduce the performance of the aero-engine and increase the specific fuel consumption. With the continuous increase of the temperature before the turbine, the improvement of the service life brought by the optimization of the cooling scheme of the rotor blades is more and more limited. Therefore, under the condition that the temperature at the outlet of the combustion chamber is certain, by optimizing the guide vanes to reduce the temperature of the gas flow at the root region of the rotor blades, another effective measure to improve the service life of the rotor blades can be taken.

[0004] However, the existing turbine guide vane distribution structure is generally arranged at the upper and lower end wall regions of the flow passage with high aerodynamic loss to reduce the flow, and arranged at the middle radial region of the flow passage with low aerodynamic loss to increase the flow, thereby reducing the aerodynamic loss of the blades, but such structure ignores the migration path of the high-temperature gas flow in the combustion chamber at the guide vanes, which is easy to cause the temperature of the gas flow at the root region of the downstream rotor blades to further increase and affect the service life of the blades. SUMMARY

[0005] An object of the present application is to provide a turbine guide vane design method capable of adjusting the temperature distribution of the high-temperature gas flow along the blade height direction, in particular reducing the temperature of the high-temperature gas flow at the blade root.

[0006] The turbine guide vane design method for adjusting the temperature distribution of high-temperature gas flow along the blade height direction comprises the following steps: selecting a plurality of blade profiles in the blade root area, the middle blade area and the blade tip area of the turbine guide vane respectively; adjusting the outlet effective angle of each blade profile, and further adjusting the throat width at the blade height where the blade profile is located, so that the throat width of the blade tip area is greater than the throat width of the middle blade area, wherein the narrowest throat width at the blade height where the blade profile is located has a first intersection point and a second intersection point with the circumferentially adjacent two turbine guide vanes, the first intersection point is the leading edge of one of the turbine guide vanes, and the second intersection point is located on the blade body of the other turbine guide vane, and the included angle between the line connecting the second intersection point and the leading edge point of the other turbine guide vane and the turbine guide vane ordinate is the outlet effective angle.

[0007] In one or more embodiments, the throat width of the blade tip area is greater than the throat width of the middle blade area by 15-25%.

[0008] In one or more embodiments, the method further comprises the following steps: determining the peak flow channel position of the high-temperature gas flow; and locating the minimum throat width below the peak flow channel position.

[0009] In one or more embodiments, the throat width of the blade root area is greater than the throat width of the middle blade area.

[0010] In one or more embodiments, the blade root area is 0-33% of the blade height, the middle blade area is 33-66% of the blade height, and the blade tip area is 66-100% of the blade height.

[0011] In one or more embodiments, the stacking line design is adopted for each blade profile to obtain the three-dimensional profile of the designed guide vane.

[0012] In one or more embodiments, the form of the radial stacking curve includes one or more of Bezier curve, polynomial curve or spline curve.

[0013] In one or more embodiments, the outlet effective angle is set in the range of 5-10°.

[0014] Another object of the present application is to provide a turbine comprising turbine guide vanes, wherein the throat width between each adjacent circumferential guide vane is set to be small in the middle and large at both ends along the blade height direction.

[0015] In one or more embodiments, the radial height of the narrowest throat is lower than the radial height of the peak of the high-temperature gas.

[0016] The turbine guide vane design method adjusts the throat width by using the calculated relationship between the outlet effective angle of the blade profile and the throat width, and adjusts the flow direction of the high-temperature gas flow in the combustion chamber by using the throat width, so as to change the temperature distribution of the high-temperature gas flow in the radial direction, reduce the incoming flow temperature of the gas flow in the blade root area of the rotor blade, and thereby improve the service life of the blade. BRIEF DESCRIPTION OF DRAWINGS

[0017] The above and other features, properties, and advantages of the present application will become more apparent by referring to the following description in conjunction with the accompanying drawings, in which:

[0018] Figure 1 is a structural schematic diagram of a turbine guide vane and a throat;

[0019] Figure 2A is a schematic diagram of a two-dimensional blade profile of a turbine guide vane;

[0020] Figure 2B is a schematic diagram of an outlet effective angle;

[0021] Figure 3 is a radial distribution of the throat width of a blade profile along the height direction of the flow passage

[0022] Figure 4 is a radial distribution diagram of the geometric outlet angle of a blade profile along the height direction of the flow passage;

[0023] Figure 5 is a radial distribution diagram of the installation angle of a blade profile along the height direction of the flow passage;

[0024] Figure 6 is a radial distribution of the inlet and outlet gas temperatures of a guide vane along the height direction of the flow passage;

[0025] Figure 7 is a flowchart of a turbine guide vane design method. DETAILED DESCRIPTION

[0026] The present application will be further described below in conjunction with specific embodiments and drawings, and more details are set forth in the following description in order to fully understand the present application, but the present application can certainly be implemented in various other ways different from the description, and those skilled in the art can make similar generalizations and deductions according to actual application conditions without departing from the connotation of the present application, so the protection scope of the present application should not be limited by the content of the specific embodiments.

[0027] It should be noted that these and other subsequent drawings are only examples, and are not drawn according to the condition of the same scale, and should not be used as a limitation on the actual protection scope required by the present application.

[0028] The aero-engine mainly comprises a compressor, a combustion chamber and a turbine. High-temperature and high-pressure gas discharged from the combustion chamber is changed in direction by a high-pressure turbine guide vane, expanded and accelerated, and impacts turbine moving blades at a certain angle to make the turbine moving blades rotate and output power.

[0029] In the central region of the combustion chamber flame tube, fuel combustion generates a high-temperature core. In the region near the wall surface of the flame tube, the temperature of the gas is relatively low due to the distance from the combustion core and the effect of wall cooling. Therefore, the temperature field of the high-temperature gas at the outlet of the combustion chamber is non-uniform, showing a distribution characteristic of high in the center and low in the periphery. Usually, the peak temperature of the high-temperature gas is located near 50% of the height of the flow passage.

[0030] The high-pressure turbine guide vane is connected with the combustion chamber. The distribution of the outlet temperature of the combustion chamber changes when passing through the guide vane: on the one hand, the turbine guide vane cooling gas can reduce the local gas temperature, and on the other hand, the flow guiding effect of the guide vane can change the gas flow path.

[0031] The turbine guide vane is composed of a plurality of blades in the circumferential direction, as shown in Figure 1 The first guide vane 1 and the second guide vane 2 are two guide vanes adjacent in the circumferential direction along the Y direction, have a pressure surface 7 (blade basin) and a suction surface 6 (blade back), and the minimum distance position between the first guide vane 1 and the second guide vane 2 is matched with the lower edge plate 3 and the upper edge plate 4 to form a throat 5 of the guide vane. The throat width determines the size of the gas flow, and therefore the radial distribution of the throat width along the Z direction determines the radial migration direction of the high-temperature gas flow from the leading edge to the trailing edge of the guide vane.

[0032] However, the current radial flow distribution of the turbine guide vane mainly considers the aspect of reducing aerodynamic loss. Usually, the flow is reduced in the upper and lower end wall regions of the flow passage with high aerodynamic loss, or the flow is increased in the middle radial region of the flow passage with low loss to reduce the aerodynamic loss of the blade, which easily leads to further increase of the inlet temperature of the downstream rotor blade root region, and ignores the influence of the radial migration of the guide vane on the gas temperature distribution and the strength and service life of the downstream rotor blade. The high-pressure turbine rotor blade simultaneously bears the high-temperature gas ablation and the centrifugal tensile force caused by high speed, and the tensile stress is the largest in the blade root region. The blade strength and endurance reserve in this region is low, and it is difficult to meet the engine life requirement. This is the key position restricting the improvement of the service life of the rotor blade.

[0033] To solve the above problems, the turbine guide vane of the present disclosure controls the throat width of the guide vane according to the temperature distribution characteristics of the combustion chamber exhaust gas, thereby controlling the radial distribution of the high-temperature gas flow, guiding the high-temperature core region of the combustion chamber to be away from the lower end region, reducing the inlet gas temperature of the rotor blade root region, and improving the service life of the blade. The aerodynamic performance of the guide vane and the downstream rotor blade is also considered.

[0034] The turbine guide vane design method of the present disclosure comprises the following steps: selecting a plurality of blade profiles in the blade root region, the mid-blade region and the blade tip region of the turbine guide vane respectively, and profiling the blade root, the mid-blade and the blade tip respectively; adjusting the outlet effective angle of each blade profile, and further adjusting the throat width at the blade height where the blade profile is located, so that the throat width in the blade tip region is greater than the throat width in the mid-blade region

[0035] Specifically, as shown in the blade profile diagram, Figure 2A The two-dimensional profile section is composed of a blade back and a blade basin, and the smooth and continuous whole profile line ensures excellent aerodynamic performance. The minimum distance o between the adjacent two guide vanes defines the throat width at this blade height. It can be understood that the minimum distance between each layer of adjacent blade profiles in the blade height direction is defined, forming the throat distribution along the blade height direction.

[0036] The blade profile has parameters: throat width o, grid distance t of the vane, installation angle s of the blade profile, outlet effective angle a, and chord length c.

[0037] The straight line connecting the leading edge points of the blade profiles in the plane vane is called the head line E, and the installation angle s of the blade profile is defined as the angle between the blade profile chord line X and the head line E, which represents the inclination of the blade profile in the vane.

[0038] Continuing to refer to Figure 2B The minimum throat width o has a second intersection point M and a first intersection point N with the first guide vane 1 and the second guide vane 2 respectively. It can be understood that the first intersection point N is the leading edge point of the second guide vane 2. The connecting line between the second intersection point M and the leading edge P of the first guide vane 1 where it is located is called the first connecting line Q, and the outlet effective angle a is defined as the angle between the first connecting line Q and the head line E. The first connecting line Q forms a triangle with the throat width o and the grid distance t, and the angle β of the triangle is approximately equal to 90°. Since β is approximately equal to 90°, the throat width o can be approximately considered as equal to t*sin(α), and the difference is ignored.

[0039] Therefore, for the two-dimensional blade profile section of the blade, under the condition that the grid distance t is constant, the throat width o can be adjusted by changing the outlet effective angle a.

[0040] It should be noted that in the present embodiment, the blade root region is generally located at 0%~33% of the blade height, the mid-blade region is generally located at 33%~66% of the blade height, and the blade tip region is generally located at 66%~100% of the blade height. However, it can be understood by those skilled in the art that the blade root region, the mid-blade region and the blade tip region include but are not limited to the above range.

[0041] The radial direction of the guide vane is designed using a spline curve, and a three-dimensional surface is formed by stacking curves along the stacking axis. The form of the radial stacking curve is controlled to be not limited to Bezier curves, polynomial curves, or combinations of several spline curves. The desired throat width radial distribution curve along the blade height is constructed as follows: Figure 3 As shown. In this embodiment, the stacking axis of the guide vanes is the center of the leading edge diameter of the guide vanes.

[0042] Multiple two-dimensional airfoils can be used in the blade root, middle, and tip regions at the blade height to achieve greater freedom in controlling the radial distribution of the throat width. Since the throat width can guide the flow direction of high-temperature combustion gases, the throat width in the blade tip region can be made larger than that in the middle region. For example, if the throat width in the blade tip region is 15-25% larger than that in the middle region, the highest-temperature combustion gases located near 50% of the flow channel height will flow towards the blade tip under the guidance of the increased throat width in the blade tip region. This will guide the high-temperature core area of ​​the combustion chamber outlet combustion gases upward, reducing the incoming flow temperature in the rotor blade root region.

[0043] Preferably, the peak position of the high-temperature gas in the blade height direction is determined; the effective outlet angle of the airfoil surface located in the middle region of the blade is adjusted so that the minimum throat width is located below the blade height position where the highest gas temperature is located. This design ensures that most of the high-temperature gas flow discharged from the combustion chamber can be guided towards the blade tip through the throat width design.

[0044] like Figure 3 and Figure 4 As shown, when the peak temperature of the high-temperature combustion gas in the combustion chamber is located at 50% of the flow channel height, below 50% of the flow channel height but above 45%, the effective exit angle of the guide vane's airfoil surface along the blade height direction gradually increases, thereby causing the throat width to gradually increase along the blade height direction. The increasing trend of the throat width along the blade height direction is a smooth curve with a gradually increasing slope, so that the throat width of the blade tip profile is preferably 15% to 25% greater than that of the blade mid-section profile.

[0045] Therefore, under the guiding effect of the guide vanes, the combustion gas migrates from the radial height where the throat width is small to the radial height where the throat width is large. Consequently, the high-temperature core region of the combustion gas discharged from the combustion chamber gradually migrates upwards as it moves from the leading edge to the trailing edge of the guide vanes, and the peak temperature radial position shifts above 50%. Therefore, the combustion gas temperature decreases in the region below 50% of the blade height. Figure 6 As shown in the diagram, the dashed line represents the gas temperature at the inlet of the guide vane, and the solid line represents the gas temperature at the outlet of the guide vane. It can be seen that after the turbine guide vane is adjusted according to the above design, the temperature distribution curve of the high-temperature gas is significantly shifted upward, thereby reducing the incoming flow temperature at the blade root.

[0046] Continue backFigure 3 and Figure 4 As shown in Figs. 1 and 2, the outlet effective angle of the blade profile surface in the blade root area is greater than that in the middle blade area below the 50% blade height where the highest temperature of the high-temperature gas is located, such as below the 45% blade height, so as to increase the throat width of the blade root profile section, increase the flow rate and axial velocity of the gas flow in the blade root area, and reduce the aerodynamic loss of the downstream rotor blade root by lowering the flow capacity of the lower end area, thereby delaying the development of the end wall passage vortex of the downstream rotor blade and reducing the aerodynamic loss of the rotor blade root, and improving the turbine efficiency.

[0047] As shown in Figs. 1 and 2, the outlet effective angle of the blade profile surface in the blade root area is greater than that in the middle blade area below the 50% blade height where the highest temperature of the high-temperature gas is located, such as below the 45% blade height, so as to increase the throat width of the blade root profile section, increase the flow rate and axial velocity of the gas flow in the blade root area, and reduce the aerodynamic loss of the downstream rotor blade root by lowering the flow capacity of the lower end area, thereby delaying the development of the end wall passage vortex of the downstream rotor blade and reducing the aerodynamic loss of the rotor blade root, and improving the turbine efficiency. Figure 4 and Figure 5 As shown in Figs. 1 and 2, the outlet effective angle of the blade profile surface in the blade root area is greater than that in the middle blade area below the 50% blade height where the highest temperature of the high-temperature gas is located, such as below the 45% blade height, so as to increase the throat width of the blade root profile section, increase the flow rate and axial velocity of the gas flow in the blade root area, and reduce the aerodynamic loss of the downstream rotor blade root by lowering the flow capacity of the lower end area, thereby delaying the development of the end wall passage vortex of the downstream rotor blade and reducing the aerodynamic loss of the rotor blade root, and improving the turbine efficiency.

[0048] The guide vane installation angle of the tip area is greater than that of the middle blade area, and the guide vane installation angle of the blade root area is greater than that of the middle blade area, and the outlet effective angle of each blade profile surface in the radial direction deviates by 5° to 10°, and the guide vane installation angle s at different radial positions deviates by 3° to 7°.

[0049] The specific value of the guide vane installation angle of the two-dimensional blade profile and the design of the blade profile contour line should consider the aerodynamic performance of the guide vane and the thickness distribution law of the blade profile. In the direction of the blade height, the thickness of the blade profile in the leading edge area of each two-dimensional blade profile is the same in the radial direction, and the thickness of the blade profile in the trailing edge area gradually decreases from top to bottom, so as to facilitate the design and installation of the impact cooling sleeve inside the hollow guide vane.

[0050] The turbine guide vane with the above throat width radial distribution has excellent aerodynamic performance, can guide the high-temperature core area of the combustion chamber outlet gas to move upward, and reduce the incoming flow temperature of the high-temperature gas in the rotor blade root area. This area simultaneously bears high temperature and high centrifugal force, and reducing the incoming flow temperature of the high-temperature gas at this key position can improve the strength reserve and service life of the rotor blade root, and improving the flow capacity of the lower end area can reduce the aerodynamic loss of the downstream rotor blade root, which takes into account the aerodynamic performance and strength service life of the rotor blade, and improves the reliability of the blade.

[0051] The height position, profile section number and combustion chamber outlet temperature peak position of the above two-dimensional blade profile are only examples, and need to be adjusted according to the actual combustion chamber outlet temperature peak position.

[0052] In combination with the introduction of the above turbine guide vane design method, it can also be understood that a turbine, by adjusting the radial position of the two-dimensional modeling section, increasing the number of modeling sections, and the stacking rule along the blade height direction, the throat width between adjacent circumferential guide vanes of the turbine presents the distribution characteristics of small in the middle and large at both ends along the blade height, the radial height of the minimum throat width is lower than the radial height of the peak temperature of the combustion chamber outlet gas, the throat width of the tip region is 15% to 25% larger than that of the middle region, and the increase amount of the throat width of the tip region blade profile relative to the throat width of the middle region blade profile is determined according to the requirement of reducing the inlet flow temperature of the rotor blade root region. It can be understood that the larger the increase amount of the throat width of the tip region relative to the throat width of the middle region, the lower the inlet flow temperature of the rotor blade root region.

[0053] Meanwhile, specific words are used in the present application to describe the embodiments of the present application. As "one embodiment", "an embodiment", and / or "some embodiments" means a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that the "one embodiment" or "one alternative embodiment" mentioned in different positions in the specification twice or more does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be properly combined.

[0054] Although the present application is disclosed with the preferred embodiments as above, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the technical solution of the present application, fall within the protection scope defined by the claims of the present application.

Claims

1. A turbine guide vane design method for adjusting the temperature distribution of high-temperature gas flow along the blade height direction, characterized in that, Includes the following steps: Multiple airfoil surfaces are selected in the root, middle, and tip regions of the turbine guide vane; Adjust the effective exit angle of each of the aforementioned blade surfaces, thereby adjusting the throat width at the leaf height where the blade surface is located, so that the throat width in the leaf tip region is greater than the throat width in the leaf middle region. Among them, the narrowest throat at the blade height where the airfoil is located has a first intersection point and a second intersection point with the two circumferentially adjacent turbine guide vanes. The first intersection point is the leading edge of one of the turbine guide vanes, and the second intersection point is located on the blade body of the other turbine guide vane. The second intersection point and the leading edge point of the other turbine guide vane to which it is located form a line, and the angle between the line and the forehead line of the turbine guide vane is the effective exit angle.

2. The turbine guide vane design method as described in claim 1, characterized in that, The throat width in the leaf tip region is 15-25% greater than the throat width in the leaf middle region.

3. The turbine guide vane design method as described in claim 1, characterized in that, The method also includes the following steps: Determine the flow channel location of the peak value of the high-temperature gas flow; The minimum throat width is located below the flow channel position of the peak value.

4. The turbine guide vane design method as described in claim 3, characterized in that, Make the throat width in the leaf root region greater than the throat width in the leaf middle region.

5. The turbine guide vane design method as described in claim 1, characterized in that, The leaf root region is 0% to 33% of the leaf height, the leaf middle region is 33% to 66% of the leaf height, and the leaf tip region is 66% to 100% of the leaf height.

6. The turbine guide vane design method as described in claim 1, characterized in that, The overlapping line design is used for each airfoil to obtain the three-dimensional airfoil of the designed guide vane.

7. The turbine guide vane design method as described in claim 6, characterized in that, The form of the control radial stacking curve includes one or more of the following: Bezier curve, polynomial curve, or spline curve.

8. The turbine guide vane design method as described in claim 1, characterized in that, The effective exit angle is set within the range of 5° to 10°.

9. A turbine, including turbine guide vanes, characterized in that, The throat width between adjacent circumferential guide leaves is set to be narrower in the middle and wider at both ends along the leaf height direction.

10. The turbine as claimed in claim 9, characterized in that, The radial height of the narrowest throat is lower than the radial height of the high-temperature gas peak.

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