A design method of low-resistance and high-efficiency vane-type pre-whirl nozzle suitable for an aero-engine pre-whirl cooling system

Abstract

The application discloses a design method of a low-resistance high-efficiency vane type pre-swirl nozzle, which adjusts a vane aerodynamic load and an end area lag angle, specifically sets a vane installation angle of each vane type section to be 10-30 degrees less than a vane outlet geometric angle, makes the vane type load distribution present a post-loading feature, reduces the vane installation angle of the upper and lower end area vane type of the vane type pre-swirl nozzle by 1-10 degrees compared with other areas, reduces the vane outlet geometric angle of the upper and lower end area vane type by 1-10 degrees compared with other areas, increases the vane installation angle of the vane type section of the vane by 1-10 degrees compared with other areas, and corrects the end area lag angle of the vane type pre-swirl nozzle. The application increases the vane installation angle, makes the vane type load distribution present a post-loading feature, reduces the end area passage vortex system structure strength and loss of the vane type pre-swirl nozzle, improves the outlet airflow uniformity of the vane type pre-swirl nozzle, and improves the flow coefficient and the pre-swirl efficiency of the pre-swirl system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aero-engine pre-swirl cooling system, and particularly relates to a low-resistance and high-efficiency blade type pre-swirl nozzle design method for a pre-swirl cooling system. BACKGROUND

[0002] With the continuous improvement of the performance of aero-engines, the temperature before the turbine is continuously increased, which causes the turbine components to bear more and more severe thermal load, and thus efficient cooling of the high-temperature components is needed. As a component system for providing cooling gas with appropriate pressure and temperature to the turbine rotor blade, the pre-swirl system has become a research hotspot at home and abroad due to its great potential for temperature reduction. As one of the core components of the pre-swirl system, the performance of the pre-swirl nozzle directly determines the flow resistance and temperature change characteristics of the pre-swirl system, and further affects the cooling effect of the turbine rotor blade. At present, the blade type pre-swirl nozzle is one of the pre-swirl nozzles with the best performance, but due to the constraints of the engine structure, the aspect ratio of the blade type pre-swirl nozzle is usually less than 0.5, which causes large viscous loss in the end region of the blade type pre-swirl nozzle, and further increases the flow resistance of the pre-swirl system. In addition, the blade flow angle of attack is increased, which reduces the pre-swirl efficiency and weakens the temperature reduction effect of the pre-swirl system. The above factors jointly worsen the cooling effect of the turbine rotor blade, thereby affecting the safe operation of the turbine component. In view of the above problems, it is urgent to seek a low-resistance and high-efficiency blade type pre-swirl nozzle design method to reduce the flow resistance of the pre-swirl system, improve the temperature reduction of the pre-swirl system, and further improve the cooling performance of the turbine rotor blade. SUMMARY

[0003] (I) Technical problem

[0004] In view of the above defects and deficiencies of the prior art, the technical problem to be solved by the present application is to provide a low-resistance and high-efficiency blade type pre-swirl nozzle design method suitable for an aero-engine pre-swirl cooling system. By adjusting the aerodynamic load of the blade type pre-swirl nozzle and correcting the blade end region angle of attack, the flow loss of the blade type pre-swirl nozzle is reduced, the pre-swirl efficiency of the blade type pre-swirl nozzle is improved, the temperature reduction effect of the blade type pre-swirl nozzle is improved, and the efficient cooling of the turbine rotor blade is realized.

[0005] (II) Technical scheme

[0006] In order to achieve the above purpose, the present application provides a low-resistance and high-efficiency blade type pre-swirl nozzle design method suitable for an aero-engine pre-swirl cooling system, which comprises at least the following steps:

[0007] SS1. Determine N profile sections at different blade height positions along the blade height direction, wherein N≥3, at least one profile section at the blade tip, one profile section at the midspan and one profile section at the blade root are included, and the profile sections have the same shape and size, each profile section includes a suction surface profile line and a pressure surface profile line, and more than three control points are arranged on the profile lines, and the profile lines are smoothly connected by a circular arc at the leading edge and the trailing edge of the profile;

[0008] SS2. Form an initial configuration of the blade type pre-swirl nozzle by three-dimensional stacking of the N profile sections along the blade height direction, and during the three-dimensional stacking, the profile sections have the same blade installation angle, blade inlet geometric angle and blade outlet geometric angle, and the blade installation angle is 10-30° smaller than the blade outlet geometric angle;

[0009] SS3. Based on the initial configuration of the blade type pre-swirl nozzle formed by the stacking of step SS2, the blade installation angle of the profile sections at the blade tip and the blade root at the upper and lower end regions is reduced by 1-10° compared to other regions, the blade outlet geometric angle of the profile sections at the blade tip and the blade root at the upper and lower end regions is reduced by 1-10° compared to other regions, and the blade installation angle of the profile section at the midspan in the middle part of the blade is increased by 1-10° compared to other regions, to obtain a final configuration of the blade type pre-swirl nozzle.

[0010] The blade type pre-swirl nozzle is used in the turbine pre-swirl system of an aero-engine, and the purpose is to improve the performance of the cold quality pre-swirl system. In the low-resistance and high-efficiency blade type pre-swirl nozzle design method provided by the application, the viscous loss of the end region of the blade type pre-swirl nozzle is reduced by adjusting the aerodynamic load of the blade type pre-swirl nozzle, the flow resistance of the cold quality pre-swirl system is reduced, and the supply pressure is reduced.

[0011] In the low-resistance and high-efficiency blade type pre-swirl nozzle design method provided by the application, the blade installation angle of each profile section is set to be 10-30° larger than the blade outlet geometric angle, and the purpose is to increase the blade installation angle and make the blade load distribution present a rear loading feature, reduce the transverse pressure gradient in the front part of the blade passage, delay the intersection of the pressure surface branch and the suction surface branch of the horse-shoe vortex, reduce the secondary flow intensity in the passage, and reduce the viscous loss in the end region of the nozzle.

[0012] The application provides a low-resistance high-efficiency blade type pre-swirl nozzle design method, wherein the installation angle of the blade type pre-swirl nozzle upper and lower end area blade profile is reduced by 1-10° compared with other areas, the blade outlet geometric angle of the upper and lower end area blade profile is reduced by 1-10° compared with other areas, and the installation angle of the middle diameter blade profile section is increased by 1-10° compared with other areas, so as to correct the lag angle of the blade type pre-swirl nozzle end area, increase the airflow pre-swirl of the blade type pre-swirl nozzle outlet, improve the airflow uniformity of the blade type pre-swirl nozzle outlet, improve the pre-swirl efficiency, improve the temperature drop effect of the cold quality pre-swirl system, and thus improve the cooling effect of the turbine rotor blade.

[0013] In the scheme, in step SS1, the suction surface profile and the pressure surface profile of each blade profile section are configured by using Bezier curves, and each curve generally has more than three control points.

[0014] In the scheme, in step SS1, the radius of the blade profile leading edge and the blade profile trailing edge is 0.1-3.0 mm.

[0015] In the scheme, in step SS2, the inlet geometric angle of the blade type pre-swirl nozzle is generally 0°.

[0016] In the scheme, in step SS2, the blade outlet geometric angle is generally 40°-90°.

[0017] (Three) technical effects

[0018] Compared with the prior art, the low-resistance high-efficiency blade type pre-swirl nozzle design method suitable for the pre-swirl cooling system of an aero-engine provided by the application can achieve the following effects:

[0019] 1) The low-resistance high-efficiency blade type pre-swirl nozzle design method provided by the application can effectively reduce the flow resistance of the cold quality pre-swirl system, improve the temperature drop effect of the cold quality pre-swirl system, and thus improve the cold gas quality of the turbine rotor blade and improve the cooling effect of the rotor blade.

[0020] 2) The low-resistance high-efficiency blade type pre-swirl nozzle design method provided by the application can effectively reduce the flow resistance of the cold quality pre-swirl system, improve the temperature drop effect of the cold quality pre-swirl system, and thus improve the cold gas quality of the turbine rotor blade and improve the cooling effect of the rotor blade. DRAWINGS

[0021] Fig. 1 is a pressure surface view of the blade type pre-swirl nozzle according to the embodiment of the application.

[0022] Fig. 2 is a suction surface view of the blade type pre-swirl nozzle according to the embodiment of the application.

[0023] Fig. 3 is a blade profile section view of the blade type pre-swirl nozzle according to the embodiment of the application.

[0024] Fig. 4 This is an entropy cloud diagram of the outlet section of the blade-type pre-swirl nozzle according to an embodiment of the present invention.

[0025] Fig. 5 This is a schematic diagram of the radial distribution of the outlet airflow of the blade-type pre-swirl nozzle in an embodiment of the present invention.

[0026] Fig. 6 This is a schematic diagram of the radial distribution of the total pressure recovery coefficient at the outlet of the blade-type pre-swirl nozzle in an embodiment of the present invention.

[0027] Label Explanation:

[0028] 1. Blade pressure surface; 2. Blade tip blade section; 3. Medium diameter blade section; 4. Blade root blade section; 5. Blade type pre-swirl nozzle blade suction surface; 6. Blade leading edge; 7. Blade trailing edge. Detailed Implementation

[0029] To better understand the present invention, the following embodiments further illustrate the content of the invention, so that the advantages and features of the invention can be more easily understood by those skilled in the art. It should be noted that the following descriptions are merely preferred embodiments of the present invention, but the content of the invention is not limited to the following embodiments. In fact, various modifications and variations can be made to the present invention without departing from the scope or spirit of the invention, which will be apparent to those skilled in the art. For example, features shown or described as part of one embodiment can be used with another embodiment to produce yet another embodiment. Therefore, it is intended that such modifications and variations be included within the scope of the appended claims and their equivalents.

[0030] like Figs. 1-3 As shown, the low-resistance, high-efficiency blade-type pre-swirl nozzle design method for aero-engine pre-swirl cooling systems provided by this invention includes at least the following steps:

[0031] SS1. Determine N airfoil sections located at different blade height positions along the blade height direction, where N≥3. The N airfoil sections include at least one tip airfoil section 2, one mid-diameter airfoil section 3, and one root airfoil section 4. The shape and contour of each airfoil section are the same and have the same size. Each airfoil section includes a suction surface profile 5 and a pressure surface profile 1. The suction surface profile 5 and the pressure surface profile 1 are generally configured using Bézier curves, and each curve generally has more than three control points (in this embodiment, each curve has seven control points). The suction surface profile 5 and the pressure surface profile 1 are smoothly connected by the arcs of the leading edge 6 and the trailing edge 7 of the airfoil. The radii of the leading edge 6 and the trailing edge 7 are 0.1 to 3.0 mm. In this embodiment, the leading edge radius of the airfoil at the root, mid-diameter, and tip sections is 0.5 mm, and the trailing edge radius of the airfoil at the root, mid-diameter, and tip sections is 0.2 mm.

[0032] SS2. The initial configuration of a blade-type pre-swirling nozzle is formed by three-dimensionally stacking N airfoil sections along the blade height direction. During the three-dimensional stacking of the blades, each airfoil section has the same blade mounting angle, blade inlet geometry angle, and blade outlet geometry angle. Specifically, the blade inlet geometry angle is 0°, the blade outlet geometry angle is 40° or greater, and the blade mounting angle is 10–30° smaller than the blade outlet geometry angle. In the embodiment, the blade-type pre-swirling nozzle has an inlet geometry angle of 0° at the blade root, mid-diameter, and tip sections, and the design requires an outlet geometry angle of 76° and a mounting angle of 66° for each section. The blade-type pre-swirling nozzle reduces the lateral pressure gradient at the front of the blade passage by increasing the mounting angle, thus delaying the convergence of the horseshoe vortex pressure surface branch and suction surface branch, reducing the secondary flow intensity in the passage, and decreasing the viscous loss in the nozzle tip region.

[0033] SS3. Based on the initial configuration of the blade-type pre-swirl nozzle formed in step SS2, the blade installation angles of the blade tip and root airfoil sections located in the upper and lower end regions are reduced by 1–10° compared to other regions. The blade exit geometry angles of the blade tip and root airfoil sections located in the upper and lower end regions are reduced by 1–10° compared to other regions. The blade installation angle of the mid-diameter airfoil section located in the middle of the blade is increased by 1–10° compared to other regions, thus obtaining the final blade-type pre-swirl nozzle configuration. In the embodiment, by reducing the installation angles of the upper and lower end regions of the blade-type pre-swirl nozzle by 2°, i.e., the installation angles of the root and tip sections are 64°; reducing the exit geometry angles of the upper and lower end regions by 1°, i.e., the exit geometry angles of the root and tip sections are 75°; and increasing the installation angle of the near-mid-diameter section of the blade-type pre-swirl nozzle by 1°, i.e., the mid-diameter section installation angle is 67°, the pre-swirl of the airflow at the outlet of the blade-type pre-swirl nozzle is increased, thereby enhancing the temperature reduction effect of the pre-swirl system.

[0034] The use of blade-type pre-swirl nozzles in aero-engine turbine pre-swirl systems aims to improve the performance of the cryogenic mass pre-swirl system. The invention provides a low-resistance, high-efficiency blade-type pre-swirl nozzle design method. By adjusting the aerodynamic load of the blade-type pre-swirl nozzle, the viscous loss in the nozzle tip region is reduced, thereby decreasing the flow resistance of the cryogenic mass pre-swirl system and consequently lowering the supply air pressure. Furthermore, by correcting the lag angle of the blade-type pre-swirl nozzle tip region, the uniformity of the outlet airflow is improved, pre-swirl efficiency is increased, and the temperature drop effect of the cryogenic mass pre-swirl system is improved, thus enhancing the cooling effect of the turbine rotor blades.

[0035] The blade-type pre-swirl nozzle design method mentioned in this invention can effectively reduce the channel vortex intensity and the resulting under-deflection and over-deflection of the end-region airflow, improving the uniformity of the outlet airflow. Numerical calculation results show that compared with the blade-type pre-swirl nozzle without this invention, the secondary flow in the end-region of the pre-swirl nozzle optimized by this invention is significantly reduced (see...). Fig. 4The radial deviation of the outlet airflow angle is less than 1°, see Fig. 5 The uniformity of exhaust gas is significantly improved. Meanwhile, the total pressure recovery coefficient of the pre-swirl nozzle optimized using the blade-type pre-swirl nozzle optimization method mentioned in this invention is relatively increased by 1.40%, see... Fig. 6 The temperature drop of the pre-swirl system is increased by 0.9%. This demonstrates that the method proposed in this invention can effectively reduce the flow resistance of the pre-swirl system and improve its temperature drop performance.

[0036] In summary, this invention can be directly applied to the pre-spin cooling system of aero-engines.

[0037] This invention explores a design method for a low-drag, high-efficiency blade-type pre-swirl system and designs a blade-type pre-swirl nozzle design method suitable for aero-engine pre-swirl cooling systems, which is also the original intention of the work described in this invention.

[0038] Furthermore, it should be noted that the specific examples described in this specification may differ in geometry, name, etc. All equivalent or simple variations made to the construction, features, and principles described in this patent concept are included within the protection scope of this patent. Those skilled in the art to which this patent pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, as long as they do not depart from the structure of the invention or exceed the scope defined in these claims, all of which should fall within the protection scope of this invention.

Claims

1. A design method for a low-resistance, high-efficiency blade-type pre-swirl nozzle suitable for aero-engine pre-swirl cooling systems, characterized by reducing flow losses, improving pre-swirl efficiency, and enhancing temperature reduction by adjusting the aerodynamic load of the blade-type pre-swirl nozzle and correcting the lag angle of the blade tip region. The design method includes at least the following steps: SS1. Determine N blade profile sections located at different blade height positions along the blade height direction, wherein N≥3, the N blade profile sections include at least one blade tip blade profile section, one medium diameter blade profile section and one blade root blade profile section, and the shape profiles of each blade profile section are the same and have the same size, each blade profile section includes a suction surface profile line and a pressure surface profile line, each suction surface profile line and pressure surface profile line is provided with more than three control points, and the suction surface profile line and pressure surface profile line are smoothly connected by the arcs of the blade leading edge and the blade trailing edge; SS2. The N airfoil sections are stacked in three dimensions along the blade height direction to form the initial configuration of the blade-type pre-swirl nozzle. During the three-dimensional stacking of the blades, each airfoil section has the same blade mounting angle, blade inlet geometry angle, and blade outlet geometry angle. The blade mounting angle of each airfoil section is 10~30° smaller than the blade outlet geometry angle, so as to achieve the back-loading characteristics of the airfoil load distribution, reduce the transverse pressure gradient at the front of the blade channel, delay the convergence of the horseshoe vortex pressure surface branch and suction surface branch, reduce the secondary flow intensity in the channel, and reduce the viscous loss in the nozzle end region. SS3. Based on the initial configuration of the blade-type pre-swirl nozzle formed in step SS2, the blade installation angles of the blade tip airfoil section and the blade root airfoil section located in the upper and lower end regions are reduced by 1~10° compared with other regions. The blade exit geometry angles of the blade tip airfoil section and the blade root airfoil section located in the upper and lower end regions are reduced by 1~10° compared with other regions. The blade installation angle of the medium diameter airfoil section located in the middle of the blade is increased by 1~10° compared with other regions. This is to correct the lag angle of the blade-type pre-swirl nozzle end region, increase the pre-swirl of the airflow at the outlet of the blade-type pre-swirl nozzle, improve the uniformity of the airflow at the outlet of the blade-type pre-swirl nozzle, and obtain the final blade-type pre-swirl nozzle configuration.

2. The design method for a low-resistance, high-efficiency blade-type pre-swirl nozzle suitable for aero-engine pre-swirl cooling systems according to claim 1, characterized in that, In step SS1, the suction surface profile and pressure surface profile of each blade section are configured using Bézier curves, and more than three control points are set on each curve.

3. The design method for a low-resistance, high-efficiency blade-type pre-swirl nozzle suitable for aero-engine pre-swirl cooling systems according to claim 1, characterized in that, In step SS1, the radii of the leading edge and trailing edge of the blade are 0.1~3.0 mm.

4. The design method for a low-resistance, high-efficiency blade-type pre-swirl nozzle suitable for aero-engine pre-swirl cooling systems according to claim 1, characterized in that, In step SS2, the blade inlet geometry angle is 0°.

5. The design method for a low-resistance, high-efficiency blade-type pre-swirl nozzle suitable for aero-engine pre-swirl cooling systems according to claim 1, characterized in that, In step SS2, the blade exit geometry angle is set to 40°~90°.

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