CN115013089B - Design method and system for rectifying support plate of turbine rear case with wide operating condition and rearward shielding - Google Patents

Abstract

The present invention provides a method and system for designing the rectifying strut plate of the turbine rear casing under wide working conditions and backward shielding. The method separately designs the cross-sections of the characteristic primitives with different blade heights to ensure a good match for the three-dimensional flow at the outlet of the low-pressure turbine. ; For each characteristic primitive cross-section, use the inlet geometric angle, outlet geometric angle, grid pitch, chord length, occlusion width and axial extension length to describe the blade profile; use the quadratic deflection curve method to obtain the blade pressure surface And the suction surface shape line, combined with the leading edge and trailing edge radius parameters, respectively use ellipse and arc to shape the leading edge and trailing edge of the blade; realize the three-dimensional shape of the blade according to the required stacking method. This method has a high degree of freedom, requires few variables, and is flexible and convenient to adjust. It can flexibly adjust the backward shading rate of the final low-pressure turbine while performing good aerodynamic rectification, and even achieve complete backward shading, which is helpful for rapid design of low-pressure turbines. Aerodynamic loss and strong infrared stealth effect of the rear receiver components.

Description

Design method and system for rectifying support plate of turbine rear case with wide operating condition and rearward shielding

technical field

The invention belongs to the field of aviation turbine engine design, and particularly relates to a design method and system for a turbine rear case rectification strut with wide operating conditions and backward shielding, which is a parameterization of a turbine rear case rectification strut with both rectification and rearward shielding design method.

Background technique

In aircraft stealth technology, radar stealth and infrared stealth are the two most important aspects. Gas turbine engine is the main source of power for combat aircraft, and its intake/exhaust system is the main source of radar scattering and infrared radiation. The premise of realizing the stealth of combat aircraft is to reduce the infrared and radar signatures of the intake/exhaust system as much as possible. Infrared detection uses the physical characteristics of the object itself, that is, all objects with a temperature greater than absolute zero (-273.15°C) will emit infrared radiation to the outside world at all times, and as the temperature increases, the intensity of infrared radiation will increase sharply. During the operation of the gas turbine engine, a large amount of high-temperature gas will be discharged, and the temperature is much higher than the ambient temperature, which greatly increases the difficulty of the aircraft's backward infrared stealth.

The key to the infrared stealth of the engine exhaust system is to minimize the infrared radiation intensity of the exhaust system in the rear direction. The specific methods are: 1) By adjusting the gas composition, adding substances containing infrared shielding materials to the gas, so that the ejected gas will form an infrared shielding layer, thereby reducing the infrared radiation of the tail flame; 2) Air injection technology , this technology introduces the low-temperature gas from the surrounding environment into the tail nozzle and mixes it with the high-temperature gas, thereby reducing the infrared radiation of the tail flame; 3) shielding the high-temperature radiation source, by arranging a shielding device downstream of the low-pressure turbine, thereby avoiding or reducing it. The probability of detection by an infrared detection device.

It is a potential way to improve the infrared stealth performance of aero-engines by using the rectifier plate of the turbine rear casing to shield the high-temperature low-pressure turbine components. The rectifying support plate of the turbine rear case needs to take into account the functions of rectification, force bearing and rearward shielding, and its design and development are extremely difficult. On the one hand, the rectifying strut needs to direct the airflow after the final low-pressure turbine to the axial direction to increase the thrust of the engine. On the other hand, the rectifying strut needs to shield the high-temperature and low-pressure turbine components to reduce the intensity of backward infrared radiation, thereby improving the engine's backward infrared stealth performance. At present, the design method of the rectifying support plate of the turbine rear casing that can flexibly realize the full rearward shielding is extremely lacking. The present invention fully considers the rearward shading of the rectifying strut and the design requirements of aerodynamic rectification, and proposes a parametric design method and system for the rectifying strut based on the secondary deflection curve, which can be used for the development of a turbine rear case with wide working conditions and backward shading Provide theoretical and technical support.

Contents of the invention

In order to solve the problems in the prior art, the present invention provides a parametric design method for the rectification strut plate of the aero-engine turbine rear case that can realize rectification and rearward shielding. Compared with the existing design methods, this method can conveniently and flexibly adjust the backward shading rate of the final low-pressure turbine while aerodynamic rectification, and even achieve complete backward shading, which is helpful for the rapid design of low aerodynamic loss and strong infrared The stealth-effective rear casing components can reduce the temperature of the exhaust pipe as much as possible without reducing the operating temperature of the engine, and make the outlet airflow of the exhaust pipe along the axial direction of the engine as much as possible to maximize the thrust.

In order to achieve the above object, the technical solution adopted in the present invention is: a method for designing a rectifying support plate of the rear case of a turbine with a wide operating condition and backward shielding, comprising the following steps:

S1, select characteristic sections with different blade heights to model respectively; for the different characteristic sections, they all include two parts: turning section and axial extension section; where the turning section is defined by the inlet geometric angle, outlet geometric angle, There are 5 geometric parameters to control distance and occlusion width, and the axial extension section is controlled by the axial extension length;

S2, using the quadratic deflection curve method to obtain the pressure surface profile and the suction surface profile of the transition section that satisfy the five geometric parameters of inlet geometric angle, outlet geometric angle, chord length, grid pitch and shading width;

S3, obtain the pressure surface profile and suction surface profile line of the axial extension section by giving the axial extension length after the turning section, and combine the pressure surface profile line and suction surface profile line of the turning section and the axial extension section respectively Obtain the complete geometrical lines of the pressure surface and suction surface of the blade;

S4, determine the diameter of the leading edge and trailing edge of the blade according to the structural requirements, and shape the leading edge and trailing edge of the blade by using ellipse and arc respectively, so as to obtain the initial primitive blade shape of different characteristic sections;

S5, respectively fit the complete geometrical lines of the pressure surface and suction surface of the blade obtained in S3; at the same time, add some control points at different axial positions to adjust and iterate the profiled lines of the blade, and then combine the obtained profiled lines to adjust the The leading edge and trailing edge are shaped to obtain the primitive airfoil shape that meets the aerodynamic performance requirements;

S6, determine the blade stacking form, set the circumferential and axial stacking parameters, combine the blade stacking form and the primitive blade shape obtained in S5, and obtain the three-dimensional shape of the blade.

In S1, at least three different feature primitive sections are selected for modeling respectively.

The inlet geometric angle is determined according to the inlet airflow angle at the height of the local blade to reduce the flow separation at the inlet; the outlet geometric angle is set to 90 degrees to achieve axial exhaust; the chord length is adjusted according to the structural size limit and the flow turning angle; The grid pitch is determined according to the number of blades of the rectifying support plate 2 and the pitch diameter of the local blade height; the shielding width d is used to precisely control the backward shielding rate of the final low-pressure turbine components, including the realization of full shielding design; the axial extension length l to determine the length of the axial extension.

The occlusion width d specifically refers to: the projection overlap distance between the front edge of the current rectifying strut 2 and the trailing edge of the adjacent rectifying strut 2 on the engine outlet section, if the two overlap, then d is positive; if the two do not overlap, Then d is negative. When d is 0, it means that the rectifying strut 2 just blocks the rear observation line of sight from the tail of the engine, and positively and backwardly blocks the high-temperature and low-pressure turbine components; when d increases, the observation line of sight blocked by the rectifying strut 2 The angle increases accordingly.

In S5, non-uniform B-spline curves are used to fit the profile lines of the blade pressure surface and suction surface obtained in S3 respectively.

In S2, the quadratic deflection curve method divides the molded line into a leading edge segment, a middle segment, and a trailing edge segment. The first section is a Bezier spline curve, which realizes the deflection from the circumferential direction to the axial direction; the middle section is a one-section or two-section Bezier spline curve, connecting the leading edge section and the trailing edge section.

The root of the blade adopts a "C"-shaped flow channel profile, and the tip of the blade adopts an "S"-shaped flow channel profile.

In addition, the present invention provides a design system for the rectifying strut plate of the rear case of a turbine with wide operating conditions and backward shielding, including a design element determination module, a profile design module, an initial primitive airfoil acquisition module, a primitive airfoil update module and Blade 3D modeling design module.

The design element determination module is used to select characteristic sections with different blade heights for modeling respectively; for the different characteristic sections, it includes two parts: a turning section and an axial extension section; wherein, the turning section is defined by the inlet geometric angle, the outlet geometric angle, the Chord length, grating pitch and shielding width are controlled by 5 geometric parameters, and the axial extension section is controlled by the axial extension length;

The profile design module first uses the quadratic deflection curve method to obtain the profile line of the pressure surface of the turning section and the profile line of the suction surface of the turning section that meet the five geometric parameters of inlet geometric angle, outlet geometric angle, chord length, grid pitch and shading width; Then after the turning section, the pressure surface profile and the suction surface profile line of the axial extension section are obtained by a given axial extension length, and the pressure surface profile and the suction surface profile line of the turning section and the axial extension section are combined respectively to obtain The complete geometry of the pressure and suction sides of the blade;

The initial primitive blade shape acquisition module is used to determine the diameter of the leading edge and trailing edge of the blade according to the structural requirements, and use ellipses and arcs to shape the leading edge and trailing edge of the blade respectively, so as to obtain the initial primitive blade shape of different characteristic sections ;

The primitive blade shape update module is used to fit the complete geometric lines of the obtained blade pressure surface and suction surface respectively; at the same time, add several control points at different axial positions to adjust and iterate the blade shape lines, and then combine the obtained The profile line shapes the leading edge and trailing edge of the blade to obtain the primitive blade profile that meets the aerodynamic performance requirements;

The blade three-dimensional modeling design module is used to determine the blade stacking form, set the circumferential and axial stacking parameters, and combine the blade stacking form and the primitive blade shape obtained by S5 to obtain the three-dimensional shape of the blade.

The present invention also provides a computer device, including a processor and a memory. The memory is used to store a computer executable program. The processor reads and executes the computer executable program from the memory. When the processor executes the computer executable program, it can realize The present invention relates to a design method for a rectifying strut plate of a turbine rear casing with wide working conditions and backward shielding.

The present invention can also provide a computer-readable storage medium, in which a computer program is stored, and when the computer program is executed by a processor, it can realize the turbo rear occlusion under wide working conditions in the present invention. Design method of casing rectifier strut.

Compared with the prior art, the present invention has at least the following beneficial effects:

The present invention separately designs the characteristic primitive cross-sections with different blade heights to ensure a good match for the three-dimensional flow at the outlet of the low-pressure turbine. For each characteristic primitive cross-section, the inlet geometric angle, outlet geometric angle, grid pitch, The shade width and axial extension length are used to describe the geometry of the blade. On the one hand, the quadratic deflection curve method combined with typical characteristic geometric parameters is used to control the shape lines of the blade pressure surface and suction surface, and the leading edge and trailing edge of the blade are shaped by ellipses and arcs; the above method can achieve direct adjustment through the shading width The design requirements for the backward shading rate (including full shading) have the advantages of clear physical meaning of geometric parameters, convenient and flexible adjustment, and high modeling accuracy; The stacked molding can better design the geometric shape of the rectifying strut with high aerodynamic performance and full rearward shielding.

The rectifying strut design method described in the present invention can conveniently and flexibly adjust the backward shading rate of the final low-pressure turbine at the same time of aerodynamic rectification, and even realize complete backward shading, which is helpful for the rapid design of low aerodynamic loss and strong infrared The stealth-effective rear casing components can reduce the temperature of the exhaust pipe as much as possible without reducing the operating temperature of the engine, and make the outlet airflow of the exhaust pipe along the axial direction of the engine as much as possible to maximize the thrust; the obtained The rectifying strut plate of the turbine rear case is located after the final low-pressure turbine and before the afterburner flame stabilizer. The back occlusion of the widget.

Description of drawings

Figure 1 is a schematic diagram of the arrangement of rectifying struts in the rear casing of the turbine, where (a) is a three-dimensional partial cross-sectional schematic diagram, and (b) is a schematic diagram of the end surface structure.

Figure 2 is a three-dimensional schematic diagram of a rectifying strut and a schematic diagram of different blade height profiles.

Fig. 3 shows the blade shapes and design parameters of different blade height primitives, in which (a) is the design line and design parameters of the blade root, (b) is the design line and design parameters of the leaf center, and (c) is the design line of the blade top and design parameters.

In the accompanying drawings, 1—hub; 2—straightening plate; 3—casing; 4—tail cone; 21—blade root profile; 22—blade midline; 23—blade top profile; 211—blade Root turning section pressure surface; 212—blade root turning section suction surface; 213—blade root axial extension section pressure surface; 214—blade root axial extension section suction surface; 215—blade root runner centerline; 221—blade center Pressure surface of turning section; 222—suction surface of midblade turning section; 223—pressure surface of axially extending section of midblade; 224—suction surface of axially extending section of midblade; 225—centerline of flow channel in midblade; 231—turning section of blade top Pressure surface; 232—suction surface of blade tip turning section; 233—pressure surface of blade tip axial extension section; 234—suction surface of blade tip axial extension section; 235—blade tip runner centerline.

Detailed ways

In order to make the technical solutions and beneficial effects involved in this application more clear, the technical solutions involved in this application will be explained in more detail below in conjunction with the drawings in the description of the drawings of this application. The specific implementations described in this application are only some of the implementations of the application, not all of them. The explanations with reference to the accompanying drawings are exemplary, and the purpose is to explain the application, but not to limit the application. Based on the implementations of the present application, all other implementations obtained by persons of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application. Embodiments of the present application will be described in detail below in conjunction with the accompanying drawings.

The present invention provides a method for designing the rectifying support plate of the rear case of a turbine with wide working conditions and backward shielding, which specifically includes the following steps:

S1, considering that the low-pressure turbine components of aero-engines are rotating components, and their internal flow presents highly three-dimensional flow characteristics, resulting in different flow states at different blade height sections. In this design method, three or more different characteristic sections are selected for modeling to adapt to the airflow angle distribution of the outlet flow of the low-pressure turbine. For the different characteristic sections, it includes two parts: the turning section and the axial extension section; wherein, the turning section is controlled by 5 geometric parameters including the inlet geometric angle, the outlet geometric angle, the chord length, the grid pitch and the shielding width. The extension section is controlled by the axial extension length;

S2. Using the quadratic deflection curve method, obtain the pressure surface profile and the suction profile line of the transition section that meet the five geometric parameters of inlet geometric angle, outlet geometric angle, chord length, grid pitch, and shading width. The quadratic deflection curve method divides the molded line into a leading edge segment, a middle segment and a trailing edge segment. The leading edge segment is a Bezier spline curve, which realizes the deflection from the near axial direction to the circumferential direction; the trailing edge segment is One section of Bezier spline curve realizes the deflection from the circumferential direction to the axial direction; the middle section is one or two sections of Bezier spline curve connecting the leading edge section and the trailing edge section. The inlet geometric angle is determined according to the inlet airflow angle at the local leaf height to reduce the flow separation at the inlet. The outlet geometric angle is generally set at 90 degrees to achieve axial exhaust. The chord length is adjusted according to structural size constraints and flow turning angles. The grid pitch is determined according to the number of blades of the rectifying strut 2 and the pitch diameter of the local blade height. The shading width parameter can precisely control the rearward shading rate of the last-stage low-pressure turbine components, including the realization of full shading design.

S3, obtain the pressure surface profile and suction surface profile line of the axial extension section by giving the axial extension length after the turning section, and combine the pressure surface profile line and suction surface profile line of the turning section and the axial extension section respectively Obtain the complete geometrical lines of the pressure surface and suction surface of the blade;

S4, determine the diameter of the leading edge and trailing edge of the blade according to the structural requirements, and shape the leading edge and trailing edge of the blade by using ellipse and arc respectively, so as to obtain the initial primitive blade shape of different characteristic sections;

S5, considering that the rectifying branch plate 2 and the meridian flow path are both diffuser flow, the flow inside it is more sensitive to the geometrical line, which requires fine design. The non-uniform B-spline curves are used to fit the complete geometrical lines of the pressure surface and the suction surface of the blade respectively. On this basis, several control points are added at different axial positions, and the shape line of the blade, especially the shape line of the suction surface, is fine-tuned and iterated to obtain the primitive airfoil shape that meets the aerodynamic performance requirements.

S6. Carry out three-dimensional blade modeling, first determine the blade stacking form, including leading edge and trailing edge stacking, etc. Then further set the stacking parameters in the circumferential and axial directions to realize the three-dimensional shape of the blade's bending and sweeping. Combining the primitive blade shapes of different blade heights and the three-dimensional stacking rules, the three-dimensional shape of the blade can be obtained.

Specifically, as shown in Figure 1, the rectifying strut 2 is located after the final low-pressure turbine of the aero-engine and before the afterburner flame stabilizer; the rectifying strut 2 is installed on the hub 1 and the casing 3, and the hub 1 and the casing 3 Coaxial setting, the tail cone 4 is smoothly connected with the hub 1, and the tail cone 4 is installed at the air outlet. The rectifying struts 2 are evenly distributed on the hub 1 so as to rectify the airflow at the outlet of the last stage low-pressure turbine. More importantly, the curved line of the rectifying strut 2 can also shield the last-stage low-pressure turbine from the rear, thereby reducing the infrared radiation signal from the rear of the engine.

Considering that the low-pressure turbine part of an aero-engine is a rotating part, its outlet airflow presents a highly three-dimensional feature, and has different outlet airflow angles at different blade height sections. In order to adapt to the airflow angle distribution of the outlet flow of the low-pressure turbine, the application selects three or more different characteristic primitive cross-sections for modeling respectively. As can be seen from Fig. The three sections of the top profile 23 have different geometric features, which can well meet the flow and shielding requirements of different blade height regions.

根据当地叶高处的进口气流角确定，能够有效减小进口攻角，从而避免整流支板2 进口的流动分离现象。出口几何角（β₁、β₂、β₃）一般设定为90度左右，这样可以实现轴向排气 和推力最大化。弦长（C ₁、C ₂、C ₃）根据轴向尺寸限制和流动转折角进行调整。栅距（P ₁、P ₂、P ₃） 根据整流支板2的叶片数和当地叶高的节径进行确定。轴向延伸段主要通过轴向延伸长度 （l ₁、l ₂、l ₃）进行控制。 Figure 3 shows the parametric design method and modeling examples of the primitive airfoil. For different characteristic sections, it is composed of turning section and axial extension section. Its turning section passes through the inlet geometric angle (α ₁ , α ₂ , α ₃ ), the outlet geometric angle (β ₁ , β ₂ , β ₃ ), the chord length ( C ₁ , C ₂ , C ₃ ), the grid pitch ( P ₁ , P ₂ , P ₃ ) and occlusion width ( d ₁ , d ₂ , d ₃ ) are controlled by five geometric parameters respectively. Import geometric angle

Determined according to the inlet airflow angle at the local vane height, the inlet angle of attack can be effectively reduced, thereby avoiding the phenomenon of flow separation at the inlet of the rectifying strut 2 . The outlet geometric angles (β ₁ , β ₂ , β ₃ ) are generally set at about 90 degrees, so as to maximize axial exhaust and thrust. The chord lengths ( C ₁ , C ₂ , C ₃ ) are adjusted for axial size constraints and flow break angles. The grid pitch ( P ₁ , P ₂ , P ₃ ) is determined according to the number of blades of the rectifying strut 2 and the pitch diameter of the local blade height. The axial extension is mainly controlled by the axial extension length ( l ₁ , l ₂ , l ₃ ).

In particular, this design method utilizes the shading width ( d ₁ , d ₂ , d ₃ ) to precisely control the rearward shading rate of the last-stage low-pressure turbine components. The definition of this parameter is: the projection overlap distance of the leading edge of the current rectifying strut 2 and the trailing edge of the adjacent rectifying strut 2 on the engine outlet section. If the two coincide, then d is positive; if the two do not coincide, then d is negative. When d is 0, it means that the rectifying strut 2 can just block the rearward observation line of sight from the tail of the engine, and positively and backwardly shield the high-temperature and low-pressure turbine components. With the increase of d , the angle of observation line of sight that can be blocked by the rectifying strut plate 2 is also larger, which can enhance the blocking effect of the side and rear. In the example shown in FIG. 3, a smaller positive value is used for the occlusion width d .

Then, for the turning section, according to the above five geometric parameters, the quadratic deflection curves are used to describe the blade root pressure surface profile 211, the blade mid-blade pressure surface profile 221, the blade top pressure surface profile 231 and the blade root suction surface profile 212. The shape line 222 of the blade mid-blade suction surface and the shape line 232 of the blade top suction surface; for the axial extension section, according to the axial extension length, use a straight line to describe the blade root pressure surface shape line 213, the blade middle pressure surface shape line 223, Blade top pressure surface molding line 233, blade root suction surface molding line 214, blade mid-blade suction surface molding line 224, blade top suction surface molding line 234; combining the turning section and axial extension section molding line, the blade pressure surface can be obtained and the complete geometry of the suction surface.

Further, the diameters of the leading edge and trailing edge of the blade are determined according to the structural requirements, and the leading edge and trailing edge of the blade are modeled using ellipses and arcs respectively, so as to obtain the initial primitive blade shapes of different characteristic sections; through the above steps, the efficient , Quickly obtain primitive airfoil shapes of different characteristic sections.

Furthermore, it can be seen from the modeling example of the fully shielded rectifying strut 2 that the geometric characteristics of the airfoils of the rectifying strut 2 with different blade heights are completely different. At the blade root, the airflow angle of the incoming flow is small, the tangential velocity component is large, and the flow turning angle generated in order to achieve axial flow guidance is relatively large. In order to achieve full shielding in the rear direction, as shown by the centerline 215 of the blade root flow passage, the contour of the formed flow passage is "C"-shaped. At the tip of the blade, the airflow angle of the incoming flow is relatively large, the tangential velocity component is small, and the flow turning angle generated in order to achieve axial flow guidance is relatively small. In order to achieve full shading in the rear direction, as shown by the centerline 235 of the blade tip flow passage, the formed flow passage profile is "S" shaped. The reason for the different flow channel profiles at different blade heights is: when the turning angle is larger, the circumferential deflection angle of the blade itself is larger, and the axial flow guide and backward shielding can be realized at the same time with a smaller chord length; When the turning angle is small, the circumferential deflection angle of the airfoil itself is smaller. If a "C" profile is used to achieve full backward shielding, a longer chord length is required, which is not conducive to controlling the axial size; and The "S" profile can achieve axial flow guide and full rearward shielding with a relatively short chord length.

Further, in order to fine-tune the airfoil design of the rectifying strut 2, a profile line fine-tuning method based on non-uniform B-spline curves has also been developed. Firstly, non-uniform B-spline curves are used to fit the profiles of the blade pressure surface and suction surface respectively. On this basis, several control points are generated at different axial positions, and the profile of the blade, especially the profile of the suction surface, is fine-tuned and iterated to obtain the primitive airfoil profile that meets the aerodynamic performance requirements.

Finally, as shown in Figure 2, a certain three-dimensional stacking method is selected for three-dimensional shaping of the blade. First, determine the blade stacking form, including leading edge and trailing edge stacking, etc. Then further set the circumferential and axial stacking parameters to realize the three-dimensional shape of the blade's bending and sweeping. The three-dimensional shape of the blade can be obtained by combining the primitive leaf shapes of different leaf heights and the three-dimensional stacking rule.

In addition, the present invention may also provide a computer device, including a processor and a memory, the memory is used to store the computer executable program, the processor reads part or all of the computer executable program from the memory and executes it, and the processor executes the part Or when all the calculation executable programs can realize the design method of the rectifying strut plate of the rear casing of the turbine in the wide working condition of the present invention.

The present invention can also provide a turbine rear casing rectifying strut plate design system with wide working condition backward shielding, including a design element determination module, a profile design module, an initial primitive airfoil acquisition module, a primitive airfoil update module and Blade 3D modeling design module.

The design element determination module is used to select characteristic sections with different blade heights for modeling respectively; for the different characteristic sections, it includes two parts: a turning section and an axial extension section; wherein, the turning section is defined by the inlet geometric angle, the outlet geometric angle, the Chord length, grating pitch and shielding width are controlled by 5 geometric parameters, and the axial extension section is controlled by the axial extension length;

The profile design module first uses the quadratic deflection curve method to obtain the profile line of the pressure surface of the turning section and the profile line of the suction surface of the turning section that meet the five geometric parameters of inlet geometric angle, outlet geometric angle, chord length, grid pitch, and shading width. ; Then after the turning section, the geometric profile of the extension section is obtained through a given axial extension length, and the complete geometric profile of the pressure surface and suction surface of the blade can be obtained by combining the pressure surface profile of the turning section and the suction surface profile of this section ;

The initial primitive blade shape acquisition module is used to determine the diameter of the leading edge and trailing edge of the blade according to the structural requirements, and use ellipses and arcs to shape the leading edge and trailing edge of the blade respectively, so as to obtain the initial primitive blade shape of different characteristic sections ;

The primitive blade shape update module is used to fit the complete geometric lines of the obtained blade pressure surface and suction surface respectively; at the same time, add several control points at different axial positions to adjust and iterate the blade shape lines, and then combine the obtained The profile line shapes the leading edge and trailing edge of the blade to obtain the primitive blade profile that meets the aerodynamic performance requirements;

The blade three-dimensional modeling design module is used to determine the blade stacking form, set the circumferential and axial stacking parameters, and combine the blade stacking form and the primitive blade shape obtained by S5 to obtain the three-dimensional shape of the blade.

In another aspect, the present invention provides a computer-readable storage medium, in which a computer program is stored, and when the computer program is executed by a processor, it can realize the wide working condition backward occlusion described in the present invention. Design method of rectifying strut for turbine rear case.

The computer equipment may be a notebook computer, a desktop computer or a workstation.

Processors can be central processing units (CPUs), graphics processing units (GPUs), digital signal processors (DSPs), application-specific integrated circuits (ASICs), or off-the-shelf programmable gate arrays (FPGAs).

For the memory of the present invention, it can be an internal storage unit of a notebook computer, a desktop computer or a workstation, such as a memory, a hard disk; an external storage unit can also be used, such as a mobile hard disk, a flash memory card.

Computer readable storage media may include computer storage media and communication media. Computer storage media includes volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. The computer-readable storage medium may include: a read-only memory (ROM, Read Only Memory), a random access memory (RAM, Random Access Memory), a solid-state hard drive (SSD, Solid State Drives) or an optical disc, and the like. Wherein, the random access memory may include a resistive random access memory (ReRAM, Resistance Random Access Memory) and a dynamic random access memory (DRAM, Dynamic Random Access Memory).

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any person familiar with the technical field within the technical scope of the disclosure of the present invention, according to the present invention Any equivalent replacement or change of the created technical solution and its inventive concept shall be covered within the scope of protection of the present invention.

Claims (5)

1. A method for designing a turbine rear casing rectifying support plate with wide working condition backward shielding is characterized by comprising the following steps:

s1, selecting characteristic sections with different leaf heights to respectively shape; aiming at the different characteristic cross sections, the different characteristic cross sections respectively comprise a turning section and an axial extension section; wherein,the turning section is controlled by 5 geometric parameters including an inlet geometric angle, an outlet geometric angle, chord length, grid distance and shielding width, and the axial extension section is controlled by the axial extension length; wherein the inlet geometry angle is determined based on the inlet airflow angle at the local blade height to reduce the flow separation at the inlet; the outlet geometry angle is set to 90 degrees to achieve axial venting; the chord length is adjusted according to the size limitation of the axial structure and the flow turning angle; the grid distance is determined according to the number of blades of the rectifying support plate (2) and the pitch diameter of the local blade height; by using the width of the shadedThe backward shielding rate of the final-stage low-pressure turbine part is accurately controlled, and the full shielding design is realized; by axial extensionlTo determine the length of the axial extension; width of shieldingdSpecifically, the method comprises the following steps: the axial projection coincidence distance of the front edge of the current rectifying support plate (2) and the tail edge of the adjacent rectifying support plate (2) on the cross section of the outlet of the engine is equal to the axial projection coincidence distance of the front edge of the current rectifying support plate and the tail edge of the adjacent rectifying support plate (2) on the cross section of the outlet of the engine, and if the front edge of the current rectifying support plate and the tail edge of the adjacent rectifying support plate are coincident with each other, the front edge of the current rectifying support plate and the tail edge of the adjacent rectifying support plate are coincident with each otherdIs positive; if the two are not coincident, thendIs negative whendWhen the number is 0, the rectification support plate (2) just blocks the backward observation sight from the tail of the engine, and the high-temperature low-pressure turbine part is shielded from the front and the back;dthe observation sight angle shielded by the rectification support plate (2) is increased along with the increase of the angle;

s2, respectively obtaining a turning section pressure surface molded line and a turning section suction surface molded line which meet 5 geometric parameters including an inlet geometric angle, an outlet geometric angle, a chord length, a grid pitch and a shielding width by using a secondary deflection curve method; the molded line is integrally divided into a front edge section, a middle section and a tail edge section by a secondary deflection curve method, wherein the front edge section is a 1-section Bezier spline curve, and deflection from the near-axial direction to the circumferential direction is realized; the tail edge section is a 1-section Bezier spline curve, and deflection from the circumferential direction to the axial direction is realized; the middle section is a Bezier spline curve towards 1 section or 2 sections and is connected with the front edge section and the tail edge section;

s3, obtaining a pressure surface molded line and a suction surface molded line of the axial extension section through setting the axial extension length behind the turning section, and respectively combining the pressure surface molded line and the suction surface molded line of the turning section and the axial extension section to obtain a complete geometric molded line of a pressure surface and a suction surface of the blade;

s4, determining the diameters of the front edge and the tail edge of the blade according to the structural requirements, and modeling the front edge and the tail edge of the blade by utilizing an ellipse and an arc respectively so as to obtain initial primitive blade profiles with different characteristic sections; the blade root adopts a C-shaped flow channel outline, and the blade top adopts an S-shaped flow channel outline;

s5, fitting complete geometric molded lines of the pressure surface and the suction surface of the blade obtained in the S3 respectively by using a non-uniform B-spline curve; meanwhile, adding a plurality of control points at different axial positions, adjusting and iterating the molded lines of the blade, and modeling the front edge and the tail edge of the blade by combining the obtained molded lines to obtain an elementary blade profile meeting the pneumatic performance requirement;

and S6, determining a blade stacking form, setting circumferential and axial stacking parameters, and combining the blade stacking form and the element blade profile obtained in the S5 to obtain the three-dimensional shape of the blade.

2. The method for designing the turbine rear casing rectifying support plate with the wide-working-condition backward shielding function according to claim 1, wherein in S1, at least 3 characteristic element sections with different blade heights are selected to be respectively shaped.

3. A design system of a turbine rear casing rectification support plate with wide working condition backward shielding is characterized by being used for realizing the design method of claim 1 or 2, and comprising a design element determining module, a molded line design module, an initial element blade profile obtaining module, an element blade profile updating module and a blade three-dimensional modeling design module;

the design element determining module is used for selecting characteristic sections with different blade heights to respectively shape; aiming at the different characteristic cross sections, the different characteristic cross sections respectively comprise a turning section and an axial extension section; the turning section is controlled by 5 geometric parameters including an inlet geometric angle, an outlet geometric angle, chord length, grid distance and shielding width, and the axial extension section is controlled by the axial extension length;

the molded line design module firstly utilizes a secondary deflection curve method to respectively obtain a turning section pressure surface molded line and a turning section suction surface molded line which meet 5 geometric parameters including an inlet geometric angle, an outlet geometric angle, chord length, grid spacing and shielding width; then obtaining a pressure surface molded line and a suction surface molded line of an axial extension section by giving an axial extension length behind the turning section, and respectively combining the pressure surface molded line and the suction surface molded line of the turning section and the axial extension section to obtain a complete geometric molded line of a pressure surface and a suction surface of the blade;

the initial element blade profile acquisition module is used for determining the diameters of the front edge and the tail edge of the blade according to the structural requirements, and modeling the front edge and the tail edge of the blade by utilizing an ellipse and an arc respectively so as to obtain initial element blade profiles with different characteristic sections;

the element blade profile updating module is used for respectively fitting complete geometric molded lines of the pressure surface and the suction surface of the obtained blade; meanwhile, adding a plurality of control points at different axial positions, adjusting and iterating the molded lines of the blade, and modeling the front edge and the tail edge of the blade by combining the obtained molded lines to obtain an elementary blade profile meeting the pneumatic performance requirement;

the blade three-dimensional modeling design module is used for determining a blade stacking form, setting circumferential and axial stacking parameters and combining the blade stacking form and the obtained element blade profile to obtain the three-dimensional modeling of the blade.

4. A computer device, comprising a processor and a memory, wherein the memory is used for storing a computer executable program, the processor reads the computer executable program from the memory and executes the computer executable program, and the processor can realize the design method of the turbine rear casing fairing plate of the wide-working-condition rear shielding in claim 1 or 2 when executing the computer executable program.

5. A computer-readable storage medium, wherein the computer-readable storage medium has a computer program stored therein, and the computer program, when executed by a processor, is capable of implementing the wide-regime aft-shielding aft-case fairing design method as claimed in claim 1 or 2.

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