A method for fitting a total pressure distortion simulation board with a ring

Abstract

The application discloses a kind of total pressure distortion simulation plate's ring fitting method.By the ring processing of target atlas, the distortion position, circumferential range and distortion intensity of distortion area on each ring surface of simulation plate are determined;Then according to the relationship between the circumferential range of each ring of simulation plate shielding area and low pressure area, the circumferential size, orientation and distortion intensity of each ring shielding area are determined;Simulation plate is tested, and the opening rate of each ring is determined according to the relationship between the opening rate of each ring surface shielding area of simulation plate and distortion intensity and is evenly opened;Finally, the simulation plate of each ring surface is surrounded by envelope line into a whole and is numerically simulated, the total pressure distortion atlas generated is checked, the total pressure distortion atlas is corrected, and finally the total pressure distortion atlas meeting the condition is obtained.The application can quickly obtain the total pressure distortion simulation plate design meeting the requirements, and greatly reduces the design iteration number.

Description

Technical Field

[0001] This invention relates to the field of aero-engines, and more particularly to a method for fitting loops in a total pressure distortion simulation plate. Background Technology

[0002] Intake distortion is a significant factor contributing to the instability of aero-engines. It is unavoidable during actual flight, as engines almost always operate under non-uniform intake conditions. Its impact on aero-engine performance is primarily manifested in a reduction in engine stability margin, thereby affecting aerodynamic stability. Modern engines operate in increasingly harsh flight environments, with constantly increasing aircraft speed, altitude, and maneuverability. The increasing use of high angle-of-attack post-stall maneuvers further exacerbates the problem of intake distortion's impact on aerodynamic stability. Existing theoretical research, experimental results, and accident cases demonstrate that aerodynamic instability in engines can lead to serious adverse effects, such as reduced engine performance, structural damage, and engine shutdown or failure. These hazards severely threaten the safe and reliable flight of aircraft.

[0003] When obtaining an airworthiness certificate for an aircraft engine, aerodynamic stability is a mandatory assessment. The current standard procedure for inlet total pressure distortion (IPD) testing involves first designing and fabricating an IPD simulation device. This device generates the desired pressure distortion at the engine inlet cross-section. The device is then installed at a designated location upstream of the engine, and the distortion test is conducted on a ground-based or high-altitude test platform, measuring the pressure distortion at the engine inlet cross-section using probes. If the calculated IPD differs from the experimental conditions, the distortion generator is removed, refabricated, and the above steps are repeated until the distortion flow field matches the target conditions. Various types of IPD simulation devices have been developed, such as distortion nets, insert spoilers, and simulation boards. The appropriate simulation device must be selected based on the characteristics of different engines and the specific test requirements. Simulation boards are widely used due to their simple structure and high simulation accuracy. The principle behind the total pressure distortion generated by airflow through a simulation plate is to utilize the blocking effect of the orifice plate on the airflow, creating a low-pressure zone as the airflow passes through the orifice plate, thus generating the required steady-state distorted flow field. Turbulence is then created using the shape of the simulation plate's edges. Currently, the mainstream design method for simulation plates involves first dividing the target spectrum into high- and low-pressure regions, then using the shape of the low-pressure zone as the basis for geometrically modeling the simulation plate. Numerical calculations are then performed to obtain relevant parameters such as the total pressure recovery coefficient, the low-pressure zone angle, and the distortion intensity. The results from each simulation plate are compared with the target spectrum, and the scheme closest to the target spectrum data is selected. Further adjustments, such as opening perforations, are made to repeatedly refine the simulation plate's distortion parameters to more closely match the target spectrum and meet technical requirements. In this process, the design and debugging of the simulation plate rely entirely on experience, lacking analytical methods, and is time-consuming and labor-intensive. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for fitting the loops of a total pressure distortion simulation plate, addressing the deficiencies mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A method for fitting loops in a total pressure distortion simulation plate includes the following steps: Step 1) Divide the target total pressure distortion spectrum into equal toroidal sections to determine the distortion location, circumferential range, and distortion intensity of the distortion region on each toroidal section of the simulation plate; Step 2) Obtain the relationship between the circumferential range of each ring of the shielding area of ​​the simulation board and the circumferential range of the low-voltage area, and determine the circumferential dimensions, orientation and distortion intensity of each ring of shielding area; Step 3) Conduct experiments on the simulation board to obtain the relationship between the aperture ratio and distortion intensity of each ring of the simulation board's shading area; Step 3.1) To make holes uniformly in each ring of the simulation board according to the preset aperture threshold, so that the hole rate of the shading area of ​​each ring is the preset minimum hole rate threshold. Step 3.2) Test each ring of the simulation board to obtain the distortion intensity of each ring of the simulation board; Step 3.3) Increase the number of holes in each ring of the simulation board according to the preset aperture threshold, so that the opening rate of the shading area of ​​each ring increases by the preset percentage threshold. Step 3.4) Test each ring of the simulation board to obtain the distortion intensity of each ring of the simulation board; Step 3.5), repeat steps 3.3) to 3.4) until the aperture ratio of each ring of shading area is greater than or equal to the preset maximum aperture ratio threshold; Step 3.6) Fit the aperture ratio and distortion intensity of the shading area of ​​each ring of the simulation board to obtain the relationship between the aperture ratio and distortion intensity of the shading area of ​​each ring of the simulation board. Step 4): For each ring of the simulation board, based on its determined distortion intensity and the relationship between its shading area aperture ratio and distortion intensity, determine its shading area aperture ratio and then uniformly open holes according to the preset aperture threshold. Step 5), enclose the occlusion areas of each torus into a whole using an envelope; Step 6) Place the simulation plate in the flow field under the target working condition to perform numerical simulation and obtain the distortion pattern of the AIP section; Step 7), compare the obtained distorted map with the target map: Step 7.1) If the distortion intensity of a distortion region on a certain toroidal surface of the distortion map is greater than the distortion intensity of the corresponding toroidal surface of the target map and the absolute value of the difference between the two is greater than the preset intensity threshold, then the diameter of each opening on the toroidal surface is increased according to the preset step size threshold. Step 7.2): If the distortion intensity of a distortion region on a certain toroidal surface of the distortion map is less than the distortion intensity of the corresponding toroidal surface of the target map and the absolute value of the difference between the two is greater than the preset intensity threshold, then the diameter of each opening on the toroidal surface is reduced according to the preset step size threshold. Step 7.3), then proceed to step 6) until the difference between the distortion intensity of the distortion region on each torus of the distortion map and the distortion intensity of the corresponding torus of the target map is less than the preset intensity threshold.

[0006] As a further optimization of the design method of the total pressure distortion simulation plate of the present invention, the number of toroidal surfaces to be divided is greater than or equal to 5 and less than or equal to 8.

[0007] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects: This invention uses a loop-based fitting method to fit the simulation board, which can quickly obtain a total pressure distortion simulation board design that meets the requirements, and significantly reduce the number of design iterations. Attached Figure Description

[0008] Figure 1 This is the target total pressure distortion spectrum in an embodiment of the present invention; Figure 2 This is a schematic diagram of the division of equal toroidal surfaces provided by the present invention; Figure 3 The present invention provides a diagram showing the relationship between the range of the shielding area with different circumferential and radial dimensions and the circumferential range of the low-pressure area, obtained based on empirical data. Figure 4 This is a schematic diagram of the ring-splitting model of the simulation board in an example of the present invention; Figure 5 This is a schematic diagram of the simulated plate after holes are opened on each toroidal surface in an example of the present invention; Figure 6 The simulation spectrum of the total pressure distortion of the target provided by this invention; Figure 7 A flowchart illustrating the design method of the total pressure distortion simulation board provided by this invention. Implementation

[0009] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings: This invention can be implemented in many different forms and should not be considered limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully express the scope of the invention to those skilled in the art. In the drawings, components are enlarged for clarity.

[0010] The present invention first provides a target total pressure distortion map, such as... Figure 1 As shown. To address the distortion present in the target image, the image is divided into rings during the design process. The cross-section is divided into five rings of equal area using the equal-ring method, as shown below. Figure 2 As shown.

[0011] Figure 3 The diagram shows the relationship between the circumferential and radial shielding area and the circumferential area of ​​the low-pressure zone, obtained from previous experience data. The horizontal axis represents the circumferential shielding area, the vertical axis represents the circumferential area of ​​the low-pressure zone, and k represents the radial shielding area, extending from the outer diameter to the inner diameter.

[0012] Figure 4The diagram shows the ring-by-ring modeling design of the simulation board. First, the approximate location of the blocking area of ​​each ring is determined based on the location of the low-pressure region in the target spectrum. Then, the circumferential location and range of the blocking area of ​​each ring are determined based on the relationship between the range of different circumferential blocking areas and the circumferential range of the low-pressure region. Next, the aperture ratio of each ring is determined based on the influence of the aperture ratio on the distortion intensity, and the drilling operation is performed. Figure 5 This is a schematic diagram of a simulation plate after holes are opened on each toroidal surface in an example of the present invention.

[0013] Numerical simulation was performed by placing the simulation plate under a specific flow field, and the total pressure distortion spectrum of the AIP interface was obtained as follows: Figure 6 As shown.

[0014] The design process of the simulation board is as follows Figure 7 As shown.

[0015] To obtain a simulation plate that achieves the target pressure distortion spectrum, this invention provides a method for fitting the loops of a total pressure distortion simulation plate, comprising the following steps: Step 1) Divide the target total pressure distortion spectrum into equal toroidal sections to determine the distortion location, circumferential range, and distortion intensity of the distortion region on each toroidal section of the simulation plate; Step 2) Obtain the relationship between the circumferential range of each ring of the shielding area of ​​the simulation board and the circumferential range of the low-voltage area, and determine the circumferential dimensions, orientation and distortion intensity of each ring of shielding area; Step 3) Conduct experiments on the simulation board to obtain the relationship between the aperture ratio and distortion intensity of each ring of the simulation board's shading area; Step 3.1) To make holes uniformly in each ring of the simulation board according to the preset aperture threshold, so that the hole rate of the shading area of ​​each ring is the preset minimum hole rate threshold. Step 3.2) Test each ring of the simulation board to obtain the distortion intensity of each ring of the simulation board; Step 3.3) Increase the number of holes in each ring of the simulation board according to the preset aperture threshold, so that the opening rate of the shading area of ​​each ring increases by the preset percentage threshold. Step 3.4) Test each ring of the simulation board to obtain the distortion intensity of each ring of the simulation board; Step 3.5), repeat steps 3.3) to 3.4) until the aperture ratio of each ring of shading area is greater than or equal to the preset maximum aperture ratio threshold; Step 3.6) Fit the aperture ratio and distortion intensity of the shading area of ​​each ring of the simulation board to obtain the relationship between the aperture ratio and distortion intensity of the shading area of ​​each ring of the simulation board. Step 4): For each ring of the simulation board, based on its determined distortion intensity and the relationship between its shading area aperture ratio and distortion intensity, determine its shading area aperture ratio and then uniformly open holes according to the preset aperture threshold. Step 5), enclose the occlusion areas of each torus into a whole using an envelope; Step 6) Place the simulation plate in the flow field under the target working condition to perform numerical simulation and obtain the distortion pattern of the AIP section; Step 7), compare the obtained distorted map with the target map: Step 7.1) If the distortion intensity of a distortion region on a certain toroidal surface of the distortion map is greater than the distortion intensity of the corresponding toroidal surface of the target map and the absolute value of the difference between the two is greater than the preset intensity threshold, then the diameter of each opening on the toroidal surface is increased according to the preset step size threshold. Step 7.2): If the distortion intensity of a distortion region on a certain toroidal surface of the distortion map is less than the distortion intensity of the corresponding toroidal surface of the target map and the absolute value of the difference between the two is greater than the preset intensity threshold, then the diameter of each opening on the toroidal surface is reduced according to the preset step size threshold. Step 7.3), then proceed to step 6) until the difference between the distortion intensity of the distortion region on each torus of the distortion map and the distortion intensity of the corresponding torus of the target map is less than the preset intensity threshold.

[0016] The number of toruses used for partitioning should preferably be an integer greater than or equal to 5 and less than or equal to 8.

[0017] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

[0018] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0019] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for fitting loops in a total pressure distortion simulation plate, characterized in that, Includes the following steps: Step 1) Divide the target total pressure distortion spectrum into equal toroidal sections to determine the distortion location, circumferential range, and distortion intensity of the distortion region on each toroidal section of the simulation plate; Step 2) Obtain the relationship between the circumferential range of each ring of the shielding area of ​​the simulation board and the circumferential range of the low-voltage area, and determine the circumferential dimensions, orientation and distortion intensity of each ring of shielding area; Step 3) Conduct experiments on the simulation board to obtain the relationship between the aperture ratio and distortion intensity of each ring of the simulation board's shading area; Step 3.1) To make holes uniformly in each ring of the simulation board according to the preset aperture threshold, so that the hole rate of the shading area of ​​each ring is the preset minimum hole rate threshold. Step 3.2) Test each ring of the simulation board to obtain the distortion intensity of each ring of the simulation board; Step 3.3) Increase the number of holes in each ring of the simulation board according to the preset aperture threshold, so that the opening rate of the shading area of ​​each ring increases by the preset percentage threshold. Step 3.4) Test each ring of the simulation board to obtain the distortion intensity of each ring of the simulation board; Step 3.5), repeat steps 3.3) to 3.4) until the aperture ratio of each ring of shading area is greater than or equal to the preset maximum aperture ratio threshold; Step 3.6) Fit the aperture ratio and distortion intensity of the shading area of ​​each ring of the simulation board to obtain the relationship between the aperture ratio and distortion intensity of the shading area of ​​each ring of the simulation board. Step 4): For each ring of the simulation board, based on its determined distortion intensity and the relationship between its shading area aperture ratio and distortion intensity, determine its shading area aperture ratio and then uniformly open holes according to the preset aperture threshold. Step 5), enclose the occlusion areas of each torus into a whole using an envelope; Step 6) Place the simulation plate in the flow field under the target working condition to perform numerical simulation and obtain the distortion pattern of the AIP section; Step 7), compare the obtained distorted map with the target map: Step 7.1) If the distortion intensity of a distortion region on a certain toroidal surface of the distortion map is greater than the distortion intensity of the corresponding toroidal surface of the target map and the absolute value of the difference between the two is greater than the preset intensity threshold, then the diameter of each opening on the toroidal surface is increased according to the preset step size threshold. Step 7.2): If the distortion intensity of a distortion region on a certain toroidal surface of the distortion map is less than the distortion intensity of the corresponding toroidal surface of the target map and the absolute value of the difference between the two is greater than the preset intensity threshold, then the diameter of each opening on the toroidal surface is reduced according to the preset step size threshold. Step 7.3), then proceed to step 6) until the difference between the distortion intensity of the distortion region on each torus of the distortion map and the distortion intensity of the corresponding torus of the target map is less than the preset intensity threshold.

2. The method for fitting the total pressure distortion simulation plate according to claim 1, characterized in that, The number of toruses used for partitioning is greater than or equal to 5 and less than or equal to 8.

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