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CN-122016327-A - Optimization method of engine height-speed characteristic test point

CN122016327ACN 122016327 ACN122016327 ACN 122016327ACN-122016327-A

Abstract

The invention belongs to the technical field of aeroengine performance, and particularly relates to an optimization method of an engine height-speed characteristic test point. The method comprises the steps of obtaining the height and speed characteristics of an engine based on overall performance simulation calculation of the engine, preprocessing height and speed characteristic data, obtaining a three-dimensional curved surface of the height and speed characteristics through interpolation, determining the nearest point of a test point, fitting a local plane to obtain a local plane normal vector, calculating the local plane normal vector to obtain cosine similarity, judging validity of the cosine similarity to obtain optimized test point data, obtaining interpolation curved surface change graphs of the test points before and after optimization, obtaining a relation graph of the change degree of the curved surface along with the change of the cosine similarity, and obtaining a concentrated area of the optimized test points.

Inventors

  • TIAN YU
  • HUANG NINGPING
  • LIANG YAN
  • REN DINGDING
  • WANG JUNQI

Assignees

  • 中国飞行试验研究院

Dates

Publication Date
20260512
Application Date
20251227

Claims (8)

  1. 1. A method for optimizing an engine height-speed characteristic test point, comprising: Step 1, calculating corresponding thrust according to the height-speed characteristics in the engine envelope range based on the overall performance simulation of the engine, and forming the height-speed-thrust into test point data; step 2, interpolation and processing are carried out on the test point data obtained in the step 1, and a three-dimensional curved surface is obtained; step 3, searching the nearest point of the test point in the interpolation point obtained in the step 2, and obtaining nearest point data; Step 4, establishing a plane equation form for each test point and the nearest neighbor point data thereof, and solving and obtaining a local fitting plane equation and a local plane normal vector of each test point according to the nearest neighbor point data; Step 5, calculating the similarity degree of the local plane normal vector in the step 4 to obtain cosine similarity data, and step 6, screening the cosine similarity data calculated in the step 5 according to a set cosine similarity threshold to obtain new test point data after kicking points; step 7, repeating the step 4, the step 5 and the step 6, and obtaining optimized test point data; step 8, according to the optimized test point data obtained in the step 7, obtaining an optimized three-dimensional curved surface through interpolation, calculating projection coordinates of the test point data before optimization to the optimized three-dimensional curved surface, and calculating Euclidean distance between the projection coordinates and the test point coordinates before optimization to obtain a distance average value; Step 9, changing a set cosine similarity threshold, repeating the steps 7 and 8, and obtaining the relation that the degree of change of the curved surface changes along with the set cosine similarity threshold, wherein the degree of change of the curved surface is represented by a distance average value; And step 10, determining a mutation point with a distance mean value smaller than a first set value and a cosine similarity threshold value larger than a second set value in the relation curve according to the relation curve of the change degree of the curved surface along with the change of the set cosine similarity threshold value, further obtaining optimized test point data corresponding to the cosine similarity threshold value at the mutation point, taking the optimized test point data as a final optimization result, and further determining a test point concentrated area after optimization.
  2. 2. The method for optimizing engine height-speed characteristic test points according to claim 1, wherein step 2 specifically comprises: the method comprises the steps of 1, carrying out equidistant interpolation on test points obtained in the step in a data range to generate equidistant grids to obtain interpolation point data, carrying out integral standardization on original test points and interpolation data to obtain standardized test point data and interpolation data, drawing a three-dimensional curved surface according to the standardized test point data and the interpolation point data, requiring the three-dimensional curved surface to strictly pass through all standardized test point data, and ensuring the smoothness of the curved surface.
  3. 3. The method for optimizing engine height-speed characteristic test points according to claim 2, wherein step 3 specifically comprises: And step 3, searching k nearest points for each test point data in the interpolation point data obtained in the step 2to obtain nearest point data, wherein the searching method is to gradually expand the range to search k points with nearest space distance, and k is not less than 3.
  4. 4. The method for optimizing engine height-speed characteristic test point according to claim 3, wherein step 5 specifically comprises: And (3) sequentially calculating the cosine values of included angles of the two local plane normal vectors according to the local plane normal vectors obtained in the step (4) to obtain the similarity degree of the two adjacent local plane normal vectors in the direction, and obtaining cosine similarity data.
  5. 5. The method for optimizing engine height-speed characteristic test points according to claim 4, wherein step 6 is specifically: And (3) according to the cosine similarity data obtained in the step (5), obtaining two normal vectors corresponding to the first cosine similarity data which is continuously larger than the cosine similarity threshold, removing test point data corresponding to the second normal vector, and obtaining new test point data after kicking.
  6. 6. The method for optimizing engine height-speed characteristic test point according to claim 1, wherein, In step 10, the first set value is 0.7-0.75, and the second set value is 0.97-0.98.
  7. 7. The method for optimizing engine height-speed characteristic test point according to claim 5, wherein in step 4: and fitting the nearest neighbor point data by adopting a least square method to obtain a local plane and a local plane equation, and obtaining a local plane normal vector according to the local plane equation.
  8. 8. A storage medium having stored thereon a computer program for performing the method of any of claims 1-7.

Description

Optimization method of engine height-speed characteristic test point Technical Field The invention relates to the technical field of aeroengine performance, in particular to an optimization method of an engine height-speed characteristic test point. Background In the section 5.2.2 of GJB 243A-2004 "aviation gas turbine Power plant flight test requirement", the section mentions "the engine working state for determining the engine height-speed characteristic" when the engine height-speed characteristic identification test is carried out, and a series of enough flying height and speed points are selected in the flight envelope of the aircraft and helicopter. The "sufficient" is not quantitatively explained, and if the "carpet covering" method is adopted, the test flight cost is too high, and the test flight is necessary under relatively limited conditions. The main idea of the current foreign engine performance test is to establish an engine performance calculation model according to flight test data, input a checking test result into the performance calculation model to replace a flight test and determine a flight test state point and engine thrust. The current method for selecting the test points of the height-speed characteristics is to combine the experience of the test flight project of similar engines, qualitatively select 2-3 heights, qualitatively select 3-5 speed points on each height to form a test point matrix, and because of the difference of the height-speed characteristics of different types of engines, the test points selected according to experience cannot judge whether the test points are representative or not and the rule suitability of specific engines, and the minimum selected test points cannot be ensured. The existing method for optimizing the height-speed characteristic test points on the two-dimensional plane has the defects of poor space property, incapability of reflecting the influence of height change and the like. Disclosure of Invention The embodiment of the invention provides an optimization method of an engine height-speed characteristic test point, which aims to solve the problems that the selection of the existing test point mainly depends on test flight project experience, whether a selected result has representativeness and specific engine rule suitability cannot be judged, the change rule information of the height-speed characteristic in the engine envelope range cannot be mastered, and the influence of poor space and height change cannot be reflected when the test point is optimized on a two-dimensional plane. The technical scheme of the invention is as follows: an optimization method of an engine height-speed characteristic test point, comprising: Step 1, calculating corresponding thrust according to the height-speed characteristics in the engine envelope range based on the overall performance simulation of the engine, and forming the height-speed-thrust into test point data; step 2, interpolation and processing are carried out on the test point data obtained in the step 1, and a three-dimensional curved surface is obtained; step 3, searching the nearest point of the test point in the interpolation point obtained in the step 2, and obtaining nearest point data; Step 4, establishing a plane equation form for each test point and the nearest neighbor point data thereof, and solving and obtaining a local fitting plane equation and a local plane normal vector of each test point according to the nearest neighbor point data; Step 5, calculating the similarity degree of the local plane normal vector in the step 4 to obtain cosine similarity data, and step 6, screening the cosine similarity data calculated in the step 5 according to a set cosine similarity threshold to obtain new test point data after kicking points; step 7, repeating the step 4, the step 5 and the step 6, and obtaining optimized test point data; step 8, according to the optimized test point data obtained in the step 7, obtaining an optimized three-dimensional curved surface through interpolation, calculating projection coordinates of the test point data before optimization to the optimized three-dimensional curved surface, and calculating Euclidean distance between the projection coordinates and the test point coordinates before optimization to obtain a distance average value; Step 9, changing a set cosine similarity threshold, repeating the steps 7 and 8, and obtaining the relation that the degree of change of the curved surface changes along with the set cosine similarity threshold, wherein the degree of change of the curved surface is represented by a distance average value; And step 10, determining a mutation point with a distance mean value smaller than a first set value and a cosine similarity threshold value larger than a second set value in the relation curve according to the relation curve of the change degree of the curved surface along with the change of the set cosine similarity threshold value, furth