CN-121980705-A - High-precision wind tunnel spray pipe molded surface design method based on spinning process coupling

Abstract

The invention discloses a high-precision wind tunnel spray pipe molded surface design method, and belongs to the technical field of wind tunnel spray pipe molded surface design based on a computer. The method solves the problems of poor process feasibility and high number of profile correction iterations of the traditional wind tunnel jet pipe profile design method in the prior art, adopts modeling software to construct an initial profile mathematical model, integrates geometric constraint, builds a wall thickness initial distribution model and optimizes wall thickness distribution, quantifies objective functions according to constraint and model parameters of the step S1, optimizes the objective functions, refines the constraint to obtain refined constraint conditions, adopts design software to combine the refined constraint conditions to carry out parameterized modeling according to the wall thickness initial distribution model and the wall thickness parameters, and builds a process feedback mechanism to correct and compensate the initial profile modeling to finish the high-precision wind tunnel jet pipe profile design. The invention effectively improves the pneumatic performance and the material utilization rate, and can be applied to high-precision pneumatic verification tests.

Inventors

• WANG BILING
• QI XINXIN
• LIANG WEI
• GAO LIANGJIE
• YUAN YE

Assignees

• 中国航空工业集团公司沈阳空气动力研究所

Dates

Publication Date

20260505

Application Date

20260128

Claims (4)

1. 1. The high-precision wind tunnel spray pipe profile design method based on spinning process coupling is characterized by comprising the following steps of: S1, modeling software is adopted to perform profile parameterization modeling, namely an initial profile mathematical model is built, geometric constraint is integrated, a wall thickness initial distribution model is built, and wall thickness distribution is optimized; s2, quantifying an objective function according to the constraint and the initial profile mathematical model parameters in the step S1, optimizing the objective function, and refining the constraint to obtain refined constraint conditions; S3, carrying out parameterization modeling by adopting design software in combination with refined constraint conditions according to the wall thickness initial distribution model and the wall thickness parameters, and constructing a process feedback mechanism to correct and compensate the preliminary modeling of the profile so as to finish the design of the high-precision wind tunnel spray pipe profile.
2. 2. The method for designing the profile of the high-precision wind tunnel nozzle based on the spinning process coupling according to claim 1, wherein in the step S1, the method comprises the following steps: s11, constructing an initial profile mathematical model comprising an inlet section, a throat section and an expansion section according to a characteristic line method based on pneumatic performance; In the step S11, the initial profile mathematical model building process is as follows: defining an axial Mach number distribution function by adopting a characteristic line method of the improved Sivells; The axial Mach number distribution function is expressed as: Wherein, the For the initial mach number of the inlet, For Mach number variation amplitude, k is a profile steepness parameter, As a parameter of the location of the feature, Is the axial position of the spray pipe; Establishing the association between the length of the spray pipe and the curvature of the molded surface, and completing the construction of an initial molded surface mathematical model; correlation of nozzle length and profile curvature Expressed as: Wherein, the Is the cross-sectional area at the axial position x of the nozzle, Is of critical cross-sectional area, 、 The first and second derivatives of the sectional area to the axial coordinate are respectively; S12, integrating geometric constraints, namely setting geometric limit constraints of an embedded spinning process and the change rate of the slope of the profile to realize curvature continuity; in the S12, the geometrical limit constraint of the embedded spinning process is expressed as the minimum curvature radius Profile slope rate of change Parameterized discrete is carried out by adopting NURBS curves, control points are defined, and curvature continuity is realized through weight adjustment; s13, establishing a wall thickness initial distribution model based on the flow characteristics of the spinning material, and optimizing the wall thickness distribution; In the S13, the initial distribution model of the wall thickness Expressed as: Wherein, the For the initial wall thickness of the inlet, L is the total length of the nozzle, Is the control point spacing; Adopting finite element analysis to simulate spinning process, restraining local thinning rate and dynamically adjusting wall thickness gradient of expansion section.
3. 3. The method for designing the profile of the high-precision wind tunnel nozzle based on the spinning process coupling according to claim 2, wherein the step S2 comprises the following steps: S21, quantifying an objective function, namely defining a pneumatic performance target, a process feasibility target and a structural strength target; In the S21, pneumatic performance target Expressed as: Wherein, the As discrete points of the outlet cross section The mach number at which the optical axis is oriented, For the target mach number, Is the total number of discrete points; Process feasibility goal Expressed as: ; Structural strength target Expressed as: , is the variation of wall thickness during spinning; S22, performing target optimization by adopting an NSGA-II algorithm, and optimizing algorithm parameters to obtain population scale, cross probability and iteration times; s23, further refining constraint of profile design, namely setting curvature radius, thinning rate, outlet Mach number, soft constraint medium-sized surface roughness and spinning forming force in hard constraint to obtain refined constraint conditions.
4. 4. The method for designing the profile of the high-precision wind tunnel nozzle based on the spinning process coupling according to claim 3, wherein in the step S3, the method comprises the following steps: s31, a collaborative platform architecture and an integrated tool chain are adopted; in the step S31, parameterized modeling, CFD simulation and FEA simulation are carried out by adopting design software, and an algorithm library is optimized; S32, generating an automatic iterative logic initial design based on the wall thickness initial distribution model and the wall thickness parameters output in the step S1; In the step S32, during performance verification, the outlet Mach number distribution, the total inlet pressure and the outlet static pressure in the boundary condition are obtained through CFD simulation calculation and are matched with the target Mach number; during process verification, the FEA simulation is used for simulating spinning, and stress distribution and thinning rate are output; finally, through iterative correction of wall thickness initial distribution model Dynamically adjusting the coordinates of the control points and the wall thickness parameters by adopting an optimization algorithm based on simulation results of performance verification and process verification until a preset convergence condition is met; S33, a process feedback mechanism is constructed, a spinning test database is established, forming force-rebound quantity relations of different materials are recorded, the profile compensation quantity is reversely corrected, and the high-precision wind tunnel spray pipe profile design is completed.

Description

High-precision wind tunnel spray pipe molded surface design method based on spinning process coupling Technical Field The invention relates to a high-precision wind tunnel spray pipe profile design method, in particular to a spinning process coupling-based high-precision wind tunnel spray pipe profile design method, and belongs to the technical field of wind tunnel spray pipe profile design based on a computer. Background In the field of national defense science and technology industry, in the significant special development represented by hypersonic aircrafts and new generation aeroengines, wind tunnel tests are used as a ground scale for pneumatic characteristic verification, and the data reliability directly determines the engineering realization precision of equipment performance. The traditional wind tunnel spray pipe mostly adopts a sectional welding or integral forging process, geometric precision deviation (typical error is more than or equal to 0.5 mm) at a joint is caused by sectional welding, airflow disturbance is caused, the material utilization rate of integral forging is lower than 40% when large-scale blanks are processed, residual stress deformation is easy to generate in heat treatment, and high surface quality (Ra is less than or equal to 1.6 mu m) of a complex molded surface is difficult to realize through machining. The traditional spray pipe profile design only considers the aerodynamic performance requirement (such as a characteristic line method and an MOC method), is not coupled with the constraint of a manufacturing process, and causes the problems that (1) a theoretical profile curvature abrupt change point (such as a throat transition zone) exceeds the limit of a spinning forming process (wrinkling is generated when the minimum curvature radius R is less than 0.3 m), (2) the design-manufacturing iteration period is long, the deviation between an actual measured profile and a theoretical value is more than or equal to 0.2mm, and (3) the flow characteristic of a spinning material is not considered in wall thickness distribution, and the local thinning rate is more than 20%. In view of the foregoing, a method for designing a high-precision wind tunnel nozzle profile based on spinning process coupling is needed. Disclosure of Invention The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. It should be understood that this summary is not an exhaustive overview of the invention. It is not intended to identify key or critical elements of the invention or to delineate the scope of the invention. Its purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later. In view of the above, the invention provides a high-precision wind tunnel jet pipe profile design method based on spinning process coupling, which aims to solve the problems of poor process feasibility and multiple profile correction iteration times in the traditional wind tunnel jet pipe profile design method in the prior art. The technical scheme is that the high-precision wind tunnel spray pipe profile design method based on spinning process coupling comprises the following steps: S1, modeling software is adopted to perform profile parameterization modeling, namely an initial profile mathematical model is built, geometric constraint is integrated, a wall thickness initial distribution model is built, and wall thickness distribution is optimized; s2, quantifying an objective function according to the constraint and the initial profile mathematical model parameters in the step S1, optimizing the objective function, and refining the constraint to obtain refined constraint conditions; S3, carrying out parameterization modeling by adopting design software in combination with refined constraint conditions according to the wall thickness initial distribution model and the wall thickness parameters, and constructing a process feedback mechanism to correct and compensate the preliminary modeling of the profile so as to finish the design of the high-precision wind tunnel spray pipe profile. Further, in S1, the method includes the following steps: s11, constructing an initial profile mathematical model comprising an inlet section, a throat section and an expansion section according to a characteristic line method based on pneumatic performance; In the step S11, the initial profile mathematical model building process is as follows: defining an axial Mach number distribution function by adopting a characteristic line method of the improved Sivells; The axial Mach number distribution function is expressed as: Wherein, the For the initial mach number of the inlet,For Mach number variation amplitude, k is a profile steepness parameter,As a parameter of the location of the feature,Is the axial position of the spray pipe; Establishing the association between the length of the spray pipe and the curv