Research On Model Validation Method Of Computational Fluid Dynamics Simulation

Computational Fluid Dynamics is a subject which can effectively assist in the design of fluid mechanics related systems,and it has been widely used in the field of aircraft manufacturing.It solves the computational model in fluid mechanics based on the existing computer software technology and numerical approximation method,and then completes the simulation of real fluid parameters,which provides the basis for the analysis and design of hydromechanics researchers.Verification,Validation and Accreditation is the main means to quantify and improve the reliability of CFD simulation.In-depth research on VV&A process and model validation method of CFD simulation will have an important impact on the development of the field of fluid mechanics in the future.The main contents of this paper are as follows:Combined with the characteristics of CFD simulation process,the sources and propagation methods of uncertainty in CFD simulation process are analyzed;Then,according to the uncertainty analysis of CFD simulation process,the process model of CFD simulation VV&A is constructed,and the basic flow of each stage of CFD simulation VV&A is described respectively.Aiming at the problem of single output CFD model validation,a model validation method of CFD simulation based on feature extraction is proposed,considering the influence of model input uncertainty as aleatory uncertainty.Firstly,combined with the problem description,the principle of response feature,the utilize of GMM to estimate the probability density function and the utilize of Bayesian factor to solve the feature consistency are explained in detail;Then,the flow of model validation method of CFD simulation based on feature extraction is constructed;Finally,it is applied to a compressor internal and external flow field model.Aiming at the problem of multiple output CFD model validation,a comprehensive means of CFD model validation based on improved PCA is presented,considering the influence of model input uncertainty as aleatory uncertainty.To start with,the tenet of principal component analysis based on MIC is described at length,and the process of improved principal component analysis is constructed;Then,the flow of CFD model validation fusion evaluation method based on improved principal component analysis is constructed;Finally,it is applied to an axial compressor rotor blade model.Aiming at the problem of CFD model validation based on expert evaluation opinions,a synthetic means of CFD model validation based on improved fuzzy comprehensive evaluation is presented.To begin with,the tenet of the fuzzy comprehensive method based on the minimum membership degree weighted average criterion is described at length,and the process of method is constructed;Then,combined with the hierarchical validation model of CFD simulation,the tree index system of credibility evaluation of CFD simulation model is set up,and the comprehensive evaluation process of CFD model verification based on improved fuzzy comprehensive evaluation is constructed;Finally,it is applied to the credibility evaluation of an axial flow compressor.The auxiliary tool of CFD simulation model verification is developed and designed.Firstly,the requirements analysis of CFD simulation model validation auxiliary tool is carried out to clarify its main functions and overall structure;then,the realization of the main interface and each function section of CFD simulation model validation auxiliary tool are described at length;finally,the auxiliary tool is applied to an axial compressor.