Research On Air Environment Optimization Of Aircraft Service Zone And Mesh Strategy

With the rapid development of civil aviation,the transportation volume of air traffic continues to rise.The situation of aircraft service zone is complex,and its air environment is very important.In the design of the air environment,Computational fluid dynamics(CFD)is widely used.In CFD simulation,the preprocessing time is about 40%-60%of the total time,and reasonable meshing is very important for CFD simulation.In the design of cabin air supply parameters,the traditional trial and error method is inefficient and time-consuming,so it is necessary to improve its design efficiency.Therefore,a set of semi-empirical mesh strategy is proposed,and the inverse design method based on proper orthogonal decomposition(POD)is applied to the optimization design of air environment in aircraft service zone.Firstly,the meshing results of numerical simulation cases in a large number of literatures are analyzed and summarized in this study,and the complexity of geometric models of indoor flow field simulation is classified.The recommended values of grid foundation size for different types of geometric models are given.The flow field simulation results with different mesh types were compared for the medium complex geometry model and complex geometry model.Absolute error and normalized root mean square error(RMSE)were used to evaluate the simulation results,and the grid types of indoor flow field simulation for different types of geometric models were recommended.Secondly,considering the wall treatment model selected in the simulation,wall function and corresponding wall y~+value requirements,face quality,mesh volume change rate and prism layer setting,a semi empirical mesh strategy is proposed.The mesh strategy is applied to three models with experimental data.The strategy has been verified in the indoor flow field simulation of three geometric models with different complexity.Through the analysis and fitting of the relevant meshing results,the evaluation criteria of the mesh strategy are obtained.Finally,the above meshing strategy is applied to the flow field simulation of aircraft service zone,and the grid evaluation criteria are used for evaluation.This study takes the air supply angle,air supply volume and air supply temperature as the optimization variables,and carries out the optimization design with multiple objectives such as air distribution and temperature uniformity in the service zone of the aircraft.It is found that the sample size can be greatly expanded by POD method.Through the analysis of 56 CFD simulation cases,5663 sets of flow field data under air supply parameters are obtained by interpolation.This study realizes the multi-parameter POD optimization,and the optimization design results are verified to meet the design requirements.The results show that the inverse design method based on POD can realize the multi-objective and multi parameter design optimization in the real design scene,reduce the number of simulation cases by more than 90%,and effectively improve the optimization design efficiency.