Optimization Design Of Structure Of Heavy Truck Intake System Based On Analysis Of Flow Field Characteristics

With the development of highway transportation industry,the number of heavy trucks is gradually increasing,and the maintenance problems and environmental pollution problems are also gradually increasing.As part of the engine intake system,the intake system of heavy truck is responsible for providing clean air and low pressure loss to the engine,which is of great significance to improve the service life and working efficiency of the engine and reduce emissions.Therefore,combined with the problems of low filtration efficiency and large pressure drop in the intake system of heavy trucks,In this paper,the computational fluid dynamics(CFD)method is proposed to improve the structure of the intake system of heavy trucks.The specific work is as follows:In order to study the performance of the intake system of heavy truck,the actual three-dimensional model and the mathematical model under steady state condition are built.The flow field analysis software Fluent is used to analyze the flow field in the intake system of heavy truck,and the two-phase coupling method of discrete phase model(DPM)is used to study the distribution of particle motion trajectory in the intake system.It is concluded that the structural problems existing in the intake system of heavy truck are as follows: the blade and intake grid have great influence on the filtration efficiency and pressure drop of the intake system of heavy truck,and the velocity distribution near the central axis of the blade is uneven,which affects the filtration efficiency of the intake system.By analyzing the influence of blade shaft diameter,blade diameter,blade spiral angle,spoiler translation distance,intake grid spacing and intake grid inclination angle on the internal flow field characteristics and performance indexes of heavy truck intake system,it is obtained that the above structural parameters have a great influence on the flow field and performance of heavy truck intake system,the primary and secondary effects of its structural parameters on filtration efficiency and pressure drop synthesis are determined by means of variance analysis and mean comparison method,from large to small,as follows: blade diameter,spoiler translation distance,blade shaft diameter,intake grid inclination angle,intake grid plate spacing,blade spiral angle.The multi-factor experimental design and optimization analysis of the intake system of heavy truck are carried out by orthogonal test method.The primary and secondary effects of factors on filtration efficiency in the range of orthogonal testvariables are obtained as follows: blade diameter,blade shaft diameter,intake grid inclination angle,blade helix angle,spoiler translation distance,intake grid spacing;The primary and secondary effects on pressure drop are as follows: inlet grid inclination angle,blade spiral angle,blade shaft diameter,intake grid plate spacing,spoiler translation distance,blade diameter.The optimal factor level combination is determined,and the optimal factor level combination is verified and analyzed under different working conditions before and after optimization.It is proved that the performance of the intake system of heavy truck is improved and the overall speed uniformity is improved by comparing the performance of the optimized intake system of heavy truck.The two-dimensional structural engineering drawing of the optimized intake system of heavy truck is drawn,and the structural improvement design of the intake system of heavy truck is completed.