Rapid Modeling Of Heavy Truck Body For CFD Simulation

Modern experimental research shows that the aerodynamic characteristics of the truck greatly affect the performance of the truck such as fuel economy,power performance,handling stability and comfort.Therefore,in order to ensure that the final modeling scheme has good aerodynamic characteristics,CFD(computational Fluid Dynamic)technology will be introduced into the modern heavy truck body modeling project to conduct CFD simulation analysis of the body modeling scheme.In the early stage of the project,the scheme with high wind resistance coefficient will be selected,or the unreasonable aerodynamic characteristics of the scheme will be modified.At this point,the digital model engineer needs to change the 2d sketch scheme to 3d digital model with CAS(Computer Aided Styling)software,and then carry out CFD simulation.However,in the traditional 3d modeling process,the digital model engineer will not consider the requirements of CFD simulation model,but only consider the requirements of modeling expression and surface quality.Therefore,after obtaining the 3d body digital model,a lot of mesh repair work needs to be done in the pre-processing software,which is time-consuming and labor-intensive.In addition,although CAS modeling software is widely used in modern truck modeling development projects,relevant theoretical research is not perfect.Therefore,based on the actual requirements,this paper improves the relevant theories of automobile 3d modeling and proposes a cfd-oriented rapid modeling method for heavy truck body.The specific theoretical and methodological studies are as follows:1.Research the basic theory of 3d modeling.It includes the definition of car body A class surface and the research of modeling method of car body A class surface.The definition,mathematical expression and mathematical method of synthesizing 3d feature wireframe from 2d feature line in Nubers modeling software.2.The shortcomings of traditional modeling methods in CFD simulation were studied,and a fast modeling method for CFD simulation was proposed.It mainly includes manual modeling of the main body surface in Alias environment,parameterized automatic modeling of some parts,and preprocessing of the model based on CFD simulation requirements.3.Study the parameterized modeling method of some truck parts for CFD simulation.Based on the CFD simulation requirement,the simplified method of heavy truck body parts is studied.This paper studies Rhino's plug-in secondary development method,and develops the parameterized modeling plug-in of each truck body part based on Rhino.4.Taking the schematic sketch of type 1 concept truck in horizontal project and CFD simulation requirements as the design input,digital design(3d modeling)practice is carried out using the above fast modeling method and theory to create the digital model of concept truck body.Finally,the digital model is imported into the CFD preprocessing software for grid processing.The traditional modeling method is compared with the fast modeling method proposed in this paper to verify the feasibility and practicability of the modeling method and theory proposed in this paper.