Study On Drag Reduction Of Automobile Tail Based On High Precision Aerodynamic Drag Calculation

The fuel consumption of automobiles is one of the most concerned issues for domestic and foreign automakers,and the aerodynamic drag of automobiles is closely related to fuel consumption.Scholars at home and abroad have done a lot of research on the calculation of aerodynamic drag,but there is no unified and standardized computing system,leading to the different accuracy of aerodynamic drag.In addition,in the actual automotive aerodynamic drag reduction applications,engineers often rely on their own experience to modify certain parts.It is difficult to achieve an optimal drag reduction effect.Therefore,it is necessary to make a comprehensive drag reduction design for the automobile from the theory.For this reason,and based on previous studies of aerodynamic drag calculations,this article deeply analyzes the influence of different grids and solution settings on the calculation accuracy of the aerodynamic drag.Under the premise of both practicality and high efficiency,a high-precision aerodynamic drag calculation system for automobiles is proposed.Using this calculation method,the drag reduction of the rear part of the car is studied,and the conclusion is applied to a real car model.Good results have been achieved and it has important guiding significance for car development.The main research content of this article are as follows:1.By studying the influence of the computational domain size,the thickness and the number of the boundary layers,the number and the quality of the grid,the boundary conditions,discrete schemes and turbulence models on the accuracy of the aerodynamic drag calculation,a set of vehicle aerodynamic drag calculation method based on iterative optimization is obtained.It provides reliable numerical support for vehicle drag reduction research.2.Influence of the parameters such as the vertical diffuser angle,lateral diffuser angle and the channel width on the aerodynamic drag are studied,by using the high precision calculation method based on 25° Ahmed model.Finally,the design principle of the tail drag reduction scheme is obtained.3.The drag reduction conclusion of model is applied to the Zhong Qi model,which verifies the feasibility of the conclusion,and provides theoretical guidance for drag reduction of real vehicle tail.4.Finally,the parameters of the diffuser was optimized.Then,the optimizedparameters are subdivided into the real vehicle model,simulated and calculated.The results are compared with the original model and the model before optimization.It is proved that after optimizing the parameters of the rear diffuser,the drag reduction effect is better.