Matching And Simulation Analysis Based On CFD Of The Vehicle Active Grille System

The vehicle active grille system is one of the new technologies in recent years.The active grille system regulates the cooling air volume into the vehicle grille by the controlling of the attack angle of the active grille blade under different working conditions.The system is capable of the reduction of the aerodynamic drag of the vehicle to improve the fuel economy of the vehicle while ensuring the suitable working temperature environment of the engine.The active grille system shows the obvious effect on the reduction of the wind resistance and the improvement of the motive power when the vehicle runs at high speed.In this paper,the computational fluid dynamics(CFD)method was used to carry out CFD numerical simulation and analysis for a SUV with active grille system.The detailed data of the flow field in the vehicle’s outflow field were obtained by the simulation.The modeling of the blade and the control strategy of the attack angle of the blade were designed and optimized according to the result of the CFD numerical simulation.The research contents of this paper are as follows:1)The theory and method of numerical simulation of automobile wind tunnel were analyzed and explored in combination with the methods that automobile factory frequently used.The three-dimensional simulation of the wind tunnel test is carried out by the STAR-CCM+.2)The three-dimensional model of the active grille system was established on the base of the flow field performance of the vehicle wind tunnel numerical simulation.An experimental scheme for the attack angle of the active shutter blade at the change of the driving speed of the vehicle was preliminary designed.In order to obtain the the law of the wind resistance,heat dissipation capacity and the flow field in the engine room with the change of the attack angle of the active shutter blade,the related simulation tests had been completed.The design of the control strategy for active shutter blade under different driving conditions was preliminarily designed in accordance with the result of the simulations.3)The force situation of the vehicle body and the cooling information of the cooling module under the attack angle of the different active grid system were obtained by the two dimensional fluid solid coupling simulation that completed in ANSYS Fluent.It turned out a preferable engine cabin flow field result under the optimizing work by using GA-PSO optimization algorithm.4)The mathematical model of active grid system was established on account of the heat balance equation of engine cabin and the CFD simulation result.The control model of the active grid system was established and the simulation calculation was completed,and the simulation result was used to adjust the attack angle of the active grille blade under distrinct driving conditions.5)The verification and analysis of the active grille system and its control scheme showed the the effect of reducing 3.17% fuel consumption under the NEDC.Finally,the design and optimization of the active grille system was summarized and prospected.