电动汽车机舱散热问题CFD仿真分析优化及试验验证

Improvement of Cooling Capability for Electric Vehicles Using CFD Simulation of Under-Hood Flow

某电动汽车样车在空调降温试验中,驾驶员和副驾驶的头部平均温度没有达到降温预定值,制冷能力不足。为提高空调制冷能力,采用计算流体力学(Computational Fluid Dynamics,CFD)仿真分析法,研究了前机舱流场,分析了格栅和空调冷凝器的通风量。通过配置冷凝器导流罩和调整格栅开口,增加了格栅新风的进气量,减少了高温气体回流冷凝器,从而提高了冷凝器的散热能力。在最终的试验中,头部平均温度整改后比整改前降低了5℃,降温效果明显改善,达到并超过了预定值。这种通过机舱流场优化提高散热能力的方法和工程经验,对其它电动汽车机舱散热能力的开发具有借鉴意义。

The average head temperature of the pilot and copilot was found to be higher than the target value in the air conditioning performance test of an electric vehicle prototype,demonstrating a lack of cooling capability of the vehicle.A 3-D CFD simulation of electric vehicle under-hood flow was conducted to investigate the flow distribution and the cause of insufficient cooling capability.Through adding a condenser deflector and adjusting the grill opening,the air intake volume of the grill section was increased largely during electric vehicle idling,which meant more fresh air would go through the condenser and the hightemperature circumfluence was reduced during both electric vehicle idling and moving.In the final test after the modification,the average head temperature of the pilot and copilot was 5℃ lower than before and even lower than the target value.Hence,under-hood components packaging is critical to the cooling capability of electric vehicles.