电动汽车气流能量回收装置的设计与性能分析

Design and performance analysis of airflow energy recovery device of electric vehicle

为了探索电动汽车行驶气流能量回收技术以增加续航里程,借鉴小型风力发电机的研究方法,在电动汽车前舱内设计了一个由风道和升阻结合式垂直轴风力机组成的气流能量回收装置,并分析风道引起的汽车头部流场变化对整车风阻的影响.根据风能浓缩理论,考虑电动汽车前舱空间尺寸约束,设计了风道结构,通过CFX仿真验证了风道的增速作用.在CATIA中建立整车模型、带风道的整车模型、带风道和风力机的整车模型,将3个模型分别导入Ansys CFX中,研究风能回收装置对整车空气动力学性能的影响.基于相似性原理,采用放大比例的风道和风力机模型进行台架试验,得到了不同风况下的风道内流场.结果表明:风能浓缩后风速增加了约30%;采用风道和风力机的电动汽车风阻系数比原车降低8.84%;当风道与风力机处于最佳匹配位置时,风力机启动风速约为4.78 km·h^(-1),最高转速可达458 r·min^(-1).

To explore the airflow energy recovery technology for increasing the driving range of electric vehicle,an airflow energy recovery device was designed. Based on the research method of small wind power generator,the device was constructed with lift-drag hybrid vertical axis wind turbine（ VAWT） and air duct. After added air duct,the flow around the vehicle head was changed,and the effects of flow change were analyzed. Based on energy conversion theory with considering dimension constraints of electric vehicle cabin space,the structure of air duct was designed. The effects of air duct on wind speed enhancement were verified through CFX simulation. The models of original car,original car with air duct and original car with wind turbine and air duct were established in CATIA. The effects of airflow energy recovery device on the vehicle aerodynamic drag were investigated in Ansys CFX. Based on the similarity principle,the bench tests were conducted on a scale-up model to obtain the flow fields inside the air duct. The results show that the wind speed can be increased by 30% after concentrated by the air duct.When wind energy recovery device is added,the aerodynamic drag of the electric vehicle is reduced byabout 8. 84%. When air duct and wind turbine are in the best matching position,the cut-in speed of wind turbine is about 4. 78 km·h-（-1） with the maximum rotational speed of 458 r·min-（-1）.