Design And Experimental Research On The Frontal Airflow Energy Recovery Device Of Electric Vehicle

Under the restriction of factors such as power battery performance and cost, it still remains difficult to significantly increase the driving range of electric vehicles. Consequently, reduction of driving resistance and energy consumption of electric vehicles and full use of renewable energy seem to be one good way to increase the driving range. From the viewpoint of combining frontal airflow energy recovery and drag reduction of electric vehicles, this paper designs and develops the integrated system of air duct and wind turbine in utilization of the cabin space of electric vehicles. The wind energy recovery system converts wind energy into electrical energy which will increase the driving range of pure electric vehicles. The main research content is as follows:Based on the study of the small scale wind power generation theory and the characteristics of all kinds of small wind turbines, the lift-drag combined type vertical axis wind turbine(VAWT)is selected. According to the current research of small wind power generation system used in special occasions, the overall scheme of the final wind energy recovery system is determined.Through real vehicle test, the relationship between vehicle speed and the wind speed in the front cabin of pure electric vehicle is compared in the case of adding air duct and another case of not adding air duct. Based on the energy conversion theory of concentrated wind energy generator,this paper studies the effect of different air ducts on the growth rate and the guiding effect of the air flow. According to the available wind energy and the dimensions of electric vehicle front cabin space, blade numbers, blade chord length, solid ratio, blade airfoil, and blade materials of lift-type wind turbine is designed. On the basis of lift-type wind turbine, the effects of different types and different blade numbers of drag-type blades on the starting performance and output power of the original lift-type wind turbine are studied by means of experiments, and then the final lift-drag type VAWT program is determined. To verify the performance of air duct and wind turbine, this paper establishes air duct and wind turbine models in CATIA and the models are imported into Ansys Workbench, the flow field of air duct is obtained in the operation process of wind turbine, modal analysis also identifies the vulnerable damage parts of wind turbine.After the design of air duct and wind turbine is completed, the effect of wind energy recovery system on the vehicle’s aerodynamic drag and lift is studied in Ansys CFX. The originalcar model, the original car with air duct model, the original car with wind turbine and air duct model are established in CATIA. The calculation results of the external flow field are visualized by Ansys CFX, the changes of pure electric vehicle outflow field and aerodynamic performance are analyzed.Finally, in order to verify the actual performance of the wind energy recovery system, and to find out the relationship between the recovery efficiency and vehicle speed, two bench tests are made in the laboratory. The first bench test sets up a platform including wind turbine, air duct,medium sized fan, and measuring instruments. The flow field and the wind turbine speed are measured in different wind conditions and different wind turbine locations, and the optimal matching position of the wind turbine and the air duct is found. A large fan is used in the second bench test. On the basis of the first test, generator, rectifier, storage battery, and other devices are added. The wind energy utilization coefficient of wind speed in 20km/h-60km/h is obtained.Finally, take Chery Ruiqi M1 EV pure electric vehicles for example, this paper estimates how much energy the energy recovery system can save as well as cost savings for pure electric vehicles.