Design And Optimization Of Aerodynamic Drag Reduction Device For Truck Bottom Based On IDDES Transient Simulation

As of September 2021,the number of trucks in my country is 32.42 million.Freight vehicles will consume a lot of fuel during operation and generate a large amount of carbon emissions.The carbon emissions generated by them account for a large proportion of the carbon emissions generated in the transportation industry.It is of great significance for my country to achieve the carbon peak in 2026 and carbon neutrality in 2030.The average speed of automobiles is increasing.With the increase of vehicle speed,the proportion of aerodynamic resistance in the total resistance increases.Therefore,reducing the aerodynamic resistance of the vehicle can effectively reduce the fuel consumption rate of the vehicle and improve the power performance of the vehicle.For new energy vehicles,it can effectively increase its cruising range.In this paper,the bottom flow field of the truck model is studied,and the wheeled GTS model and a flat-top truck model are selected as the research objects.Based on the different bottom flow field characteristics of the two models,the corresponding bottom drag reduction device is creatively designed to realize the The drag reduction control is carried out at the bottom of the vehicle,and the drag reduction mechanism of the drag reduction device is studied.The main work of this paper is as follows:(1)Wind tunnel tests are carried out on the wheeled GTS model to verify the accuracy of the IDDES model based on Transition SST.IDDES mode is a hybrid RANS/LES mode with both computational accuracy and computational efficiency.The IDDES model based on Transition SST is used to carry out numerical simulation calculation of the outer flow field of the GTS model and the flat head truck model,and the bottom flow fields of the two models are studied respectively;(2)According to the characteristics of the bottom flow field of the wheeled GTS model,the corresponding drag reduction device,the diversion block,is designed.The designed drag reduction device was applied to the car model,the aerodynamic characteristics of the wheeled GTS model were optimized,and a drag reduction effect of 4.89% was achieved;Multi-parameter optimization of the drag reduction device has been carried out to increase the drag reduction effect to 7.05%;(3)According to the characteristics of the flow field at the bottom of the flat-top truck model,the aerodynamic structure at the bottom of the model was optimized,and a drag reduction effect of 2.57% was achieved after optimization;for the flat-top truck model after the optimization of the aerodynamic structure,the corresponding drag reduction was designed.The device,the side plate,achieved a drag reduction effect of 5.37%;the algorithm of the drag reduction device was optimized by multiple factors,and the drag reduction effect of the final optimal configuration was 7.40%.