Abstract:

A channel-type drag reduction method that connects the side and rear of van trucks was proposed to reduce the aerodynamic resistance of van trucks and avoid excessive changes in the shape and size of existing vehicles. The influence of basic parameters of connected channel such as shape, position, size of inlet and outlet and bending shape inside channel on drag reduction effect of van truck was explored by using computational fluid dynamics method, and finally an optimal drag reduction model of connected channel was obtained. The shape of the inlet and outlet of the channel model was quadrilateral and located 36 mm from the tail of the side air inlet and 39 mm from the side of the tail air outlet, while the inlet and outlet had the same size. The shape inside the channel was linear and the aerodynamic drag coefficient of the model was 0.494 2. The effect of the new drag reduction method in the side wind environment was further investigated. The results show that, compared with the original model, the aerodynamic drag coefficient reduction rate of the proposed tunnel model is 2.62% without crosswind, and the average aerodynamic drag coefficient reduction rate is 3.47% with crosswind. The channel type drag reduction can reduce the aerodynamic drag of the vehicle by introducing the airflow from the side to the rear of the vehicle and improving the vortex state of the rear to achieve the purpose of reducing the aerodynamic drag of the vehicle when driving. This new coupled channel drag reduction method provides a new drag reduction method for future research on aerodynamic drag reduction of van trucks.

Key words: vehicle energy saving, van truck, channel type drag reduction, fluid simulation, air inlet and outlet, side wind condition