Abstract:
PATAC, Pan Asia Technical Automotive Center Co., Ltd, reduced scale wind tunnel(RSWT) was constructed and came into operation in December 2018 which is a powerful facility for vehicle aerodynamic development at the early styling stage. It is the first professional automotive RSWT in domestic OEMs, and also an advanced vehicle RSWT in the world. It will promote PATAC's aerodynamic development capability on full vehicle performance. The wind tunnel (WT) was designed for a model scale of 40%. It is a 3/4 open jet, closed return the wind tunnel. The test section adopts double radius turntable, which makes the model close to the jet area of the nozzle and effectively reduces the space of test section. The turntable can be rotated within ±30° yaw angle to simulate the crosswind effects on road vehicle. The high-precision six-component force measuring balance ensures the accurate aerodynamic test. There is an integrated five-belt system inside the balance system. The center moving belt is a stainless steel belt which is used to simulate moving ground and reduce the influence of the ground boundary layer. Other four belts are polymers and used to drive the wheels at high speed corresponding to the wind speed. The boundary layer removing system includes the primary suction scoop at the nozzle exit, a secondary suction slot located just upstream of the turntable leading edge and the tertiary blowing slot on the front of turntable, which can effectively control the influence of the ground boundary layer. The intelligent traversing and model positioning system provides accurately and rapidly positioning for flow measurement and rapid movement of the model. By means of finally commissioning and calibrating, the PATAC RSWT flow quality and measured forces meet the specified requirements, and some parameters are better than other WTs for example longitudinal static pressure gradient and pressure fluctuation. The testing results coincide with those measured in Tongji WT with difference less than 1%.