Effect of deflector devices on the aerodynamic characteristics of high-speed maglev trains

Due to the existence of suspension gap, the flow field around the suspension frame of high-speed maglev trains is turbulent and aerodynamically complex, which in turn affects the suspension and guidance performance of the trains. Based on Computational Fluid Dynamics (CFD), a numerical simulation model of the three-car marshalling high-speed maglev train is established to study the aerodynamic characteristics and the flow field structure. The results show that the airflow through the suspension gap impacts directly on the windward side of the suspension frame of the head car at a speed of 500 km/h. This creates a differential pressure drag which increases the aerodynamic drag of the head car significantly. A large area of the positive pressure area is formed at the bottom of the car body due to the airflow turbulence of the suspension frame, leading to a large increase in the aerodynamic lift force of the head car that is much higher than that of the middle car and the tail car. According to the results, three different types of deflector devices are proposed to control the airflow through the gap by changing the structure of the nose of the head car, which can significantly improve the pressure distribution on the train surface. The aerodynamic drag, aerodynamic lift and pitch moment of the train are effectively and synergistically reduced. Compared with the original maglev train, all three types of deflector devices (plate, short wedge, long wedge) can achieve both aerodynamic drag and lift forces reduction, among which the best long wedge deflector device can reduce the overall aerodynamic drag force by 3.6%, the head car aerodynamic lift by 40.6% and the head car pitch moment by 80.3%, with the best comprehensive aerodynamic characteristics.