Aerodynamic braking device for high-speed trains: Design, simulation and experiment

Abstract

This paper proposes the design of an aerodynamic braking device for a high-speed train. The design is based on the parameters of the high-speed train and the working principles of airplane wings. The proposed device is a unidirectional opening model driven by hydraulics. The prototype uses hard-wired signals to transmit braking commands on eight levels. The important characteristics of the device include a synchronous action and a fault-oriented security design. Its functions include service braking, gradual braking, emergency braking and self-checking. Simulation results show that deceleration in the high-speed zone between 250 and 500 km/h can be improved by between 8 and 60%. When the train runs at 500 km/h, the braking deceleration rate can be improved by 0.12 m/s 2 . The simulation results are found to agree with wind tunnel test results. The braking characteristics are also investigated using a test bed, which mimics the aerodynamic load exerted on the prototype when the train is running between 0 and 550 km/h. It is clearly demonstrated that the proposed principle of the aerodynamic braking system is feasible and its design scheme is reasonable. The aerodynamic braking device can survive a 50,000 N aerodynamic load, and the time taken to achieve the maximum braking capacity, which is the time taken to take the brake panel from its closed position of À5 to the maximum angle of 75 , is less than 3 s. The proposed prototype therefore offers an important step in the design of practical systems.

Numerical simulation of a bird impact on a composite aerodynamic brake wing of a high-speed train

“…Moreover, a small change in the slant angle of the wing can drastically disrupt the air flow field around the panel and lead to drag overshoot. [19][20][21] On the basis of the geometric relations between the various components of the wind-drag braking device, the effective area suffering aerodynamic drag at one point, S t , [22][23][24] and the equivalent area change ratio, ", can be expressed as follows where S 1 is the area of the brake wing, S 0 is the initial equivalent wind-drag area, 0 is the initial rising angle of the wing, t is the angle between the brake wing and the horizontal line at an arbitrary point and Á is the rotation angle of the brake wing. Figure 14 presents the rotation angle of the brake wing during the bird impact under the two conditions.…”

Comparison of different configurations of aerodynamic braking plate on the flow around a high-speed train

“…Before the opening of the Shinkansen line in Hokkaido in 1955, research was conducted into aerodynamic braking, in which a variety of aerodynamic braking plates were developed, and some full-scale vehicle tests were carried out (Takami & Maekawa, 2017; CONTACT Jiqiang Niu niujq@swjtu.edu.cn Yoshimura et al, 2000). In recent years, researchers in other countries have also begun to study the aerodynamic braking technology of high-speed trains (Jianyong et al, 2014;Lee & Bhandari, 2018;Puharić et al, 2010). Some tests and simulations show that the brake force of the vehicle is effectively increased by opening the aerodynamic brake.…”

“…Some tests and simulations show that the brake force of the vehicle is effectively increased by opening the aerodynamic brake. For example, the deceleration caused by the aerodynamic braking of a train passing through a tunnel is 0.2 g (Puharić et al, 2010), and the train's deceleration can be improved by between 8% and 60% for a train speed between 250 and 500 km/h (Jianyong et al, 2014). Based on the study carried out by Wu et al (2011), the amplitude of the pressure waves caused by two meeting trains and its complexity are found to increase when opening the braking plates.…”

Aerodynamic behavior of a high-speed train with a braking plate mounted in the region of inter-car gap or uniform-car body: A comparative numerical study

“…Some aerodynamic braking devices used in full-scale tests are presented in Figure 1. 11,12 In recent years, with the rapid development of China's high-speed railway system and the continuous improvement in train speed, aerodynamic braking has been gradually studied, [13][14][15][16][17][18] with some scaled model experiments and full-scale train tests having been conducted. 14 The configuration of the aerodynamic braking device in these tests is similar to the first image of Figure 1.…”