Investigation on the Aerodynamic Efficiency of Braking Spoiler for High Speed Train Applications

The demand for high speed rail networks is rapidly increasing in developing countries like India. One of the major constraints in the design and implementation of high speed train is the braking efficiency with minimum friction losses. Recently, the aerodynamic braking concept has received good attention and it has been incorporated for high speed bullet trains as a testing phase. The braking performance is extremely important to ensure the passenger safety specifically for the trains moving at more than 120[Formula: see text]km/h. In this paper, an Indian train configuration WAP7 (wide gauge AC electric passenger, Class 7) has been assumed with the locomotive and one passenger car. Aerodynamic braking system design is done by opening a spoiler over the train to amplify the aerodynamic drag at high speeds. The magnitude of braking force depends on the position and orientation of the braking spoiler. It creates differential drag forces at various deflection angles to decelerate the trains instantaneously in proportion to the running speeds. Drag created by the braking spoiler is observed numerically with the help of CFD simulation tools for further validation through wind tunnel experiments. Striking aerodynamic results are obtained with and without braking spoilers on the passenger cars and the spoiler at 40[Formula: see text]–50[Formula: see text] orientation makes greater drag coefficient as compared to the other angles.