Enhancement of train braking efficiency by optimal flow control characteristics with aerodynamic braking system

The high speed rail network is an essential part for any country to achieve the development goals within the stipulated time. The speed enhancement proposal is adversely affected by the braking efficiency of conventional systems during the emergency as well as the service braking conditions. The present work is focused on the improvement of braking efficiency in a large train configuration through cost effective aerodynamic braking system (ABS) which is in the state of research in developing countries. The flow behavior around the star locomotive of Indian railways (WAP7) with a coach model is considered for the feasibility study without and with ABS that is installed at the mid-section of the locomotive. A detailed steady-state flow field characterization is done to compute the amount of aerodynamic drag that is being developed by the ABS in the WAP7 configuration at the speed range of 100 km/h to 180 km/h. In the idealized train model, the braking plates are deflected at various angles (0°–90°) and the aerodynamic drag is evaluated for each 10° increment in the spoiler angle. Further, the standard k–ω turbulence model with SST coupled equation solver is used for the CFD simulations because of its familiarity over the turbulence behavior as specified by ANSYS Inc. The distribution of wake vortices, separation bubbles and low pressure zones are well-captured through the computational analysis while deploying the ABS at various angles. It is observed that the aerodynamic drag is significantly improved as the spoilers are deflected more than 40° that reduces the braking distance without any mechanical losses. This novel effort could revolutionize the braking system present in the WAP7 loco and similar configurations in the near future with an enhanced braking efficiency.