BODY SHAPE OPTIMIZATION OF INDIAN RAILWAYS DIESEL LOCO WDP=4GM AND PASSENGER CARS FOR HIGHER SPEEDS

Abstract

Development of high speed trains and increasing operational speeds of conventional passenger and freight rolling stock have resulted in growing interest in railways aerodynamics. Environmental issues, comfort demands and reduction of energy consumption are the key issues to which aerodynamic improvements can largely contribute. Resistance to forward motion of a high speed passenger train at high speed is dominated by aerodynamic drag so the aerodynamic design is a major issue for the system performance. In view of the importance of aerodynamics design of moving bodies, the aim of present work is to develop an aerodynamic shape for high speed trains for Indian Railways. This is expected to minimize the specific power consumption and increase the dynamic stability of the trainsystem. A model of the locomotive was prepared from wood and aluminum to a geometric scale of 1:50. This model was kept on railway track and it was prepared in timber to the same scale as the Locomotive and aerodynamic analysis of the existing WDP-4GM loco and passenger cars had been done by conducting experiments in the wind tunnel on the scaled, which is present in Civil Engg. Department. A numerical model of the existing and optimized locomotive has been created in Solid Edge and imported in GAMBIT. Analysis at various speeds has been carried out for the loco alone and with one and two passenger cars with CFD codes in FLUENT using k-omega turbulence model. The variation of pressure and velocity over the locomotive and passenger cars, and variation of coefficient of drag with the speed have been studied for existing design to obtain the inputs for aerodynamic design of the loco and passenger car shape. Force on the prototype train has been calculated using the coefficient of drag obtained from experimental and numerical analysis. The effect of side skirting also investigated by CFD analysis, Comparison of the drag on existing train and optimized train with side skirting shows the reduction of 59.5 % and 61.2 % in drag for train running with ten and fifteen passenger cars respectively within the range of Reynolds No. from 55000 to 4000000.