Aerodynamic performance of a pantograph cover for high-speed train

Three-dimensional unsteady turbulent flow around Faiveley CX pantograph was described by large-eddy simulations. The aerodynamic force distributions on the structures of the pantograph were explored comparing non-cover and cover cases against the incoming flow velocity of 200, 300, 400 km/h. The averaged drag and lift forces exerted on each component of the pantograph followed the second-order polynomial relations against the incoming flow velocity. The pantograph cover reduced the overall drag forces on the pantograph because the large recirculating zone with the strong negative pressure affected to the lower parts of the pantograph. In addition, when the pantograph cover was employed, the wall-normal direction of the lift force was changed from positive (uplift force) to negative (down force). By using the force and momentum balance considering all components of the pantograph, its aerodynamic uplift force was estimated, which was improved by including the specific forces around the knee joints, where the strong flow directly impinged. The pantograph cover reduced the mean and standard deviation values of the aerodynamic uplift forces as 40∼48 % and 5∼17 % compared to those for non-cover cases. Although more power was necessary to raise up the panhead to contact the catenary wire, it would help to improve the controller design to maintain the current collection performance by decreasing the uplift force fluctuations.