Analysis On Train Aerodynamic Drag And Its Influence In Strong Wind Area

Parked vehicles often slide without aim because of longitudinal aerodynamic force, gradient and other external conditions. At the same time, there appears many problems with the aerodynamic drag of running train increasing rapidly, such as lack of locomotive traction, increase of energy consumption and so on. Therefore, study on longitudinal aerodynamic force and aerodynamic drag of trains is pressing.Theoretical analysis, numerical calculation and wind tunnel test were applied in this paper. Based on numerical calculation of aerodynamic drag under different conditions, research on the minimum number of hand brake vehicles and traction calculation had been carried out. Finally the conclusions are as follows:Train’s longitudinal aerodynamic force is proportional to the square of wind speed, maximally at the wind angle of30degrees. With the maximum instantaneous wind speed and its direction in history, the slope and anti-wind facilities of Xinjiang Railway, formula for calculating the minimum number of hand brake vehicles in strong wind have been deduced.The most powerful train’s aerodynamic drag is at the sideslip angle of30degrees. Train’s aerodynamic drag with the wind-break wall of the earth type can be reduced by20%～40%, with other kinds of wind-break walls being reduced by60%～75%. According to resultant force graph, we can infer the balancing speed under specific environmental wind. Taking the single-deck train for example, train’s balancing speed can reach170km/h without environmental wind, but in the condition of the earth wind-break wall, train’s balancing speed will reduce to67km/h and45km/h at the environmental wind speed of32m/s and46m/s, and in the condition of other wind-break walls, train’s balancing speed will reduce to80km/h and58km/h at the environmental wind speed of32m/s and46m/s.Research conclusions of this paper provide reliable scientific basis for anti-sliding of parked trains and traction calculation, also improving and revising the current "Train Operation Safety in Strong Wind". So that the research conclusions have important application value.