The Aerodynamic Numerical Simulation And Study On Drag Reduction Of EMU

With the continuous improvement of train speeds, air resistance increases sharply. Research shows that the air resistance is proportional to the square of the train speed. Therefore, reduce aerodynamic drag of trains not only save energy, but also can effectively reduce the noise pollution caused by air, enhance passenger's comfort, and prepare for the further increasing of speed.The analysis of reducing the resistance of trains needs multiple models and condition. Compared to the traditional wind tunnel experiment, numerical simulation has many advantages like advance research, no restriction, rich information, low cost, short cycle and so on. This article uses the method of computational fluid dynamics, apply software FLUENT, simulate the aerodynamic of the EMU, and analysis of reducing resistance.Create finite element model applicable to the aerodynamic performance using the high-speed EMU as original model, simulation on the external flow area in open air. The information like pressure distribution, aerodynamic drag coefficient, velocity distribution for flow area is concluded. Compare with the experimental data and verify the calculation model and method of calculation is accurate and reliable.By simulating 350km/h high-speed operating conditions in open air, the detailed analysis of the pressure distribution and velocity distribution is made, the result shows that: the train's air shield of air-conditioned and pantograph formed high-pressure area on the surface; the airtight of the surface is bad, there are many gaps in the vehicle junction and bogie's zone, the air poured into and formed vortex. As the speed increased, the key diversion part need to be optimized which did in this article: modify the air shield of air-conditioned and pantograph to reduce the high pressure area; add extra windshield, apron board, modified the head of the train to increase the airtight; move partition wall, add the bottom board to optimize air flow status. There total of 10 types of programs. The calculation and analysis show that these programs are effective in reducing the aerodynamic drag of the diversion part, but four of then increase the aerodynamic drag of the train. The optimal model is combined by the rest programs which reduce the resistance effective, the rate of reduction in resistance is 20.3%.The numerical study of various programs accumulates experience for the future design of vehicle shape, and provides reference for the independent intellectual property on the development of vehicles and improvements the level of vehicle design.