Air Distribution-based Research In Urban Rail Compartment For Optimization Of Air Duct Structure

The air-conditioned train has become one of the main means of transport for people to travel. Due to the requirement of perfect air comfort, good indoor air environment of urban rail carriages has become one of basic requirements for designing urban rail train. In this paper, the carriage and the air supply duct have been coupled. Factors affecting comfort and the mechanism of interaction of them have also been studied in this thesis, which has practical significance.In this paper, a physical and mathematical model of urban rail cars has been built, which has been calculated under different air pressure, air temperature and heat load conditions, temperature, velocity and pressure distribution by Fluent using realizable k-s turbulence model. According to the simulation results, the air duct of urban rail carriages has been optimized.The results show that the inside pressure drop increases with the width of the air vents and cabin heat load increaseing. When other conditions are constant, infiltration rate increases with load increasing and the return air pressure decreasing. In order to reduce air infiltration rate, suggested outlet width is maintained at1cm to2cm.Under the condition that the structure and position of return air inlet and air outlet are certain, the air distribution inside the carriages depends on inlet air duct structure. The influence of the temperature of the supply air and the heat load inside on air distribution can be ignored.By the way of adjusting air volume and temperature, it can be achieved to satisfy the body’s comfort and reduce energy consumption at the same time.According to the result of optimization of the air duct inside the carriages, it is found that static pressure orifice plate added in the proper position of the air dust can improve the air distribution inside the carriages so that perfect passenger’s comfort.