Study On Air Supply System And Air Distribution Of 250 Km/h Electric Multiple Units Cushioned Sleeping Berth Car

With the speed promotion on large railway areas, the train speed has been improved and the electric multiple unit (EMU) has been widely used in railway transportation. 250km/h EMU cushioned sleeping berth car is improved and developed on the basis of the seating car. Compared with the seating car, in order to meet the needs of inner decoration, there are big changes in the duct structure and air supply fashion of sleeping car as follows: the section area of the underfloor duct reduces by 20%, and the section area of the vertical branch air supply duct reduces by 30%, the vertical air supply outlets are added at the windows. Both of the air distribution and air supply volume of the room change accordingly, so they need to be studied to improve the indoor environment quality of the train and increase the air-conditioning system design efficiency.Taking air-conditioning system and air distribution of the 250km/h EMU cushioned sleeping berth car as examples in this paper, researches are studied as follows:Firstly, the simulation of the air conditioning system is done; adjusting the air sup -ply volume by regulating the connection area between the vertical pipe and the under -floor duct, the unbalance rate is controlled in less than 10%.The simulation results of temperature and velocity fields in the car are that: both of them are well distributed, which satisfies the comfort demands.Secondly, the experiment mockup is established by the simulation results of the area between the vertical pipe and the underfloor duct. The volumes of the vertical pipe and outlets have been tested. By contrast, the simulation and the experiment results are very close, and the tendancy is accordant. The results satisfy the engineering demand. This air supply volume adjusting solution by changing the simulation model is proved to be feasible and effective.Lastly, the temperature and velocity fields have been tested. The results of the test and the simulation are very close, both of them can meet the railway standard. The results are evaluated by the indexes of ununiformity coefficient and Air Diffusion Performance Index (ADPI).