Analysis Of Thermal Environment In The Carriage Of CRH3

The high-speed rail has just started to emerge in China and has huge potential of development. The way of air supply from the air-conditioner in the carriage will affect temperature, humidity, pollutant concentration, comfort level and so on. Studying the environment of carriage will provide important basis for improving comfort level and optimizing air supply way.In China, CRH3 is the first train which reaches 350km/h. A comfortable and healthy environment is requested. Based on the train, the influence of the high-speed on air-conditioning system load and air distribution is discussed by load calculation, site measurement and numerical simulation.In this paper, the influence on the system load by speed increasing is analyzed. The analysis includes load calculation, surface temperature computation and air supply parameters determination. The result indicates that increased speed mainly influences the heat exchange coefficient of train outside surface, which further influences the train body heat transfer coefficient, inside surface temperature, and outside colligation temperature. The air distribution is analyzed by the site measurement and numerical simulation. The test indicates that the inside temperature is mostly between 22-25℃. The temperature differences on various heights are mostly under 3℃, while the temperature differences on the same level are basically under 2℃. The change of the outdoor temperature and the train's speed has little effects on the indoor temperature. It indicates that the air-conditioning system works well. The indoor humidity is low. The formaldehyde and benzene density is in the normal value, and the toluene and TVOC density is beyond the normal value. In order to satisfying a good air quality, it should be checked strictly when choosing material. The simulation result indicates that the temperature in the carriage is well distributed, which satisfies the comfort demands. There is great temperature gradient near the wall, luggage rack and person.The thermal environment is analyzed and evaluated by calculation, test and simulation in this paper, which can provide reference for the air distribution design in CRH3.