Quality Analysis On Air-Conditioning System And Compartment Of CRH2 High-Speed Train

The development of high speed railway and increasing of velocity have bring great convenience for person's quick trip. At the same time, the requirements of riding comfortableness were getting higher and higher along with the improvement of living standards. Therefore, the quality of flow field inside and thermal comfortableness attract more and more attention from designers and passengers. In terms of high-speed train, compared with conventional-speed train, its air-conditioning system has a large difference, so it is necessary to build complicated model of air-conditioning system and passenger compartment。Thus, it is quite necessary to simulate the overall flow field and do the profound and comprehensive research of airflow organizing inside the train and atmosphere quality as the train running at a high speed, entering into a tunnel and the two trains encountering.Based on three dimensional N-S equation of compressible viscous fluid and high Re number two-equation k-εturbulent model with floating lift effect, the changes of high-speed air-conditioned train flow field in passenger compartment were calculated numerically by means of the finite volume method. First, the condition of air blowing on air supply outlet was analyzed, then the draft truck and air supply outlet were adjusted and calculated, these can guarantee the uniformity of all air supply outlet and good distribution of flow field; secondly, Airflow organization of passenger compartment in the summer and winter different environment was analyzed as the train running at a high speed of 350km/h, and the thermal comfortableness was evaluated by flow field index and comfortable index; also, the paper studies the effect of pressure wave on flow field of high-speed passenger compartment as two trains passing by each other and through tunnel under constant speed; finally, the different of several typical evaluation criteria were analysed and the criteria which was adapted to the evaluation for flow field of our country's high-speed air-conditioned train was recommended.The results show that reasonable air supply is key to guarantee the uniform distribution of flow field and thermal comfortableness. Compared with conventional air-conditioning train, the distribution of parameters in flowing field is quite homogeneous, the air quality is good and the thermal comfortableness is higher; the high speed, low temperature, high humidity and bad comfortableness in corridor and its sides area were caused by the symmetrical distributed air-supplied outlet in the roof, but these areas are not the man main region and the impact is not big.Under the speed of 350km/h and the pressure of fresh air inlet for-250Pa, air-conditioning system in high-speed train could ensure the air supply in chamber and can not lead to excessive concentrations of CO2. For opening-train air-conditioning system, pressure wave will be delivered to passenger compartment through the inlet of fresh air, this lead to the fluctuations in chamber, and its trends accord with trends of pressure wave outside the train; but the effect of its high-head fan could make that the inside pressure changes is far less than the outside and can not cause the sense of non-comfortableness; in addition, lowing pressure outside train in the process of passing train will influence the fresh air volume entered inside train and cause the inside concentrations of CO2 to elevate.