Numerical Calculation Of The Air Conditioning Duct Of EMU Under High Temperature/High Altitude Condition

Lanzhou-Xinjiang railway line where environment is very bad,has the characteristics of large variation in temperature,high altitude variation,large blown sand.So in this line,keeping the flow field distribution and good thermal comfort in the train is very important.Now,most of researches are under the plain environment.In this paper,it not only used the CFD technology to make a detailed numerical study on the air conditioning duct under the general condition,but also calculated the limit plain condition and the plateau condition.Also,the passenger compartment has evaluated.In this paper,CRH380B EMU's VC03 carriage is the object of study with k-? standard turbulence model and SIMPLE algorithm,making the numerical simulation study of the air-conditioning ventilation system and the compartment air distribution and heat transfer conditions.The research contents are as follows:(1)Establishing a calculation model of CRH380B EMU's VC03 carriage air-conditioning ventilation system.The whole vehicle model was segmented by tetrahedron unstructured grid.The paper has made the detailed introduction and calculation for the surface temperature of the body,solar radiation and the body's heat to determine the boundary conditions of numerical calculation.(2)Under the general working condition,the limit plain condition and the plateau condition,numerical calculated the EMU model and simulated the temperature and velocity fields.According to indoor ventilation,heating and air conditioning in the UIC 553-2004 standard,the numerical calculation results are evaluated.(3)Then in the sitting posture legs,waist and head level,were evenly distributed around the human body around 135 points.Air diffusion performance index(ADPI)was used to evaluate the thermal comfort of the passenger compartment under the condition of the limit plain and plateau conditions,to further examine the design of the air conditioning system of the vehicle meets the requirements.The results showed that the temperature distribution of the car under the general condition,the limit plain condition and the plateau condition are all in accordance with the 553-2004 UIC standard;The interior temperature of limit plain conditions was higher than standard plain condition,the average interior temperature was 25.26 ?;the plateau condition overall interior temperature has dropped,the average temperature inside was 24.65 ?.The air distribution index ADPI of the limit and plateau condition are respectively 84.4%and 81.5%,in the standard range.To conclude,the design of CRH380B EMU's VC03 carriage air-conditioning ventilation system is reasonable,could meet the requirements.