Study On Flow Field And Passenger Comfort In EMU Compartment

With the progress of society and the improvement of people’s living standards,more stringent requirements have been put forward for the thermal comfort of EMU compartments.To make the passengers in the compartment feel comfortable.The compartment is required to have a lower air velocity,suitable temperature,lower carbon dioxide concentration,appropriate relative humidity,and enough fresh air volume,and small pressure fluctuations.Taking the comfort of passenger as the main line,the flow field and comfort in EMU compartment are studied by means of theoretical analysis and numerical simulation.The main contents are as follows:(1)The simulation model of three-carriage train of 300 km/h EMU under different operating environments were established.Based on three-dimensional,steady or unsteady and incompressible or compressible viscous turbulent flow models,the computational fluid dynamics software FLUENT was used to carry out the simulation calculation,the pressure or pressure time history curves at each fresh vent and waste vent was obtained,and pressure time history curves were fitted in segments,prepare for the flow field and passenger comfort in the EMU compartment.(2)The air supply system was optimized in order to solve the problems of air flow distribution in each passenger room and non-uniform air supply of air supply system,in the extreme environment of summer and winter,the distribution of air velocity,temperature,carbon dioxide volume concentration and relative humidity in the middle compartment of EMU driving on flat ground was studied.Results showed that the optimized air supply system has better effect,the regularities of distribution of indoor air velocity in different environments is similar,and the parameters basically meet the standard.(3)The influence of pressure fluctuation during EMU passing through tunnel,meeting on the flat and in the tunnel on the flow field in extreme environment in summer was studied.The variation of air velocity,temperature,carbon dioxide volume concentration and relative humidity with time and the regularities of distribution of each parameter were analyzed.Result showed that the regularities of distribution of each parameter was similar to that of the EMU in the extreme in summer when it runs stably on the flat ground,thepressure fluctuation has the greatest influence on the air velocity and relative humidity,but has little effect on the temperature and carbon dioxide volume concentration,and the parameters basically meet the standard.(4)The flow field index and thermal comfort index were introduced to evaluate the air flow organization in the EMU compartment under different operating environments.The influence of pressure fluctuation outside the train on the pressure inside the train and the comfort of passengers were studied.The suppression effect of fans on the pressure fluctuation outside the train were analyzed.Results showed that satisfactory air flow organization can be obtained in the train under various working conditions,the pressure in each position in the middle compartment of EMU was basically the same,the pressure coming into the carriage from the air port will not affect the comfort of passengers,and the suppression effect of fans were good.