Study On The Influence Of Door Opening And Closing On The Thermal Environment Of Subway Carriage

With the rapid development of subway transportation in China,passengers have put forward higher requirements for the thermal environment of subway carriage.The present researches on the thermal environment of subway carriage mainly focus on the steady state condition during the closing time of subway door,and the research on the thermal environment of subway carriage during subway door opening and closing is less.However,the subway door are opened and closed quite frequently during the process of operation,and the thermal environment in the carriage are easily affected by the opening and closing of the door.In order to better ensure the thermal environment of the subway carriage,and reduce the adverse effect of door opening and closing on the thermal environment of subway carriage,and realize the fine control of the thermal environment of the subway carriage,it is necessary to study the influence of door opening and closing on the thermal environment of the subway carriage.By discussing the influencing factors of the thermal environment of the subway carriage during the opening and closing of the door,the main factors of the thesis are determined: door opening time and platform temperature.In order to ensure the reliability of the numerical simulation results,the carriage of Zhengzhou Metro Line 1 was selected as the research object,and the temperature distribution and velocity distribution were measured at the opening and closing moments of the door,and compared with the simulation results;in order to obtain the change of the thermal environment of the subway carriage during the opening and closing of the door,firstly,the thermal environment of subway carriage under the steady state condition during door closed is simulated and analyzed;secondly,in order to study the influence of door opening time and platform temperature on the thermal environment of subway carriage,taking the simulation results of steady state condition as the initialization condition,,the unsteady simulation of the thermal environment of subway carriage during the door opened is carried out;finally,in order to study how long it takes for the thermal environment of the carriage to recover to steady state after the door is closed,taking the simulation results of unsteady state condition during the door opened as the initialization conditions,and the unsteady simulation is carried out again.The main results are as follows:(1)When the platform temperature is constant,the longer the door opening time,the greater the influence of the door opening time on the temperature field in the carriage.Although the velocity field in the carriage is fluctuating,the fluctuation is very small,it means that the door opening time has little influence on the velocity field in the carriage.(2)When the door opening time is constant,the lower the platform temperature,the greater the temperature difference between the platform and the carriage,the greater the influence of the platform temperature on the temperature field in the carriage,and the velocity field is almost unaffected.(3)When studying the influence of the door opening time on the thermal environment of the subway after the door is closed,it is found that when the door opening time is 10 s,20s,30 s and 40 s,the time for the thermal environment to recover to steady state is 34 s,39s,41 s and 43 s,which shows that the time for the thermal environment to recover to steady state is also more longer.With the increase of door opening time for 10 s,the time increment to recover steady state for the thermal environment of subway carriage is getting more smaller,which shows that the impact of door opening time on the thermal environment in the carriage is gradually slowing down.(4)When studying the influence of platform temperature on the thermal environment of the carriage after the door is closed,it is found that with the increase of platform temperature,the difference between the platform temperature and the average temperature of the carriage is smaller,and the time for the thermal environment of the carriage to recover to steady state.When the platform temperature is 12?,14?,16?,18? and 20?,it takes 45 s,42s,38 s,32s and 23 s for the thermal environment of the carriage to recover to steady state after the door closed.The researches of this thesis can provide theoretical basis and reference for the fine control of the thermal environment of the present subway carriage.