Simulation Study On Airflow Organization Of Air Conditioning System In B-type Subway Car

In recent 30 years,with the rapid development of China's economic strength,urban rail transit projects are also growing.Because of its safety and punctuality,subway has become an important means of transportation for people to choose when they travel.The thermal comfort of passengers in the subway car is closely related to the air distribution in the air conditioning area.When the ambient temperature is very high in summer,using the traditional mechanical refrigeration air conditioning refrigeration will invest a lot of energy consumption,and the passengers will still have a sense of stuffy heat.Because of the outstanding energy-saving effect of evaporative cooling air conditioning,this paper studies the air distribution in the subway car based on the characteristics of evaporative cooling air conditioning,which lays a theoretical foundation for the application of evaporative cooling system in the subway air conditioning system in the future.This paper mainly simulates the air distribution of B-type subway cars under different air supply conditions in summer,and studies the thermal comfort of passengers under different air supply modes.Firstly,the physical model of B-type subway empty carriage is established by usi ng computational fluid dynamics(CFD)software ICEM,and then the numerical simul ation of air flow field in the carriage is carried out by using FLUENT software to ex plore the relationship between various factors affecting air distribution.Three different exit boundary conditions are simulated and the most suitable exit boundary conditions are discussed.Secondly,the physical models of B-type subway car with full load and fixed nu mber of passengers are established respectively,and the air flow field in the car is si mulated by FLUENT software.The influence of different air supply conditions(air su pply temperature,air supply speed and air supply angle)on the air temperature and s peed field in the car is discussed,and the best air supply conditions under different c onditions are explored.According to the simulation results,the air flow performance i n the car is evaluated and analyzed.At last,the physical model of air distribution in B-type subway is established,and the best air distribution condition is analyzed after simulation.The temperature distribution,velocity distribution and economy of the two air distribution forms are compared under the same air supply condition,which provides suggestions for the design of air distribution in the summer urban B-type subway car.