A CFD Simulation Of The Air-conditioning System In The Side-Platform Subway Station

With the large-scale constructing of the subway in China, the platform environment in subway station is concerned by more and more researcher. A better environment in platform not only can provide us a safe and comfort circumstance when we waiting trains, it can also reduce the initial investment, running consumption and shows its importance in the sense of energy saving.Combined with the project of Tianjin Metro, based on the original plan of air-conditioning system designed by No. 3 Survey and Design Institute, we selected the North-West Station as a representative, establishing a three dimension models. We confirmed the boundary condition according to the actual calculation of the heat load, suggested a reasonable air-conditioning system design based on analysis of the heat and moisture load and their distribution, and at the same time, found out problems in the process. After created qualified grids, discretized physical characteristic, we computed the temperature and velocity field within the standard Model by utilizing CFD techniques. The thesis focuses on the temperature design of supply air, the influence on the platform brought by stopcock wind and local exhaust and the possibility of actualizing the VAV system.It is found that: the standard Model can be used to predict flows at the station and resultant velocity and temperature field under some reasonable presumptions; the impact brought by stopcock wind is variable according to the different tunnel structures; the temperature of is related with the distribution of heat load; the VAV system has advantage in energy saving, but when the air volume reduced to a certain degree, we should consider the alteration of rising the temperature of supply air, and increasing the quantity of it.In addition, the thesis is meaningful in many aspects, such as: how to create grids in complex model, how to simplify the boundary condition, and how to transfer transience to steadiness.