The Dynamic Simulation For The Flow Of Island Platform In Subway

Along with the speediness of city plan, city traffic becomes more and more crowded. Underground is used as solving city traffic bottleneck's important methods because of its safety, comfort, speediness and beauty. Speeding up the underground, increasing the undergrounds'density and augmenting the passenger capacity bring about the speediness of piston wind externally, and this make passengers more uncomfortable. Therefore studying the dynamic influence to the platform and controlling of the piston wind, improving the comfort of the metro environment have practical significance. The heat flow of heat source in the subway station is changed dynamically, so it is not objective to simulate the velocity-field and temperature-field by the simple static simulation, we can see the relation and effects.The object of this paper is the Xia wafang subway station on NO.1 line of Tianjin.The research is about the temperature field and velocity field at different time. That is an island platform with double-layer, the ventilation system of which is divided into two parts: station hall part and platform part, the top space of platform layer is used to set the supply-air and exhaust duct, the be area below the platform board is applied to install the return and exhaust duct, and the top space of station hall is used as the air supplication model.The main research method was the combination of field testing and CFD simulation. First, a full-scale physical model was built according to the actual size of the station, and the simulation was performed with measured boundary conditions. Then the numerical results were verified by comparing with the experiment data to confirm the reliability of the model.The following conclusions are drawn from this research:(1) According to the simulation of the Pistons wind simulated , it is found air swirl on the stairway, because the pressure in the seconed floor rises after 12 second and the impact of the piston wind falls down near the entrance stair. So we can find the simulation is creadital and reliable.(2) On the morning and afternoon peak periods platform temperature and velocity field dynamic simulation, the temperature and velocity distribution of cloud has a great difference that is an advantage of using this simulation, although the same train arrived at the platform at all times, but due to a train is about to leave, and the other is just metro stops.Even the trains stop in the same side, the time is different, so thermal and piston wind combined effects will be different, it is more reality to use the dynamic simulation.