CFD Simulation Study On Environmental Control System Of A Subway Station Platform In Wuhan

With the acceleration of urbanization in our country, Urban population increases sharply, and urban congestion and pollution problems have become more obvious. Actively developing urban rail transit is one of the key to solve these problems. The subway has many advantages such as high speed, punctuality, great conveyance ability, comfort and convenience etc, so it becomes extremely popular. When we make good efforts to construct subway, its environmental problems should not be ignored, because the metro space is relative airtight and stream is crowded. Because subway cost and operating expenses are high, and the later reconstruction cost is also high, it is very necessary to research and analysis the actual effect of its environmental control system design before the construction.In this paper, CFD technology was applied. We simulated and studied air distribution in a Wuhan underground railway station platform. The temperature field, velocity field and the PMV distribution under four kinds of programs (two kinds of air supply temperature, two kinds of air supply terminal) were found. We analyzed and compared the four kinds of simulation results under four programs, and then predicted indoor thermal comfort.,which can provide a basis to select a reasonable temperature difference and air supply terminal device to optimize its air conditioning and ventilation system design.Using CFD technology, this paper also probes into different smoke control scheme under practical effect when the platform public area and rail line area where there is a fire. Aiming at the platform public area fire, we analyzed three conditions flue gas diffusion. By comparison, we found:"mechanical smoke"scheme can effectively control flue gas diffusion, and"mechanical smoke + rail top smoke"scheme made more better, but some smoke had went into the tunnel and the smoke endanger scope expanded. Smoke screen has impact on the beauty of architectural construction, but it can effectively slow flue gas diffusion speed. For the platform rail line area fire, we studied three schemes smoke effect, and found that"mechanical smoke + rail top smoke + piston wind smoke"scheme had effectively controlled the smoke diffusion. On this basis, setting"stair supply air"or"smoke-preventing air curtain", it can effectively prevent smoke from entering stairs, and can ensure the stairs with 1.5m/s downward flow. But the airflow destroyed flue gas stratified phenomenon, so it cannot effectively expel platform smoke. As a result,they should not be adopted.This research's conclusions and Suggestions not only can provide evidence for optimization design of subway platform environmental control system, but also can be beneficial to CFD technology popularization and application in environmental control system simulation studies.