Simulation Based On FLUENT And Safe Evacuation On Atrium Building Fire

Atrium building can improve the air quality of indoor space and good lighting conditions and appearance, is very common in large shopping complex. With its fuel-intensive, dangerous fire hazards, personnel-intensive and complexity of structures, smoke in atrium fire can be spreading rapidly along the upper atrium space, which result in a more severe fire situation. Part of atrium building is connected to the surrounding areas, when the fire occurs, smoke quickly filled up the whole space and spread to neighboring buildings easily. At present, although China has formulated regulations on smoke control and evacuation in atrium buildings, it is not sufficient to catch up with the rapid development of multiple-type buildings because of certain irrationality in those regulations, in-depth study in related fields is needed so as to continuously update and improve relevant regulations and standards. Therefore, it is urgent to study on smoke spread process and evacuation countermeasure in atrium buildings.In recent years, studied mainly concerning on building fires have focused on only fire smoke or evacuation respectively, and then conducted safety assessment by comparing with related safety standards. Instead, this paper conducts researches by combining smoke spread process with personnel evacuation through numerical simulation.This paper firstly elaborates domestic and overseas researches on smoke, personnel evacuation and fire simulation techniques in atrium buildings, and introduces research contents, methods and theoretical basis of fire simulation. Secondly, based on Cabins Fire Safety Concept and simplified model of solid fuel combustion, the temperature distribution and movement of the gas in the cabin fire was simulated by software of Fluent. The applicability of using partially premixed model in cabin fire simulation is verified by experimental results. Then the Changes in cabin fire smoke condition and CO concentrations while starting the mechanic exhaust system is analyzed. Thirdly, software of Fluent is used to illustrate different fire scenarios in atrium building of a shopping plaza in Guangzhou and build numerical models considering the position of combustion source and air tuyere by designing different atrium fire scene. Results from the simulation show that mechanic exhaust system has a dual role of strengthening oxygen diffusion and diluting smoke, effectively reduces CO concentration inside the building when the fire occurs; The higher location of air tuyere restricts the sufficient burning of the combustibles and make it easier for outside air supplement, thus achieving a lower temperature in atrium buildings; CO concentrations maintains at high level when the smoke moves to further locations; The smoke is less toxically harmful when the fire occurs in the center of atrium compared to the situation when the combustion starts from the corner; while at the bottom of atrium the smoke temperature rise relatively slow and the CO concentrations grow relatively fast, which result in a higher damage in toxicity than in high temperature for personnel evacuation.Base on the atrium fire simulation of smoke spread characteristics, domestic and foreign evacuation models are summarized and an extended cellular automation model is brought out for large space building fire case. Then a real evacuation procedure on atrium building of a shopping plaza in Guangzhou is analyzed by the new model. The influence of smoke diffusion on personnel evacuation time is analyzed and some improvement measures and a shunt personnel evacuation methods are also brought out. The simulated results show that this new model occupies preferable practicability and intelligence.The research results in this paper can be used for certain reference and guidance for smoke spread and control, evacuation and performance-based fire safety design similar buildings.