中庭火灾烟气流动数值模拟

NUMERICAL SIMULATION OF SMOKE MOVEMENT IN ATRIUM FIRES

根据中庭火灾特点 ,提出了考虑辐射换热损失和壁面传热损失、不考虑燃烧过程、视火焰为体积热源 ,浮升力作用下火灾烟气湍流流动的场模型。并将辐射换热损失计入壁面传热损失 ,简化辐射换热模型计算。运用该场模型对中庭模型实验装置火灾烟气流动进行了数值模拟。采用通用软件 PHOENICS进行数值计算。研究表明 ,数值模拟结果与中庭模型实验装置火灾试验结果吻合 ;

With the rapid development of computational fluid dynamics (CFD), compute modeling has been successfully developed to be an important aid in the field of fire science. Compared with zone models, which are frequently used in fire safety design, field models have not yet reached the stage of being an important design tool in fire protection design, mainly due to the limitations and complexities imposed by the modeling of turbulence, radiation exchange and combustion. It is the objective of this study that introducing a reliable, practical and economical fire field model for simulating atrium fire smoke movement, which can be utilized in atrium fire protection design. In this paper, the field model for smokes flow in atrium, taking into account strong buoyancy, turbulence, radiation exchange and wall heat lossess, are developed, according to the characteristics of the atrium fire. Realistic combustion processes in the burning fuel are not included. In order to avoid complicated radiation exchange models, radiation heat effects are combined to the wall heat loss. The model,in which the fire is taken as a volumetric heat source, is applied to study the smoke movement in atrium fires. A general-purpose compute program PHOENICS was developed to meet this need. Results of numerical calculations based on the field model are compared with test data for a fire in the small-scale atrium test facility. Reasonable comparisons of the resulting temperatures are obtained. The method treating the fire as a volumetric heat source without simulating the combustion process in the present study is a viable means to study smoke movement in atrium fires. A significant shortcoming of the field model used in the present study is discussed. A turbulent combustion sub-model must be included.