热辐射对中庭火灾烟流的影响

Thermal Radiation Effects on Smoke-flow 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紊流流动的场模型。引入 6通量辐射换热模型 ,分析热辐射对中庭火灾烟流的影响。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。采用PHOENICS通用软件进行数值计算。结果表明 ,由于中庭温度相对较低 ,辐射换热的影响较小 ,将壁面传热系数取最大值 ,从而将辐射换热的影响计入壁面传热损失的计算方法是可行的 ,应进一步完善数学模型 。

The field models for smoke flow in atrium, takings into account strong buoyancy, turbulence, radiation exchange and wall heat losses are developed according to the characteristics of the atrium fire. Realistic combustion processes in the burning fuel have not been included. A six-flux radiation model is included in a general mathematical model for fires, which are taking as a volumetric heat source, It is applied to the predictions of fire smoke development in a small-scale atrium. In order to avoid complicated radiation exchange models, radiation heat loss effects are combined to the wall heat loss. A General-purpose compute program PHOENICS has been 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. The resullts indicate that radiation transfer has the minor effects, due to the relatively low temperatures encountered. The method that the effect of radiation is included in the calculation of wall heat transfer losses by using maximum heat transfer coefficient is feasible. The field model used in the present study is not good enough, which a turbulent combustion sub-model must be included.