套室内扩散燃烧火灾的三维数值模拟

采用非稳态湍流模型和湍流与化学反应相互作用的涡耗散燃烧模型,对套室内扩散燃烧的火灾进行了三维空间数值模拟.给控制方程添加不同源项以反映化学反应净产生速率对流场的影响,采用交错网格有限容积法将计算区域进行离散,用SIM-PLE算法求解离散控制方程.通过对套间内3种不同释热率情况下火灾的数值模拟,研究了套间内火灾发展、烟气温度分布和燃烧产物浓度分布规律.研究表明火源释热率的大小对烟气温度场的影响较大,对燃烧产物CO2浓度场的影响不很明显.释热率较小时,较短时间内仍能产生大量的烟气;释热率较大时,烟气层迅速形成,温度上升程度更为剧烈.此研究结果对于准确预测套室内火灾传播规律、有效阻止套室内烟气扩散和设计合理的排烟结构有一定的指导意义.图8,参12.

Numerical Simulation on Non-premixed Combustion Fire in an Apartment Unit

Unsteady turbulence model and eddy-dissipation combustion model based on turbulence chemistry interaction was used,three dimension distribution of non-premixed combustion fire in an apartment unit was simulated numerically.The chemistry reactant rate had great effect on the distribution of airflow,which was reflected by the different source terms added in the control equations.The air fluid flow and heat transfer problems were resolved by finite method in interlacing grid with SIMPLE algorithm.By studying fire process of different heat release rate,the development of apartment fire and smoke temperature and combustion product concentration distribution law are discussed preliminary.The results show that the heat release rate has great effect on smoke temperature field,but little effect on CO2 concentration field.When the heat release rate is small,much smoke produces in short time.While the heat release rate is large,the smoke layer emerges immediately and the temperature rises sharply.A basis is given for predicting the fire trend,preventing smoke diffusion and designing architecture for exhausting smoke effectively.8figs.,12refs.