3m直径煤油池火灾火焰特性的数值研究

为了预测油池火灾的火焰特性,采用CFD模拟技术开展静风状态下3 m直径煤油液池的火灾场景模拟,探讨火焰温度、火焰羽流速度、辐射热通量、燃烧产物质量分数等油池火焰特性参数随高度的变化关系;并结合火焰形态分布,提出一种4区域模型,即将湍流扩散火焰划分为油气混合燃烧区、燃烧火焰区、烟尘区和热烟气区来分析燃烧气流在不同高度的实际物理化学特性。此外,通过经验公式和CFD模拟2种方法分别计算出3 m直径煤油池火灾的火焰高度、火焰表面的辐射通量及热辐射破坏半径,并对计算结果进行比较分析,结果表明:2种方法可互相补充完善,有助于池火灾的热辐射危害性评估。

Numerical Research on Flame Characteristic of a Three-meter Diameter Kerosene Fire

A three-meter diameter kerosene fire in open stagnant air was simulated for forecasting flame characteristics.Based on CFD(Computational Fluid Dynamics) simulation,the relations of flame temperature,plume velocity,thermal radiation flux,and the mass fraction of CO2 with height were discussed.On the base of the variation flame characteristic,combining true fire profile,a four-zone model of pool fire was proposed.Buoyant turbulent diffusion flames can be divided into four parts: mixed firing zone,combustion flame zone,smoke zone,and hot gas zone.The characteristics of combustion gas flow in each zone were analyzed.Furthermore,flame height,surface emissive power and thermal radiation damage radius of pool fire were calculated using experience formula and CFD simulation,and the calculation results were compared and analyzed.The results show that these two methods can be mutually complementary,which helps to the fire hazard assessment.