耦合风扰作用下火源热烟羽受限扩散规律实验研究

Experimental Study on Confined Diffusion Law of Fire Plume under the Effect of Coupled Wind Turbulences

通过分析庚烷油池火燃烧反应及燃烧参数,提出一个半经验模型用来预测20MW火灾强度对应隧道火源燃烧参数.针对3个风口非对称布置在火源两侧的特殊情况,根据密度修正弗诺德准则搭建1/14缩尺模型试验,以电加热空气模拟火源热烟羽.针对不同纵向风速、排烟量组合,详细测量隧道内温度场分布.试验结果表明,热烟气扩散受到两者的耦合影响,上游无风环境以及临界风速送风情况,均不能达到理想的控制效果.CFD数值模拟与试验结果相比,具有较好的一致性,可进一步拓展试验结果的参考范围.

Based on the analysis of the combustion process in heptane pool fires,a semi-empirical model has been developed to evaluate the physical characteristics for a 20 MW fire in Chongming tunnel.With respect to three vents located on both sides of the fire in an asymmetrical arrangement,a series of experimental tests were carried out on a 1/14 reduced model tunnel.For the experimental simulations,fire-induced smoke was simulated by a heated air release using the semi-empirical model,and then deduced from the modified Froude similarity.Detailed temperature distributions inside the tunnel had been carried out.According to the test results,smoke management could satisfy the design standard neither at critical ventilation nor at no supply condition.It was also shown that the smoke propagation behavior was influenced by the longitudinal velocity,exhaust rate,and by their coupling effect. Moreover,the CFD predictions of the computational fluid dynamics codes were validated in good agreement with the test results,which allowed the results of the fire tests to be effectively applied to any tunnel and ultimately expanded the value of the test program.