置障空间可燃气体火焰传播特性数值模拟研究

Numerical Simulation Study on Flame Propagation Characteristics of Combustible Gas in Obstacle Space

为揭示置障管道内丙烷浓度对火焰传播特性影响,借助ANSYS Fluent软件,利用Zimont燃烧模型开展了置障管道内不同丙烷浓度预混气体燃爆规律的大涡模拟研究。结果表明:在阻塞率为0,0.5,0.7,0.9障碍物管道中火焰锋面速度峰值均随给定初始浓度的增加呈现先增大后减小的趋势,且峰值速度随阻塞率的增大而增大,丙烷体积分数为4.5%、阻塞率为0.9时,火焰传播峰值速度可达178.93 m/s;阻塞率越大,涡团规模越大,导致流场紊乱程度增大,湍流脉动增强,火焰面与流场相互作用,促使火焰面褶皱破碎,加速了已燃气体与未燃气体分子间的无规则运动,对燃烧反应起到激励作用;数值模拟结果直观展示了火焰传播进程及火焰结构的发展细节。

In order to reveal the effect of the concentration of propane on the flame propagation characteristics in the barrier pipeline,we have carried out the large eddy simulation with the aid of ANSYS Fluent software and Zimont combustion model.The results show that the peak velocity of the flame in the pipeline increases first and then decreases with the increase of the given initial concentration.In the barrier pipeline with 0,0.5,0.7 and 0.9 blocking rates,the peak velocity increases with the increase of the blocking rate.The peak velocity of the flame propagation is up to 178.93 m/s when the concentration of propane is 4.5%and the blocking rate is 0.9 in the barrier pipeline.The larger the blocking rate is,the larger the scale of vortex cluster is,which leads to the increase of turbulent turbulence and turbulent turbulence.The interaction between flame surface and flow field results in the folding and breaking of flame surface,which accelerates the irregular movement between combustible and unburned gas molecules and stimulates the combustion reaction.The numerical simulation results reflect the development details of the flame propagation process and the flame structure.