管道类结构中障碍物阻塞比对可燃液体蒸气爆燃特性的影响

Effect of obstacle blockage ratio on deflagration characteristics of combustible liquid vapor in channel-like structure

为探究可燃液体蒸发扩散诱导的非均匀蒸气浓度分布下障碍物阻塞比对管道类结构爆燃特性影响,利用矩形截面管道模型开展爆燃实验。采用高速摄像机和压力传感器测量并记录爆燃火焰和压强的传播过程。在障碍物宽高比固定的条件下,研究阻塞比对火焰传播速度、压强和出口位置CO体积分数等的影响。研究结果表明:障碍物边缘对火焰前沿的剪切作用能够在一定程度上促使火焰传播加速。火焰传播速度随阻塞比增大而先增大后减小,最大传播速度为97.5 m/s。爆燃压强的变化趋势与火焰传播速度的类似,当达到当前实验条件下的临界阻塞比0.40时,爆燃压强达到峰值。最大压强和爆炸威力指数均表现出随障碍物阻塞比增大而先增大后减小的趋势。此外,管道结构洞口处CO体积分数随阻塞比增大而呈单调增大趋势,最高CO体积分数达到730×10^(-6)。

In order to explore the influence of obstacle blockage ratio on channel-like structure deflagration characteristics with non-uniform vapor concentration distribution induced by the evaporation and diffusion of combustible liquid,deflagration test was performed using a rectangular cross-section channel model.The propagation of deflagration flame and pressure was recorded by high speed camera and pressure sensor.The effects of blockage ratio on the flame propagation speed,pressure and CO volume fraction near the portal were analyzed and studied at the fixed obstacle aspect ratio.The results show that the shear effect of obstacle edges on flame front can accelerate the flame propagation to some extent.Flame propagation speed firstly increases and then decreases with the increase of blockage ratio,and the maximum propagation speed is 97.5 m/s in the current tests.The variation trend of deflagration pressure is similar to that of flame propagation speed.When blockage ratio reaches the critical value of 0.40 under the current experimental condition,deflagration pressure reaches the peak value.The maximum pressure and explosive power index both increase firstly and then decrease with the increase of blockage ratio.In addition,the measured CO volume fraction near channel portal increases monotonously with the increase of blockage ratio,which can be mainly attributed to the combined influence of obstacles and the incomplete local thermochemical reaction caused by non-uniform concentration distribution,and the maximum CO volume fraction reaches 730×10^(-6).