基于小尺度实验的燃料蒸气-空气预混气体泄爆动力学研究

Explosion venting dynamics of fuel vapor-air premixed gas based on small scale experiments

利用体积为2 L的亚克力材质容器搭建了小尺度可燃气体泄爆实验系统,基于小尺度实验开展了不同泄爆面积条件下的石油燃料蒸气-空气预混气体泄爆过程研究,获得了典型开口率条件下的内外场超压随时间的动态变化特征,分析了开口率对超压及火焰参数的影响,并对泄爆模式进行了分类。研究结果显示:(1)在不同泄爆系数条件下,石油燃料蒸气-空气预混气体的泄爆模式包括泄爆失败诱导的封闭燃烧、泄爆成功诱导的射流燃烧、泄爆成功诱导的外部爆炸,三种泄爆模式的内外场超压-时间动态曲线、超压峰值、火焰传播速度、火焰传播距离均具有显著差异,且小尺度实验与中尺度实验中均出现破膜超压峰值、火焰射流超压峰值、外部爆炸超压峰值Δp_(1)、Δp_(2)、Δp_(3);(2)当泄爆系数Kv≤39.68时,内场最大超压峰值、外场轴向最大超压峰值、最大火焰传播速度、轴向火焰传播距离均随着Kv的增大而增大,径向火焰传播距离随着Kv的增大而减小;(3)当Kv≤4.41时,外场轴向和径向最大超压峰值分别由外部爆炸引起(Δp3(ver)和Δp3(hor)),当7.94≤Kv≤39.68时,外场轴向和径向最大超压分别由火焰射流冲击和泄爆膜破裂引起(Δp_(2(ver))和Δp_(1(hor)));(4)泄爆成功和泄爆失败的临界泄爆系数在Kv=39.68和Kv=158.74之间,发生外部爆炸和射流燃烧的临界泄爆系数在Kv=4.41和Kv=7.94之间。

A small-scale flammable gas explosion venting test system was built by using a 2 L acrylic glass container.Based on the small-scale experiments,the explosion venting process of petroleum fuel vapor-air premixed gas under different explosion relief areas was studied.The dynamic characteristics of overpressure in the internal and external fields with time under the condition of typical opening ratio were obtained.The effects of opening ratio on overpressure and flame parameters were analyzed,and the explosion releasing modes are classified.The results show that:(1)Under the conditions of different venting coefficients,the venting modes of petroleum fuel vapor-air premixed gas include closed combustion induced by venting failure,jet combustion induced by venting success and external explosion induced by venting success.The overpressure-time dynamic curve,overpressure peak value,flame propagation velocity and flame propagation distance of three venting modes are analyzed.The results show that there are significant differences between the small-scale experiment and the medium-scale experiment.There are membrane breaking overpressure peak(Δp_(1)),flame jet overpressure peak(Δp_(2)),and external explosion overpressure peak(Δp_(3));(2)When Kv≤39.68,the maximum overpressure peak in the internal field,the maximum axial overpressure peak in the external field,the maximum flame propagationvelocity,and the axial flame propagation distance all increase with the increase of Kv,and the radial flame propagation distance decreases with the increase of Kv;(3)When Kv≤4.41,the peak values of axial and radial maximum overpressure are caused by external explosion(Δp3(ver)andΔp3(hor));when 7.94≤Kv≤39.68,the peak values of axial and radial maximum overpressure are caused by impingement of flame jet and rupture of explosion relief plate respectively(Δp_(2(ver))andΔp_(1(hor)));(4)The critical Kv of successful venting and failed venting is between 39.68 and 158.74,and the critical Kv of external explosion and jet combustion is between 4.41 and 7.94.