管道氢气-空气预混气体爆炸特征的试验研究

Experimental study on explosion tendency of hydrogen-air premixed gases in the duct

为研究管道内氢气与空气预混气体的爆炸规律,使用尺寸为150 mm×150 mm×1000 mm的方形透明管道,通过试验观测了氢气体积分数从10%到40%的爆炸火焰形状、传播速度与压力变化规律。火焰传播与压力分别由高速摄像机与压力传感器记录测量。结果表明,爆炸火焰特征及压力变化受氢气体积分数的影响很大。火焰在管道内的最大传播速度及压力峰值随氢气体积分数增大而急剧增大。最大火焰传播速度由18.3 m/s增大到304.2 m/s,传播时间由123.5ms缩短到10.5 ms。压力峰值由2.95 k Pa增大到34.06 k Pa。当氢气体积分数为25%及以上时,火焰速度持续上升,没有出现郁金香火焰,压力波先出现短时间强烈正负压振荡,后长时间微小振荡。火焰特征、传播速度、压力变化及爆炸响声均能够很好地反映氢气爆炸的强度。

This paper is to introduce an experimental study on the explosion tendency of the hydrogen-air premixed gases in the conduit,which is a transparent squared tube with its inner size of150 mm × 150 mm × 1 000 mm.In the paper,we prefer to focus our study on the principle and the shape of the flaming in addition to its propagation speed and explosion pressure under the hydrogen volume fraction of 10%,15%,20%,25%,30%,40%,respectively.For the said research purpose,we have investigated the flame propagation process and its pressure change experimentally by using a high-speed video camera and pressure sensors.The results of our experiments and analysis show that the volume fraction of the hydrogen tends to produce a deeply influential effect on the above said items under study.The maximum flame propagation speed in the duct and the pressure peak can both be dramatically increasing with the increase of the hydrogen fraction.The maximum flame propagation speed in the said conduit can be growing up from 18.3 m/s to 304.2 m/s,which may respectively stand for 18.3 m/s,59.6 m/s,159.6 m/s,254.2 m/s,304.2m/s in correspondence with the hydrogen volume fraction of15%,20%,25%,30%,40%.The flaming propagating time in the conduit proves to have reduced from 123.5 ms to 10.5 ms in correspondence with 123.5 ms,31.0 ms,15.5 ms,11.0 ms,10.5 ms.The pressure peak can potentially increase from 2.95 k Pa to 34.06 k Pa with the values of 2.95 k Pa,3.75 k Pa,8.68 k Pa,20.00 k Pa,33.75 k Pa,34.06 k Pa in regard with the hydrogen volume fraction of 10%,15%,20%,25%,30%,40%.What is more,it has been found that,when the hydrogen volume fraction is 25% or above,the flame propagation speed tends to be going on to rise,but with no tulip flame shape accompanying.In addition,the explosion pressure wave turns to be oscillating,with the pressure wave being strongly oscillated between the positive values and the negative values for a short period.And,then,the weak oscillation proves to keep lasting for a long while.Furthermore,it can be said that the greater the hydrogen volume fraction,the stronger the oscillation will be.Thus,briefly speaking,the characteristics,propagation speed of the flame,its pressure changes and explosion noise can be expected to well account for the strength of the hydrogen explosion.