管道截面突缩对爆轰波起爆特性的影响

为研究管道截面突缩对爆轰波起爆特性的影响,在突缩比为5:3的截面突缩管道及直管内对不同初始压力下甲烷氧气预混气体的起爆特性进行了实验研究,利用离子探针获得管道内火焰传播速度,并通过二维数值模拟探究了3种不同突缩比的截面突缩管道内火焰及压力的传播特性.实验结果表明,截面突缩管道内爆轰波起爆距离随着初始压力的降低而逐渐增加...

Influence of Sectional Sudden Contraction of Tubes on Initiation Characteristics of Detonation Waves

In order to study the influence of sectional sudden contraction of tubes on the initiation characteristics of detonation waves,this paper conducted an experimental study on the premixed gas of methane and oxygen under different initial pressures in a sectional sudden contraction tube with a section ratio of 5∶3 and a straight tube,and obtained the flame propagation velocity in the tubes by using the ion probe.Two-dimensional numerical simulation was performed to investigate the propagation characteristics of flame and pressure in the sectional sudden contraction tubes with different section ratios.The experimental results show that the initiation distance of the detonation wave in the sectional sudden contraction tubes increased gradually with the decrease of the initial pressure.Under the initial pressures of 20 kPa and 15 kPa,the detonation distances of the sectional sudden contraction tube were reduced by 22%and 19%,respectively,compared with that of the straight tube.The simulation results show that when the pressure wave propagated to the section of sudden contraction,the back pressure was formed due to the obstruction of the section.The pressure wave temporarily reduced the flame propagation speed.After passing the section,the flame propagation speed rose rapidly until it reached the over explosion state.When the length of the detonating tube was 30 cm to 50 cm and the diameter was 40 mm to 60 mm,the detonation wave initiation distance first decreased and then increased.Therefore,there existed an optimal detonator size near the detonating tube length of 40 cm and the diameter of 50 mm,which can minimize the initiation distance.