氮气喷出对管道瓦斯爆炸的阻爆研究

为探究喷出氮气对瓦斯爆炸火焰传播的抑制能力，设置三种氮气喷头布置方式来进行阻爆实验，采用的氮气喷出压力有0.1、0.2、0.3、0.4和0.5 MPa，爆炸开始后喷射氮气，爆炸结束后氮气立刻关闭。结果表明，单喷头距泄压口20 cm时，各压力下喷出的氮气都未能阻爆，但火焰在整个管道内的平均传播速度随氮气压力增大而减小；单喷头距泄压口35 cm时，喷气压力0.5 MPa下成功阻爆，其他喷气压力下未能阻爆；双喷头喷气时，喷气压力0.3、0.4、0.5 MPa情况下都能够阻爆，且喷气压力越大，火焰被阻止的位置越靠前。阻爆的实现，需要氮气在阻爆位置将管道截面上的预混气稀释到可燃极限以下，因而氮气量是影响稀释的重要参数。单喷头时，喷头距离泄压口远更易于实现阻爆。采用双喷头时，氮气区扩大，阻爆所需氮气压力、氮气总量比单喷头时都大为降低。

The spurted nitrogen preventing the gas explosion in pipe

After the gas explosion, preventing the propagation of explosion flame can better eliminate the disaster. In this paper, three kinds of nitrogen nozzle arrangement are set to carry out experiments for explosion prevention. The nitrogen pressures used in experiments include 0.1, 0.2, 0.3, 0.4 and 0.5 MPa, Nitrogen is spurted into the pipe after the occurrence of the explosion and immediately shut down after quenching the explosion. The results show that the spurted nitrogen under each pressure can not prevent the explosion with single nitrogen nozzle, which is 20 cm away from the vent. But the average propagation speed of the flame in the whole pipe decreases with the increase of nitrogen pressure. With single nitrogen nozzle, which is 35 cm away from the vent, the spurted nitrogen at pressure 0.5 MPa succeed in explosion prevention, while the explosion can not be prevented at other pressure. When double nozzle is used to spurt nitrogen, the explosion is prevented in the case of pressure 0.3, 0.4 and 0.5 MPa. And the greater the nitrogen pressure, the more forward the flame is blocked. The explosion prevention requires nitrogen to dilute the premixed gas below the combustible limit. Nitrogen volume is the important parameter affecting dilution. With single nitrogen nozzle, the situation of nozzle far from the vent is easier to prevent the explosion than that of nozzle near from the vent. When double nozzles are used, the nitrogen region will enlarge. With double nozzle, lower nitrogen pressure and less nitrogen quantity are required for preventing the explosion as comparing with single nozzle.