组合多孔介质与氮气幕协同抑制瓦斯爆炸实验研究

Experimental study on the synergistic suppression of gas explosion by combined porous media and nitrogen curtain

为探究组合多孔介质与氮气幕抑制瓦斯爆炸的协同作用,在自主设计的爆炸管道内开展了爆炸实验。氮气幕距离点火位置0.9 m。实验选择的组合多孔介质是由孔隙密度为10 ppi的泡沫铁镍与20、30、40 ppi的泡沫铁镍形成的组合体,以及10 ppi的泡沫铁镍与20、40 ppi的泡沫铜组成的组合体。研究表明:合理改变多孔介质的组合能提升与氮气幕共同抑制瓦斯爆炸的效果;第一层使用泡沫铁镍和第二层使用泡沫铜的组合显著削减火焰到达多孔介质时的强度,降低超压峰值,同时能够防止刚度低的泡沫铜形变而造成淬熄失败;抑爆效果最佳的组合为孔隙密度为10 ppi的泡沫铁镍与40 ppi的泡沫铜形成的组合多孔介质。

To investigate the synergistic effect of N2 and combined porous media to suppress gas explosion,the experiments were carried out in an independently designed explosion pipe.The nitrogen curtain was 0.9 m away from the ignition location.The combined porous media used in the experiments consist of a combination of iron-nickel foam with pore densities of 10,20,30 and 40 ppi,as well as a combination of iron-nickel foam with 10 ppi and copper foam with 20 and 40 ppi.The results show that nitrogen curtains cause intact flames to propagate forward in a fragmented manner,diluting the concentration of combustible gases upstream of the porous medium and slowing down the flame propagation speed.The porous medium,on the other hand,effectively absorbs the precursor shock wave and disrupts the positive feedback mechanism,leading to further weakening of the flame propagation speed towards the porous medium and enhancing the quenching performance of the medium.The porous media with high pore density as the second layer of the combined porous media,can block the nitrogen from escaping upstream of the porous media,significantly reducing the concentration of combustible gases upstream,the flame propagation speed then decreases rapidly,and the slowed down flame is more easily quenched by the combined porous media.When the pore density of the second layer increases,the first overpressure peak remains largely unchanged,while the second overpressure peak rises sharply,which increases the risk of explosion.The combination of iron-nickel foam in the first layer and copper foam in the second layer significantly reduces the intensity of the flame when it reaches the porous media and lowers the overpressure peak,while the high strength of iron-nickel foam in front of the copper foam prevents the low strength copper foam from deforming and causing quenching failure.The combination with the best explosion suppression effect is the pore density 10 ppi of iron-nickel foam metal and 40 ppi of copper foam to form a combination of porous media.