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末端开敞刚柔障碍物混合环境下瓦斯燃爆特性研究

Study on gas explosion characteristics in a mixed environment of open-end rigid and flexible obstacles

  • 摘要: 煤矿巷道瓦斯爆炸事故极易受场域内设施布局和结构特征的诱导而呈现显著差异,一直是防灾减灾工作的难点。利用刚性障碍物和柔性障碍物表征巷道内的固定和非固定设施,探究管道右端开敞刚柔障碍物混合环境下的瓦斯燃爆特性。基于瓦斯爆炸实验平台,将刚性障碍物、柔性障碍物分别置于距离点火端40、50 cm处,设定刚性障碍物阻塞率为0.4、柔性障碍物阻塞率分别为0.2、0.4、0.6,开展管道右端闭口和敞口环境下的火焰传播过程、火焰耗散行为,以及爆炸压力演化过程等实验研究。实验结果表明:敞口环境下的最大火焰速度以柔性障碍物阻塞率0.4时最大,较闭口环境下的火焰速度增幅可达746.07%;刚柔障碍物混合环境下右端敞口时呈现出2个压力峰值现象,第一压力峰值达到后线性下降至最大负压,并呈现出低频、高幅、振荡增加效应形成第二压力峰值;第一压力峰值和第二压力峰值以柔性障碍物阻塞率0.2时达到最大,较闭口空管条件的增幅分别可达112.83%、197.31%;火焰尖端速度的变化诱导了不同程度的燃料和产物的排出,对爆炸压力的最大值形成负反馈机制,导致管内的最大爆炸压力随柔性障碍物阻塞率增大而呈现先减小后增大的变化趋势。研究结果可为煤矿巷道内防灾减灾工作提供一定的理论指导。

     

    Abstract: The differentiation characteristics of gas explosion accidents in coal mine roadways are highly susceptible to the induction of facility layout and structural features within the field, which has long been a key challenge in prevention and mitigation of disaster. This study employs rigid and flexible obstacles to characterize fixed and non-fixed facilities in the roadway and investigates the gas explosion characteristics in a mixed environment of rigid and flexible obstacles open on the right end of pipelines. Based on the gas explosion experimental platform,the rigid obstacle and the flexible obstacle were placed at 40 cm and 50 cm away from the ignition end respectively. The blocking rate of the rigid obstacle was set at 0. 4,and the blocking rates of the flexible obstacle were set at 0. 2,0. 4,and 0. 6 respectively. The flame propagation process and flame dissipation behavior in the closed and open environments on the right end of pipelines were carried out,as well as experimental studies on the evolution process of explosion pressure,etc. The experimental results show that the maximum flame interruption speed is at its highest when the blocking rate of flexible obstacles is 0. 4, which can enhance the flame speed by 746. 07% compared to the closed environment. In a mixed environment of rigid and flexible obstacles,when the right end is open,two peak pressure phenomena are presented. After reaching the first pressure peak,it linearly decreases to the maximum negative pressure and sexhibits a lowfrequency,high-amplitude, and oscillation-increasing effect to form the second pressure peak. The first and second peak pressures reach their maximum when the blocking rate of the flexible obstacle is 0. 2,with increases of 112. 83% and 197. 31% respectively compared to the conditions of a closed air duct. The variation in the velocity at the flame leads to different degrees of fuel and product discharge, creating a negative feedback mechanism on the maximum explosion pressure. Consequently, the maximum explosion pressure inside the pipe shows a trend of first decreasing and then increasing as the blocking rate of the flexible obstacle increases. The research results can provide certain theoretical guidance for prevention and mitigation of disaster in coal mine roadways.

     

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