多功能煤与瓦斯突出模拟试验系统研制与应用

Development and application of multi-functional test system for coal and gas outburst simulation

基于模块化思路,自主研制了多功能煤与瓦斯突出模拟试验系统,由试件腔体和五大模块(加载模块、渗流模块、诱突模块、巷道模块和采集模块)组成,试件腔体尺寸φ200 mm×700 mm、密封气压10.0 MPa、轴向应力20.0 MPa,巷道内径200 mm、长10 m、透光率94%,突出口径25,50,100 mm可选,集型煤一次性成型、渗透性测试和突出两相流可视化等多功能于一体。以煤与瓦斯突出灾害较为严重的河南龙山煤矿为工程背景,开展突出模拟试验,结果表明:(1)测试得到型煤试件渗透率为9.88×10^(-3)μm^(2),诱突过程达到毫秒级,突出启动后,高压气体裹挟煤粉持续抛向巷道,形成煤‐瓦斯两相流,突出煤粉9540.0 g,相对突出强度47.7%;(2)突出过程中,巷道空气受压缩产生多道以正相压和负相压交替向前传播的冲击波,冲击波超压峰值在巷道中部5.5 m处达到最大,为15.41 kPa,同时产生向后运动的稀疏波,导致试件腔体内煤层气压上升21%;(3)突出煤粉流受突出阵发性和突出煤粉解吸气体影响,出现多次再加速过程,在第二次加速后达到速度峰值42.6 m/s,冲击波则以超声速超前于煤‐瓦斯两相流传播,波阵面速度高达361.76 m/s,远大于煤粉流速度;(4)突出两相流温度主要受控于煤层瓦斯解吸吸热和冲击波扰动,呈现出“短暂上升‐快速下降‐缓慢回升”的演化趋势,表现为越靠近突出口,下降幅度越大,最大下降2.1℃,越远离突出口,上升幅度越大,最大上升0.6℃。测试结果表明,该试验系统稳定可靠,能准确测定试件渗透率,并真实模拟再现突出全过程,为深入研究突出机制、指导现场突出防控提供有效手段。

A multi-functional test system for coal and gas outburst simulation,composed of specimen cavity,loading module,seepage module,outburst inducing module,roadway module and data acquisition module,was independently developed based on modular development idea.The size of specimen cavity is φ200 mm×700 mm,and its sealing gas pressure and axial loading stress are respectively 10.0 MPa and 20.0 MPa.The size and light transmittance of the roadway are φ200 mm×10 m and 94%,respectively.The diameter of the outburst mouth is optional with 25 mm,50 mm and 100 mm.The test system can realize the functions of one time forming of coal samples,permeability test of coal samples and visualization of coal-gas two-phase flow.Taking Longshan Coal Mine in Henan Province as the engineering background,the outburst simulation test was carried out,and the results show that:(1)the permeability of the coal specimen is 9.88×10^(-3)μm^(2),and the outburst inducing process reaches the millisecond level.After the outburst is trigger,the pulverized coals entrained by high-pressure gas continue to be thrown into the roadway to form a coal-gas two-phase flow.The outburst pulverized coal is 9540.0 g,and the relative outburst strength is 47.7%.(2)During the outburst process,the roadway air is compressed to produce multiple shock waves that gradually attenuate in the form of alternating positive pressure and negative pressure,and the peak value of the shock wave overpressure reaches a maximum of 15.41 kPa at 5.5 m in the middle of the roadway.At the same time,the backward moving rarefaction wave generates to make the coal seam pressure in the cavity increase by 21%.(3)The outburst pulverized coal flow has the multiple reacceleration processes due to the paroxysmal outburst characteristics and the gas desorption,reaching the peak velocity of 42.6 m/s after the second acceleration.The shock wave propagates in the roadway ahead of the coal-gas two-phase flow at supersonic speed,and the wave front velocity is as high as 361.76 m/s which is much higher than that of the pulverized coal flow.(4)The two-phase flow temperature is mainly controlled by the endothermic process of the gas desorption and the disturbance of the shock wave,showing an evolutionary trend of“short rise,rapid decline and slow recovery”.The closer to the outburst mouth,the greater the decline of the temperature,with a maximum decrease of 2.1℃.The farther away from the outburst mouth,the greater the rise,and the maximum rise is 0.6℃.It is shown that the test system is stable and reliable,and can accurately measure the permeability of the specimen,realistically simulate the whole process of outburst,which provides an effective means for in-depth study of outburst disaster causing mechanism and guiding outburst prevention and control in coal mines.