为了提高水射流破煤岩性能和卸压增透效果,通过理论分析建立了高压气液两相射流的冲击动压模型,推导出影响其破煤岩性能的关键参数体系.采用自主研发的高压气液两相射流破煤岩试验系统,研究了关键参数对气液两相射流的破煤岩特性的影响规律,结果表明:与纯水射流相比,气液两相射流破煤岩压力阈值降低约50％,破碎深度增加25％,破碎坑直径是纯水射流的2倍,破煤岩效率提高80％以上.煤岩体破碎是气-液-固三相耦合作用的结果:气体的掺入改变射流的结构,产生局部脉动作用,强化了射流破岩能力;高压液相脉动冲击作用激发裂纹起裂,高压气相的多级溃灭作用促进裂纹扩展;气相多级溃灭与液相脉动冲击交替作用,最终使煤岩体裂隙贯通、破坏.%In order to improve the coal rock-breaking capacity of water jet and pressure-relief and permeability effect,by establishing the impact dynamic pressure model of high pressure gas-liquid two-phase jet,the key parameters were obtained which affected the capacity of coal rock-breaking.Experimental tests about the characteristics of impacting coal rocks were conducted by self-designing rock breaking test system of high pressure gas-liquid two-phase jet.The results showed that the rock breaking threshold pressure was reduced by 50％,the breaking depth increased 25％,the diameter was 2 times and the efficiency increased about 80％ by comparing with pure water jet.The coupling between the gas-liquid-solid three phases resulted in breaking coal:the structure of jet was changed and formed local impulse by mixing gas,which strengthened coal rock-breaking ability;cracks were motivated under high pressure liquid pulsation,which promoted by multilevel collapsing of tiny gas phase.By the multilevel alternation of liquid pulsation and gas phase,the coal rock was broken finally when the original cracks were connected.
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