煤层水力割缝自吸磨料喷嘴特性与参数

摘要

High-pressure water jet becomes invalid in cutting hard coal seam,and abrasive jet cutting technology is difficult to achieve continuous addition of abrasives.In order to overcome these difficulties,a self-priming abrasive jet nozzle using the forward and backward nozzle structure was designed on the basis of the principle of ejector.This nozzle can achieve continuous inhalation of coal particles produced by slotting to form abrasive jet,with the slotted capacity improved.By simulating the two-phase liquid-solid interaction,it was found that coal particles in the nozzle experience three acceleration stages at intake, mixing chamber and nozzle, respectively.According to the volume of particles and the final velocity of the particles,the most optimal nozzle structure was obtained:the front nozzle diameter is 3 mm,the back nozzle diameter is 5 mm,and the length of the back nozzle is 15 mm.The comparison of the experiments results showed that the slotting efficiency of the self-priming abrasive nozzle was improved significantly compared to that of the traditional cutting seam.%针对煤矿纯水射流割缝遇硬煤失效,而磨料射流割缝技术难以实现磨料连续添加等问题,基于引射原理,采用前后双喷嘴结构,设计出一种自吸式磨料射流割缝喷嘴,可以连续吸入割缝产生的煤粒形成磨料射流,提高割缝能力.通过液固两相数值模拟,发现煤粒在喷嘴内经历了3个加速阶段：吸入口加速段、混合腔加速段和后喷嘴加速段.以提高吸入量和最终煤粒的速度为指标,得到喷嘴的最优结构：前喷嘴直径为3 mm,后喷嘴直径为5 mm,后喷嘴长度15 mm.对比割缝实验结果表明,自吸式磨料射流割缝喷嘴的割缝效率较传统割缝喷嘴明显提高.