用于煤矿安全切割的前混合磨料射流加速机理研究

前混合磨料射流具有切割各种材料无火花、所需设备压力低以及操作简单等优点,具有广泛应用井下安全切割的功能。笔者根据建立的磨料粒子运动方程,推导出具有普遍意义的匀速流场内粒子路程函数以及用数值分析法求解出粒子在喷嘴内的速度;通过理论分析和具体的数值计算,磨料最主要的加速过程是在收缩段内完成,磨料粒子从喷嘴喷出时已能高达水流速度的95 %以上,磨料粒子在离开喷嘴在射流的核心段内仍将继续得到加速;同时发现,在条件允许的情况下,喷嘴的收缩段应适当长些,喷嘴圆柱段长度为喷嘴出口直径的2 .5～3.0倍最合适。

Study on Acceleration Mechanism of Abrasive Particles of DIA Jet in Coalmine Safe Cutting

Due to its sparkles, low pressure needed, and easy-to-operate, DIA jet will be widely applied in safe cutting in coalmine. According to its motion equation formulated, road function was deduced and velocity of abrasive particle in the nozzle was calculated by numerical analysis. According to theoretical analysis and numerical calculation, it was found that the main accelerating process of the abrasive particles was accomplished in the contracting section of the nozzle. When the abrasive particles jetted from the nozzle, they already gained 95% of the velocity of the water jet. They continued to accelerate at the core section of the jet flow when leaving the nozzle. The appropriate length of the cylindrical section of the nozzle was 2.5～3.0 times of the outlet diameter of the nozzle.