前混合磨料水射流喷嘴外流场磨料加速过程研究

摘要

前混合磨料水射流与后混合磨料水射流相比,磨料粒子速度松弛情况和混合均匀性好得多.磨料在系统中加速情况影响系统的能量传递效率和切割能力,加速过程可分为管内加速、喷嘴加速以及喷嘴外流场核心段加速三个过程.本文应用液固两相流理论,对喷嘴外流场磨粒进行受力分析,建立外流场加速模型,研究表明,磨料粒子在喷嘴外流场核心区加速,达到速度最大值,在过渡段和空气掺混,粒子速度下降,在喷嘴外流场速度松弛比大于喷嘴内流场,但喷嘴外流场核心段速度增量远远小于喷嘴段.%The pre-mixed abrasive water jet compared with the post-mixedabrasive water jet,The former is more than the latter of the abrasive particle velocity relaxation and mixing uniformity.The acceleration condition of abrasive in the system effect the energy transfer efficiency and the cutting ability,the process of acceleration can be divided into the tube acceleration,the nozzle acceleration and the nozzle outer flow field core segment acceleration section of the three process.Liquid-solid twophase flow theory is applied in this article,stress analysis was carried out on the flow field of abrasive out of the nozzle,outer flow field acceleration model is set up,research have shown that abrasive particles accelerate in the nozzle outer flow field core,reach a maximum speed,mixed with the air in the transition section,particle velocity decreased,the speed of nozzle outer flow field relaxation ratio is greater than the flow field inside the nozzle,but the nozzle outer flow field core section of the velocity increment is far less than the nozzle.