磨料水射流中磨料颗粒的受力分析

对磨料水射流中磨料颗粒的受力进行了分析，采用量级比较和典型函数法重点研究了Basset力、虚拟质量力、Magnus力和Saffman力与Stokes力的相对重要性。结果表明，对磨料水射流进行模拟研究时，必须考虑惯性力、重力、压差力和Stokes力对磨料颗粒运动的影响。当磨料颗粒在喷嘴的收缩段和直柱段中运动时，磨料颗粒所受的Basset力、虚拟质量力与Stokes力处于同一量级，对磨料颗粒的运动影响很大，不可忽略；随着时间的推移，当磨料颗粒从喷嘴射出后，磨料颗粒所受的Basset力、虚拟质量力与Stokes力相比要小得多，对磨料颗粒的运动影响很小，可以忽略；磨料水射流喷嘴外流场中，流体粘性的存在限制了磨料颗粒的旋转，磨料颗粒所受的Magnus力比Stokes力小得多，可以忽略；在喷嘴外的自由射流区域，由于流速梯度沿径向变化较慢，磨料颗粒所受的Saffman力同Stokes力相比也可以忽略。

Analysis of forces acting on abrasive particles in abrasive water jet

Forces acting on the abrasive particles in the abrasive water jet were analyzed. The magnitude comparison method and the typical function method were used to analyze the relative importance of Bas,set force, virtual mass force, Magnus force and Saffman force with Stokes force. It is found that the inertia force, gravity, pressure difference force and Stokes force are important for the motion of abrasive particles and can not be neglected. Basset force and virtual mass force are on the same magnitude as Stokes force and are important for the motion of abrasive particles during the initial phase of particle movement in the convergent section and straight tube section of the nozzle. After the abrasive particles ejected from the nozzle exit, Basset force and virtual mass force are small quantities compared with Stokes force and can be neglected. In the external flow field of the nozzle, fluid viscosity confines the rotation of abrasive particles, which makes Magnus force neglectable compared with Stokes force. Meanwhile, in the free streamwise region outside the nozzle, the velocity gradient in the, radial direction is small and Saffman force can also be neglected compared with Stokes force.