软性磨粒流中颗粒碰撞和颗粒体积分数对磨削效果的影响

Particle Collision and Volume Fraction Within the Solid-liquid Flow Which Will Affect the Machining Process

结构化流道中加工壁面的切削情况与流道中的颗粒对壁面的压力(WPP)有着密切联系,而颗粒碰撞恢复系数(RCPC)和颗粒体积分数(PVF)是影响WPP的主要因素.结合硬球模型和Preston切削方程建立了数学模型;利用欧拉-拉格朗日条件下的颗粒轨迹模型(DPM),对锯齿形直流道的加工壁面在不同RCPC值及不同PVF值的情况下进行数值模拟;使用粒子图像测试系统(PIV)对锯齿形直流道内不同PVF值的颗粒运动进行跟踪分析.结论表明,RCPC值或PVF值的提高都能增大WPP,而WPP增大可以有效提高切削的效果.且相同条件下,不同位置壁面的WPP差异很大,顶部壁面及侧壁面边界层剪切力作用会显著影响颗粒速度,导致WPP明显减小.

The cutting condition in the structural flow passage is closely connected to the wall＇s particle pressure（WPP）. The restitution coefficient of particle collision （RCPC）and the particle volumetric fraction（ PVF） will affect the WPP. The mathematical model was established using hard-sphere model the Euler-Lagrange and Preston equation;the Discrete conditions. DPM was used in the Particle Model （DPM）was set up under simulation of the processing wall in the jagged flow passage with different RCPC and different PVF. The particle movement was traced and analyzed with different PVF, using particle image velocimetry system （PIV）. The result showed that WPP increased when either RCPC or PVF was raised, and the WPP＇s increasement improved the processing effect. WPP differed greatly at different walls under the same condition. The top wall and the side wall＇s shearing action would greatly affect particle velocity and thus decreased WPP.