三相旋流抛光磨粒运动的测量与微气泡补偿

研究了气液固三相旋流流场抛光机理和规律。设计了三入口的抛光加工流道,对气液固三相旋流抛光流场进行了数值模拟。基于模拟结果设计了气液固三相磨粒流旋流流场测量平台,并通过粒子图像测速法(PIV)测量了微气泡补偿条件下气液固三相旋流抛光的流场参数,获得了微气泡补偿区域流场的运动图像、速度矢量图和涡量图。PIV测量试验数据显示:在微气泡补偿区域,磨粒速度主要集中在30m/s到80m/s,同一测量点高速磨粒出现频率明显增加,少数磨粒速度达到100m/s以上;磨粒平均速度从33.8m/s增大到44.2m/s,经4h抛光后硅片表面最大粗糙度从10.4μm下降到1.3μm。理论和试验研究表明,气液固三相旋流抛光流场中微气泡溃灭引发的空化冲击效应可增大磨粒动能,提高抛光效率,实现B区域的均匀化抛光。

Measurement of abrasive particles by three-phase swirling polishing and its microbubble compensation

The polishing mechanisms and rules of a gas-liquid-solid three-phase swirling flow field were explored.A polishing flow channel with three entrances was designed and the numerical simulation for the gas-liquid-solid three-phase swirling flow field was carried out.Then, a measuring table for the gas-liquid-solid three-phase swirling flow field was designed.The parameters of gas-liquid-solid three-phase swirling flow field were measured by the Particle Image Velocimetry (PIV) under the condition of microbubble compensation and the motion images ,velocity vector images, and the vorticity graphs of the flow field in the microbubble compensation region were obtained.The test data by the PIV show that the speeds of abrasive particles mainly concentrate between 30 m/s and 80m/s in microbubble compensation region, high speed abrasive particles in the same measurement point are signficantly increased, and the speeds of a parts of abrasive particles can be more than 100 m/s.Furthermore, the average speed of abrasive particles is increased from 33.8 m/s to 44.2 m/s and the maximum surface roughness of a silicon wafer decreases from 10.4 μm to 1.3 μm after the 4 h polishing.The research on theory and testing indicates that the cavitation impact effect caused by microbubble collapse in the gas-fluid-solid three-phase swirling polishing flow field increases the kinetic energy of abrasive particles and improves the polishing efficiency, so as to achieve the homogenization polishing of the region B.