基于超声波激振强化的软性磨粒流光整加工模拟与试验研究

Numerical and Experimental Study on Softness Abrasive Flow Finishing Based on Turbulence Enhancement by Ultrasonic Vibration

为了提高软性磨粒流加工过程中的湍流强度分布均匀性与材料去除率,提出一种基于超声波激振湍流强化的软性磨粒流光整加工方法。在磨粒流约束流道内引入超声激励,利用超声波的空化效应控制流道内的流体流态。建立考虑液固及声场耦合的磨粒流加工动力学模型,对其加工过程中的流场特性进行了模拟研究,并搭建超声强化磨粒流加工试验平台进行验证。数值仿真结果表明,非定常流场可获得更为均匀的速度矢量和湍动能分布,超声波激振引起空化效应能够有效地增强软性磨粒流的湍流强度和避免加工死角的出现,同时揭示湍流增强导致磨粒流动轨迹复杂多变是加载超声波激振抑制磨粒流的过加工和粗糙度值翘尾现象形成的原因。加工试验表明,该方法可减小加工时间约6 h,能够得到更为均匀的表面质量。

To make the turbulence intensity of the softness abrasive flow more homogeneous and increase the material remove rate＇ in the finishing process, a technology of softness abrasive flow finishing based on turbulence intensity enhancement using ultrasonic wave is brought forward. The ultrasonic vibration is excited on the abrasive flow in the constrained flow channel to control the regime by the cavitation effect of the ultrasonic wave. An abrasive flow dynamic model considering the coupling of liquid-solid flow and sound field is established and the flow characteristics in the machining processing are numerically investigated. Meanwhile, an ultrasound-enhanced abrasive flow machining experimental platform is investigated experimentally. The results show that more homogeneous velocity field and turbulence energy distribution are obtained in an unsteady numerical simulation. It can be concluded that the turbulence intensity of the softness abrasive flow is effectively enhanced with less dead angle because of the cavitation effect. The ultrasonic vibration can also restrain the excessive machining of the abrasive flow and the roughness can be maintained at about the minimum value without increase again. The machining experiments indicate that softness abrasive flow finishing method can reduce the machining periods about 6 hours. The surface quality is greatly improved and becomes more uniform.