气-液-固三相磨粒流光整加工及其工艺参数优化

考虑用流体抛光法加工大尺度工件存在效率低下问题,本文提出了一种气-液-固三相磨粒流抛光方法。该方法在约束流场中引入微纳米气泡,利用气泡在溃灭时释放的能量加速驱动磨粒运动,从而有效提升抛光效率。实验显示:在加工过程中,离心泵的发热会导致流体黏度下降,进而影响工件近壁面的湍动能和动压力的大小及分布,而加工工件近壁面的湍动能和动压力会对表面纹理的均匀性和材料的去除效率有重要影响。针对上述实验结果,文中基于对磨粒流抛光机理的研究,提出一种通过改变入口流速来补偿温升带来的湍动能和动压力变化的方法,实验求得了抛光流体温度从20℃到60℃之间的9个均等点对应的最优入口流速值。实验表明,相对未加入气泡时,该抛光方法的加工效率得到提高,而调速补偿明显提升了工件表面加工质量。

Gas-liquid-solid abrasive flow polishing and its process parameter optimization

A gas-liquid-solid three-phase abrasive flow finishing method was proposed to improve the efficiency of fluid-based finishing for large-scale workpieces. By introducing micro-nano bubbles into a restrain flow field, the method utilized the energy released by the bubble collapsing to accelerate the motions of abrasive particles and to improve the finishing efficiency. During the finishing process, the fluid viscosity might decline owing to the centrifugal pump heat, and it could influence the amplitudes and profiles of turbulent kinetic energy and dynamic pressure in the near-wall region. Furthermore, the turbulent kinetic energy and dynamic pressure of near-wall region have a major impact on the uniformity of the surface texture and the removal efficiency. On the basis of the results mentioned above, a method to change the inlet velocity to compensate the temperature rising brought by the turbulent kinetic energy and dynamic pressure changes was proposed, and the optimal inlet velocity of finishing fluid temperature from 20℃ to 60℃ between the corresponding nine equal points was obtained. Experimental results show that the gas-liquid-solid three-phase abrasive flow finishing method improves the efficiency respect to traditional methods without the bubble processing, and the inlet velocity compensation improves the quality of workpiece surfaces significantly.