Acoustophoresis-assisted fluid jet polishing

Abstract

The current work proposes a novel technique of acoustophoretic-assisted Fluid Jet Polishing (FJP). The underlying principle involves migrating abrasive particles to desired locations (pressure nodes) within the jet using standing acoustic waves. The migration of particles occurs on account of the radiation force arising from the difference in the acoustic impedance of the particles and the carrier fluid. The current work analyzes the proposed FJP procedure using multiphase simulations involving a combination of Eulerian and Lagrangian approaches. The influence of acoustophoresis on circular and square cross-sectioned nozzles has been primarily evaluated. Though the pressure nodes in circular nozzles can help achieve precise annular erosion, they do not alter the inhomogeneous W-shaped erosion profile usually observed in conventional FJP systems. In contrast, the acoustic forcing in square cross section nozzles propels the particles toward the jet axis, thereby manifesting a U-shaped erosion profile for specific operating conditions that have been identified via a systematic analysis. Such particle focussing/redistribution capabilities provide a unique means of controlling erosion, removing machining inhomogeneity, and enhancing the material removal rate during the FJP process.