Semi-resolved CFD-DEM modeling of gas-particle two-phase flow in the micro-abrasive air jet machining.

Abrasive air jet (AAJ) machining is attractive for micromachining hard and brittle materials, while it is usually a big challenge to numerically investigate the particle velocity and concentration distribution in the particle erosion process in the AAJ. In this work, a recently developed semi-resolved CFD-DEM approach which bridges the simulation gap between the resolved and unresolved CFD-DEM, is further improved to reconstruct the background information with a double cosine kernel function. The semi-resolved CFD-DEM is then employed to numerically investigate the gas-particle two-phase flow in the AAJ and numerical results show that this semi-resolved CFD-DEM is more accurate in modeling particulate flow in the fine AAJ nozzle than the conventional unresolved CFD-DEM. We further conduct mechanism investigations on the AAJ micromachining process including particle flow characteristics inside the cylindrical nozzle, velocity, and concentration distribution over the nozzle exit, which are essential jet characteristic features. We identified the particle flow patterns, analyzed the particle distribution, and its correlation with air pressure, abrasive mass flow rate, and turbulence effects. The present simulation results and analyses can be great helpful in understanding the erosion mechanism and optimizing the setting parameters to improve the cutting performance of AAJ. The semi-resolved CFD-DEM approach is used to investigate the gas-particle two-phase flow in AAJ. Unlabelled Image • A double cosine kernel function (SCKF) was introduced into a recently developed semi-resolved CFD-DEM. • The semi-resolved CFD-DEM with SCKF was shown to be effective in investigating abrasive air jet (AAJ). • The particle-scale distribution information in a fine AAJ nozzle was studied. • The effects of process parameters and turbulence on particle distribution were analyzed. [ABSTRACT FROM AUTHOR]