Effectiveness analysis of abrasive flow polishing S-shaped elbow with side holes based on large eddy simulation

Aiming at the practical processing problems such as the difficulty of polishing the inner surface of the S-shaped elbow with wall openings and the difficulty of removing the burrs at the cross holes, the solid-liquid two-phase abrasive flow precision polishing method was used for smoothing. Based on the large eddy simulation method, the KET sub-grid model was selected to simulate the abrasive flow polishing S-shaped elbow with side holes, and the processing experiment was carried out. Numerical simulation results showed that under different outlet conditions, the movement state of the abrasive flow in the S-shaped elbow with side holes has significantly changed. When only a certain section of the side holes was set as the outlet alone, the fluid velocity, turbulent kinetic energy, and wall shear force at the side holes were obviously increased, resulting in a better polishing effect. The experimental study found that the inlet pressure had a greater impact on the removal of the edge burrs of the cross hole, the fillet processing, and the inner surface roughness. The increase of the inlet pressure could effectively improve the polishing effect on the side hole wall. The optimal process parameters for abrasive flow polishing of S-shaped elbows with side holes were determined by the uniform test design method, and the roughness prediction model was established. The research results could provide theoretical guidance and data support for the actual production and processing.