Study on the Influence of Nozzle Structure on Abrasive Particle Erosion Characteristics

Abstract

To address nozzle erosion in abrasive water jet polishing and extend component service life, this study investigates the influence of nozzle geometry on wear and internal erosion. Computational Fluid Dynamics (CFD) via FLUENT and mathematical modeling via MATLAB were used to compare cylindrical, conical, and conical-straight nozzles. The simulations indicate that the conical-straight nozzle achieves the highest solid-liquid two-phase velocity ratio of 95.7% (with a water-phase velocity of 79.3 m/s and an abrasive-phase velocity of 75.9 m/s), compared to 91.7% for the conical and 88.2% for the cylindrical nozzle. This paper establishes a editable mathematical relationship between jet velocity and nozzle length. A 480-hour erosion experiment under 2 MPa pressure was performed. Scanning Electron Microscopy (SEM) characterization revealed that the peak erosion rate of the conical-straight nozzle is only 1.2 kg/(m2·s), exhibiting a highly uniform and smooth worn surface compared to the severe fatigue micro-cracking and deep erosion pits observed in the cylindrical design. These findings quantitatively validate the superior wear resistance and acceleration efficiency of the conical-straight composite structure, providing critical references for high-precision jet manufacturing.