Effects of swirling impeller nozzle parameters on abrasive waterjet erosion

Radial jet drilling (RJD) enhances oil and gas production by constructing radial boreholes from the main wellbore, with the nozzle as its core component. The swirling abrasive waterjet (SAWJ) generated by a swirling impeller nozzle (SIN) offers both high erosion capacity and wide coverage, yet how the nozzle structural parameters affect this performance remains unclear. To address this gap, a computational fluid dynamics coupled with the discrete phase model with non-spherical drag correction is developed to simulate the SAWJ impingement flow field. Eight structural parameters are evaluated against the erosion rate (Rerosion) and the equivalent erosion radius (Req) by a controlled-variable method, with Pearson correlation analysis quantifying their sensitivity. The SIN converts pressure energy into a three-dimensional swirling velocity field, and the swirl number peaking at 1.172 within the impeller section and decaying to 0.551 at the nozzle exit. The nozzle outlet diameter is the dominant parameter, showing a strong negative correlation with Rerosion (correlation coefficient CC = −0.88) and a strong positive correlation with Req (CC = 0.79). The impeller length is the only parameter positively correlated with both indicators. On this basis, optimized nozzle parameter ranges are proposed for RJD applications.