Study on the Effect of Structural Parameters of Swirling Impeller Nozzles Based on Design of Numerical Experiments

Shale oil and gas represent strategically important unconventional energy resources, and radial jet drilling (RJD) combined with hydraulic fracturing is a key technology for enhancing their recovery. The swirling abrasive water jet generated by a swirling impeller nozzle can effectively form radial boreholes. However, the quantitative impact of nozzle structural parameters and their interaction effects on the erosion rate (Er) remained unexplored. In this study, a computational fluid dynamics-discrete phase model (CFD-DPM) coupled numerical model was established, and an unreplicated 25 full-factorial design of experiments (DOE) was employed to investigate five key structural parameters of the SIN. Following the effect sparsity principle, third-order and higher-order interaction effects with contribution rates below 1% were pooled into the error term. This analysis of variance (ANOVA) framework enabled the quantitative analysis of both main effects and interaction effects on Er. The results indicated that the outlet diameter (B) was the most critical structural parameter, yielding a contribution rate of 44.19% to Er. The ranked influence of the main effects followed the order B > E > D > C > A. Within the investigated parameter ranges, Er exhibited a positive correlation with the impeller length (C), whereas all other parameters showed negative correlations. The contribution rate of each interaction effect remained below 5%, confirming that their influence on Er was secondary. These findings provide a quantitative basis for the structural optimization of SIN in RJD applications.