Open Access

ARTICLE

Effect of Nozzle Orifice Number on Jet Dynamics and Rock-Breaking Performance of Multi-Orifice Abrasive Water Jets

Shurong Feng¹, Dongping Zeng^1,2,3,*, Fada Zhou², Yanan Zhao¹, Hao Liu¹

1 Power China Zhongnan Engineering Corporation Limited, Changsha, China
2 School of Energy and Power Engineering, Changsha University of Science and Technology, Changsha, China
3 School of Hydraulic and Ocean Engineering, Changsha University of Science and Technology, Changsha, China

* Corresponding Author: Dongping Zeng. Email:

Fluid Dynamics & Materials Processing 2026, 22(9), 5 https://doi.org/10.32604/fdmp.2026.088471

Received 04 July 2026; Accepted 21 September 2026; Issue published 28 September 2026

Abstract

The influence of nozzle orifice number on the jet dynamics and rock-breaking performance of multi-orifice abrasive water jets (MOAWJ) is systematically examined for precision drilling in pumped storage power station construction. A VOF-DPM (Volume of Fluid–Discrete Phase Model) two-way coupling framework is first employed to characterize the flow-field structure, velocity distribution, and spatial evolution of abrasive particles for different orifice configurations. The resulting jet characteristics are then used as initial conditions in an SPH-FEM (Smoothed Particle Hydrodynamics-Finite Element Method) coupling model to simulate the transient rock-breaking process and elucidate the underlying micromechanical mechanisms. The results show that increasing the number of orifices reduces inlet throttling and abrasive-particle agglomeration, while improving flow uniformity among the individual orifices and maintaining better jet collimation. The mean water-phase velocity at the outlet is only weakly dependent on the orifice count and remains approximately 231 m/s. In contrast, the mean abrasive-phase velocity initially decreases and then increases with increasing orifice number, reaching a maximum of 205.80 m/s for the seven-orifice configuration. Increasing the orifice count also broadens the spatial distribution of abrasive particles, reduces the pronounced asymmetry observed near the side orifices, and promotes a more uniform distribution of erosive action. The rock-breaking process exhibits four distinct stages, while increasing the number of orifices enhances inter-orifice stress superposition and water-wedge effects, driving a transition in the dominant failure mechanism from depth-controlled to area-controlled rock removal. At 300 μs, the seven-orifice configuration produces a total rock-breaking volume 85.3% greater than that obtained with four orifices.

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Keywords

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