Numerical Simulation of Flow Field Characteristics In and Out of the Nozzle of Abrasive Water Jet

Abstract

In the cutting system of abrasive water jet (AWJ), abrasive and water can be either pre-mixed or post-mixed. To compare the different properties of abrasive particle acceleration between the two mixing methods, we employed the FLUENT software to conduct numerical simulation on the flow fields of AWJ nozzle in both cases, and accordingly obtained the acceleration process of abrasive particles in the nozzle. Subsequently, the speed field and the turbulent kinetic energy were plotted in the distribution map, based on which we analyzed the causes to in-nozzle negative pressure and massive energy loss of the post-mix AWJ system. The corresponding result shows that: under the effect of the large-area vortex turbulence in the mixed cavity, a noticeable area of negative energy appears in the abrasive inlet, sucking abrasives in. In light of the small number of turbulent kinetic energy in the flow field of the nozzle in the pre-mix AWJ, and the low energy consumption in the acceleration process of AWJ, we theoretically validated the feasibility of chemical pipeline cutting by using the pre-mixed low-pressure AWJ.