Study On The Cutting Performance Of Abrasive Water Jet And Simulation Of The Velocity Field Inside And Outside The Nozzle

This article emphasis on the effect of the cutting parameters for Abrasive water jet (AWJ) such as water pressure, nozzle traverse speed, standoff on the surface quality of the marble and ceramics. And also the simulation of the velocity field of the multi-phase flow inside and outside the AWJ nozzle was carried out by multi-phase flow control equations and FLUENT software. The simulation results were verified by experiments.The effect of cutting parameters such as water pressure, nozzle traverse speed and standoff on the marble and ceramics were researched. The cutting performance is characterized by kerf width, kerf taper and striation drag angle. The research results show that an increase in water pressure and a decrease in nozzle traverse speed will result in a decreased striation drag angle, and standoff has little effect on it. An increase in water pressure, a decrease in nozzle traverse speed and standoff will result in a decreased kerf taper. The kerf width will decrease with an enhancement in nozzle traverse speed, and a decrease in water pressure and standoff. An increase in water pressure and the decrease in nozzle traverse speed and stand off distance will result in an increasd area of smooth zone. An increase in abrasive mass flow will result in good quality of the cutting surfaces. The quality of cutting surface can be divided into structural breakage zone, abrasive wear zone and striation drag zone. The striation drag zone should be avoided in abrasive water jet machining.The simulation of the velocity field inside and outside the AWJ nozzle was carried out by the multi-phase flow equations and Fluent software. The two-dimensional simulation results of the gas-liquid two phase flow inside ultra pressure water jet nozzle show that the angle and length of inner taper can affect the velocity field and the swirl character of the two phase flow. When the taper angle of the nozzle is 30° , the velocity field can avail the abrasive mixing with high pressure water and acceleration. When the taper angle of the nozzle is 18.5° , the velocity field can reduce the nozzle wear. The two-dimensional velocity field of the gas-solid two phase flow inside abrasive jet nozzle shows that abrasives are all distributed aroud the center domain of the nozzle. The velocity along the axis of the nozzle increases with a decrease in cross-section area of the nozzle. The velocity of the two phase flow at the outlet center of the nozzle is lower and it is higher near the outlet wall. The two-dimensional velocity field of liquid-solid two phase flow inside and outside the nozzle shows that an increase in arc radius which connects the inner taper surface and the mixing tube and a decrease in the length of the mixing tube and inner taper angle will cause an increased velocity at the outlet of the nozzle. The optimum standoff should be in the distance of 5 times higher than the diameter of the nozzle. The...