Hydrodynamics Characteristics of High Speed Multl-Phase Flow in AWJ Nozzles : 2nd Report, Measurement of Exit Phase-Velocities and Velocity Change in Nozzles

The experimental results on the abrasive water jet (AWJ) are described in this paper. AWJ is the high-speed water jet containing solid particles and is used for cutting of various industrial materials. In order to obtain the velocities of solid, gas and liquid phases at the mixing nozzle exit, the momentum of jet was measured. Phase velocity distribution in the axial direction of jet was also estimated based on the measured pressure distribution in the AWJ nozzle with the aid of the continuous and the momentum equations. The result shows that the decrease of the liquid phase velocity in the mixing nozzle is small in the case of the gas liquid two phase flow, and the velocity of liquid phase is remarkably reduced on the contrary in the gas liquid-solid three-phase flow. In the latter case, the total momentum of jet is reduced comparing with two phase flow. It is also found that the mean velocity of solid particles at the mixing nozzle exit is about 30% of the velocity of liquid phase