CFD Simulation of the Cavitation Behaviour in Single Jet Process via Outlet Pressure

Abstract

Cavitation effect is the most common phenomenon in the process of jet. In this work, the method of CFD numerical simulation is used to study the cavitation behaviour in the process of single hole jet. In order to obtain the mixing situation and change process of gaseous water and liquid water produced in the nozzle, the Euler multiphase flow model and the realizable k-epsilon model in the turbulence model are used. The simulation results show that the degree and frequency of liquid column breakage of cavitation water jet are far higher than those of ordinary water jet. And the structure of the nozzle also has the most ideal situation. When the nozzle inlet size is 20 mm, the nozzle diameter is 1 mm, and the nozzle length is 5 mm, which is most conducive to the growth and diffusion of cavitation bubbles. The cavitation effect increases with the increase of the inlet jet velocity, but the promotion effect does not increase significantly when the inlet velocity is greater than 2.5 m/s. From the perspective of energy consumption, the optimum velocity at this time is 2.5 m/s. And the pressure environment at the nozzle outlet also affects the cavitation phenomenon, mainly as follows: positive pressure can inhibit the cavitation effect, negative pressure can promote the cavitation effect, but the negative pressure has a limited effect on the degree of cavitation.