Experimental and Numerical Simulation of Flow Pattern Evolution in a Flow Mixing Nozzle under a Moderate Inlet Flow Rate.

Abstract

A flow mixing nozzle is a novel two-phase flow nozzle with a simple structure and has broad application prospects in the industrial field. However, the research on the working characteristics of this nozzle is mainly focused on a low inlet flow rate. There are few research studies on the working characteristics of the moderate and high flow rates which are more concerned in the industrial field, which limits the application of the flow mixing nozzle. In this paper, the experimental and simulation studies on the internal two-phase flow pattern and spray form of the flow mixing nozzle under a moderate inlet flow rate are carried out. The results show that the change in the two-phase inlet flow rate and the tube hole distance of the nozzle will affect the gas and liquid inertia force, thus affecting the working characteristics of the nozzle. The enhancement of gas inertia force will cause the flow pattern inside the nozzle to change to an unstable radially concave cone, and the spray form will be converted to atomization; the atomization effect of the liquid is better. The enhancement of the liquid inertial force will cause the flow pattern inside the nozzle to change to a radially convex cone, and the spray form will be converted to breakup; the atomization effect of the liquid is poor. The liquid surface tension maintains the existence of the cone inside the nozzle and plays a dominant role in jet atomization when the gas and liquid inertial forces are weak. In addition, the study also found that because of the compressibility of gas, the orifice has a reinforcing effect on gas inertia force.