Numerical and Experimental Study on Jet Trajectories and Mixing Behavior of Venturi-Jet Mixer

Abstract

An investigation of the jet trajectories and mixing behavior of venturi-jet mixers, in which turbulent jet injects fluid at an arbitrary angle to mix incompressible fluids, is described in this paper. Numerical results of an incompressible cross flow-jet mixing in venturi-jet mixers are presented and validated against experimental results. Jet trajectories, concentration decay of tracer jet, spatial unmixedness, and mixing length are computed for a range of injection angles (45 deg≤θo≤135 deg). Twenty-five cases are studied with five different initial injection angles, each with five different jet momentum ratios. As an example of practical insights that can be gained from such detailed analysis, the resulting flow field is used to obtain an equation for trajectory and tracer concentration in the mixer. The penetration of jet scales with the third root of the jet-to-mainstream momentum ratio and that of with square root of downstream distance. The decay of mean concentration scales with the inverse of axial distance and with the negative root of injection angle. The results show a consistency in the experimental data and simulation has provided a good insight into the flow details and has paved the way in optimization of the geometry based on jet injection angle to get a good mixing efficiency.