IMPACT OF RECIRCULATION ZONES ON THE NEAR-FIELD ENTRAINMENT CHARACTERISTICS OF A SWIRLING LIQUID JET

Abstract

Using three-dimensional numerical simulations, we analyze the entrainment of the ambient fluid at the interface of a swirling liquid jet for swirl numbers of 0.5 ≤ S ≤ 1.55 and moderate axial Reynolds number of Re = 50 and Re = 100. We have identified the generation of axial and azimuthal shear layers developing at the interface and visualized the path traced out by the ambient air. The results indicate that the surrounding air exhibits toroidal recirculation zones, which causes the accumulation of ambient air at the interface leading to the engulfment of the ambient fluid. We also observed that the entrainment rate is higher for higher swirl numbers. Furthermore, we have also estimated the entrainment coefficients for different swirl numbers, which range from 0 to 0.15.