Impact of recirculation zones on near field entrainment characteristics of a swirling liquid jet*

Swirling flow is one of the handful of problems in fluid dynamics which involves wide range of applications in combustion chambers, cyclone separators, turbomachines etc.Swirl enhances mixing and flame stability in combustion chambers.This study is an approach to understand the near field entrainment characteristics of a swirling liquid jet.Volume of fluid based three dimensional numerical simulations have been carried out for Swirl numbers ranging from 0.5 to 1.55. There are two main objectives of this paper (1)To understand the impact of recirculation zones on entrainment of air and (2)To identify the near field entrainment characteristics of the swirling jet.The results indicates that, multiple recirculation zones develops in the flow near the shear layers which enhances entrainment of the ambient air. For swirl numbers varying from 0.5 to 1.1, a consistent increment in the entrained mass of air has been observed .Moreover the entrainment coefficient ranges from 0 to 0.4 for the present range of swirl numbers and Reynolds number considered.