Study on the flow in the near field of swirling hollow jet from swirl nozzle

The liquid sheet flow in the near region from swirl nozzle was analyzed theoretically. Surface tension force was considered as the ruling factor, and a set of non-linear differential (integral) equations describing the liquid sheet flow was conducted using the theorem of momentum. The equations were solved by digital calculation. The results showed that the sheet in space was a multi-tulip shaped hollow jet, whose velocity and sheet thickness changed periodically along the nozzle axis. The results can be considered as the basic jet flow pattern from swirl nozzle before the liquid sheet is broken up into droplets by its instability and perturbation in practical jets as observed in experiments.