Numerical investigation on inner flow field of pressure swirl nozzle
                                                                  FAN Hua, YANG Gang, LI Bing
          （Beijing Aerospace Petrochemical Technology and Equipment Engineering Corporation Limited, Beijing 100166, China）

Abstract: Aiming at experimental study on the atomization characteristics of pressure swirling nozzle is high cost, long time and difficult to be realized in theoretical calculation, the internal flow mechanism and atomization characteristics of the pressure swirling nozzle were studied by Fluent digital simulation.The inner flow field of pressure swirl nozzle was simulated using the VOF model in order to investigate the flow mechanism and predict the atomization characteristics efficiently. The gasliquid interface of the swirl nozzle exit was captured and the liquid film thickness at the outlet of nozzle was described. Variation of the different section fields of pressure,density and velocity in the nozzle was analysed and the spray cone angle of nozzle was predicted. The simulation results show that air core is created at the center of the pressure swirl nozzle and the out side atomization characteristics such as the spray cone angle and the thickness of the liquid film can be obtained by analyzing the air core diameter and speed at the nozzle exit. The spray cone angle of the simulated is compared with the trial value, which show they are reasonable. The Fluent numerical simulation can be used as a design tool for swirl nozzle.

Key words: pressure swirl nozzle; numerical simulation; flow field characteristics; gasliquid twophase flow