Numerical Simulation of Internal Flow and External Atomization in Pressure Swirl Nozzle

A computational fluid dynamics (CFD) study is carried out on the internal flow characteristics of pressure swirl nozzle and the breakup of external liquid film outside the nozzle. The numerical simulation of two-phase flow shows the unsteady characteristics inside the nozzle and the breaking mechanism of liquid film outside the nozzle. In the nozzle, the numerical simulation reveals the three-dimensional velocity distribution in the swirl chamber and the nozzle outlet. At the same time, the study shows that the breakup of liquid film is caused by the circumferential disturbance wave produced by R-T instability under the condition of 0.7 MPa inlet pressure. The influence of inflow characteristics on the instability of liquid film is pointed out. (paper)