Investigation on spatial breakup characteristics of low-pressure jets with particle image velocimetry experiment and volume of fluid–level set simulation

In order to study the spatial breakup characteristics of the initial section of low-pressure jets, an experiment was performed to investigate the flow fields and concentration fields of jet flows with different nozzle geometric parameters and also the different working pressures using a particle image velocimetry system. The flow field of different axial planes, axial time-average velocity, and the length of the initial sections of jet flows were also analyzed. A numerical simulation was carried out using finite volume method and volume of fluid–level set method to describe the breaking process of the initial section, capturing unstable development of gas–fluid interface, measuring the length of the initial sections of jet flows. Both experiment and simulation results show that the broken degree of jet is more intense for nozzles with smaller aspect ratio; the outlet velocity of jet increases with the working pressure; and the value of u / u m decreases with the increase in pressures in the same cross section of jet flow. The experimental values are slightly higher than the simulation values with an error of <8% for the cross-sectional velocity distribution. The initial length of jet increases with pressures, where the experimental values are lower than the simulation values with an error of