LAUSR

Abstract In this study, the spray patterns of different fluids exiting pressurized chamber through the nozzle were observed and compared. The effects of injection temperature and pressure on jet velocity and liquid carbon dioxide (LCO2) breakup were investigated. When the liquid was expelled from the chamber (45 bar) to the atmosphere through nozzle, the 1st- wind-induced jet breakup regime for H2O and the atomization regime for LCO2 were observed. Three different breakup regimes of LCO2 ranging from normal atomization to Rayleigh breakup were observed depending on the velocity, which can be explained by changes of the Reynolds number in Reynolds–Ohnesorge diagram. As the downstream pressure decreased (with increasing velocity), the choked flow was formed due to the phase change at the flash boiling point. The transition to choked flow moved to higher pressure differences with decreasing injection temperatures, indicating the delayed phase change.