Large Eddy Simulation of Cavitating Nozzle Flows and Primary Jet Break-Up with Gas-Entrainment into the Nozzle
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We present results of a Large Eddy simulation of a cavitating nozzle flow and its injection into gas. The focus of the investigation is set on gas-entrainment into the nozzle, which occurs when vapor reaches the nozzle outlet and gas enters the nozzle from the outflow region driven by the pressure gradient. The numerical setup is based on a reference experiment, where liquid water is discharged into ambient air through a step nozzle. For the cavitating liquid a barotropic equilibrium cavitation model is utilized, which is embedded in a homogeneous mixture model for the liquid-vapor mixture and the non-condensable gas phase. Full compressibility of all components is taken into account by the high order implicit Large Eddy approach and thus enables us to capture the effects of collapsing vapor structures. Four different operating points are investigated. Special emphasis is put on the operating points with gas-entrainment and its effect on the jet characteristics. Additionally, mass flux and erosion are analyzed.