Scale Adaptive Simulations Applied to Fully Cavitating Turbulent Flow in Injector Nozzles

Abstract

The unsteady and turbulent pressure-driven cavitating flow under fully cavitation conditions through a sharp-edged orifice is examined by numerical simulations. Unsteady cavitating flow is a typical flow configuration in fuels injectors and brings a challenge to the numerical models for two-phase flows, because of the high-pressure gradients involved, and the high ratio of liquid and vapor density. Under this flow condition, computationally intensive unsteady simulations are necessary to accurately simulate the irregular cyclic process of bubble formation, growth, filling by water jet re-entry and its breakoff. The capabilities of Reynolds Averaged Simulations are assessed to ensure a suitable cavity structure prediction to capture the main shedding frequencies and the vapor fraction variations along the nozzle. This study is focused on the modified version of Shear Stress Transport turbulence model, involving a Scale Adaptive Simulations sub-model related to unsteady turbulence modeling. The proposed option would allow studies of developed cavitating flows by means of an unsteady less expensive Reynolds Averaged Simulations simulation, instead of the Large Eddy Simulations option due to this last option applied for simulating turbulent flows in complex geometries (i.e., industrial flows) are not completely affordable nowadays.