Study of surface wettability effect on cavitation inception by implementation of the lattice Boltzmann method

摘要

Cavitating flow through the orifice is numerically solved by implementation of the lattice Boltzmann method. The pseudo-potential single-component multiphase Shan-Chen model is used to resolve inter-particle interactions and phase change between the liquid and its vapor. The effect of surface wettability on the cavity formation and shape is studied by imposing an appropriate wall boundary condition for the contact angle between the liquid-vapor interface and the solid surface. Efficiency of the numerical approach presented is examined by computing the cavitation inception, growth, and collapse for internal cavitating flows over a sack-wall obstacle placed inside a channel and through a convergent-divergent nozzle section. The results obtained demonstrate that hydrophobic walls act as surface nuclei and contribute to the process of cavitation inception even at high cavitation numbers. In contrast, the solid wall with hydrophilic properties shows no contribution to the onset of cavitation in the geometries studied. High values for the flow velocity corresponding to low cavitation numbers are needed to observe the cavitation inception over the geometries studied with the hydrophilic solid wall. The study shows that the present computational technique based on the implementation of the lattice Boltzmann method with the Shan-Chen model employed is robust and efficient to predict the cavitation phenomena by considering surface wettability effects and also accurate enough for computing the cavitating flow properties at different conditions. Published by AIP Publishing.