Effect of wall roughness on the hydrodynamic cavitation phenomena in a circular venturi using RANS numerical simulations

Abstract

Hydrodynamic cavitation is the recent advanced oxidation technique that finds applications in wastewater treatment, nanoparticle synthesis, mineral processing, sterilization, chemical synthesis. Owing to such overwhelming industrial applications, it has received a considerable attention in the recent past. Venturi and orifice geometries are linear flow devices for hydrodynamic cavitation, whilst vortex diode type geometries are often terms as rotating flow devices. In this work, RANS numerical simulations were conducted in a venturi over a wide range of geometrical parameters, such as 10°≤α≤30° (Half convergent angle), 4°≤β≤12° (Half divergent angle), 0≤L/d≤2(Throat length to throat diameter ratio). The pressure inlet condition is employed with a pressure drop of 400 kPa and wall roughness height (KS) of 1 mm. Cavitation phenomenon is explained in detail by presenting numerical results on vapor volume fraction contours, pressure, velocity and turbulent kinetic energy profile along venturi axis length. All else being equal, the numerical simulations revealed that the inclusion of surface roughness indeed enhances the intensity of cavitation.