Sonochemical effect induced by hydrodynamic cavitation: Comparison of venturi/orifice flow geometries

Abstract

This study presents comparative assessment of four cavitation devices (three venturis and an orifice) in terms of cavitational yield. A fourfold approach was adopted for assessment, viz. CFD simulations of cavitating flow, simulations of individual cavitation bubble dynamics, high speed photographs of cavitating flow and model reaction of potassium iodide oxidation. Influence of design parameters of cavitation devices on nature of cavitation produced in the flow was studied. Number density of cavitation bubbles in the flow and interactions among bubbles had critical influence on cavitation yield. Orifice gave the highest cavitational yield per unit energy dissipation in flow (despite lower working inlet pressure) due to low density of cavitation bubbles in flow. On contrary, occurrence of large cavitation bubble clouds in venturi flow had adverse effect on cavitational yield due to high interactions among cavitation bubbles resulting in interbubble coalescence and recombination of oxidizing radicals generated from cavitation bubbles. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4705–4716, 2017