Bubble Collapse Phenomenon of Multiphase Flow Field in a Venturi Tube

Abstract

Microbubbles have various properties and are expected to be used in a wide range of fields. In this research, we focus on one of microbubble generators with a converging- diverging nozzle, i.e. a Venturi tube. In order to control bubble distribution of generated bubble diameter, knowledge of bubble generation mechanism in the tube is required. The purpose of this research is to clarify the effect of complex flow in a Venturi tube on bubble collapse. In this research, we focus on the change of pressure loss coefficient calculated from the pressure distribution in the tube and the sound pressure generated at the time of bubble collapse. For results of the experiment, the pressure loss coefficient increased due to the cavitation in the liquid single-phase flow. The same tendency was further obtained in the bubbly flow. It was also confirmed that the collapse behavior of bubbles differed depending on the inlet conditions, and sound pressure increased under conditions where rapid bubble collapse occurred.