NUMERICAL JUSTIFICATION OF NEED TO IMPLEMENT DEGENERATE CAVITATION TO MAXIMUMLY INCREASE GAS ABSORPTION SURFACE

BNFAHV

Abstract

The study examines a numerical and theoretical investigation of the distribution of sound-pressure amplitudes in the liquid medium surrounding a gas bubble, aimed at solving problems of highly efficient gas absorption by liquids under high-intensity ultrasound. The necessity of forming a region of degenerate cavitation to intensify mass-transfer processes in «gas-liquid” systems is substantiated. The influence of the ultrasound pressure amplitude and frequency, as well as the position of the gas bubble relative to the emitter, on the formation of regions of developed and degenerate cavitation and on the interaction of shock waves with the interfacial boundary is investigated. To perform the modeling, the acoustic-field propagation equation in a cavitating liquid was used, transformed into the Helmholtz equation and supplemented with the appropriate boundary conditions. The boundaries of the cavitation zones were determined based on the Gilmore model. The results obtained show that a gas bubble always locally and significantly alters the structure of the acoustic field and is surrounded by a near-wall layer without cavitation, followed by a region of developed cavitation. At the same time, the formation of a region of degenerate cavitation reduces the thickness of the non-cavitating layer at the interfacial boundary, which decreases shock-wave attenuation and increases the gas-liquid interfacial area. It is shown that the maximum intensity of cavitation action is achieved at optimal bubble-emitter distances at a frequency of about 22 kHz. The results confirm the promise of creating a region of degenerate cavitation for enhancing gas-absorption processes and may serve as a basis for the development and improvement of energy-efficient ultrasonic absorption technologies.