Acoustic analysis on the dynamic motion of vapor-liquid interface for the identification of boiling regime and critical heat flux

Abstract

In this study, the feasibility of identifying boiling regimes through acoustic emission (AE) measurement is tested, and the relationship between AE features and boiling dynamics is investigated. Conventional pool quenching experiments are performed using a spherical test section to investigate the entire boiling regime from film boiling to nucleate boiling. The AE measurements and accompanying optical visualization enable analyses of the AE features of each boiling regime, which are characterized by statistical and spectral parameters. The recorded boiling dynamics provide the history of vapor-liquid interface motion to verify the characteristics of AE features. The present work analyzes different acoustic features generated from different boiling regimes including nucleate boiling, transition boiling, boiling crisis, and film boiling. Each boiling regime is characterized by its measured AE signal with respect to various parameters. At the same time, optical visualization of the boiling process accompanies the AE measurements. A comparison of the wave information in vapor-liquid interface motion with AE features proves the feasibility of AE measurement for clear identification of boiling regimes and offers an insight into understanding boiling dynamics with respect to vapor behaviors.