Hysteresis in microbubble emission boiling (MEB) under highly subcooled conditions

Abstract

Hysteresis in so-called ‘microbubble emission boiling (MEB)’ in a pool is investigated experimentally. Correlation among the heat transfer characteristics, the behavior of the vapor bubbles over the horizontal circular heat-transfer surface, and the induced boiling sound is indicated under various highly subcooled conditions for the processes of increasing and decreasing the power input to the heaters. Variations of the boiling sound is depicted by monitoring the spectrogram. Spatio-temporal variation of the vapor bubbles’ oscillation and their synchronous behavior in the MEB are illustrated. It is indicated that the variation of the fundamental frequency of the vapor bubbles’ oscillation almost coincides in the increasing and decreasing processes of the power input to the heaters, whereas the heat transfer characteristics becomes worse in the decreasing process in the MEB regimes.

Keywords

• microbubble emission boiling (meb)
• hysteresis
• pool boiling
• subcooled boiling
• heat transfer characteristics
• boiling sound
• vapor bubbles