Boiling heat transfer of subcooled water in a horizontal rectangular channel (Observation of MEB and MEB generation)

Abstract

Forced convection boiling of subcooled water was performed in a horizontal rectangular channel with heated surface on the bottom. The experiment was conducted for heating surfaces, 10 mm, 20 mm and 40 mm in length. Microbubble Emission Boiling, MEB, was observed in subcooled transition boiling and easy to be generated for the shorter heating surfaces. In higher flow velocity of subcooled water, MEB was generated at even lower subcooling. Stormy MEB was observed at both the higher subcooling and the higher flow velocity of water. In the stormy MEB, the heat flux rose up rapidly above CHF (Critical Heat Flux) with larger acoustic noise and vibration.