Pool Boiling on a Single-Crystal Sapphire Surface. A Measuring Method of Quantities upon Liquid-Solid Contacts.

Abstract

In this report, a novel method for measuring the fundamental quantities upon liquid-solid contact in pool boiling is developed to obtain a better understanding of the mechanism of high-heat-flux nucleate boiling, CHF, and transition boiling. The method consists of observation of the liquid-solid contact situation and the image processing technique. The liquid-solid contact situation was observed from below the heat transfer surface by a high speed video camera. A single-crystal sapphire plate was chosen for the heat transfer surface because of its high transparency and high thermal diffusivity. It was confirmed experimentally that the following quantities on liquid-solid contact, i. e. liquid-solid contact area fraction, number density of dry areas, and the spatial and time unit-scales of fundamental structures in boiling, could be measured by this method.