ISSN Online: 2377-424X
ISBN Print: 978-1-56700-474-8
ISBN Online: 978-1-56700-473-1
International Heat Transfer Conference 16
STUDY ON CHARACTERISTICS OF FORMATION AND EVAPORATION OF MICROLAYER USING LASER INTERFEROMETRY DURING NUCLEATE POOL BOILING FOR WATER AND ETHANOL
Résumé
As an effective heat transfer mode, nucleate boiling has become one of the hottest research topics in heat and
mass transfer fields. It was confirmed that a thin liquid film with the thickness in micron meter scale
(microlayer), which is thought to play an important role in boiling heat transfer, was formed beneath the boiling
bubbles. Since the difficulty in the experimental measurement on microlayer evaporation, the characteristics
of the microlayer and its contribution to boiling heat transfer was primarily examined by numerical simulation.
The experimental study on the characteristics of microlayer evaporation is quite limited. In this study, by using
the laser interferometric method, the 2-dimensional distribution of microlayer and its variation during one
bubble cycle was observed and measured. Furthermore, the microlayer evaporation was analyzed based on the
volume change of microlayer by ignoring the internal flow of microlayer. As the results, it was shown that the
depletion of microlayer was quicker for ethanol than that of water, since the latent heat of ethanol was smaller.
In addition, it was also shown that the quicker depletion of microlayer occurred for the conditions of higher
heat flux. It was confirmed that the microlayer evaporation occupied significant proportion in total evaporation,
during the nucleate boiling for water and ethanol, for the experimental conditions adopted in this study.