title: A study of subcooled pool boiling of water: contact area of boiling bubbles with a heating surface during a heating process.
abstract: The contact area of bubbles with a transparent heating surface was optically measured during subcooled pool boiling of water on the ground. In the experiments, boiling bubbles were attached to the heating surface with a bubble holder and nearly reproduced the bubble behavior observed in low gravity. DC power was applied to the ITO heater and increased until the heater surface burned out. In quick heating, that is about 20 second until burnout and equal to the heating time during the low gravity period, the contact area was smaller than that for long time heating at the same heat flux. The experimental results suggest the reason why the critical heat flux in pool boiling is higher than the widely accepted predictions in microgravity. In a drop shaft experiment with constant heating, the contact area increased dramatically at the start of microgravity and became constant. Boiling bubbles coalesced and remained just over the heating surface.
authors.affiliation: Department of Mechanical Engineering, Tokyo University of Science, Noda, Chiba 278-8510, Japan. suzuki@rs.noda.tus-ac.jp
authors.forename: Koichi
authors.initials: K
authors.lastname: Suzuki
authors.forename: Saika
authors.initials: S
authors.lastname: Takahashi
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Ohta
mesh_terms: D018534:Earth, Planet; D006112:Gravitation; D006361:Heating; D006358:Hot Temperature; D018715:Microscopy, Video; D008962:Models, Theoretical; D010825:Physics / Q000379:methods*; D013997:Time Factors; D014867:Water; D014893:Weightlessness
chemical_list: D014867:Water