title: High heat flux cooling by microbubble emission boiling.
abstract: In subcooled flow boiling of water in a horizontal rectangular channel, microbubble emission boiling occurred at higher subcooling of liquid in transition boiling, and the heat flux increased more than the critical heat flux. The maximum heat flux reached 10 MW/m(2) for a channel with 12 mm x 14mm cross-section at 40K liquid subcooling and 0.5 m/sec liquid velocity. For smaller rectangular channels with 14 mm x 5mm, 14mm x 3mm, and 14mm x 1mm cross-sections, the maximum heat flux was 7 MW/m(2)-more than 20 times the cooling limit of a present day CPU. Microbubble emission boiling is expected to realize high heat flux cooling for electronic devices. In convection boiling with subcooled water jet, the same boiling regime and heat flux were obtained for a downward heating surface and an upward heating surface. In subcooled flow boiling with strong convection, the hydrodynamic force is predominant for vapor-liquid exchange. Accordingly, microbubble emission boiling is expected for high heat flux cooling or high heat flux heat transfer in microgravity.
authors.affiliation: Department of Mechanical Engineering, Faculty of Science and Technology, Science University of Tokyo, Chiba, Japan. suzuki@rs.noda.tus.ac.jp
authors.forename: Koichi
authors.initials: K
authors.lastname: Suzuki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Saitoh
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Matsumoto