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Measurement of surface dryout near heating surface at high heat fluxes in subcooled pool boiling
| Title: | Measurement of surface dryout near heating surface at high heat fluxes in subcooled pool boiling |
| Authors: | Ono, Ayako Browse this author | | Sakashita, Hiroto Browse this author →KAKEN DB |
| Keywords: | Pool boiling | | Critical heat flux | | Macrolayer | | Dryout | | Subcooled boiling | | Conductance probe |
| Issue Date: | 31-Jan-2009 |
| Publisher: | Elsevier |
| Journal Title: | International Journal of Heat and Mass Transfer |
| Volume: | 52 |
| Issue: | 3-4 |
| Start Page: | 814 |
| End Page: | 821 |
| Publisher DOI: | 10.1016/j.ijheatmasstransfer.2008.07.042 |
| Abstract: | The authors have conducted measurements of liquid-vapor behavior in the vicinity of a heating surface for saturated and subcooled pool boiling on an upward-facing copper surface by using a conductance probe method. A previous paper [A. Ono, H. Sakashita, Liquid-vapor structure near heating surface at high heat flux in subcooled pool boiling, Int. J. Heat and Mass Transfer, 50(2007), 3481-3489] reported that thicknesses of a liquid rich layer (a so-called macrolayer) forming in subcooled boiling are comparable to or thicker than those formed near the critical heat flux (CHF) in saturated boiling. This paper examines the dryout behavior of the heating surface by utilizing the feature that a thin conductance probe placed very close to the heating surface can detect the formation and dryout of the macrolayer. It was found that the dryout of the macrolayer formed beneath a vapor mass occurs in the latter half of the hovering period of the vapor mass. Two-dimensional measurements conducted at 121 grid points in a 1mm×1mm area at the center of the heating surface showed that the dryout commences at specific areas and spreads over the heating surface as the heat flux approaches the CHF. Furthermore, transient measurements of wall void fractions from nucleate boiling to transition boiling were conducted under the transient heating mode, showing that the wall void fraction has small values (<10%) in the nucleate boiling region, and then steeply increases in the transition boiling region. These findings strongly suggest that the macrolayer dryout model is the most appropriate model of the CHF for saturated and subcooled pool boiling of water on upward facing copper surfaces. |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/42769 |
| Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 坂下 弘人
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