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Measurement of surface dryout near heating surface at high heat fluxes in subcooled pool boiling

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タイトル: Measurement of surface dryout near heating surface at high heat fluxes in subcooled pool boiling
著者: Ono, Ayako 著作を一覧する
Sakashita, Hiroto 著作を一覧する
キーワード: Pool boiling
Critical heat flux
Subcooled boiling
Conductance probe
発行日: 2009年 1月31日
出版者: Elsevier
誌名: International Journal of Heat and Mass Transfer
巻: 52
号: 3-4
開始ページ: 814
終了ページ: 821
出版社 DOI: 10.1016/j.ijheatmasstransfer.2008.07.042
抄録: 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.
資料タイプ: article (author version)
出現コレクション:雑誌発表論文等 (Peer-reviewed Journal Articles, etc)

提供者: 坂下 弘人


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