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Liu, W.; Podowski, M. Z.*
Nihon Kikai Gakkai Netsu Kogaku Konfuarensu 2015 Koen Rombunshu (CD-ROM), 2 Pages, 2015/10
This paper gives prediction to the transient heat transfer at Departure of Nucleate Boiling (DNB) point for subcooled flow boiling. The prediction is carried out by solving the heat conduction equations in cylindrical coordinates with convective boundary condition, which changes with the change of the heat transfer mode on the heated surface. DNB is assumed to happen at the complete dryout of liquid sublayer trapped between the heated wall and an elongated vapor clot, during the passing time of the vapor clot. Important parameters including initial thickness of the liquid sublayer, vapor clot length, vapor clot velocity and void fraction etc., are calculated from the Liu - Nariai model. The initial heater surface temperature is derived from the Jens-Lottes correlation. The transient changes of liquid sublayer thickness, surface temperature at DNB are reported. No obvious temperature jumping is observed at DNB. To predict temperate excursion at Critical Heat Flux (CHF), more simulations to the transient boiling and film boiling processes are needed.
Liu, W.; Nariai, Hideki*
Journal of Heat Transfer, 127(2), p.149 - 158, 2005/02
Times Cited Count：17 Percentile：53.46(Thermodynamics)Homogeneous nucleation, although being discounted as a mechanism for vapor formation for water in most conditions, is found being possible to occur under some extreme conditions in subcooled flow boiling. In this paper, firstly, the existence of the homogeneous nucleation governed condition is indicated. Followed, a criterion is developed to judge a given working condition is the conventional one or the homogeneous nucleation governed one. With the criterion, subcooled flow boiling data are categorized and typical homogeneous nucleation governed datasets are listed. CHF triggering mechanism for the homogeneous nucleation governed condition is proposed and verified. Parametric trends of the CHF, in terms of mass flux, pressure, inlet subcooling, channel diameter and the ratio of heated length to diameter are also studied.
Kinoshita, Hidetaka; Nariai, Hideki*; Inasaka, Fujio*
JSME International Journal, Series B, 44(1), p.81 - 89, 2001/01
no abstracts in English
Sudo, Yukio; ; ; Kaminaga, Masanori
Journal of Nuclear Science and Technology, 23(1), p.73 - 82, 1985/00
Times Cited Count：36 Percentile：94.24(Nuclear Science & Technology)no abstracts in English
Nguyen, T. B.; Shibamoto, Yasuteru; Satou, Akira; Okawa, Tomio*
no journal, ,
Accurate predicting DNB heat flux in subcooled flow boiling is vital for safety assessment of nuclear reactors or other high heat flux components. A mechanistic model for predicting DNB heat flux has become a demanding task, because existing correlations are no longer accurate with the development of new generations of reactors with more complex working environments than before. Measurement of the liquid layer thickness beneath the vapor blanket moving along the heated wall is among important factors for the development of DNB mechanistic model. Available data of the sublayer thickness or so-called macro layer has been measured but only for pool boiling. The present study aims to produce a dataset of liquid sublayer thickness for flow boiling using laser displacement sensor. Synchronized high-speed movies are also collected for analyzing the change of the data during the period when the mass vapor pass.
