Showing papers by "Kaichiro Mishima published in 2002"
TL;DR: Based on detailed analyses of heat exchange processes arising among the droplet, the vapor phase and the heated wall, a non-equilibrium mechanistic heat transfer model for post-dryout dispersed flow regime was developed, in which six heat transfer paths were taken into account as discussed by the authors.
51 citations
TL;DR: In this paper, a forced convective critical heat flux (CHF) in a rectangular channel that depended on an inclination angle was investigated, and a comparison of the model prediction with experimental results showed good agreement between the measured and predicted CHF with varying inclination angle.
Abstract: Forced convective critical heat flux (CHF) in a rectangular channel that depended on an inclination angle was investigated. The experiment has been performed with a one side-heated thin rectangular channel under the atmospheric pressure with the inclination angle varying from 10° to 90° and mass flux from 0 to 400 kg/m2·s. The CHF was found to decrease with the inclination angle remarkably at low mass flux. Flooding CHF analysis was carried out based on the result of flow visualization in the channel, and the incorporation of inclination angle into a model was proposed. A comparison of the model prediction with experimental results showed good agreement between the measured and predicted CHF with varying inclination angle. The model was combined with a conventional CHF correlation for evaluation of mass flux, and finally a forced convective CHF correlation for an inclined thin rectangular channel was proposed.
5 citations
01 Jan 2002
TL;DR: In this article, the effect of radiation induced surface activity on boiling phenomenon, surface wettability in high-temperature environment or Leidenfrost condition and critical heat flux (CHF) of oxide metals irradiated by gamma rays were investigated.
Abstract: To delineate the effect of Radiation Induced Surface Activity (RISA) on boiling phenomenon, surface wettability in high-temperature environment or Leidenfrost condition and critical heat flux (CHF) of oxide metals irradiated by gamma rays were investigated. When the temperature of the heating surface reaches the wetting limit temperature, water-solid contact vanishes because of a stable vapor film between the droplet and the metal surface, i.e., a Leidenfrost condition. The wetting limit temperature increased with integrated irradiation dose. The CHF of oxidized titanium was improved up to 100% after 800 kGy 60 Co gamma ray irradiated. Radiation Induced Boiling Enhancement (RIBE) phenomenon was firstly confirmed through the experiments.Copyright © 2002 by ASME
4 citations
TL;DR: In this article, a half-circumferentially heated round tube under low-pressure conditions was used for flow boiling of water and critical heat flux (CHF) experiments.
Abstract: Heat transfer for flow boiling of water and critical heat flux (CHF) experiments in a half-circumferentially heated round tube under low-pressure conditions were carried out. To clarify the flow patterns in the heated section, experiments in the round tube under the same conditions were also carried out, and their results were compared. The experiments were conducted with atmospheric-pressure water in test sections with inner diameter D = 6 mm, heated length L = 360 mm, inlet water subcooling ΔTin = 80 K, and mass velocity G from 0 to 2000 kg/(m2·s) for the half-circumferentially heated round tube and from 0 to 7000 kg/(m2·s) for the full-circumferentially heated tube. The experimental data demonstrated that the wall temperature near the outlet of the half-circumferentially heated tube remained almost the same until CHF. It was found that burnout occurred when the flow regime changed from churn flow to annular flow, and the liquid film on the heated wall dried out although liquid film on the unheated wall remained. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(3): 149–164, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10022
3 citations