Showing papers by "Kaichiro Mishima published in 1995"
TL;DR: In this article, critical heat flux (CHF) for flowboiling of water in small-diameter tubes under low-pressure conditions was measured over a wide range of parameters, and the results were compared with several existing CHF correlations and theoretical models.
Abstract: Critical heat flux (CHF) for flow-boiling of water in small-diameter tubes under low-pressure conditions was measured over a wide range of parameters, and the results were compared with several existing CHF correlations and theoretical models. The experiment was conducted with atmospheric-pressure water in tubes with inner diameter D ranging from 1.0 to 6.0 mm, heated length-to-diameter ratio L/D from 1 to 100, inlet water subcooling ΔTin from 0 to 90 K, and mass velocity G from 0 to 19740 kg/(m2·s). The highest CHF attained in this experiment was 158 MW/m2. The results demonstrated the effects of channel geometry and subcooling under low-pressure condition. In, addition, the flow pattern near CHF conditions in a tube with small diameter and short heated length was observed using a high-speed video system. The theoretical model of Celata et al. (Int J. Heat Mass Transf., 1994) for a subcooled condition showed good agreement with the present subcooled data when L/D≥25.
18 citations
TL;DR: The void fraction measurement experiment of pressurized water reactor (PWR) fuel assemblies has been conducted since 1987 under the sponsorship of the Ministry of International Trade and Industry as a Japanese national project as mentioned in this paper.
Abstract: The void fraction measurement experiment of pressurized water reactor (PWR) fuel assemblies has been conducted since 1987 under the sponsorship of the Ministry of International Trade and Industry as a Japanese national project. Two types of test sections are used in this experiment. One is a 5 x 5 array rod bundle geometry, and the other is a single-channel geometry simulating one of the subchannels in the rod bundle. Wide gamma-ray beam scanners and narrow gamma-ray beam computed tomography scanners are used to measure the subchannel void fractions under various steady-state and transient conditions. The experimental data are expected to be used to develop a void fraction prediction model relevant to PWR fuel assemblies and also to verify or improve the subchannel analysis method. The first series of experiments was conducted in 1992, and a preliminary evaluation of the data has been performed. The preliminary results of these experiments are described.
10 citations