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Horiguchi, Naoki; Yoshida, Hiroyuki; Abe, Yutaka*
Journal of Nuclear Science and Technology, 56(3), p.278 - 290, 2019/03
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Venturi scrubber (VS) has been installed in NPPs as one of the components of filtered venting systems. It can eliminate fine aerosol particles including fission products from polluted gas. Under extremely high-velocity conditions during severe accident, the data related to the droplet in the VS, which affects decontamination performance, is insufficient. This objective is to obtain the diameter of the extremely high-speed droplets and clarify an applicability of the existing correlations for the diameter. To visualize the extremely high-velocity droplet, an optical system with high frame rate and high resolution was developed. Visualization experiment using the VS under air-water condition was conducted, and droplet diameter distributions and Sauter mean diameter (SMD) were obtained. By comparing experimental data with values evaluated by existing correlations, it was clarified that the Nukiyama-Tanasawa equation can evaluate the SMD with good accuracy in the gas velocity range 82-250 m/s.
The Japan Society of Multiphase Flow*; Special Committee for Examination of Thermohydraulic Analysis Code based on Three-Fluid Model*
PNC TJ9565 94-001, 530 Pages, 1994/03
The purpose of the present study is to improve a numerical prediction method for multiphase flows based on the three-fluid model. Conducted were (1)improvement of a numerical method, (2)survey and examination on constitutive equations for mass transfer terms in annular-mist flow, (3) survey and verification of constitutive equations for momentum transfer terms, (4)collection of experimental database on steam-water and air-water annular-mist flows and numerical analyses of the database to verify the prediction method, (5)extensivc survey on expelimental techniques for annular-mist flow and (6)examination on the governing equations. As a result, the following conclusions were obtained: (a)multi-fluid modeling for all flow regimes were completed, (b)numerical stability of the three-fluid model was darified, (c)stability-enhanced solution method was developed, (d)ill-posedness of the equation system was revealed, (c)a physically-rational and well-posed multi-fluid model was proposed for dispersed flows, (f)systematic survcy and evaluation of constitutive equations for entrainment and deposition were conducted and summarized, (g)a theoretical method for evaluating film thickness, interfacial shear stress and wall shear stress was presented, and (h)it was confirmed that FIDAS-1DS can accurately predict critical heat fluxes under atmosphelic pressure, and that it can givc qualitatively good predictions concerning film thickness, droplet flow rate and so forth of the air-water annular-mist flow.
The Japan Society of Multiphase Flow*; Special Committee for Examination of Thermohydraulic Analysis Code based on Three-Fluid Model*
PNC TJ9565 93-001, 265 Pages, 1993/04
The purpose of the present study is to improve a numerical method for multiphase flows based on the three-fluid model. Conducted were (1) improvement of a numcrical scheme, (2)examination on the validity of governing equations, (3)survey and verification of available constitutive equations, (4)development of theoretical constitutive equations and (5) numerical analyses of experimental database on steam-water and air-water annular-mist flows. As a result, the following conclusions were obtained: (a)multi-fluid modelling for all flow regimes were completed, (b)numerical stability of the three-fluid model was clarified, (c)stability-enhanced solution method was developed, (d)a physically-rational and well-posed multi-fluid model was proposed for dispersed flows, (e)systematic survey and evaluation of available constitutive equations for entrainment was conducted and summarized, (f)a theoretical method for the evaluation of film thickness and interfacial shear stress was presented, and(g)it was confirmed that FIDAS-1DS can accurately predict critical heat fluxes under atmospheric pressure, and that it can give qualitatively good predictions conserning film thickness, droplet flow rate and so forth of the air-water annular-mist flow.
Nakao, Yasuhiro*; Yoshida, Hiroyuki; Horiguchi, Naoki; Kaneko, Akiko*; Abe, Yutaka*
no journal, ,
no abstracts in English
Horiguchi, Naoki; Yoshida, Hiroyuki; Nakao, Yasuhiro*; Kanagawa, Tetsuya*; Kaneko, Akiko*; Abe, Yutaka*
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no abstracts in English
Nakao, Yasuhiro*; Horiguchi, Naoki; Yoshida, Hiroyuki; Kanagawa, Tetsuya*; Kaneko, Akiko*; Abe, Yutaka*
no journal, ,
no abstracts in English
Horiguchi, Naoki; Yoshida, Hiroyuki; Nakao, Yasuhiro*; Kanagawa, Tetsuya*; Kaneko, Akiko*; Abe, Yutaka*
no journal, ,
no abstracts in English
Horiguchi, Naoki; Yoshida, Hiroyuki; Nakao, Yasuhiro*; Kaneko, Akiko*; Abe, Yutaka*
no journal, ,
no abstracts in English
Horiguchi, Naoki; Yoshida, Hiroyuki; Narushima, Yuki*; Katono, Kenichi*
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Droplet entrainment and deposition in annular dispersed flow are important phenomena to predict dryout phenomena. Many correlation equations have been proposed to determine the coefficients of entrainment and deposition, but the clarification of entrainment and deposition phenomena is an issue because of the complexity of them and the difficulty of experiments. Detailed numerical simulation is useful for it but requires validation using the correlation equations. In this presentation, we explain the results of the detailed numerical simulation of droplet entrainment and deposition phenomena in annular dispersed flow using TPFIT developed by JAEA and the comparison of the coefficients quantified from the numerical simulation data with the ones using the correlation equations.
