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Ebihara, Kenichi; Watanabe, Tadashi
Dai-18-Kai Suchi Ryutai Rikigaku Shimpojiumu Koen Yoshishu (CD-ROM), 7 Pages, 2004/12
The Ishii-Grolmes experimental correlation, which represents the inception criteria of the droplet entrainment, has been reproduced by the lattice Boltzmann simulation[Ebihara et al., Nagare 23, 253(2004)]. It has been observed in the simulation that the droplet broke off the wave which was generated on the smooth interface of the horizontal stratified two-phase flow. The numerical and physical influence on the reproduction of the experimental correlation is discussed in this paper. It is verified that the lattice size was enough for the reproduction of the experimental correlation though the discretization of the lattice affects the simulation result numerically. It is also seen that the shape of the generated wave and the flow velocity distribution affect the simulation results as the physical influence.
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 92-001, 173 Pages, 1992/05
The purpose of the present study is to improve a numerical analysis method for multiphase flows based on the three-fluid model. The improvement will be conducted for the following three items; (1)modeling of the multiphase flow, (2)constitutive equations (3)numerical method. A systematic survey was carried out for the aforementioned three items. As a result, a reliable plan for the improvement was proposed. Experimental database for air-steam and air-water two-phase annular flow was also presented in this report, which will be useful for the future improvement of the constitutive equations. As for the numerical method, a method for improving the computational efficiency was proposed. It was confirmed that the CPU time decreases about 95% with the proposed method.
Horiguchi, Naoki; Yoshida, Hiroyuki; Nakao, Yasuhiro*; Kaneko, Akiko*; Abe, Yutaka*
no journal, ,
no abstracts in English
Horiguchi, Naoki; Yoshida, Hiroyuki; Narushima, Yuki*; Katono, Kenichi*
no journal, ,
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.
