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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.
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.
