1987 Volume 1 Issue 1 Pages 79-95
The one-dimensional transient two phase flow analyzer MINCS has been developed as a computational tool for the development and assessment of constitutive models. In order to assess the numerics of MINCS, it has been applied to the numerical benchmark problems for the two-fluid model proposed by the Workshop on Two-Phase Flow Fundamentals under the auspices of the US Department of Energy and the Electric Power Research Institute.
Although the adequacy of constitutive equations has primary importance compared with the accuracy of numerics in two-phase flow simulation, numerical stability is required for computer codes in order to assess the adequacy of constitutive equations. Even with such a stable numerical solution method, difficulties related to the numerics often appear in a complex manner coupled with those of constitutive relations in, for example, safety analyses of light water reactors. Therefore, it is worthwhile to investigate each numerical difficulty by isolating it from physical problems. In this report, the benchmark calculations by MINCS are discussed focusing on the numerical treatment of the missing phase in a single-phase flow and spatial and/or temporal transitions from a single phase to two-phase and vice versa. The selected problems for this purpose are the disappearance of liquid droplets due to evaporation, inception of boiling due to external heating, expulsion of steam by subcooled water and sedimentation. A systematic numerical treatment of missing phase mentioned above and the transition has been developed and assessed through the benchmark calculations.
