Development of Numerical methods for simulation of Rapid Multi-Phase Interactions
Techniques commonly used in the calculations of multi-phase flow, such as local parameter averaging and continuity phase assumptions, may result in large calculational inaccuracies for phenomena with rapid phase change. For example, with vapor explosions, a large degree of pseudo-diffusion (i.e. numerical diffusion) of components in dispersed states or with discontinuous fronts may occur, and local information, useful for modeling and evaluation of the phenomena, may be lost. Pseudo-diffusion of the components which act as high-temperature heat sources affects component distributions throughout the entire system. Numerical divergence is also often caused by fluctuation of these high-temperature components. In this paper, two treatment methods are proposed to avoid these problems. One method is a dispersed component method, which was developed for dispersed components. This method includes special modeling for some local parameters and some treatments to suppress pseudo-diffusion and numerical divergence. The other is a multi-region scheme, where a calculation domain is divided into an expanding, multi-phase mixture region and the surrounding, single-phase continuum region. The front of the mixture region is tracked using an adaptable grid to accurately follow the interface. By this method, numerical diffusion at the interface can be avoided. The effectiveness of these treatments is demonstrated by numerical simulations.
- Journal of nuclear science and technology
Journal of nuclear science and technology 34(5), 466-475, 1997-05-25
Atomic Energy Society of Japan