A Derivation of the Nonlocal Volume-Averaged Equations for Two-Phase Flow Transport

Abstract

In this paper a detailed derivation of the general transport equations for two-phase systems using a method based onnonlocalvolume averaging is presented. Thelocalvolume averaging equations are commonly applied in nuclear reactor system for optimal design and safe operation. Unfortunately, these equations are limited to length-scale restriction and according with the theory of the averaging volume method, these fail in transition of the flow patterns and boundaries between two-phase flow and solid, which produce rapid changes in the physical properties and void fraction. Thenon-localvolume averaging equations derived in this work contain new terms related withnon-localtransport effects due to accumulation, convection diffusion and transport properties for two-phase flow; for instance, they can be applied in the boundary between a two-phase flow and a solid phase, or in the boundary of the transition region of two-phase flows where thelocalvolume averaging equations fail.