A Moving Boiling-Boundary Model of an Arbitrary-Powered Two-Phase Flow Loop

Abstract

Usually, analysis of two-phase flow requires a substantial amount of mathematical effort, on the one hand by virtue of the intrinsic complexity of the physical phenomena involved and, on the other hand, because more often than not, the resulting equations are usually rather cumbersome. Several different approaches have been taken in order to solve particular cases by making some assumptions and applying approximations. One of these cases is the Clausse-Lahey model introduced twenty years ago, that proposes a system of differential-algebraic equations that approximately describes the transient behavior of a one-dimensional vertical two-phase flow channel. It uses a spatial scheme based on nodes that move with time, which reproduces experimental results better than traditional methods for the same
number of nodes. In this paper, the Clausse-Lahey moving boiling-boundary model is extended to allow the inclusion of transient non-uniform power sources, to handle non-constant inlet enthalpy and arbitrary external pressure differences, so models of systems of industrial interest can be built. Some numerical results are shown as illustrations of the kind of problem the proposed extension to the original Clausse-Lahey model allows to solve.