Volume Modeling

Abstract

A volume, as its name suggests, is a fluid mixing or splitting component. For water/steam, the flow regime can be single-phase or two-phase flow. Regarding two-phase flow, two kinds of models are presented: one for the homogeneous flow model and the other for the two-fluid formulation with two zones (a liquid and a steam zone). The phenomena taken into account are the condensation flow of the steam phase into the liquid phase, the vaporization flow of the liquid phase into the steam phase and the thermal exchanges between the two phases, between the two phases in the volume and the cooling fluid flowing outside the volume through the tube bundle, and between the two phases in the volume and the ambient. In this chapter, the different types of volume components are presented: simple dynamic volume, dynamic drum, pressurizer, two-phase cavity, tank, static drum, mixer, splitter, and steam dryer. Detailed descriptions of the physical equations for the component models are provided: modeling assumptions, fundamental equations, and correlations with their validity domains. A test-case for each component model is given that includes the structure of the model, parameterization data, model calibration, and results of simulation. The full description of the physical equations is independent of programming languages and tools.