TABLE OF CONTENTS Another family of models for two-phase flow is that given by Leung, another contributor to the DIERS project. The model of particular interest here is the homogeneous equilibrium model (HEM) for one-component two-phase flashing flow (Leung, 1986a). In addition to the basic model, the author has treated two-phase flashing flow in a horizontal duct (Leung, 1990a; Leung and Grolmes, 1987 ), in an inclined duct (Leung, 1990a; Leung and Epstein, 1990a), with a subcooled liquid (Leung and Grolmes, 1988) and with non-condensable gas (Leung and Epstein, 1991), has presented a unified approach for nozzles and pipes (Leung, 1990b) and an overall comparison of flashing flow methods (Leung and Nazario, 1990). He has also given a model for two-phase non-flashing flow (Leung and Epstein, 1990b) and has shown the similarity between the flashing and non-flashing flow models (Leung, 1990a).
Applications of the model given by Leung include its use for: two-phase flow in storage vessels (Leung, 1986b); pressure relief valves (Leung, 1992a); and venting of reactors (Leung and Fauske, 1987; Leung and Fisher, 1989). These applications are described in Sections 15.5, 15.6 and Chapter 17, respectively.
The homogeneous equilibrium flow model of Leung (1986a) follows on from an earlier model by Grolmes and Leung (1984) which was restricted to an in let condition of all liquid flow. This has been generalized by Leung to allow the handling of two-phase flow at the inlet.
The basic momentum and energy balance relations are:
where
