A Generalization of the System Mean Void Fraction Model for Transient Two-Phase Evaporating Flows

The system mean void fraction model has been successful in the prediction of a variety of transient evaporating and condensing flow phenomena; however, applications of the model have been restricted to physical situations involving complete vaporization or condensation. The major contribution of this paper is the development of a generalization of the existing system mean void fraction model, applicable to the broader class of transient two-phase flow problems involving incomplete vaporization. Present applications of the generalized system mean void fraction model to transient evaporating flows indicate good agreement with experimental void fraction and mass flux response data available in the literature. These data represent a variety of different flow geometries, types of fluids, and a wide range of operating conditions.