ABSTRACT
This chapter discusses the phenomena of two-phase flow, including techniques for prediction of the flow regimes and pressure drop in two-phase flow. Two-phase flow is always encountered in cryogenic liquid gasifiers used in such applications as self-pressurization systems and liquid natural gas delivery systems. Pressure drop and heat transfer in two-phase flow involves fluid properties of both the liquid and vapor phases, including surface tension in some cases. Boiling heat transfer is a convective mode of heat transfer, in which a phase change occurs for the fluid. If the liquid is subcooled, there may be no net vapor generation, and this case is sometimes called simply evaporation. From a thermal standpoint, film boiling is an inefficient mode of heat transfer; however, it is encountered in many cryogenic systems. As a result of the similarity in the heat transfer mechanisms, film boiling heat transfer correlations utilize some of the same dimensionless groups that are used in condensation and natural convection heat transfer.
