Chapter 5 - Flow of Multiphase Mixtures

Abstract

Multiphase flow is important in many areas of chemical and process engineering. The behaviour of the material will depend on the properties of the components, the flow rates, and the geometry of the system. In this chapter we study the flow of multiphase systems for which the composition of the mixture varies over the cross section of the pipe or channel; furthermore, the components may be moving at different velocities to give rise to the phenomenon of “slip” between the phases. The complexity of the flow is so high that design methods depend very much on the behaviour of a system. Although there is some degree of common behaviour between the various systems, the range of physical properties is so high that each system must be considered separately. In this chapter, special attention is given to three aspects of the flow of complex mixtures: the flow patterns; the hold-up of the individual phases and their relative velocities; and the relationship between pressure gradient in a pipe and the flow rates and physical properties of the phases.