ABSTRACT

Knowledge Approach ...................................................301 9.2.2 Statistical Approach.....................................................................307

9.3 Flow Pattern Imaging ..............................................................................309 9.3.1 2D Instantaneous and Average Phase Distribution.....................309 9.3.2 3D Macro-Flow Structures..........................................................317

9.4 Solids Mass Flow Measurements............................................................321 References .........................................................................................................330

A description of multiphase flow starts with the concept of flow regime. For a given flow system, defined by the particular pipeline geometry and the material flowing through it, various spatial and temporal patterns (flow regimes) arise through self-organization of the multiphase systems. These patterns are the result of forces acting on the flowing phases as well as on the interfaces between them. For example, in gas-liquid systems, the interfaces are free to deform, break up, or coalesce. In horizontal pipes, the resulting flow regimes have been described as bubbly, intermittent, stratified, or annular flow [1]. If the interfaces coalesce, then the resulting phase separation may lead to a stratified flow, where there is minimal contact between the liquid phases. In a chemical reactor, this situation would have a detrimental effect on the reaction and production rates. If, on the other hand, the interfaces between the phases break up, then a bubbling flow might result wherein the enhanced mixing would increase the reaction rate. It can be seen that the type of flow regime encountered in multiphase processes has a significant economic impact.