Gas-Liquid Two-Phase Flows in Pipes

Investigations on gas-liquid two-phase flows in pipes of good wettability started approximately 70 years ago mainly in mechanical and atomic energy engineering [34-39], Since then many experimental and theoretical studies have been carried out on this subject. Some of the findings of relevance to metallurgical operations will be briefly reviewed here. 

Focus will be on gas-liquid two-phase flows in which both fluids move vertically upwards. As shown in Fig. 1.7 the flow regimes in a vertical pipe of good wettability can be classified into the following seven categories [36]  

The nature of flow in each flow regime has been described in great detail in other texts [36,37]. Many researchers have also given the flow regime maps. The boundaries between these regimes are typically expressed as functions of the superficial velocities of gas and liquid, y g and l, defined as, 

Data on the quantities given in (1.2)-(1.5) and (1.8)-(1.12), as well as the pressure losses, and heat and mass transfer have been accumulated by numerous researchers [36,37]. Mathematical models and empirical relations have also been proposed for the quantities in mechanical, chemical, and atomic energy engineering. Most of these investigations, however, considered pipes of good wettability. 

The flow regimes in horizontal pipes of good wettability have been classified into the following (see Fig. 1.8) [36]  

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