Experimental Study on Void Fractions and Pressure Drops in Three-Phase Flow for Deep Sea Mining

Subsea minerals exist in the deep water within Japan’s exclusive economic zone. There are many technical issues which should be addressed for subsea mining. The air-lift pumping systems are one of promising methods for subsea minerals transport. Flow assurance for three-phase flow is important to design the air-lift pumping system for subsea mining. It is important to establish methods for estimating void fractions and frictional pressure drops. To establish the methods for three-phase flow, we reviewed previous studies for two- or three-phase flow. There are some models to estimate the void fractions such as slip flow model and drift flux model. There are also some models to estimate the frictional pressure drops such as homogeneous model and separated flow model. We calculated void fractions and frictional pressure drops by existing correlation and compared calculated results with experimental data in two- or three-phase flow. In addition, we proposed the methods for estimating the void fractions and frictional pressure drops in three-phase flow. These had fewer number of experimental constants than existing correlations, these could calculate void fractions and frictional pressure drops in more various conditions than existing correlations.