Separate effects of inclination on two-phase flow

Two-phase flow in an inclined pipe, i.e. not perfectly horizontal or vertical, has a number of important applications such as oil and gas pipelines, and helical coil steam generators. Despite this, there is limited study on the inclined two-phase flows. A large body of research exists on vertical two-phase flows, where the buoyancy force is parallel to the flow direction. Recent studies have systematically investigated horizontal two-phase flows, showing the effects of buoyancy acting perpendicular to the flow direction. Varying the angle of inclination can yield different body force effects from either vertical or horizontal, which can affect the void distribution, flow regime transitions, pressure drop, relative motion between gas and liquid phases.

TRSL has established a separate effects test facility to study both the effects of inclination on two-phase flows, as well as the conventional inverted U steam generator. A photo of the facility is shown in Figure 1.

Images of flow conditions at different angles are shown in Figure 2, highlighting the changes to the interfacial structure that can occur with respect to angle.

Experiments are performed with a variety of state-of-the-art instrumentation, including high-speed video camera, an impedance meter, local four-sensor conductivity probes, and gamma densitometry.