Annular Flow Film Thickness via Planar Laser-Induced Fluorescence

Annular flow is a multiphase flow regime of two-phase gas-liquid flow characterized by a thin liquid film layer on the pipe wall surrounding a fast-moving gas core. The film layer thickness significantly impacts several critical flow properties, but the literature is scarce compared to other flow regimes. In this experimental work, planar laser-induced fluorescence (PLIF) was used to study the top and bottom film thickness over a range of both liquid and gas flow rates. In addition, the measurements were compared to results from established horizontal flow data. The scarcity of literature on annular flow is especially true for the sensitivity of the film thickness to inclination angle. Therefore, annular flow film behaviors will also be potentially studied over a wide range of inclination angles, including both upward and downward vertical orientations.