Application of Molecular Tagging Velocimetry to Two-Phase (Gas/Liquid) Flows Available to Purchase

The application of Molecular Tagging Velocimetry (MTV) to two-phase flows is investigated in this paper. The two phase flows under investigation were gas/liquid flows where the two phase region was composed of “clouds” of very fine bubbles with variable bubble densities (i.e. void fractions). MTV was applied to two different flows, a turbulent fully developed channel flow and a cavitating diffuser. The presence of the bubbles was found to degrade the image contrast. The amount the contrast was degraded depended on the bubble density of the two-phase region. Specifically, as the bubble density increased the image contrast within the two-phase region dropped. Measurements were found to be possible with contrast levels as low as 20 counts. While this contrast level was below the minimum contrast level recommended for measurements in prior studies, measurements were possible with elevated noise levels.