Void distribution in slug flow

Abstract Air-water slug flow at atmospheric conditions in horizontal pipes of 31 and 53 mm i.d. has been characterized experimentally with local (optical) and cross-sectional (conductance) probes. The objective of the work is to improve the description of slug flow and the closure relations required in mean kinematic slug flow models. Local measurements include the radial void fraction distribution in the slugs, the size of the dispersed bubbles in the slug and the aeration of the liquid layer under the slug bubble. From cross-sectional holdup measurements, slug lengths and frequencies are determined, as well as the length of the highly aerated mixing zone in the front of the slugs. Measured values of film holdup at the tail of the slug bubbles and of slug frequency are compared with a physical model of slug flow derived from the work of Dukler & Hubbard.