On Flows Driven by Mechanical Stresses in a Two-Phase System

Abstract

Gas-liquid flows in annulus are analyzed for fluids in large range of viscosity ratios. The geometry corresponds to a liquid bridge co-axially placed into an outer cylinder with solid walls. The internal core consists of solid rods at the bottom and top, while the central part is a relatively short liquid zone filled with viscous liquid and kept in its position by surface tension. The gas enters into the annular duct and entrains initially quiescent liquid. The flow structures in the liquid and gas are obtained numerically for different shapes of solid rods. Solution for fully developed flow in annulus with moving core is found analytically. The regions, where the flow can be considered as locally fully developed, are identified by comparing numerical and analytical results. The role of mechanical stresses in the interface dynamics is examined and the optimal choice of supporting rods shape is discussed.