STABILITY OF ANNULAR-FLOW AND SLUGGING

In this work we propose an effective viscosity criterion for the stabi lization of annular gas-liquid and Liquid-particle flows and an inerti al mechanism which drives waves into slugs in slugging gas-liquid hows . Annular Bow is stable when the fluid having the higher effective vis cosity occupies the core region and the lower viscosity fluid is in th e annulus. The eddy viscosity criterion is shown to be very consistent with published work on annular how transitions in horizontal and vert ical gas-liquid Bows. It also applies to a variety of liquid-solid and gas-solid flows. In the second part of the paper we propose a mechani sm for explaining the growth of initially small waves and initiation o f slugs in gas-liquid how. Copyright (C) 1996 Elsevier Science Ltd.