Interfacial dynamics of air–liquid flow in eccentric drainpipe while draining from a square tank

Abstract The present study investigates the influence of liquid properties and port position on draining characteristics from a square tank. Four different liquids, water, kerosene, glycerol 20%, and glycerol 60% are used. Three different port positions of a drainpipe of 9 mm id are used. Bubbly, slug, churn, elongated slug, and annular flow are observed in the drain port. Slug and bubbles never collide and rarely distorted for viscous dominated flow, whereas they collide and distort in inertia-dominated flow like draining of water, kerosene, glycerol 20% and glycerol 60%. Empirical correlations are proposed, which shows the time of draining depends on kinematic viscosity of the liquid and delays by the eccentric position of the port. Liquid height in tank found to be varied in quadratic nature with time.