Efflux Time for Two Exit Pipe System

Based on integral balances, mathematical equation for efflux time during gravity draining of a Newtonian liquid (below its bubble point) from a large open cylindrical storage tank (Where the flow in the storage tank is essentially laminar) through two exit pipes of same diameter located at the bottom of the vessel (The flow is assumed to be turbulent in each of the exit pipes) is developed. The equation is ultimately simplified and written in dimensionless form. The equation will be of use for arriving at the minimum time required for draining the contents of a cylindrical storage vessel through two exit pipe. The equation is verified with the experimental data. A maximum deviation of 19% and an average deviation of 16% are observed. The effect of initial height of liquid on Reynolds’ number is also established. It is shown that while draining a liquid from the cylindrical storage tank through exit pipe system, Froude number remains constant.