Rise velocity of a Taylor bubble through concentric annulus

In the present work, an attempt has been made to predict the rise velocity of Taylor bubbles through concentric annuli. In order to obtain an expression of rise velocity, a potential flow field has been assumed at the nose of the bubble, whereas the effect of liquid viscosity has been considered in the falling films. The model has further been modified for very small and large annuli. The rise velocity data obtained experimentally in the present work show a close agreement with the theoretical predictions. The model predictions also agree closely with the experimental values of rise velocity reported in literature. Both experiments as well as theory indicate velocity to be a unique function of annulus dimension. The function has been obtained as a Froude number type of expression, U = 0.323 root g(D-1 + D-2) (C) 1998 Elsevier Science Ltd. All rights reserved.