Bubble motion during inclined intermittent flow

An experimental and numerical study of the motion of bubbles in inclined intermittent gas-liquid flow has been performed. A knowledge of the velocity of bubbles is critical to the determination of the pressure drop and heat transfer characteristics in such flows. Measurements show a transition in the dynamics of the bubble at a critical flow rate and this critical point has been shown to be related to the drift velocity of a bubble in a stagnant liquid. A numerical investigation of bubble drift in stagnant liquids has been performed with the use of the Volume of Fluid (VOF) technique. The results of the computations are shown to depend on the phase interface to wall contact angle, however, with a suitable choice of this parameter the calculated bubble motion matches well with the measured data, The bubble interface shape is also compared against data obtained with the use of a parallel wire conductance probe to further validate the computational results. (C) 2001 Elsevier Science Inc. All rights reserved.