Dispersed bubble flow in horizontal pipes

A set of experiments has been performed to analyse gas-phase distribution i n horizontal bubble flow. The experimental data have been obtained by means of conductance probes and include measurements of the local void fraction and the bubble diameter and velocity. Present observations show large varia tions of the local void fraction and the bubble size moving from the top to the bottom of the pipe, with local maxima located close to the upper pipe wall. Measurements also show that, at the boundary of the dispersed bubble flow regime, the bubble size, and therefore the surface available for heat and mass transfer, changes abruptly for small variations of the liquid or g as flowrate. This change allows the transition between the dispersed and th e elongated bubble regimes to be identified with good precision. Present da ta make it possible to develop a new correlation for the maximum bubble siz e in dispersed bubble flow. (C) 1999 Elsevier Science Ltd. All rights reser ved.