Bubbly flow in an axisymmetric sudden expansion: Pressure drop, void fraction, wall shear stress, bubble velocities and sizes

In this work, a theoretical and experimental study of a bubbly flow in an a xisymmetric sudden expansion is presented. A global model for the predictio n of the singular pressure drop is derived and an experimental study relati ve to the dynamic parameters of the bubbly how downstream of the singularit y is given. The singular pressure drop has been obtained as a global formul ation that integrates velocity form profiles, turbulence for every phase, a nd wall shear stress. In the experimental study, data concern pressure drop , wall shear stress, local and global void fraction, average and fluctuatin g bubble velocities and bubble sizes. These data constitute a quasi-complet e experimental data bank with respect to Bel Fdhila and Simonin's recent wo rks on the liquid phase of bubbly flow. (C) 1999 Elsevier Science Inc. All rights reserved.