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ISSN Online: 2377-424X

ISBN Print: 0-85295-345-3

International Heat Transfer Conference 10
August, 14-18, 1994, Brighton, UK

BUBBLE TRAJECTORIES IN CROSS FLOWS AND WAKE ENTERING MECHANISMS

Get access (open in a dialog) DOI: 10.1615/IHTC10.5570
pages 235-240

Аннотация

This paper describes a theoretical investigation of bubble trajectory computations in a vertical (gravity downward) concurrent upflow towards a cylinder. Focal points are 1) the examining of the importance of various forces governing bubble migration in non-uniform flow fields; 2) the exploring of the mechanisms that control the entering of bubbles into the wake. The unperturbed single phase flow field is in this approach considered to be an input that is derived either from numerical computations (e.g. by a finite-element method) or from the semi-analytical model presented in this paper. This model is based on experimental data as much as possible. No known forces on a non-deforming bubble are neglected. The pressure gradient force and the Basset history force are found important in strongly non-uniform flow regions. Turbulent velocity fluctuations and the "points" where a colliding bubble detaches from the cylinder are found to be essential. The bubble to cylinder size should be small and the liquid Reynolds number in the subcritical range to justify these conclusions.