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Laminar condensation on a moving drop. Part 1. Singular perturbation technique

Published online by Cambridge University Press:  20 April 2006

J. N. Chung
Affiliation:
Department of Mechanical Engineering, Washington State University, Pullman, WA 99164–2920
P. S. Ayyaswamy
Affiliation:
Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104
S. S. Sadhal
Affiliation:
Department of Mechanical Engineering, University of Southern California, Los Angeles, CA 90089–1453

Abstract

In this paper, laminar condensation on a spherical drop in a forced flow is investigated. The drop experiences a strong, radial, condensation-induced velocity while undergoing slow translation. In view of the high condensation velocity, the flow field, although the drop experiences slow translation, is not in the Stokes-flow regime. The drop environment is assumed to consist of a mixture of saturated steam (condensable) and air (non-condensable). The study has been carried out in two different ways. In Part 1 the continuous phase is treated as quasi-steady and the governing equations for this phase are solved through a singular perturbation technique. The transient heat-up of the drop interior is solved by the series-truncation numerical method. The solution for the total problem is obtained by matching the results for the continuous and dispersed phases. In Part 2 both the phases are treated as fully transient and the entire set of coupled equations are solved by numerical means. Validity of the quasi-steady assumption of Part 1 is discussed. Effects due to the presence of the non-condensable component and of the drop surface temperature on transport processes are discussed in both parts. A significant contribution of the present study is the inclusion of the roles played by both the viscous and the inertial effects in the problem treatment.

Type
Research Article
Copyright
© 1984 Cambridge University Press

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