Effects of Surface Tension and Non-Isothermal Wall Temperature Variation upon Filmwise Condensation on Vertical Ellipsoids/Sphere
Abstract
An analytical study is made into the process of heat transfer with the vapour condensation on non-isothermal vertical ellipsoids/sphere. The mathematical treatment leads to explicit expressions for local condensate film thickness and local heat transfer coefficients around the ellipsoidal periphery in terms of the parameters of the configuration shape-ellipticity `e' and process-the inverse Bond numbers, and the non-isothermal wall temperature variation amplitude `A'. The result indicates that these parameters have significant effects on the local heat transfer coefficients. The dimensionless mean heat transfer coefficient {Nu}, has been explicitly showed to be increased as ellipticity of vertical ellipsoids increases. However, it is nearly unaffected by both surface temperature non-uniformity with a cosine distribution and surface tension effect due to the non-uniform surface curvature. For a special object, the isothermal sphere (e = 0, A = 0), the reduced result agrees well with finite difference method's solution by Karimi. The present solutions are explicit for the heat and momentum transfer parameters bringing some convenience in practical applications.
- Publication:
-
Proceedings of the Royal Society of London Series A
- Pub Date:
- August 1993
- DOI:
- 10.1098/rspa.1993.0105
- Bibcode:
- 1993RSPSA.442..301Y