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ISSN Online: 2377-424X

ISBN Print: 0-89116-130-9

International Heat Transfer Conference 6
August, 7-11, 1978, Toronto, Canada

HEAT TRANSFER BY LAMINAR COMBINED CONVECTION IN A VERTICAL TUBE-PREDICTIONS FOR WATER

Get access (open in a dialog) DOI: 10.1615/IHTC6.3000
pages 25-30

Abstract

The partial differential equations for two-dimensional flow are treated by solving the equivalent finite-difference equations with a computer program in Fortran. The analysis accommodates various fluid and thermal boundary conditions and allows for viscosity and limited density variation with temperature.
Results presented here are for combined convection to water under various conditions of natural convection assisting or opposing the forced flow. Heat transfer results are presented in terms of the standard dimensionless groups, and utilise published data of Lawrence and Chato (1) and Scheele et al ((2),(3)) to indicate likely limits of the laminar flow regime. The results consistently show an increase in heat transfer with assisted forced flow, and a reduction with opposed flow. These heat transfer changes correlate satisfactorily in terms of a suitably defined Grashof/Reynolds number ratio.
The treatment involves a marching procedure and can predict effects related to transition. The profile transition parameter suggested by Lawrence and Chato for upward heated flows is shown not to correlate the results of Scheele et al. Other predictions usually confirm (with an interesting exception) those of Scheele et al, who used more approximate methods.