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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

THE INFLUENCE OF TEMPERATURE DEPENDENCE OF THERMOPHYSICAL PROPERTIES ON THE PREDICTION ACCURACY IN LAMINAR MIXED CONVECTION HEAT TRANSFER IN VERTICAL TUBES

Get access (open in a dialog) DOI: 10.1615/IHTC6.3010
pages 31-36

Sinopsis

Many organic liquids, such as mineral oils, used in heat transfer systems have thermophysical properties which are strongly temperature dependent. When predicting the thermal and hydraulic performance of a vertical tube convective system, inaccurate values of the thermophysical properties and/or their temperature variation coefficients can result in large errors. The properties considered are thermal conductivity, dynamic viscosity, density and specific heat capacity. The comparative loss of accuracy caused by neglecting the temperature variation of these, independently and in various combinations, is demonstrated by comparison with experiment and using two methods of computation - one full and one approximate. In this way, the relative importance of property changes can be identified. Those having greater effect must be measured accurately; those having lesser effect can be neglected thus saving computer time and cost without appreciable loss of accuracy.