The effects of property evaluation methods on the correlation of heat transfer data
Abstract
An explicit consideration of the behavior of the dimensionless parameters as functions of such underlying physical variables as DeltaT or the characteristic dimension L is used to construct better correlations. Results from the temperaturedependent methods for evaluating the dimensionless parameters, including those of Sparrow (1958), Hesse (1974), mean film temperature, surface temperature, bulk temperature, surface correction exponent, integrated average value, and bulkgeometric mean temperature, were compared to data for natural convection heat transfer from a horizontal cylinder and from a horizontal wire. Good results were obtained in a treatment of the horizontal cylinder problem with the bulkgeometric mean temperature method in which beta and rho are evaluated at T sub b and c, mu, and k at T(r = 1/3). For fixed T sub b, it is suggested that Nu is an increasing function of DeltaT, implying that Ra should also be an increasing function of DeltaT.
 Publication:

International Communications in Heat and Mass Transfer
 Pub Date:
 February 1984
 Bibcode:
 1984ICHMT..11...85B
 Keywords:

 Convective Heat Transfer;
 Data Correlation;
 Dimensionless Numbers;
 Free Convection;
 Heat Transfer Coefficients;
 Nusselt Number;
 Temperature Dependence;
 Fluid Mechanics and Heat Transfer