ISSN Online: 2377-424X
International Heat Transfer Conference 5
ANALYTICAL AND EXPERIMENTAL RESULTS FOR COMBINED FORCED AND FREE LAMINAR CONVECTION IN HORIZONTAL TUBES
Résumé
Experimental and analytical results are presented for laminar flow in horizontal circular tubes with nominally
constant wall heat flux. A finite-difference solution of the governing equations was carried out for the thermally developing region. For Ra* = 106, Nu in the developed region is more than 300% above the constant property value, and the entrance length is about 10% that for the constant property prediction (Fig. 3). Test results were obtained for electrically heated glass or steel tubes using water or ethylene glycol. The data are correlated accurately by equations (10,11) which include dimensionless groups to account for effects of variable transport properties and tube wall conduction.