ISSN Online: 2377-424X
ISBN Print: 0-89116-299-2
International Heat Transfer Conference 7
EXPERIMENTAL INVESTIGATION OF COMBINED FORCED AND FREE CONVECTIVE HEAT TRANSFER RATES IN A VERTICAL U-TUBE WITH ONE LEG HEATED
Abstrakt
The paper presents the experimental results of combined forced and free convective mean heat transfer rates to water flowing in a vertical U-tube with one leg heated. The experimental data obtained over a wide range 0.004 ≤ (Gr/Re2)≤ 4 are correlated successfully by a modified Colburn factor as a function of the Graetz number. The resulting dimensionless equations can be utilized to predict the heat transfer coefficients with an accuracy of ± 12%. The data for laminar mixed convective region are also correlated by another equation of the type suggested by Churchill for laminar, assisting, forced and free convection from vertical plates.