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HEAT TRANSFER BY FREE CONVECTION TO FLUIDS CONTAINED IN VERTICAL TUBES

Journal Article · · Dissertation Abstr.
OSTI ID:4829720

Heat transfer by free convection to water and two oils contained in vertical tubes was studied. Temperature profiles at several levels across a diameter of the tube were determined. The object of this study was the determination of the factors affecting heat transfer by free convection to liquids contained in heated vertical tubes, closed at the bottom and opening at the top into a large chamber that contained a cooling coil. Experiments were conducted with brass tubes, one foot in length, with inside diameters of 0.5, 0.75, 1, and 3 pnches. Heat fluxes varied from 230 to 13,300 Btu/hr-ft/sup 2/. The average temperature drop across the liquid film varied from 9.1 to 171.3 deg F. The results were correlated for the three smaller tubes with an equation involving two dimensionless heat-transfer groups: the Grashof number and the Prandtl number. The results for the 3-inch diameter tube followed the theoretical equation derived by Eckert and Jackson for a flat plate. Teraperature profiles for turbulent flow conditions were similar to those found in fixed bed reaotors. Turbulent flow conditions were noted in the three smaller tubes at high values of the product of the Grashof aad Prandtl numbers. The temperaiure drop between the inside wall and the isuid at the centerline of the tube deereased from the top to the bottom of the tube. A temperature difference, averaged over the height of the tube, was correlated with the product of the Grashof and Prandtl numbers. This gave a correct value of the average temperature difference for design purposes.

Research Organization:
Univ. of Delaware, Newark
NSA Number:
NSA-16-023824
OSTI ID:
4829720
Journal Information:
Dissertation Abstr., Journal Name: Dissertation Abstr. Vol. Vol: 22
Country of Publication:
Country unknown/Code not available
Language:
English