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Single-Phase Heat Transfer and Pressure Drop Characteristics of an Integral-Spine Fin Within an Annulus.


pdf icon Single-Phase Heat Transfer and Pressure Drop Characteristics of an Integral-Spine Fin Within an Annulus. (766 K)
Kedzierski, M. A.; Kim, M. S.

NISTIR 5454; 33 p. June 1994.

Journal of Enhanced Heat Transfer, Vol. 3, No. 3, 201-210, 1996.

Available from:

National Technical Information Service
Order number: PB94-194073

Keywords:

annulus; enhanced heat transfer; heat transfer; spine-fin; friction; water; ethylene glycol; prandtl number

Abstract:

The laminar, single-phase heat transfer and friction characteristics of a porcupine-like surface (integral-spine-fin) within an annulus are presented. The heat-transfer coefficient was determined using a modified version of the Wilson Plot method on a 3 m test section. Three fluids were investigated: (1) water, (2) 34% ethylene glycol/water mixture, and (3) 40% ethylene glycol/water mixture. These fluids produced a significant variation in the Prandtl number so that its exponential dependence could be determined. The annulus Reynolds numbers were varied from 100 to 1400 to obtain the Reynolds number exponent. An empirical correlation for the Nusselt number that accounts for the development of the thermal boundary layer is presented. An empirical correlation for the fanning friction factor is also provided. It is shown that the spines enhance the heat transfer through additional surface area and fluid mixing.