Numerical and Experimental Study of Turbulent Heat Transfer and Fluid Flow in Longitudinal Fin Arrays

Abstract

Heat transfer from an array of parallel longitudinal fins to a turbulent air stream passing through the interfin spaces has been investigated both analytically/numerically and experimentally. The fins were integrally attached to a heated base plate, while the fin tips were shrouded to avoid leakage. In the analytical/numerical work, a conjugate problem was solved which encompassed turbulent flow and heat transfer in the air stream and heat conduction in the fins and in the base plate. The turbulence model and computational scheme were verified by comparison with experiment. It was found that the local heat transfer coefficients varied along the fins and along the surface of the base plate, with the lowest values in the corners formed by the fin/base plate intersections and the fin/shroud intersections. The numerically determined fin efficiencies did not differ appreciably from those calculated from the conventional pure-conduction fin model. Average Nusselt numbers, evaluated from the experimental data in conjunction with the numerically determined fin efficiencies (for derating the fin surface area), agreed well with those for fully developed heat transfer in a uniformly heated circular tube.

Boiling and Evaporation in Small Diameter Channels

“…The simplest approximation is to model the vertical wall between the channels using a one-dimensional fin approximation and to treat h as if uniform around the channel perimeter at each axial location. As noted by Phillips [12], these approximations have been found by many investigators to work well in predicting measured performance, provided that the fin efficiency is above about 80%; Kadle and Sparrow [13] …”

“…In particular, the necessity of large numbers of small parallel channels suggests that designers consider circular or slot jet arrangements as an alternate to the challenge of accurate flow splitting into multiple parallel channels. 13. Excursive instability will be encountered in parallelchannel micro heat exchangers with subcooled boiling.…”

A computational study of mixed convective heat and mass transfer from a shrouded vertical non-isothermal fin array during dehumidification process

“…Basic assumption involved in those analytical studies is the constant heat and mass transfer coefficient. As shown by Sparrow et al [10], Kadle and Sparrow [16], Sparrow and Kadle [17] heat transfer coefficient varies significantly over the fin height for the case of pure heat transfer. The case of simultaneous heat and mass transfer is not different.…”

The Effects of duct height on heat transfer enhancement of a co-rotating type rectangular finned surface in duct

“…Molki et al [6] experimentally studied the heat transfer at the entrance region of an array of rectangular heated blocks and presented empirical correlations of the heat transfer for the array. Heat transfer from an array of parallel longitudinal fins in a turbulent air stream passing through the inter-fin spaces has been investigated both numerically and experimentally by Kadle and Sparrow [7]. They found that the local heat transfer coefficients varied along the fins and along the surface of the base plate.…”