On Heat Transfer by Superimposition of a Creeping Flow of a Fluid with its Stationary Free Convection

Summary

Under special circumstances heat energy has to be transferred from a bundle of parallelly arranged finned cylindrical pipes to a fluid coolant, which can be moved only in a creeping flow between the heated pipes in the direction of the cylinder axes.

The experimental and theoretical results presented here demonstrate that, by stationary heat transfer and an increasing mass flow of coolant, the effective mean temperature difference at first weakly increases behind a characteristic minimum, then reaches a pronounced maximum and finally decreases asymptotically towards zero in a high coolant mass flow. This behaviour offers the possibility of transferring large rates of heat with small amounts of coolant, an application which has, for example, increasingly interesting ecological aspects.