Air cooling of a finned cylinder with slot jets of different height

This work presents new experimental results in the cooling of an externally finned cylinder with a submerged slot jet of air. Two slots are employed with D/H equal to 2 and 4, where D is the diameter of the cylinder without fins and H the slot height. Local and mean Nusselt numbers are evaluated at several Reynolds numbers and distances from the slot exit. Empirical expressions are proposed to correlate the experimental mean Nusselt numbers and the convective heat transfer coefficients. The two slots are compared also according to the concept of efficiency, which takes into account the cooling rate and the mechanical power necessary to drive the flow.