Heat Transfer From Rods or Fins Which Extend Radially Outward From a Rotating Shaft

Abstract

The heat transfer characteristics of spokelike rods that extend outward from a rotating shaft have been determined experimentally. The experiments encompassed a number of geometrical parameters, including the length and diameter of the rods, the number of rods deployed around the circumference of the shaft, and the distance between the rods and the free end of the shaft. Also varied during the experiments was the rotational Reynolds number. Per-rod Nusselt numbers were evaluated from the experimental data. By incorporating the rod dimensions in the definition of the characteristic velocity that appears in the Reynolds number, a universal Nusselt–Reynolds–Prandtl correlation was obtained which is independent of the dimension ratios of the problem. It was also found that the Nusselt number results are independent of the number of rods in the circumferential array and are very weakly dependent on the distance from the rods to the free end of the shaft. The final correlation is conveyed by equations (18) and (19), with the Reynolds number defined by equations (7) and (10).