Rotation-induced heat transfer in a radial flow passage in a rotating shaft

Experiments have been performed to determine the heat transfer characteristics for rotationinduced flow in a radial passage in a shaft rotating about its own axis. The experiments encompassed passages whose ends were either flush with the surface of the shaft or protruded beyond the surface. For the latter, the passage was either centered in the shaft or else was offset such that the respective ends protruded different distances from the shaft surface. In the main body of experiments, both ends of the passage were open. Supplementary experiments with only one open end and others with an internal blockage were carried out to gain insight into the pattern of fluid flow. When the passage was centered in the shaft, there was negligible fluid throughflow, but even a small offset gave rise to a significant throughflow. For the centered case, the heat transfer coefficient was insensitive to whether the passage did or did not protrude beyond the shaft. Offsetting of the passage provided significant heat transfer enhancement relative to the centered case, and even a slight offset doubled the heat transfer coefficient.