Heat Transfer in a Rotating Square-Sectioned Channel Fitted With In-Line Ribs

This investigation studies convective heat transfer in a square-sectioned duct that rotates about an axis perpendicular to the central axis of the duct. The leading and trailing sides of the duct are fitted with in-line ribs aligned at 45° to the central axis of the duct. The leading and trailing edges are heated and the two remaining sidewalls of the duct are adiabatic. Air is the coolant used and the direction of flow is in the radial outward direction. The duct simulates the flow and heat transfer that occurs in the passages of cooled turbine rotor blades. The presentation of results is in itself a non-trivial task as the heat transfer is a function of three independent parameters. It is shown how the performance of the section may be expressed in terms of a reduced temperature parameter and that this approach offers additional insight as compared to the conventional Nusselt number approach (which may be obtained by a simple transformation. The investigation has produced a range of experimental data to aid the validation of CFD codes designed to predict heat transfer in this class of rotating duct. Additionally empirical correlations for heat transfer on the leading and trailing edges are proposed that uncouple the individual effects of Coriolis forces and centripetal buoyancy.