Heat Transfer of a Rotating Rectangular Channel With a Diamond-Shaped Pin-Fin Array at High Rotation Numbers

This experimental study measured the detailed Nusselt numbers (Nu) distributions over two opposite leading and trailing walls of a rotating rectangular channel fitted with a diamond-shaped pin-fin array with radially outward flow for gas turbine rotor blade cooling applications. The combined and isolated effects of Reynolds (Re), rotation (Ro), and buoyancy (Bu) numbers on local and area-averaged Nusselt numbers (Nu and (Nu) over bar) were examined at the test conditions of 5000 <= Re <= 15,000, 0 <= Ro <= 0.6, and 0.0007 <= Bu <= 0.31. The present infrared thermography method enables the generation of full-field Nu scans over the rotating end walls at the realistic engine Ro conditions as the first attempt to reveal the combined rotating buoyancy and Coriolis force effects on heat transfer properties. The selected heat transfer results demonstrate the Coriolis and rotating-buoyancy effects on the heat transfer performances of this rotating channel. Acting by the combined Coriolis and rotating buoyancy effects on the area-averaged heat transfer properties, the rotating leading and trailing area-averaged Nusselt numbers are modified, respectively, to 0.82-1.52 and 1-1.89 times the static channel references. A set of physically consistent empirical (Nu) over bar correlations was generated to permit the assessments of individual and interdependent Re, Ro, and Bu effects on the area-averaged heat transfer properties over leading and trailing end walls.