Thermal Performance of a Radially Rotating Twin Pass Smooth Walled Parallelogram Channel

Abstract

An experimental study was performed to measure the detailed heat transfer distributions, Fanning friction factors (f), and thermal performance factors (TPF) of a radially rotating twinpass parallelogram channel. Laboratory scale full field Nusselt number (Nu) distributions over leading endwall (LeadingE), and trailing endwall (TrailingE) of the rotating channel are measured at the test conditions of 5000 < Re < 20,000, 0 < Ro < 0.3 and 0.028 < خ”دپ/دپ < 0.12. A selection of Nu data illustrates the individual and interactive impacts of Re, Ro, and buoyancy (Bu) numbers on local and areaaveraged heat transfer properties. Without the additional flow complexities induced by the turbulators, the degrees of Bu impacts are significantly amplified from those developed in an enhanced rotating ribbed channel. Relative to the similar rotating square twinpass channel, the heat transfer recovery over the stable wall proceeds at the lower Ro for present rotating parallelogram channel. Accompanying with the improved heat transfer performances from the squarechannel counterparts, the f values are raised. With a set of f correlations generated using the f data collected from the LeadingS and TrailingS at isothermal conditions; the TPF values at various rotating conditions were evaluated. The heat transfer correlations that determine the areaaveraged Nusselt numbers over the inlet and outlet legs and over the turning region are generated. The areaaveraged Nu, f factors, and TPF determined from the present rotating parallelogram channel are compared with those reported for the rotating twinpass channels to determine the comparatively thermal performances of the parallelogram rotating channel for turbine rotor blade cooling.