HEAT-TRANSFER ENHANCEMENT WITHIN A TURBINE BLADE COOLING PASSAGE USING RIBS AND COMBINATIONS OF RIBS WITH FILM-COOLING HOLES

A transient heat transfer method using liquid crystals has been applie d to a scale model of a turbine rotor blade passage. Detailed contours of local heat transfer coefficient are presented for the passage in w hich the heat transfer to one wall was enhanced first by ribs and then with ribs combined with holes. The hole geometry and experimental dim ensionless flow rates were representative of those occurring at the en trance to engine film cooling holes. The results for the ribbed passag e are compared to established correlations for developed flow. Qualita tive surface shear stress distributions were determined with liquid cr ystals. The complex distributions of hear transfer coefficient are dis cussed in light of the interpreted flow field.