Heat transfer enhancement in a converging passage using film cooling holes and combination of ribs with holes

An investigation has been carried out to measure heat transfer coefficients in a blade midchord convergent cooling passage. Tests were performed with a single film cooling hole, multiple holes, and combination of ribs with holes located in one of the passage walls. Thermochromic liquid crystals were used as high resolution surface temperature indicators to provide detailed distributions of internal heat transfer coefficients. The data is presented as contours of heat transfer enhancement factors. Surface shear visualization was performed using cholesteric liquid crystals.