EFFECTS OF V-SHAPED RIB ARRAYS ON TURBULENT HEAT-TRANSFER AND FRICTION OF FULLY-DEVELOPED FLOW IN A SQUARE CHANNEL

This study examines turbulent heat transfer and friction characteristics of fully developed flow of air in a square channel in which two opposite walls are roughened with aligned arrays of V-shaped ribs. The rib-roughened channel models the internal cooling passages in modern gas turbine airfoils. The angles-of-attack of the V-shaped rib arrays are 45-degrees, 60-degrees, 90-degrees (same as 90-degrees full ribs), 120-degrees, and 135-degrees. The 60-degrees V-shaped ribs with p/e = 10 have the highest ribbed wall heat transfer and smooth wall heat transfer for a given air flow rate, and the highest channel heat transfer per unit pumping power. They are recommended for internal turbine airfoil cooling, replacing 45-degrees or 60-degrees full ribs.