| This dissertation presents a comprehensive experimental investigation of the effects of V-shaped ribs on the heat transfer enhancement and the increased pressure drop for turbulent air flow in a square channel. The test section, with V-shaped rib arrays on two opposite walls, models roughened coolant flow passages in modern gas turbine blades. First, heat transfer experiments are conducted with rib angles-of-attack of 45;Naphthalene sublimation technique is employed to determine the detailed distributions of the local mass transfer coefficient on the ribbed walls and the smooth walls. By applying the analogy between heat transfer and mass transfer, the local distributions identify the regions of high and low heat transfer on the channel walls. Oblique ribs cause significant spanwise variations of the local mass transfer coefficient on the exposed surfaces of the ribbed walls, as a result of secondary flows. In the 60... |
