THE EFFECT OF COOLING CHANNEL CROSSFLOW ON FILM COOLING EFFECTIVENESS AND HEAT TRANSFER COEFFICIENT
This paper presents an experimental investigation into film cooling performance over a flat plate using thermochromic liquid crystals. Film cooling is a method used to cool turbine blades in gas turbine engines. The film cooling air flows through passages inside the blade; it is then exhausted through the film cooling holes onto the blade surface. The influence of the flow Reynolds number in the internal passages (cooling channel) on the heat transfer coefficient and film cooling effectiveness on the external surface (hot gas channel) is investigated for two hot gas channel Reynolds number (Red=6000, Red=20000). Experiments are conducted at constant blowing ratio, pressure ratio and film cooling hole mass flux. Furthermore, the effects of 45° angled ribs introduced into the cooling channel are discussed and compared to previously published literature. The transient liquid crystal method is used to determine the wall surface temperature Tw and a numerical regression method is presented to solve for the two unknowns h (heat transfer coefficient) and η (adiabatic film cooling effectiveness).