This paper investigates the variation of heat transfer coefficient and adiabatic wall effectiveness downstream of film cooling slots with forward and backward facing steps. The application of this research is the effect of secondary gas leakage throughgaps between misaligned gas-turbine engine components. Such leakage affects the temperature distribution within these components, ultimately influencing the thermal stresses which govern the lifetime of the engine.The experimental apparatus provides both mainstream and coolant flow at carefully regulated temperatures. The surface temperature of the perspex test section is monitored by an infra-red camera during a transient experiment. The camera captures a sequence of images which provides a surface-temperature history at all visible locations on the wetted surface. The local heat flux can then be obtained using the one-dimensional heat equation and Duhamel's method, which leads to measurements of heat transfercoefficient and film cooling effectiveness. Parameters such as coolant blowing rate and step size are varied in the experimental programme.
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