Effects of Shock Wave Passage on Heat Transfer in a Transonic Turbine Cascade Free

Results from a new facility for measuring heat transfer in transonic turbine cascades are repotted. An air heater has been built into the blow-down wind tunnel to heat the main flow for a 20 second run time. This allows control of the direction and magnitude of the heat transfer into the blade throughout the tests. A Heat Flux Microsensor was inserted into the blade to measure simultaneous surface heat flux and temperature. Measurements were made on the suction surface of the blades toward the trailing edge. Because of the long run times (20 s), the adiabatic wall temperature could be determined directly from the measured surface temperature and heat flux. Simultaneous pressure measurements were made with a Kulite transducer at the same distance from the leading edge to document shock passage. A separate shock tube was used to generate a shock wave which was introduced into the test section in front of the cascade. This shock was carried over the blade by the main flow. The resulting changes in heat flux correlated strongly with the unsteady pressure changes. An overall increase of 1.5 W/cm² in heat flux was recorded for a pressure increase of 7 kPa during the initial passage of the shock.