Heat Transfer Due to Unsteady Effects as Investigated in a High-Speed, Full-Scale, Fully-Cooled Turbine Vane and Rotor Stage

摘要

Experiments were conducted to examine the effects of film cooling on a gas turbine engine's high-pressure turbine section. The focus for this effort was in the tip/shroud region of a rotor stage and a high pressure turbine vane. A primary goal was to understand the unsteady flow effects. Attempts were also made to characterize the effects as caused by the fully-cooled rotor stage. Data for this investigation was taken at the U.S. Air Force's Turbine Research Facility (TRF), a transient blow-down facility with instrumentation fitted to fill-scale, high-speed, full-cooled cane and rotor stage of proprietary design. Measurements of pressure, temperature, and heat flux were taken at flow conditions non-dimensionally matched to actual engine operation. From this high speed data the relevant film-cooling parameters (heat transfer coefficients, film cooling effectiveness, and overall effectiveness) were determined over a range of operating conditions. Of specific interest were the high frequency events associated with the blade passage frequency on both the vane and shroud surfaces. It was found that tip flow and vane wake rotor interaction result in noticeable heat flux variations in time.