An Experimental Study of Film Cooling in a Rotating Transonic Turbine

• Published in: Journal of Turbomachinery; (United States) 1994-01, Vol.116 (1), p.63-70
• Main Authors: Abhari, R. S., Epstein, A. H.
• Format: Article
• Language: English
• Subjects: 20 FOSSIL-FUELED POWER PLANTS; Applied sciences; CALCULATION METHODS; Continuous cycle engines: steam and gas turbines, jet engines; COOLING; ENGINES; Engines and turbines; Exact sciences and technology; FILM COOLING; GAS TURBINE ENGINES; HEAT ENGINES; HEAT FLUX; INTERNAL COMBUSTION ENGINES 200104 > Fossil-Fueled Power Plants-- Components; MATHEMATICAL MODELS; Mechanical engineering. Machine design; TURBINE BLADES
• ISSN: 0889-504X; 1528-8900
• DOI: 10.1115/1.2928279

Time-resolved measurements of heat transfer on a fully cooled transonic turbine stage have been taken in a short duration turbine test facility, which simulates full engine nondimensional conditions. The time average of this data is compared to uncooled rotor data and cooled linear cascade measurements made on the same profile. The film cooling reduces the time-averaged heat transfer compared to the uncooled rotor on the blade suction surface by as much as 60 percent, but has relatively little effect on the pressure surface. The suction surface rotor heat transfer is lower than that measured in the cascade. The results are similar over the central 3/4 of the span, implying that the flow here is mainly two dimensional. The film cooling is shown to be much less effective at high blowing ratios than at low ones. Time-resolved measurements reveal that the cooling, when effective, both reduced the dc level of heat transfer and changed the shape of the unsteady waveform. Unsteady blowing is shown to be a principal driver of film cooling fluctuations, and a linear model is shown to do a good job in predicting the unsteady heat transfer. The unsteadiness results in a 12 percent decrease in heat transfer on the suction surface and a 5 percent increase on the pressure surface.