Driven by the need for higher cycle efficiencies, overall pressure ratios for gas turbine engines continue to be pushed higher thereby resulting in increasing gas temperatures. Secondary air, bled from the compressor, is used to cool turbine components and seal the cavities between stages from the hot main gas path. This paper compares a range of purge flows and two different purge hole configurations for introducing the purge flow into the rim cavities. In addition, the mate face gap leakage between vanes is investigated. For this particular study, stationary vanes at engine-relevant Mach and Reynolds numbers were used with a static rim seal and rim cavity to remove rotational effects and isolate gas path effects. Sealing effectiveness measurements, deduced from the use of CO2 as a flow tracer, indicate that the effectiveness levels on the stator and rotor side of the cavity depend on the mass and momentum flux ratios of the purge jets relative to the swirl velocity. For a given purge flow rate, fewer purge holes resulted in better sealing than the case with a larger number of holes.
Effects of Purge Jet Momentum on Sealing Effectiveness
Contributed by the Heat Transfer Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received July 6, 2016; final manuscript received July 22, 2016; published online October 4, 2016. Editor: David Wisler.
Clark, K., Barringer, M., Thole, K., Clum, C., Hiester, P., Memory, C., and Robak, C. (October 4, 2016). "Effects of Purge Jet Momentum on Sealing Effectiveness." ASME. J. Eng. Gas Turbines Power. March 2017; 139(3): 031904. https://doi.org/10.1115/1.4034545
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