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COMPRESSOR ROOM CONTROL ROOM
Settling Chamber
Venturi
Turbine Test Section
TEST BAY ROOM
Compressor Cooling System Outdoor Heat Exchanger
Turbine Cooling System Outdoor Chiller
Building Back Wall
Exhaust to Roof
Turbine Secondary Air
Roof Intake
Compressor
By-Pass
PLC
Dynamometer Water System
0
0.1
0.2
0.3
0.4
0.5
0.0% 0.1% 0.2% 0.3% 0.4%
εc
Leakage Mass Flow Rate [% MGP]
Rim seal, 15% pitchRim seal, 40% pitchRim seal, 65% pitchCavity, 4% pitchCavity, 36% pitchCavity, 52% pitchCavity, 88% pitch
Using a Tracer Gas to Measure Turbine Rim Seal Performance Kenneth Clark, Michael Barringer,
Andrew Coward, and Karen Thole
Penn State University
Experimental Approach Gas concentration measurements were made on a true scale, half-span, high pressure turbine vane in the START rig at engine-relevant conditions.
Results
Summary and Conclusion
References [1] PW1000G, pw.utc.com. [2] Glahn, A., and Schmitz, J., 2011, PW Report. [3] Sangan, C. M., Zhou, K., Owen, J. M., Pountney, O. J., Wilson, M., and Lock, G. D., 2011, “Experimental Measurements of Ingestion Through Turbine Rim Seals: Part 1—Externally-Induced Ingress,” ASME Paper No. GT2011-45310. [4] Barringer, M., Coward, A., Clark, K., Thole, K., Schmitz, J., Wagner, J., Alvin, M. A., Burke, P., and Dennis, R., 2014, “Development of a Steady Thermal Aero Research Turbine (START) for Studying Secondary Flow Leakages and Airfoil Heat Transfer,” ASME Paper No. GT2014-25570.
Motivation and Objective
Size of error bars
Vane
0% pitch
100% pitch
Vane
MFG leakage slot
MFG
This document has been publicly released
Secondary air is used for cooling and purging in the hot section of a gas turbine engine to maintain component durability. Using secondary air, which is bleed air from the compressor, results in a parasitic loss in terms of an engine’s thermodynamic cycle efficiency, which means it is critical to sparingly use this resource.
2% increase in efficiency
Glahn & Schmitz, 2011.
Main gas path / Hot core flow
Stator Rotor Rim seal
Rim cavity
PW1000G pw.utc.com
70-75%
25-30%
Of specific interest to this research are the rim seals between the stationary vanes and rotating blades and the gaps between adjoining airfoils. The rim seals are intended to reduce the needed secondary air that prevents hot core flow from entering uncooled cavities below the rim seal.
Airfoil cooling
Purge
Mate face gap leakage
Leakage through disk
Sangan, et. al., 2011
Fuel burn
Secondary Air
13%
5%
Current
Goal
1.E+04
1.E+05
1.E+06
1.E+05 1.E+06 1.E+07
PSU STARTGE HGIRSussexRWTH: AachenASU 1ASU 2BathPurdue: LSRTND - ART
Blade Inlet Reynolds Number,
𝐑𝐞𝐱 =
𝛒∞𝐔𝐱𝐂𝐱
𝛍∞
Rotational Reynolds Number,
𝐑𝐞𝛟 =𝛒𝛀𝐑𝟐
𝛍 𝐇𝐮𝐛,𝐏𝐮𝐫𝐠𝐞
NASA W6
Barringer, et. al., 2014
The data acquired through these experiments will be used to develop new models to better predict rim seal performance for engine hardware at engine-relevant conditions. The models will be used to design better rim seals in next generation gas turbines, which will result in a reduction in secondary air, fuel burn, and emissions.
𝜺𝒄 =𝝌 − 𝝌∞
𝝌𝒔𝒖𝒑𝒑𝒍𝒚 − 𝝌∞
Concentration Effectiveness:
Gas analyzer, 𝝌 Sampling System
Molecular ≈ Thermal diffusion
0.0
0.1
0.2
0.3
0.4
0.5
0.01 0.1 1 10
εc
Sampling flow rate [SLPM]
Rim seal, 15% pitchRim seal, 40% pitchCavity, 88% pitchAft of cavityMiddle of cavity
Seeding the secondary air with CO2 and sampling in the test section at isokinetic conditions results in concentration effectiveness in the rim seals and cavities.
Isokinetic sampling
Sampling Flow Rate Sensitivity
Map of Relevant Turbine Test Facilities
MFG
𝝌𝒔𝒖𝒑𝒑𝒍𝒚
=1%
𝝌∞=0.04% CO2
MGP
MFG
Purge
CO2
Compressor
Settling Chamber
Turbine Test Section
Concentration effectiveness in the rim seal is significantly higher closer to the MFG leakage slot, and decreases as it mixes with ingested core flow. Deeper in the cavity the effectiveness is uniform circumferentially, indicating the MFG leakage flow has completely mixed with the ingested core flow.