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.