Performance Measurement In A Transient Turbine Test .

Performance Measurement in a Transient Turbine Test Facility –Preliminary Instrumentation DevelopmentNick Atkins – Oxford Rotor GroupRoger Ainsworth – Oxford Rotor GroupThe 16th Symposium on Measuring Techniques in Transonic andSupersonic Flow in Cascades and Turbomachines, Cambridge24th September 2002Oxford Rotor Group – Nick Atkins

Structure Introduction– Transient performance testing?– Overview Mass Flow Rate Measurement––––Blowdown CalibrationResults of Preliminary TestingUncertainty AnalysisInstrumentation Design Conclusions/Future WorkOxford Rotor Group – Nick Atkins

Introduction The aims:– To help improve the aerodynamicperformance/efficiencyof future turbine designs!– To help the solution of design issuessuch as tip burn. The background:– Traditional design methods give performance predictions in the region of 2%uncertainty. Full scale steady flow rig testing is needed.– This cycle of empirical design methods and full scale rig testing is an expensiveand lengthy process. The effects of novel geometry changes are very hard topredict. This makes the implementation of design changes a potential risky andcostly process.– Steady flow rigs can’t measure heat transfer at the same time as aerodynamicperformance.Oxford Rotor Group – Nick Atkins

Transient performance testing? Advantages– The performance gains/penalties associated with design changes motivated byheat transfer can be examined.– Efficiency testing in the ORF will provide a link between the wealth of data onthe structure of the loss mechanisms and flow phenomena, and their actualquantitative effect on the overall performance of the turbine stage.– It has the potential to reduce uncertainty in the prediction of the performance ofnew designs to somewhere in the region of 0.25% to 0.5%, at a much earlierstage in the design process.– Transient testing is estimated to be about a fortieth of the cost of traditional fullscale rig testsOxford Rotor Group – Nick Atkins

Performance measurement overview&WmCT1P & γ1isentropcWOxford Rotor Group – Nick Atkins

Mass flow rate measurement - 1 Blowdown Calibration TheoryOxford Rotor Group – Nick Atkins

Mass flow rate measurement - 11V d p &tube tube tube mR dt Ttube 1 P γ 2 & plane Acal p 0 1 m Ts p γ 1planeAcal Preliminary TestingVtube d ptube R dt Ttube 1p Ts1 P γ 2 0 1 p γ 1planeOxford Rotor Group – Nick Atkins

Mass flow rate measurement - 2 0.06% variation run to runQ263 Through flow results, mass flow 29.2 kg, specific mass flow 7.2x10 -4Oxford Rotor Group – Nick Atkins

Mass flow rate measurement - 3m& true Uncertainty Analysis 1m& Ac a l p T s1γ 1 2P0 γ DESCRIPTION 1 p Calibration constant m& *C* C Acal 1* m&planeCOEFFICIENTS95m&m& true1Stage inlet total122CT 22 2 SP S 2 S S m&S % C Acal Acaltemperature CP01 01 C p p CT T &mAcal P01 p T (? 1) P01 ? Measurement plane DESCRIPTIONCOEFFICIENT1 (? 1) p 1 (? 1)1 C 1 1 pC static1meanpressure(? 1)Calibration constant2 ? 2 ?M 2 ? P 01 1Stage inlet total during a 1 C test run p 2 temperatureAcalT(? 1) P01 ? 1 (? 1) p 1 (? 1)1Cp 1 1 mean static pressure(? 1)2 ? 2 ?M 2 ? P01 1 during a test run Measurement plane p (? 1) P01 ? 1 (? 1)1 (? 1) p 1 C P01(? 1)total pressure during( )a 2 ? ?M 2 2 ? P ? P Measurement plane 1 (? 1) 01 1 (? 1) p 1 1 testC run p ( )total pressure during a2 ? 2? ?M P Measurement plane01P01test ru n 01 p ? 1? 1?2 1 Oxford Rotor Group – Nick Atkins

Mass flow rate measurement - 3m& true Uncertainty Analysis 1m& Ac a l p T s1γ 1 2P0 γ 1 p C* m& * * m&S95m&m& trueplane1222 S P01 S p ST 2 2S m&S Acal % C Acal C C C&mAcal P01 P01 p p T T DESCRIPTIONCalibration constantStage inlet totalCOEFFICIENTC Acal 1CT temperatureMeasurement planemean static pressureduring a test run(? 1) P01 ? 1 (? 1) p 1 (? 1)1Cp 1 1 (? 1)2 ? 2 ?M 2 ? P01 1 p Measurement planetotal pressure during atest ru n12C P01(? 1) P01 ? 1 (? 1)1 (? 1) p 1 (? 1)2 ? 2 ?M 2 ? P 01 1 p Oxford Rotor Group – Nick Atkins

Instrumentation Design1.200.960.75Four instrumented NGV’s spaced around the annulusaxEffect of Exit Mach No. on Mid height Mach No. distribution–PS static tapping at 90% of CMid Height Mach No. Distribution, compared to prediction(Nicholson, 1981) 2-D Linear Cascade(Sheard, 1989) Current NGV’s–SS static tapping at 30% Cax–Total tapping on aerodynamic LEOxford Rotor Group – Nick Atkins

Instrumentation Design Tube instrumentation– 5m long rake positioned in the centre ofthe piston tube. 6 static pressure tappings. Absolute anddifferential sensors, both calibratedto Druck DPI 515. 8 thermocouples. Aspirated to ensurethe have suitable time constant andcalibrated to approximately 0.1ºC.Oxford Rotor Group – Nick Atkins

Conclusions-Future Work Prototype systems have been designed, and thoroughly testedin preparation for the measurement of:––––Rotor speed and acceleration.Mass flow rateInlet flow conditionsAutomated pressure and temperature calibration systems The results of the preliminary testing indicates that performancetesting with a relative resolution in the region of 0.25% will bepossible in the Oxford Rotor Facility. Final testing with the full instrumentation. Geometry changes. Acknowledgements: Rolls Royce PLCOxford Rotor Group – Nick Atkins

PhotosPosition of experimental inlet traverse planeOxford Rotor Group – Nick Atkins

PhotosOxford Rotor Group – Nick Atkins

to Druck DPI 515. 8 thermocouples. Aspirated to ensure the have suitable time constant and calibrated to approximately 0.1ºC. Oxford Rotor Group – Nick Atkins Prototype systems have been designed, and thoroughly tested in preparation for the measurement of: