06 High Pressure Compressor Design and Testing - …€¦ · High Pressure Compressor : Design and Testing ... Advanced casing treatment Axisymetric casing treatment Casing aspiration

European Workshop on New Aero Engine ConceptsMunich, 30 June – 1 July 2010

High Pressure Compressor : Design and Testing

NEWAC is an Integrated Project Co-funded by the European Commission within the Sixth Framework Programme(2002-2006) under Thematic Priority 4 Aeronautics and Space.

Hanna Reiss, Snecma – Safran Group


Introduction

• High BPR and/or new architectures will require highly loaded, efficient and operable HPC (+20/25% vs. in-service compressor)

• The enhancement of highly loaded HPC is achievable through• Innovative concepts linked to Flow Control• Integrated and optimised design for full benefit

• Aggressive objectives are linked to the Flow Controlled Core concept


2

• Aggressive objectives are linked to the Flow Controlled Core concept• + 2.5% polytropic efficiency• + 15% stall margin• - 1/3 deteriotation loss

• Among the Flow Controlled Core theme, the topic “Tip Flow Control and Advanced Aero” is dedicated to the design and testing of a new HPC, including innovative technologies and high level objectives:• 1.5pt efficiency without SM penalty• Lower in-service deterioration � Lower sensitivity to clearance opening


Partners involved

• SNECMA, Safran Group• Cenaero• ONERA

Tip flow control SNECMA


3

and advanced aero

Selectionof innovativetechnologies

Preliminary studies of innovative

technologies

Identificationof innovativetechnologies

Definitionof the rig testarchitecture

SNECMACENAEROONERA

SNECMACENAEROONERA

SNECMASNECMA

Design of specific parts for the rig test

SNECMACENAERO


Description of the conceptAdvanced casing

treatmentAxisymetric casing

treatmentCasing

aspiration

Baseline: in-house 6 stage high loaded HPC


4

Compressor rig with “Tip FC and advanced aerodynamic ” technologies

Non-axisymetric endwall optimised design for high efficiency

3D aero optimised profiles: R1 to R4, S3S1 & S2 unchanged (low aero benefit and high integration constraint)

R6: clearance sensitivity improvement

stage high loaded HPC“ CLEAN “


HPC Design: Advanced aerodynamic design of the blad es and vanes

Efficiency-oriented approach:• 3D aero optimised profiles; non-axisymetric hubdwall (R1)• Optimised aero design from local to global scale for efficiency benefit:

2ndary effects, profile shape, blade shape, whole compressor matching• Aero adapted to the casing concepts for efficiency improvement and lower sensitivity to clearance opening• Stall margin from casing concepts (R2 to 4) partially converted into efficiency

H = 30%H = 40%


Newac Through-flow velocity

BASELINE NEWAC

Reduced tip clearance influence

New stacking

0

1.3

Isen

trop

ic M

ach

Num

ber

Baseline

H = 30%

Newac

H = 40%——— operating line— - — throttled line

Chord

Reduction of the losses through the

reduction of the isentropic Mach

number peak


HPC Design: Advanced methodology

• Aerodynamic and mechanical optimisation loops process• Front block (4 stages) CFD analysis for matching (@ nominal and open clearances)

Parameters on blade definition

Blade parameters


CFD and post processing

Meshing process

Optimisation process (objectives, constraints, parameters, responses)

Optimised geometry

Baseline

Front block CFD analysis

Dynamic analysisStatic analysisOptimisation loops include aero as well as

mechanical computations


HPC Design: Casing treatments


7

Advanced CTCircumferential groovesSmooth end-wall

Feasibility in ManufacturingAerodynamic analysis and benefits

Advanced CT

• Optimised for max SM and efficiency neutrality, with integration and manufacturing constraints

Axial Velocity at R2 tipInlet Flow (R2)Inlet Flow (R2)

Pre

ssur

e ra

tio(R

2)

3%

3%

Inlet Flow (R2)Inlet Flow (R2)

Pre

ssur

e ra

tio(R

2)

3%

3%

smooth endwall

Advanced Casing Treatment

smooth endwall

Advanced Casing Treatment

Code Name elsA (URANS)

Grid Size 1 Mo

Kind of Grid structured

Turb. Model k-eps

Smooth end-wall Treated end-wall


Performance assessment

• Assessment from CFD on final design in line with the objectives– Efficiency global stack-up & uncertainties : 1.2pt to 1.6pt / Most probable +1.4pt – Additional stall margin expected vs. baseline (from design choices on profile)– Reduced sensitivity to clearance opening from new blading and casing concepts

Clearance openingClearance opening


8

Standard mass flow (kg/s)

Ove

rall

pres

sure

rat

io

Base version Newac (tip gap closed) Newac (tip gap opened)

Newac SM

Clearance opening

Baseline SM

Polytropic efficiency

Ove

rall

pres

sure

rat

io

Base version Newac (tip gap closed) Newac (tip gap opened)

Clearance opening

Prediction

ηηηη + 1.4pt Code Name elsA (RANS)

Grid Size 10 Mo


Turb. Model k-eps


• Full mechanical validation of blades and vanes new design

Mechanical and thermo-mechanical design validation

Code Name SAMCEF

Solver Type Finite element

Grid Size 20000

Kind of Grid Un-structured

Axisymetric endwall 3D endwall


• New casing : thermo-mechanical design validated through 3D analysis• Worst case for temperature gradient identified from 2D analysis: fast deceleration

• 3D mechanical modelling with thermal loading and casing axial loading�� Low circumferential distortion thanks to a specific design (axial flange)

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Max stress @ blade hub Max stress @ disc attachAxisymetric endwall

0 200 400 600 800 1000 1200

Time (sec)

Del

ta w

ithin

lin

er

D R1D R1

Thermal gradient in linersfrom 2D analysis

130s 0,0 20,0 40,0 60,0 80,0 100,0 120,0 140,0 160,0 180,0

Rad

ial d

ispl

acm

ent

RM3-1 RM3-2 RM3-3 RM3-4 RM3-5

Displacement along circumference (in mm )

Rotor 3 @ various axial station

Code Name SAMCEF

Solver Type Finite element

Grid Size 210000

Kind of Grid Un-structured

16°0.005 mm


Manufacturing

IGV R1R2

R3R4 R5 R6

S1S2

S3 S4 S4 OGV

IGV R1R2

R3R4 R5 R6

S1S2

S3 S4 S4 OGV


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New casing manufactured

New technology with removable liners for the implementation of casing concepts and higher flexibility


Instrumentation• Instrumentation optimised in a “crowded” environment

• Performance : pressure & temperature profiles at different planes, static pressure sensors

• Fast response pressure sensors facing each rotor blade

• Mechanical integrity for rotating blades monitored thanks to optical sensors technology on casing (no telemetry)

• Strain gages for stress survey on stator vanes


Instrumentation at casing

• Strain gages for stress survey on stator vanes

• Clearance meters

• Accelerometers


Testing

• Rig-test planBreak-in @

idle / part -speed/ ADP(Low operating line)

Full compressor map0.7Nn to NnIncludes stall

Mapping (No stall)0.7Nn to Nn

Low / nominal / high operating line

Sensitivities studiesat various speed

• Tests successfully performed from 01/12/09 to 25/02/10

• All sequences of the test plan have been explored

• 27 test days, 91 test hours


Compressor rig cross-view

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• 27 test days, 91 test hours

Compressor rig in the bench


HPC rig test: Global performance assessment

Expected improvements

Improvements « as measured » Improvements in New Desig n

Efficiency 1.2 – 1.6 pt 0.9 pt 1.1 pt

Stall margin 0 - +2% No change No change

Clearance opening effects

Significant reduction- No change on effiency

- Significant reduction on SM: - No change on effiency

- Significant reduction on SM:


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opening effectseffect divided by 2 effect divided by 2

• The measured efficiency improvement reached 0.9 pt and an appropriate balance between efficiency and SM was successfully achieved as SM was adjusted to the specified level, in spite of the efficiency gain.

• These results are qualitatively in line with the prediction of an efficiency improvement and quantitatively below the predictions by around 1/3 (prediction based on CFD calculations higher than test results).

• The reduction of the sensitivity to clearance opening on SM will enable to reduce the SM specification and therefore increase the efficiency (� + 0.2pt).


HPC rig test: sensitivity studies

• VSV optimisation

� Complete Design of Experiments on VSV lead to high efficiency improvements:

• Bleed influences

� Investigation of bleed influence on efficiency:

High efficiency improvement potential with optimized VSV

With bleed

Operating Line


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Corrected Speed

Effi

cien

cy im

prov

emen

t

0.4

5.5 3.8

0.05

potential with optimized VSV

Mass flow

Effi

cien

cy

Without bleedEfficiency

improvement with bleed

Operating Line


HPC rig test: R2 advanced casing treatment

• Good behavior of the R2

• Under clearance openings, the characteristics of Stage 2 present the same slope

• High contribution of the technologies implemented on R2 in the reduction of the sensibility to clearance opening

Sta

ge 2

P/P

Closed clearances

Operating Line

Very open clearances


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• For full understanding of the unsteady mechanisms, additional calculations will be lead: unsteady calculation of a stage with advanced casing treatment.

Stage 2 Mass flow

Sta

ge 2

P/P

Open clearances

Line

Operating Line

Operating Line

Closed clearances �� 50h engine

Open clearances �� Deteriorated engine

Very open clearances �� Most deteriorated engine


HPC rig test: R4 casing aspiration

Code Name MSD (ONERA)

Grid Size 0.7 Mo


Turb. Model k-l

• Additional stability to clearance opening � optimised for highest stability on blade row and lowest loss in 2ndary air-system


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Stage 4 tip-flow aspiration instrumentation

• Behavior of R4 casing aspiration consistent with the predictions.

• Measured aspirated mass-flow on stage 4 between 0.54% and 0.63% of compressor mass-flow during all the tests, consistent with a specified aspirated mass-flow ranging from 0.4% to 0.6%.

• No negative impact on the clearances.

Aerothermal simulation - Enthalpy & particle lines from aspiration holes

Principle

Turb. Model k-l


Conclusion & outlook

• Advanced aerodynamic design including:– Innovative technologies and concepts– Advanced methology: optimisation and front block CFD analysis

• Validation through a complete rig test campaign with:– Performance assessment


– Performance assessment– Sensitivity studies

• Results globally consistent with the predictions and very satisfactory:– Efficiency improvement +0.9pt « as measured »– Significant reduction of the clearance opening effect on SM (divided by 2)– Good behavior of the stage 2, including advanced CT and 3D aero profile� 1.1pt of efficiency improvement in a new HPC desing

• Additional unsteady calculations will be lead to provide a better understanding of the advanced casing treatment

Documents

06 High Pressure Compressor Design and Testing - …€¦ · High Pressure Compressor : Design and Testing ... Advanced casing treatment Axisymetric casing treatment Casing aspiration