CAV2010 DLR Meyer Enghardt V1 · Jet Noise Active Noise Control 7 Researcher U. Tapken/ H. Siller...

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CAVCAV--Workshop 2010Workshop 2010

DLR DLR –– German Aerospace Research Center German Aerospace Research Center

Aeronautics Space Space Agency Transport Energy

Institute of Propulsion TechnologyInstitute of Propulsion TechnologyEngine Acoustics Division (Berlin)Engine Acoustics Division (Berlin)

Robert Meyer, Lars Enghardt

Hot-wire measurements of a Counter Rotating Turbo Fan (CRTF)

2/19

• DLR and the Department of Engine acoustics

• Hot-wire measurements in Counter Rotating Turbo Fan Rig (CRTF)

OutlineOutline

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DLR DLR –– Sites and EmployeesSites and Employees

� Köln -Porz

� Lampoldshausen

� Stuttgart

� Oberpfaffenhofen

Braunschweig �

� Göttingen

Berlin- - �Adlershof

� Bonn

Trauen �

� Hamburg

� Neustrelitz

Weilheim �

Berlin-Charlottenburg �

� Sankt Augustin

� Darmstadt

Bremen �

Engine AcousticsDivision

6.500 employees working in 29 research institutes and facilities

�� at 9 sites

�� in 7 field offices.

Offices in Brussels, Paris and Washington.

Sites of the Institute of Propulsion Technologies

4/19

MissionMission

DLR Institute of Propulsion Technology

� Increase in efficiency(resource management and reduction of operational costs)

� Minimization of environmental impact(pollutant and noise emission)

� Acceleration of product development cycles

Rolls-Royce TRENT 500 Siemens Power Generation V94.3A

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Organization of the Institute

Institut für AntriebstechnikProf. Dr.-Ing. Reinhard Mönig

Komponenten Querschnittsfunktionen

Fan und VerdichterDr.-Ing. Eberhard Nicke


BrennkammerDr.-Ing. Christoph Hassa


TurbineDr.-Ing. Peter-Anton Gieß (komm.)


BrennkammertestDipl.-Ing. Christian Fleing


TriebwerksakustikDr.-Ing. Lars Enghardt (komm.)


TriebwerksmesstechnikDr.-Ing. Christian Willert


Numerische MethodenDr.-Ing. Dirk Nürnberger


TriebwerkDr.-Ing. Andreas Döpelheuer


Zentrum für Verbrennungstechnik

Institute of Propulsion Technology (AT)Prof. Dr.-Ing. Reinhard Mönig

Components Cross-sectional tasks


Fan and CompressorDr.-Ing. Eberhard Nicke


CombustorDr.-Ing. Christoph Hassa


TurbineProf. Dr.-Ing. Ingo Röhle


Combustor TestDipl.-Ing. Christian Fleing


Engine AcousticsProf. Dr. rer. nat. Lars Enghardt


Engine Measurement SystemDr.-Ing. Christian Willert


Numerical Methods


EngineDr.-Ing. Andreas Döpelheuer

Center for Combustor Technology

Dr.-Ing. Edmund Kügeler

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Main Work Topics/ Structure of the Department of Engine Acoustics in Berlin

Infrastructure, Consulting: 8 Employees Overall: 29 Employees

TurbomaschineryAcoustics

Acoustic Data- and Mode analysis

Source localisation

Indoor-, Inflight- und Flyover-Measurements

Jet Noise

Active Noise Control

7 Researcher

U. Tapken/ H. Siller

Lead: Lars Enghardt

Combustion Noise

Combustor sound fields

Optical measurement technique

Entropie- and vortex noise

Liner (hot and cold)

Combustor instabilities

6 Researcher

F. Bake

Active/Passive Flow Control

Turbulence research

Hot wire measurements

Secondary flows

Drag reduction

Efficiency improvements

Compressor flows

3 ResearcherR. Meyer

Numerics/ Modelling

Numerical Acoustic and Software Development (CAA)

Source modellingand directivity

Design to noise

5 Researcher

S. Guerin

• Located on campus of the Technical University of Berlin (TU-Berlin) since 1956,• Staff: 29 (22 Scientists) plus students• More than 50% of personal supported by external funding• Very close cooperation with the

Institute of Fluid Mechanics and Technical Acoustics of TU-Berlin

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Main Strategic DirectionDepartment of Engine Acoustics

� Important role (acoustic competence) in the development of system competence for aero-engines and gas turbines

� Support of research and development activities in turbo-machine acoustic with TRACE

� Cooperation with nacelle aerodynamics to predict and consider acousticalintegration effects (system competence)

� Enhanced integration of research and development activities with other DLR-Institutes (especially Aerodynamics and Flow Technology and Atmospheric Physics)

� Strategic alliances with national and international universities

� Strategic alliances with selected industrial partners and enhanced cooperation with respect to Design-to-Noise in industrial R&D programs

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• Collaborative research Project VITAL “Environmentally Friendly Aero Engines“; 53 Partners gathering all major European engine manufacturersand national research institutes.

• Aim: Reduction of Aircraft noise and CO2 emission• The aero-acoustic performance of three fan module c oncepts was tested in

sub project 2 (Direct Driven Turbo Fan, Geared Turbo Fan and the Counter Rotating Turbo FAN)

• DLR Project Task: Measurements of the unsteady flow field at the inter-stage section of a Counter Rotating Turbo Fan (CRTF) of a fast rotating compressors.

• Two fans rotating in opposite directions, allowing even lower rotation speeds, since the two fans split the loads involved.

• Hot-wire test have been performed on high speed 1/4-scale CRTF model

European Community research program VITAL

9/19

• Main challenging aspects:– 3D velocity field– Unsteady flow structures– Highly fluctuating velocities

(periodic & stochastic fluctuations)

• Benefit:– Verification of the successful design

of new compressor concepts.

– Validation of the numeric flow calculation code (CFD) andnumerical acoustic simulation (CAA)

– Database for the numerical acousticsto improve the models for coupling acoustics and aerodynamics(modeling & prediction group)

Hot-wire measurements of a Counter Rotating Turbo Fan (CRTF)

0 50 100 150 200 250 300 35085

90

95

100

105

110

115

120

125

Rotorumfangsposition [°]

Ges

chw

indi

gkei

t [m

/s]

resampelte machinenkoordinaten54per_3probe_081113_7_U21

time signal

mean average

Fan 1Fan 2

HW 1 HW 2+3 HW 4

u

v

w

Hot-wires

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→ E² =A+B*Un with n≈0.5

Sensor wires: ● platinum-plated tungsten

wires with a diameter of d = 9-12 µµµµm

● wire lengths l =2.4 mm● wire heated during operation

to constant temperature (resistance).

● overheat factor: = 1.8(∆T ≅ 210 K).

● frequency range: f = 0 - 20 kHz.

Velocity U

Current I

Sensor (thin wire)

Sensor dimensions:length ~1 mmdiameter ~5 micrometer

Wire supports (St.St. needles)

Electric current

Principles of the hot-wire technique

Flow velocity U cooling

Wire voltage E

wire temperaturewire

electric resistance

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2X-probecorrelation

Calculation of effective velocities

Analysis procedures

Calibration Phased locked averaging

Rotor trigger interpretation

Analysis:• Mean velocities (phase averaged)• Turbulence levels• Spectra Analysis

Measured raw data

???? ? ?

0 50 100 150 200 250 300 35085

90

95

100

105

110

115

120

125

Rotorumfangspos ition [°]

Ges

chw

indi

gkei

t [m

/s]

resampelte machinenkoordinaten54per_3probe_081113_7_U21

time signal

mean average

Flow field:•3D velocity field•Highly fluctuating velocities

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Methods of analysis Calculation of mean and fluctuating velocities

0 50 100 150 200 250 300 35085

90

95

100

105

110

115

120

125


Ges

chw

indi

gkei

t [m

/s]

0 50 100 150 200 250 300 35085

90

95

100

105

110

115

120

125


Ge

sch

win

digk

eit

[m/s

]

Phase-locked averaging(PLA) technique

� Statistical averaging locked on rotor rotations

Methods of analysis:

rotation 1 rotation 2

U(t

) in

[m/s

]

Velocity U(t)

Trigger pulses(1 per ref.))(')()( tutUtU +=

Mean velocity

Fluctuating velocity

Instantaneous velocity

)(tU

Instantaneousvelocity

Mean average

)(tU

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Time averaged circumferential position

DU

/Uci

rc

0.29

0

0.58

0.87Axial U-componentbehind rotor 2

Axial U-componentbehind rotor 1

Radial V-componentbehind rotor 1

Circumferential W-componentbehind rotor 1

Circumferential W-componentbehind rotor 2

Phase locked averaged velocities

HW 1 HW 2+3 HW 4

u

v

wCRTF 1 Results: 54% rotor speed

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0 45 90 135 180 225 270 315 360

Turbulenzgrad--Nominal_54per_3probe_081113_7.bin

Sonde A10 UV

Sonde B06 UWSonde B08 UW

Methods of analysisTurbulence levels

)(

)''(

2

122

22

uwWU

wuTu

+

+⋅=

)(

)''(

2

122

22

uv VU

vuTu

++⋅=

Tuuwbehind Rotor 2

Tuuwbehind Rotor 1

Tuuvbehind Rotor 1

HW 2+3 HW 4

u

v

w

Tur

bule

nce

leve

ls

time

CRTF 1 Results: 54% rotor speed

)(

)''(

2

122

22

uwWU

wuTu

+

+⋅=

∆3%

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Methods of analysis Spectral Analysis:

Probe position: Axial: between two Rotors, Radial: 10 mm from outer casingSpectrum is influenced by wall boundary layer

Probe position: Axial: between two Rotors, Radial: 86 mm from outer casingSpectrum is influenced by core flow

Power spectral density Power spectral density

HW 2

u

v

w

HW 2

u

v

w

frequencyfrequency


1. B

PFR

1

1. BPFR2probe vibration

10. B

PFR

1

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Flow between rotor 1 and rotor 2Axial mean flow velocity U

U component correlated with rotor 1

U component correlated with rotor 2 - Upstream influence

HW 2+3

u

v

w


DU

/U

cir

c= 0

.145

DU

/U

circ=0

.014

5

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Radial flow velocity V

Flow between rotor 1 and rotor 2 Radial (V) and circumferential (W) velocity (correlated with rotor 1)

Circumferential velocity W

∆W

/U_c

irc=0

182

HW 2+3

u

v

w


DV

/Ucir

c =

0.0

72

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• In the counter rotating turbo fan hot-wire probes were placed in front of the first rotor, between both rotors and behind the second rotor. The measurements were conducted at three operating conditions ofthe compressor fan stage, relevant to noise issues (approach, takeoff/sideline and takeoff/cutback).

• With the DLR hot-wire measuring technique, unsteady flow structures of fast rotating compressors (e.g. the wake of each individual rotor blade) can be measured and analyzed in detail. The averaged mean vectors as well as the fluctuation components of the velocity are determined, which allows the local turbulencedistribution of the flow behind the rotating blades to be calculated.

• These hotwire data results verify on the one hand the successful design of the new compressor concepts and offer on the other hand valuable information for the validation of the numerical flow-calculation code (CFD) to be applied.

• In addition, the results deliver a valuable data base for the development and future use of numerical acoustic simulation (CAA) tools, in particular to improve models for coupling acoustics and aerodynamics. In future, this will enable an improved noise and efficiency prediction already in the early stage of the fan modules design process.

SummarySummary

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Thank you for your attentionThank you for your attention

Questions …?Questions …?

E-mail: [email protected] to the project will be published on the ASM E-Conference 2010

Paper: GT2010-22569

The project is supported by the European Community within the Research Program “Environmentally Friendly Aero Engines (VITAL)“

CAV2010 DLR Meyer Enghardt V1 · Jet Noise Active Noise Control 7 Researcher U. Tapken/ H. Siller...

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