Attività sperimentale e numerica per lo sviluppo di turbomacchine … · University of Genova...

University of Genova

Aerodynamics and Turbomachinery Laboratory

15 Luglio, Giornata di studio sulle Turbomacchine, Bergamo Daniele Simoni

Attività sperimentale e numerica per lo sviluppo di

turbomacchine ad elevate prestazioni

Daniele Simoni

Dipartimento di Ingegneria Meccanica, Energetica, Gestionale e dei Trasporti




• Turbomachinery research group

• Participation at EU and National (PRIN) Research Projects

• Facilities, measuring and post-processing techniques

• Turbomachinery components design

• Recent Relevant Publications

Content




Research Group - Pietro Zunino - Professor of Fluid Machines and Turbomachinery - Marina Ubaldi - Professor of Gas Dynamics and Combustion - Giovanni Tanda - Professor of Applied Physics and Heat Transfer

- Andrea Cattanei – Associate Professor of Aeroacoustics and Fluid Machines - Daniele Simoni - Associate Professor of Aircraft Engines, Turbomachinery Design and Experimental Techniques for Fluid Machines - Francesca Satta - Associate Professor of Aeronautical Propulsion and Fluid Machines - Edward Canepa - Assistant Professor of Fluid Machines - Davide Lengani – Assistant Professor of Measuring Techniques for Aerodynamic Applications - Andrea Ghiglione Ph. D., Researcher, Facilities design and manufacturing expert -Carlo Costa, Dario Barsi, Gianluca Ricci Ph. D., Researcher, experts in modeling and optimization

- Roberto Guida - Ph. D. Student - Daniele Infantino - Ph. D. Student - Matteo Dellacasagrande - Ph. D. Student - Luca Baggetta - Ph. D. Student




Participation at EU Research Projects BRITE EURAM, "Time varying wake flow characteristics behind flat plates and turbine cascades". BRITE EURAM, TURMUNSFLAT "Turbulence modelling for unsteady flows in axial turbines”. BRITE EURAM, TRANSPRETURB "Implementation and further applications of refined transition prediction methods for turbomachinery and other aerodynamics flows". FP5, ICLEAC “Instability Control of Low Emission Aero-Engine Combustors”. FP6, AIDA "Aggressive Intermediate Duct Aerodynamics for Competitive and Environmentally Friendly Jet Engines". FP6, MUSCLES "Modelling of UnSteady Combustion in Low Emission Systems”. FP6, AITEB2 “Aerothermal Investigations on Turbine Endwalls and Blades”. FP6, TLC “Towards Lean Combustion”. FP6, VITAL, Large-scale integrating project (IP), “EnVIronmenTALly Friendly Aero Engine”. FP6, TATMo “Turbulence and Transition Modelling for Special Turbomachinery Applications”. FP7, TECC-AE “Technologies Enhancement for Clean Combustion in Aero-engines”. FP7, Large-scale integrating project (IP), E-BREAK “Engine Breakthrough Components and Subsystems “ FP7, CleanSky, I-TURB “Optimal High-Lift Turbine Blade Aero-Mechanical Design”




Facilities

• Wind Tunnel for Investigations of Ducts and Airfoils

• Wind Tunnels for Detailed Cascade Investigations • Single stage large scale Axial Research Turbine

• Two-Stage Axial Research Turbine

• Centrifugal Compressor Test Rig

• Semi-anechoic chamber

• Test rig for gas turbine secondary air systems and seal cavities investigations

• Wind Tunnels for Aerodynamic Investigations of Low-Emission Injection-Systems for

Aeroengine Applications • Combustion test rig




Measuring and post-processing techniques available in the Lab

Measurements thecniques • Directional miniature pressure probes, fast response miniature pressure transducers • 2-D and 3-D Hot-Wire and Multisensor Hot-Film Anemometry (HWA) • 2-D and 3-D Laser Doppler Velocimetry (LDV) • 2-D Phase Doppler Anemometer (PDA) • Particle Image Velocimetry, 3D Stereo-PIV • Time-Resolved Particle Image Velocimetry (TR-PIV, 5000 Hz) • Non intrusive techniques for high speed flows and combustion (Schlieren, Holographic

Interferometry, Planar Mie Scattering Technique, Planar Laser Induced Fluorescence) • IR Thermography and Thermochromic Liquid Crystals for thermal measurements

Advanced post-processing • Statistical and time domain analysis of unsteady flows • Conditional sampling and ensemble averaging techniques • Frequency domain analysis, wavelet transforms, Proper Ortogonal Decomposition (POD),

Dynamic Mode Decomposition (DMD) • Intermittency and turbulence structure detection techniques

0.00 0.02 0.04 0.06 0.08 0.10

t (s)

-20

0

20

40

60

v [

m/s

]

10 100 1000 10000

f (Hz)

1E-008

1E-007

1E-006

1E-005

1E-004

1E-003

1E-002

1E-001

1E+000

1E+001

po

we

r d

en

sit

y




Experimental activities on turbine blade design/analysis




Integration between different facilities

Flat plate analysis provide a detailed view and characterization of the basic phenomena driving the boundary layer evolution over the blade surfaces

Cascade investigations allow the identification of geometrical and flow parameters on losses

Investigations in large scale rotating facilities allow verifying the observation raised from simpler facilities in a more realistic environment (also accounting for three-dimensional blade shape, unsteadiness etc.)




Example of analysis

• Wind Tunnel for Investigations of Ducts and Airfoils

Moving bars system simulating upstream incoming wakes

Countured walls designed to reproduce the desired advesre pressure gradients (simulating the suction side of higly loaded LPT blade)




0.4 0.5 0.6 0.7 0.80

0.02

0.04

0.02 0.04 0.06 0.08 0.10 0.12 0.14

x/L

y/L

u'rms

/Uref

0.4 0.5 0.6 0.7 0.80

0.02

0.04

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

x/L

y/L

u/Uref

Inflection line

Analysis on the large scale flat plate allows a deep inspection of the boundary layer evolution highlighting:

• Transition and separation processes;

• Instability mechanisms leading to transition;

• Shedding of large scale coherent structures (strongly dissipative rollup vorticies);

Example of analysis

PIV istantaneous flow fields

101

102

103

f [Hz]

10-6

10-5

10-4

10-3

10-2

Freestream

Point "B" KHband

HW velocity spectra

Simoni D., Ubaldi M., Zunino P., “A Simplified Model Predicting the Kelvin-Helmholtz Instability Frequency for Laminar Separated Flows”, ASME Journal of Turbomachinery, Vol. 138, 2016, pp. 044501-1 - 044501-6, doi: 10.1115/1.4032162




Effects of elevated free-stream turbulence on the boundary layer transition and separation process: recent FR-PIV measurement post-processed with POD

Simoni D., Ubaldi M., Zunino P., “Loss Production Mechanisms in a Laminar Separation Bubble”, Flow, Turbulence and Combustion, Vol. 89, pp. 547-562, 2012

Example of analysis

Simoni D., Ubaldi M., Zunino P., Lengani D., Bertini F.: “An Experimental Investigation of the Separated-Flow Transition Under High-Lift Turbine Blade Pressure Gradients”, Flow, Turbulence and Combustion, Vol. 88 (1-2), pp. 45-62, 2012




• Wind Tunnels for Detailed Cascade Investigations

Blade chord in the range 120 mm < C < 180 mm

Blade height 300-350 mm to ensure two dimensional flow at midspan

Moving bars system adopted to simulate upstream wakes, grid for homogeneous turbulence (0.2%<Tu<5%)

System to simultaneously rotate cascade and moving bars system to test off-design operations (i=+/-15°)

Example of analysis




s/sMAX

0.85 0.9 0.95 1 1.05 1.1

0.05

0.1-0.05 0.05 0.15 0.25 0.35 0.45 0.55 0.65 0.75 0.85 0.95

y/g

u/U0

s/sMAX

0.85 0.9 0.95 1 1.05 1.1

0.05

0.1y/g

s/sMAX

0.85 0.9 0.95 1 1.05 1.1

0.05

0.1y/g

a) steady state, low FSTI

c) unsteady case, low FSTI

b) steady state, high FSTI

Example of analysis

Lengani D., Simoni D., Ubaldi M., Zunino P., Bertini F., “Experimental investigations on the unsteady transition process of the suction side boundary layer of LPT blades”, ERCOFTAC BULLETIN, vol. 106; p. 31-36, 2016




14

Perturbation velocity vector maps: u’(t) = u(t) - U

• Steady inflow (no wakes)

• Re=70000, i = 0

• High acquisition frequency (1853 Hz)

• Large scale vortices are observable in the G2 cascade due to the

instability of the separated boundary layer.




s/sMAX

0.85 0.9 0.95 1 1.05 1.1

0.05

-0.05 0.05 0.15 0.25 0.35 0.45 0.55 0.65 0.75 0.85 0.95

y/g

u/U0

POD zoom

0 10 20 30 40Mode number

0.1

1

10

100

En

erg

y c

ap

ture

d [

%]

s/sMAX

0.85 0.9 0.95 1 1.05 1.1

0.05

0.06 0.09 0.12 0.15 0.18 0.21 0.24 0.27 0.3

y/g

u'RMS

/U0

POD zoom

s/sMAX

0.9 0.95 1 1.05

0.02

0.06y/g

Mode 6

0.02

0.06y/g

Mode 5

0.02

Vector field, zoom

Mode 1

y/g

0.02

0.06

-20 -16 -12 -8 -4 0 4 8 12 16 20

y/g

Normalized u negative positive

Mode 1

y/g

0.02

Mode 3

y/g

0.02

Mode 2

y/g

0.02

0.06y/g

Mode 2

0.02

0.06y/g

Mode 3

s/sMAX

0.94 0.96 0.98 1

0.02

Mode 6

y/g

0.02

0.06y/g

Mode 4

0.02

Mode 4

y/g

0.02

Mode 5

y/g

Lengani D., Simoni D., Ubaldi M., Zunino P.“ POD Analysis of the Unsteady Behavior of a Laminar Separation Bubble”, Experimental Thermal and Flow Sciences, Vol. 58, pp. 70-79, 2014




Lengani D., Simoni D. “Recognition of coherent structures in the boundary layer of a low-pressure-turbine blade for different free-stream turbulence intensity levels”, International Journal of Heat and Fluid Flows, Vol. 54, 2015, pp. 1-13.




Q4

Q2

Q3

Q1W

akecenterline

17

The unsteady passing wakes (red line) carries vortical structures that interact with the blade

boundary layer. An instant of the wake passing (phase averaged results) is here represented as

streamlines: the wake generates a jet like structure pointing toward the wall. In order to reduce the

complexity of such problem the POD has been applied to the PIV dataset




Perturbation velocity

vector map: u’(t) = u(t) - U

•f+=0.69, Re=70000, i = 0, =0.675 Acquisition frequency 400 Hz

• With unsteady passing wake, there are large velocity fluctuations outside of the boundary

layer.

• The interaction of the wake with the blade boundary layer is complex.

• Advanced post-processing is required to simplify and understand this problem




The phase averaged results show the wake as two large vortices convected through the blade

passage. These coherent structures are causing losses by means of the two mechanism

previously described: wake migration and their interaction with the boundary layer.




x

y

-0.4 -0.32 -0.24 -0.16 -0.08 0 0.08 0.16 0.24 0.32 0.4Mode 1

x

y

Mode 3

x

y

Mode 4x

y

Mode 2

φu[m/s]

• POD represents the flow field as a superposition of modes sorted in a descending energy order

(the first mode is the most energetic).

• The POD modes are dimensional and can be related to the Reynolds stresses: each mode is

associated to a flow feature that generate losses

Lengani D., Simoni D., Ubaldi M., Zunino P., Bertini F., Coherent Structures Formation During Wake-Boundary Layer Interaction on a LP Turbine Blade, Flow, Turbulence and Combustion, DOI 10.1007/s10494-016-9741-6, 2016




0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

x/Cx

0

0.2

0.4

0.6

0.8

1

1.2

1.4

cp

Re = 70000

Re = 300000

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

x/Cx

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

x/Cx

NL cascade FHL cascade MHL cascade

50000 100000 150000 200000 250000 300000

Re

0

1

2

3

wp/w

ref

50000 100000 150000 200000 250000 300000

Re50000 100000 150000 200000 250000 300000

Re

NL cascade FHL cascade MHL cascade

Losses

Satta F., Simoni D., Ubaldi M., Zunino P., Bertini F., “Loading Distribution Effects on Separated-Flow-Transition of Ultra-High-Lift Turbine Blades Under Steady and Unsteady Inflows” AIAA Journal of Propulsion and Power, Vol. 30, pp. 845-856, 2014

Berrino M., Simoni D., Ubaldi M., Zunino P., Bertini F: “Off-Design Performance of a Highly Loaded LP Turbine Cascade Under Steady and Unsteady Incoming Flow Conditions”, ASME Journal of Turbomachinery, Vol. 137, pp. 071009-1 - 071009-9, 2015




• Single stage large scale Axial Research Turbine

Turbine rig




• Two-Stage Axial Research Turbine

Turbine rig




Balde and vane loading distributions and total pressure maps can be measured to properly characterize the stage under realistic operation condition (accounting for three-dimensional stage design, vortex-vortex interaction process etc…)

0.5

0.45

0.4

0.35

0.3

0.25

0.2

0.15

0.1

0.05

0

0

2.4

1.9

r/h

-1

1.4

2.15

1

1.65

cpt

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

s/smax

0

0.2

0.4

0.6

0.8

1

1.2

1.4

cp

i=-4°

i=0°

i=6°

(r-rhub)/h=50%

Example of analysis

Canepa E., Formosa P., Lengani D. Simoni D., Ubaldi M., Zunino, P., “Influence of Aerodynamic Loading on Rotor-Stator Aerodynamic Interaction in a Two-Stage Low Pressure Research Turbine”, ASME Journal of Turbomachinery, 129, pp. 765-772, 2007




• Detailed unsteady three-dimensional flow field from phase-locked HW measurements downstream of the rotor row

Example of analysis




Aeroacoustics




ARGOMENTO PRINCIPALE

VENTILATORI PER SISTEMI DI RAFFREDDAMENTO AUTOMOBILISTICI

LABORATORIO DI RIFERIMENTO IN CAMPO AEROACUSTICO PER JOHNSON ELECTRIC ASTI, AZIENDA LEADER DEL SETTORE

CARATTERISTICHE

LOCALIZZAZIONE SORGENTI ACUSTICHE (PORZIONI DI PALA CHE EMETTONO RUMORE) E LORO IDENTIFICAZIONE (MECCANISMO AERODINAMICO CONNESSO)

INDIVIDUAZIONE LEGAME FRA MECCANISMO E GEOMETRIA

DEFINIZIONE INTERVENTI PER ABBATTERE IL RUMORE SENZA DIMINUIRE LE PRESTAZIONI (CONOSCENZA FLUIDODINAMICA E METODI DI PROGETTO)

NOTA

IL RUMORE E’ CAUSA DI FASTIDIO PER GLI ESSERI UMANI, QUINDI CONSIDERARE LA CORRELAZIONE FRA GLI ASPETTI FISICI E QUELLI FISIOLOGICI E PSICOLOGICI

ABBATTERE FASTIDIO E NON SOLO POTENZA ACUSTICA IRRADIATA

PSICOACUSTICA/SOUND QUALITY: VALUTAZIONE DELLA «QUALITA’ PERCEPITA» DI UN SUONO/RUMORE A PARTIRE DALLE SUE CARATTERISTICHE FISICHE




ATTREZZATURE & SOFTWARE

• CAMERA SEMI-ANECOICA (4 m x 4.6 m x h 3.4 m, fmin = 100 Hz)

• 3 ANALIZZATORI DI SPETTRO, 15 MICROFONI & 4 ACCELEROMETRI, SISTEMI PER LA VISUALIZZAZIONE DI FLUSSO

• SISTEMI PER IL CONDIZIONAMENTO DEL FLUSSO IN ASPIRAZIONE

• SOFTWARE SOUND QUALITY

• SOFTWARE PER L’IDENTIFICAZIONE DELLE SORGENTI ACUSTICHE





• TEST PLENUM ISO 10302 PER PROVE A CARICO VARIABILE

• FERITOIE CON REGOLAZIONE AUTOMATICA DELL’APERTURA

• PARETI TRASPARENTI ALLE ONDE ACUSTICHE

PARETE IN MYLAR SERRANDE MOBILI





• ROTORE CON SPAZIATURA E NUMERO PALE VARIABILI (Z=2 – 11)

• STATORI 3/4/18/19 PALE

• SERVOMOTORE BRUSHLESS

PALE Z=7 EQUISP.

Z=7 NON EQUISP.

Z=5 NON EQUISP.

Z=9 NON EQUISP.

ATTREZZATURA PER IL MONTAGGIO

GONIOMETRO RISOLUZIONE O.25°




OTTIMIZZAZIONE PSICOACUSTICA SPAZIATURA

• ONDA GENERATA DA UNA PALA: FREQ. FONDAMENTALE = FREQ. ROTAZ.

• SUONO RICEVUTO: SOMMA (INTERFERENZA) ONDE GENERATE DA CIASCUNA PALA

• L’INTERFERENZA DIPENDE DALLA SPAZIATURA TANGENZIALE:

• ROTORE EQUISPAZIATO: SOLO BPF E ARMONICHE (PICCHI INTENSI)

• ROTORE NON EQUISPAZIATO: TUTTE LE ARMONICHE DELLA FREQ. DI ROTAZ.

(I PICCHI «AFFONDANO» NELLO SPETTRO)

• OTTIMIZZANDO LA SPAZIATURA IL RUMORE RISULTA MENO FASTIDIOSO (MIGLIORE «QUALITA’») SPETTRO SPL SPETTRO SPL

Anghinolfi, Canepa, Cattanei, Paolucci, Psychoacoustic Optimization of the Spacing of Propellers, Helicopter Rotors, and Axial Fans, Journal of Propulsion and Power, 2016, DOI/10.2514/1.B35960




STUDIO TIP LEAKAGE NOISE (IDENTIFICAZIONE DELLE SORGENTI ACUSTICHE)

• IL FLUSSO DI RICIRCOLO VIENE REINGERITO DAL ROTORE GENERANDO RUMORE MOLTO INTENSO A MEDIA/BASSA FREQUENZA (CONTRIBUTO PIU’ IMPORTANTE)

• I PICCHI HANNO FREQUENZE INFERIORE ALLA BPF PER LA PREROTAZIONE POSITIVA

CONFIGURAZIONE DI PROVA FLUSSO




SPL

[dB

]

STUDIO TIP LEAKAGE NOISE

TIP LEAKAGE NOISE FREQ. < BPF

ROTORE Dest = 460 mm, Z = 9 PALE

=3000 r/min (BPF = 9x50Hz = 450 Hz)

VEL. AX. (MISURE LDA) PUNTO NOMINALE (DP)

VEL. AX. (MISURE LDA) MANDATA LIBERA (FD)

FLUSSO DI RICIRCOLO (VAX < 0, VTH > 0 )

SPETTRO SPL

Canepa, Cattanei, Mazzocut Zecchin, Milanese, Parodi, An experimental investigation on the tip leakage noise in axial-flow fans with rotating shroud, Journal of Sound and Vibration, 2016, DOI 10.1016/j.jsv.2016.04.009




Turbomachinery design

Design specification

Aero

3D analysis

Throughlow SLCM analysis

2D design procedure (ISRE-NISRE)

Thermodynamic cycle

1D design procedure

Comparison with design

specification

Mechanical

Final machine configuration

Power output, efficiency

Turbine overall boundary conditions

Meanline geometrical characteristics

Meridional flow behaviour and overall performance

Radial distribution of geometrical characteristics

Detailed 3D flow behaviour

Mechanical assessment

Optimization procedure

Design criteria modification

Axial flow turbine design method




Thanks

Daniele Simoni Tel 010 353 2459

[email protected]

Attività sperimentale e numerica per lo sviluppo di turbomacchine … · University of Genova...

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Transcript of Attività sperimentale e numerica per lo sviluppo di turbomacchine … · University of Genova...