GT2009-59108 Turbocharger: Engine Induced Excitations
Kostandin GjikaKostandin GjikaEngineering& Technology Fellow
Honeywell Turbo Technologies
ASME TURBO EXPO 2009, Power for Land, Sea and Air
Luis San AndrésLuis San AndrésMast-Childs Professor
Fellow ASME
Turbocharger Nonlinear Response Turbocharger Nonlinear Response with Engine-Induced Excitations: with Engine-Induced Excitations:
Predictions and Test DataPredictions and Test Data
ASME Paper GT 2009-59108
Ash MaruyamaAsh MaruyamaResearch Assistant (05-07)
Texas A&M University
Sherry XiaSherry XiaRotordynamics Manager
Honeywell Turbo Technologies
Supported by Honeywell Turbocharger Technologies (HTT)
Accepted for journal publication
GT2009-59108 Turbocharger: Engine Induced Excitations
Oil Inlet
Compressor Wheel
Shaft
TC Center Housing
Semi-Floating Bearing Anti-Rotating Pin
Turbine Wheel
• Increase internal combustion (IC) engine power output by forcing more air into cylinder
• Aid in producing smaller, more fuel-efficient engines with larger power outputs
Turbochargers:
GT2009-59108 Turbocharger: Engine Induced Excitations
RBS With Fully Floating Bearing
RBSWith Semi Floating Bearing
RBSWith Ball Bearing
RBS: TC Rotor Bearing System(s)
Desire for increased IC engine performance & efficiency leads to technologies
that rely on robust & turbocharging solutions
GT2009-59108 Turbocharger: Engine Induced Excitations
Bearing Types:
Shaft
Ball Bearing
Squeeze Film
Inner Race
Locking Pin
Outer Race
Ball-Bearing
Shaft
Inner Film
Outer Film
Oil Feed Hole
Floating Ring
Locking Pin
Semi-Floating Ring Bearing
(SFRB)
Floating Ring Bearing(FRB)
• Low shaft motion• Relatively expensive• Limited lifespan
• Economic• Longer life span• Prone to
subsynchronous whirl
GT2009-59108 Turbocharger: Engine Induced Excitations
Shaw & Nussdorfer (1949): Test results show superior performance of FRBs over plain journal bearings
Tatara (1970): Initially unstable FRB-supported test rotor becomes stable at high speeds, ring speed reaches constant speed
Li & Rohde (1981): Numerically show FRB-supported rotors whirl in stable limit cycles
Trippett & Li (1984): Shows lubricant viscosity changes cause unusual floating-ring speed behavior, isothermal analysis is incorrect
ENGINE INDUCED Vibrations:
Literature Review
Kirk et al. (2008): Measure shaft motions of TC on FRB attached to diesel ICE. Engine-attributed low frequency amplitudes comparable to TC subsynchronous amplitudes. Little to no insight on RBS analysis
Ying et al. (2008): TC-RBS NL analysis with engine foundation excitation. Rotor response is quite complicated showing chaos at the lowest shaft speed. Little to no insight on test data
GT2009-59108 Turbocharger: Engine Induced Excitations
TAMU-HTT VIRTUAL TOOL for Turbocharger NL Shaft Motion Predictions XLTRC2® based with a demonstrated 70% cycle time reduction in the development of new CV TCs. Since 2006, code aids to developing PV TCs with savings up to $150k/year in qualification test time
Predicted Steady-State Waterfall / Y DisplacementRBS with ODminIDmax / Oil Texaco-Havoline Energy 5W30, 150°C, 4bar
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000Frequency (Hz)
Mot
ion
Am
plitu
de
Subsynchronous ComponentsSynchronous Component
Predicted Steady-State Waterfall / Y DisplacementRBS with ODminIDmax / Oil Texaco-Havoline Energy 5W30, 150°C, 4bar
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000Frequency (Hz)
Mot
ion
Am
plitu
de
Subsynchronous ComponentsSynchronous Component
Measured Steady-State Waterfall / Y DisplacementRBS with ODminIDmax / Oil Texaco-Havoile Energy 5W30, 150°C, 4bar
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000Frequency (Hz)
Nor
mal
ized
Non
linea
r Res
pons
e Subsynchronous ComponentsSynchronous Component
Measured Steady-State Waterfall / Y DisplacementRBS with ODminIDmax / Oil Texaco-Havoile Energy 5W30, 150°C, 4bar
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000Frequency (Hz)
Nor
mal
ized
Non
linea
r Res
pons
e Subsynchronous ComponentsSynchronous Component
Predicted shaft motion
ASME DETC2007-34136
Measured shaft motion
GT2009-59108 Turbocharger: Engine Induced Excitations
• TC linear and nonlinear rotordynamic codes – GUI based
• Measure ring speeds with fiber optic sensors
• Realistic thermohydrodynamic bearing models
• Novel methods to estimate imbalance distribution and shaft temperatures
Literature Review: San Andres and students
Tools for shaft motion prediction with effect of engine excitation needed –benchmarked by tests data
2004 IMEchE J. Eng. Tribology
2005 ASME J. Vibrations and Acoustics
ASME DETC 2003/VIB-48418 ASME DETC 2003/VIB-48419
2007 ASME J. Eng. Gas Turbines Power
ASME GT 2006-90873
2007 ASME J. Eng. Gas Turbines Power
ASME GT 2005-68177
2007 ASME J. TribologyIJTC 2006-12001
2007 ASME DETC2007-34136
GT2009-59108 Turbocharger: Engine Induced Excitations
Objectives:
TAMU-HTT publications show unique -one to one- comparisons between test data and nonlinear predictions
• Refine rotordynamics model by including engine-induced housing excitations
• Deliver predictive tools validated by test data to reduce the need for costly engine test stand qualification
• Further understanding of complex TC behavior
quantification
GT2009-59108 Turbocharger: Engine Induced Excitations
TC rotor & bearing system 2 shaft model
Compressor Turbine
126.44 mm
Spacer
RBS with Semi Floating Bearing
GT2009-59108 Turbocharger: Engine Induced Excitations
Shaft2585449
Shaft245 Shaft1
444035
30252015105Shaft1
1
-0.04
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
0.04
0 0.02 0.04 0.06 0.08 0.1 0.12
Axial Location, meters
Shaf
t Rad
ius,
met
ers
Rotor C.G.
Rotor finite element model: 2 shaft model
Shaft measurements (STN 3)& predictions
Rotor: 6Y gramSFRB: Y gram
Static gravity load distribution Compressor Side: Z
Turbine Side: 5Z
Compressor TurbineSFRB
Thrust Collar
Validate rotor
model with measurem
ents of free-fee modes(room Temp)
C T
u
GT2009-59108 Turbocharger: Engine Induced Excitations
-0.04
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
0.04
0 0.02 0.04 0.06 0.08 0.1 0.12
Axial Location, meters
Shaf
t Rad
ius,
met
ers
Measured (Freq = 1.799 kHz)
Predicted (Freq = 1.823 kHz)
Compressor End Turbine End
First mode
Second mode
measuredprediction
-0.04
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
0.04
0 0.02 0.04 0.06 0.08 0.1 0.12
Axial Location, meters
Shaf
t Rad
ius,
met
ers
Measured (Freq = 1.799 kHz)
Predicted (Freq = 1.823 kHz)
Compressor End Turbine End
First mode
Second mode
measuredprediction
-0.04
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
0.04
0 0.02 0.04 0.06 0.08 0.1 0.12
Axial Location, meters
Shaf
t Rad
ius,
met
ers
Measured (Freq = 4.938 kHz)
Predicted (Freq = 4.559 kHz)
Compressor End Turbine End
First mode
Second mode
measuredprediction
-0.04
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
0.04
0 0.02 0.04 0.06 0.08 0.1 0.12
Axial Location, meters
Shaf
t Rad
ius,
met
ers
Measured (Freq = 4.938 kHz)
Predicted (Freq = 4.559 kHz)
Compressor End Turbine End
First mode
Second mode
measuredprediction
Free-free mode natural frequency & shapes:
Measured and predicted free-free natural frequencies and mode shapes agree: rotor model validation
measured Predicted % diff
KHz KHz -
First 1.799 1.823 1.3
Second 4.938 4.559 7.7
GT2009-59108 Turbocharger: Engine Induced Excitations
(Semi) Floating Bearing Ring :• Actual geometry (length, diameter, clearance) of inner and outer films, holes size and distribution• Supply conditions: temperature & pressure• Lubricant viscosity varies with temperature and shear rate (commercial oil)• Side hydrostatic load due to feed pressure • Temperature of casing • Temperature of rotor at turbine & compressor sides derived from semi-empirical model: temperature defect model
XLBRG® thermohydrodynamic fluid film bearing model predicts operating clearance and oil viscosity (inner and outer films) and eccentricities (static and dynamic) as a function of shaft & ring speeds and applied (static & dynamic) loads.
GT2009-59108 Turbocharger: Engine Induced Excitations
– TC speed ranges from 48 krpm – 158 krpm– Engine speed ranges from 1,000 rpm – 3,600 rpm– 25%, 50%, 100% of full engine load
– Nominal oil feed pressure & temperature: 2 bar, 100°C
Operating conditions from test data:
Compressor Housing
Air Inlet
Engine
Proximity Probes (X, Y)
accelerations are collected with three-axis accelerometers.
Fig. 4 Turbocharger Engine Test Facility Stand
Compressor Housing
Air Inlet
Engine
Proximity Probes (X, Y)
TC Engine Test Facility Stand
GT2009-59108 Turbocharger: Engine Induced Excitations
(S)FRB Predictions :
90
100
110
120
130
140
150
160
170
0 20000 40000 60000 80000 100000 120000 140000 160000 180000Shaft speed (rpm)
Max
imum
tem
pera
ture
(C)
100% Engine Load - Inner Film 100% Engine Load - Outer Film50% Engine Load - Inner Film 50% Engine Load - Outer Film25% Engine Load - Inner Film 25% Engine Load - Outer FilmLubricant Supply Temperature
Peak film temperatures
Supplytemperature
Inner film
Outer film
Increase in power losses (with speed) lead to raise in inner film & ring temperatures.
No effect of engine load
GT2009-59108 Turbocharger: Engine Induced Excitations
0
1
2
3
4
5
6
7
0 20000 40000 60000 80000 100000 120000 140000 160000 180000Shaft speed (rpm)
Effe
ctiv
e vi
scos
ity (c
P)
100% Engine Load - Inner Film 100% Engine Load - Outer Film50% Engine Load - Inner Film 50% Engine Load - Outer Film25% Engine Load - Inner Film 25% Engine Load - Outer Film
(S)FRB Predictions : Oil effective viscosity
SupplyViscosity: 8.4 cP
Inner film
outer film
LUB: SAE 15W-40
Increased film temperatures determine lower lubricant viscosities. Operation parameters
independent of engine load
Lubricant type: SAE 15W - 40
GT2009-59108 Turbocharger: Engine Induced Excitations
0.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
1.20
0 20000 40000 60000 80000 100000 120000 140000 160000 180000Shaft speed (rpm)
Film
cle
aran
ceC
old
clea
ranc
e
100% Engine Load - Inner Film 100% Engine Load - Outer Film50% Engine Load - Inner Film 50% Engine Load - Outer Film25% Engine Load - Inner Film 25% Engine Load - Outer Film
Clearance thermal growth relative to nominal inner or outer cold radial clearance
(S)FRB Predictions : Film clearances
nominalclearance
Inner film
outer film
Inner film clearance grows and outer film clearance decreases – RING grows more
than SHAFT and less than CASING. Material parameters are important
GT2009-59108 Turbocharger: Engine Induced Excitations
TC housing acceleration measurements:
TC center housing and compressor housing accelerations measured with 3-axes accelerometers for three engine loads: 25%, 50%, 100% of full engine load
Accelerometers accelerometers
accelerations are collected with three-axis accelerometers.
Fig. 4 Turbocharger Engine Test Facility Stand
Compressor Housing
Air Inlet
Engine
Proximity Probes (X, Y)
GT2009-59108 Turbocharger: Engine Induced Excitations
TC housing acceleration analysis:
ΔtMax Time
# points in FFT Δf
Max FFT freq.
[μs] [s] -- [Hz] [Hz]
200 3.0 2,048 2.44 2,500
Last 2,048 (out of 15,000) time data points converted to frequency spectrum via
Fast Fourier Transformations (FFTs)
0 100 200 300 400 500 600 700 800 900 10000
100
200
300
Excitation frequency [Hz]
Am
plitu
de
0 100 200 300 400 500 600 700 800 900 10000
100
200
300
Excitation frequency [Hz]
Am
plitu
de
Combined manifold & TC system natural
frequencies
Center Housing
Comp. Housing
m/s2
m/s2
100% engine load
~300 Hz
~570 Hz
1000 rpm
3600 rpm
GT2009-59108 Turbocharger: Engine Induced Excitations
0 2 4 6 8 10 12 14 16 18 200
100
200
300
Order of engine frequency
Am
plitu
de
0 2 4 6 8 10 12 14 16 18 200
100
200
300
Order of engine frequency
Am
plitu
de
TC housing acceleration analysis:
Combined manifold & TC system natural
frequencies
Center Housing
Comp. Housing
m/s2
m/s2
100% engine load
~300 Hz
~570 Hz
1000 rpm
3600 rpm
2, 4, and 6 times engine
(e) main frequency contribute
significantly
1e order frequency
does not appear
GT2009-59108 Turbocharger: Engine Induced Excitations
0
50
100
150
200
250
300
350
400
450
500
0 500 1000 1500 2000 2500 3000 3500 4000Engine Speed (rpm)
Acc
eler
atio
n pk
-pk
(m/s
ec^2
)
Center Housing AccelerationCompressor Housing Acceleration
Center and compressor housings do not vibrate as a rigid body
m/s2
TC housing total acceleration 100% engine load
Compressor housing
Center housing
GT2009-59108 Turbocharger: Engine Induced Excitations
Displacement transducers
Displacement transducers record shaft motion
relative to compressor housing
Rotordynamics model outputs absolute shaft
motion
shaft motion relative to compressor housing
needs of casing motion
Integration of housing accelerations into rotordynamics model
Note: TC Housing accelerations and TC shaft motions NOT recorded simultaneously
GT2009-59108 Turbocharger: Engine Induced Excitations
Housing accelerations into model
Center Housing
Compressor
Turbine
Semi Floating Ring Bearing Assembly
Shaft
Axial Bearing Assembly
Connection to engine mountCompressor housing
Eddy current sensor
AccelerometerSpecified housing motiondue to engine
Basic assumptions– TC housings move as a rigid body– TC housing vibrations transmitted through bearing
connections– Each bearing transmits identical housing vibrations
GT2009-59108 Turbocharger: Engine Induced Excitations
Rotordynamics model
Z Vector of rotor & ring displacements & rotations along (X, Y) at the DOFs of interest
M, K, D, G() – Matrices of rotor & ring inertias, stiffness, damping & gyroscopics at the rated rotor speed ()
Fext(t) Imposed time varying forces acting on the rotor & ring, such as imbalances, aerodynamics, side loads FB(t) Vector of bearing reactions forces including engine vibration
excitation
( ) ( )( ) t t B extM Z + D G Z + K Z F F
, ,
, , , , , , , , ,X YB R S S S S R B R B R B R BX Y
F x y x y x x y y x x y yf
Shaft motion (ring motion – base motion)
GT2009-59108 Turbocharger: Engine Induced Excitations
Housing accelerations into model
Center Housing
Compressor
Turbine
Semi Floating Ring Bearing Assembly
Shaft
Axial Bearing Assembly
Connection to engine mountCompressor housing
Eddy current sensor
AccelerometerSpecified housing motiondue to engine
01
( ) cosFN
n e nn
a t A A n t
0
Fourier coefficient decomposition of housing acceleration time data
Double time integration
2
1
( ) cosFN
ne n
n e
Ax t n tn
Procedure:Find first 10 Fourier coefficients (amplitude and phase) of center housing
acceleration and input into rotordynamics model.
Run nonlinear time transient analysis and find absolute shaft motion response.
Subtract compressor housing displacements to obtain shaft motion relative to compressor
GT2009-59108 Turbocharger: Engine Induced Excitations
RBS damped natural frequencies
0
500
1000
1500
2000
2500
3000
0 20000 40000 60000 80000 100000 120000 140000 160000 180000
Shaft speed (rpm)
Dam
ped
natu
ral f
requ
ency
(Hz)
f=99.5 Hzd=.3161 zetaN=80000 rpm
f=546.5 Hzd=.2492 zetaN=80000 rpm
f=621. Hzd=.5294 zetaN=80000 rpm
f=2025.2 Hzd=.1408 zetaN=80000 rpm
1st elastic modecyl. turb. bear. ringing mode
cyl. comp. ringing mode
conical mode
1XCritical speed
100% engine load
GT2009-59108 Turbocharger: Engine Induced Excitations
RBS response to imbalance 100% engine load
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0 40000 80000 120000 160000 200000
Shaft Speed (rpm)
Am
plitu
de 0
-pk
(-)
Test DataNonlinear Pred. - No Housing Motion (1X)Nonlinear Pred. Relative to Comp. Housing (1X)Linear Pred. (1X)
Linear Pred.
Nonlinear Pred.
Test Data
Differences between
predictions and test data attributed to
inaccurate knowledge of
imbalance distribution
Test data
NL pred.
C T
u
GT2009-59108 Turbocharger: Engine Induced Excitations
Transient time NL rotor response
XLTRC2® Nonlinear numerical integration of equation of motion (time-marching ) with bearing forces evaluated at each time step.• Gear stiff method• Component mode synthesis• Post processing in frequency domain (Virtual Tools)• Integration parameters CPU ~ 30’ per shaft speed
Δt Max Time# time steps Δf
Max FFT freq.
[μs] [s] -- [Hz] [Hz]
78.1 1 12,800 4 6,400
Results (amplitudes at) compressor nose vertical directionshown relative to maximum conical motion at the compressor shaft end
GT2009-59108 Turbocharger: Engine Induced Excitations
0
0.05
0.1
0.15
0.2
0.25
0 500 1000 1500 2000 2500 3000 3500 4000Frequency (Hz)
Am
plitu
de 0
-pk
(-)
Predictions without Housing Acceleration
TC synchronous response
1.0 krpm
3.6 krpm
1.0 krpm
3.6 krpm
0
0.05
0.1
0.15
0.2
0.25
0 500 1000 1500 2000 2500 3000 3500 4000Frequency (Hz)
Am
plitu
de 0
-pk
(-)
Test Data
TC synchronous response
1.0 krpm
3.6 krpm
0
0.05
0.1
0.15
0.2
0.25
0 500 1000 1500 2000 2500 3000 3500 4000Frequency (Hz)
Am
plitu
de 0
-pk
(-)
Test Data
TC synchronous response
1.0 krpm
3.6 krpm
1.0 krpm
3.6 krpm
0
0.05
0.1
0.15
0.2
0.25
0 500 1000 1500 2000 2500 3000 3500 4000Frequency (Hz)
Am
plitu
de 0
-pk
(-)
Predictions with Housing Acceleration
TC synchronous response
1.0 krpm
3.6 krpm
0
0.05
0.1
0.15
0.2
0.25
0 500 1000 1500 2000 2500 3000 3500 4000Frequency (Hz)
Am
plitu
de 0
-pk
(-)
Predictions with Housing Acceleration
TC synchronous response
1.0 krpm
3.6 krpm
1.0 krpm
3.6 krpm
Housing accelerations induce broad range, low
frequency shaft whirl motions
Test data shows broad frequency response at low
frequencies (engine speeds)
Waterfalls of shaft motion at compressor end 100% engine load
1000 rpm
3600 rpm
GT2009-59108 Turbocharger: Engine Induced Excitations
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0 500 1000 1500 2000 2500 3000 3500 4000Shaft speed (rpm)
Am
plitu
de p
k-pk
(-)
Test DataNonlinear Predictions
Good correlation
with test data for all shaft
speeds
Total shaft motion at compressor end (amplitude)
100% engine load
Test data
NL pred.
Am
plitu
de p
k-pk
(-)
Rotor speed (RPM)
GT2009-59108 Turbocharger: Engine Induced Excitations
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0 500 1000 1500 2000 2500 3000 3500 4000Engine speed (rpm)
Am
plitu
de 0
-pk
(-)
Test DataTest Data Peak ValueNonlinear PredictionsPredicted Peak Value
Good agreement
b/w predictions
and test data from 1750 –
2750 rpm
Subsynchronous amplitudes vs engine speed
100% engine load
Test data
NL pred.
Engine speed (RPM)
Am
plitu
de 0
-pk
(-)
GT2009-59108 Turbocharger: Engine Induced Excitations
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Orders of main engine speed
Am
plitu
de 0
-pk
(-)
Test DataNonlinear Predictions
Fig. 13. Predicted and measured subsynchronous shaft motion amplitudes versus orders of engine speed (compressor nose, vertical direction)
TC shaft self-excited freq.
2e and 4e orders engine
frequency contribute
the most to shaft
motions
14e order is due to shaft self-excited
vibration (whirl from
bearings)
Subsynchronous amplitudes vs engine orders
100% engine load
Test data
NL pred.
Orders of main engine speed
Am
plitu
de 0
-pk
(-)
GT2009-59108 Turbocharger: Engine Induced Excitations
0
200
400
600
800
1000
0 40000 80000 120000 160000 200000Shaft speed (rpm)
Sub
Sync
hron
ous
Freq
uenc
y [H
z]
Test DataNonlinear Predictionsconical modecylindrical (comp. bearing ring) modecylindrical (turb. bearing ring) mode
System (manifold & TC) natural frequency ranges
~570 Hz
~300 Hz
Subsynchronous frequency vs. rotor speed2e frequency shown
in test data and preds
4e frequency tracks rotor conical mode
Subsynchronous frequencies ~ super-harmonics of conical
mode
2e order freq.
4e order freq.
Group 1 (0.5 C)
Group 2 (2C)
Group 3 (4C)
Test
1X
Subs
ynch
rono
us fr
eque
ncy
(Hz)
Rotor speed (RPM)
GT2009-59108 Turbocharger: Engine Induced Excitations
order engine frequencies, most likely due to the engine firing
0
50
100
150
200
250
300
350
400
450
500
550
600
0 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000 3250 3500 3750 4000Engine speed (rpm)
Freq
uenc
y [H
z]
Test Data
Nonlinear Predictions
12e
2e
1e
3e
4e
5e
6e
7e
8e
9e10e11e
TC shaft self-excited freqs.
0
50
100
150
200
250
300
350
400
450
500
550
600
0 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000 3250 3500 3750 4000Engine speed (rpm)
Freq
uenc
y [H
z]
Test Data
Nonlinear Predictions
12e
2e
1e
3e
4e
5e
6e
7e
8e
9e10e11e
TC shaft self-excited freqs.
predictionmeasured
Fig. 15. Predicted and measured subsynchronous whirl frequencies
Subsynchronous freq. vs. IC engine speed
Subsynch. freqs. are
multiples of IC engine frequency
Higher engine
order frequencies
not predicted
100% engine load
Test
NL
Subs
ynch
rono
us fr
eque
ncy
(Hz)
Engine speed (RPM)
TC manifold nat freq.
GT2009-59108 Turbocharger: Engine Induced Excitations
• Engines induce significant and complex, low frequency subsynchronous whirl in turbochargers
• 2e and 4e order frequencies contribute significantly to housing acceleration
• Center housing and compressor housing do not vibrate as a single rigid body
• Engine super-harmonics excite TC rotor damped natural frequencies.
• Whirl frequencies are multiples of engine speed
Conclusions
Good agreement between predictions and test data validates the nonlinear rotordynamics model!
GT2009-59108 Turbocharger: Engine Induced Excitations
Recommendations• Validation against test data from different TCs is
needed• Housing accelerations and TC shaft motion must
be recorded simultaneously and for longer periods of time (smaller frequency step size)
Work completed in 2008• Understand why higher order subsynchronous
frequencies are not predicted• Update model to account for unequal housing
excitations at each bearing location
GT2009-59108 Turbocharger: Engine Induced Excitations
Acknowledgments
Learn more at http://phn.tamu/edu/TRIBgroup
Honeywell Turbocharging Technologies (2000-2008)
TAMU Turbomachinery Laboratory Turbomachinery Research Consortium
(XLTRC2®)
Questions?