Transcript Slide 1

ASME
TURBO EXPO
2009, Power
for Land,
SeaExcitations
and Air
GT2009-59108
Turbocharger:
Engine
Induced
Turbocharger Nonlinear Response
with Engine-Induced Excitations:
Predictions and Test Data
Luis San Andrés
Kostandin Gjika
Mast-Childs Professor
Fellow ASME
Engineering& Technology Fellow
Honeywell Turbo Technologies
Ash Maruyama
Sherry Xia
Research Assistant (05-07)
Texas A&M University
Rotordynamics Manager
Honeywell Turbo Technologies
ASME Paper GT 2009-59108
Accepted for journal publication
Supported by Honeywell Turbocharger Technologies (HTT)
GT2009-59108 Turbocharger: Engine Induced Excitations
Oil Inlet
TC Center Housing
Anti-Rotating Pin
Semi-Floating Bearing
Shaft
Compressor Wheel
Turbine Wheel
Turbochargers:
• 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
GT2009-59108 Turbocharger: Engine Induced Excitations
RBS: TC Rotor Bearing System(s)
RBS
With Fully Floating Bearing
RBS
With Semi Floating Bearing
RBS
With Ball Bearing
Desire for increased IC engine performance &
efficiency leads to technologies
that rely on robust & turbocharging solutions
GT2009-59108 Turbocharger: Engine Induced Excitations
Bearing Types:
Locking Pin
Locking Pin
Squeeze Film
Floating Ring
Ball Bearing
Outer Film
Inner Race
Inner
Film
Shaft
Outer Race
Shaft
Oil Feed Hole
Ball-Bearing
• Low shaft motion
• Relatively expensive
• Limited lifespan
Semi-Floating
Ring Bearing
(SFRB)
Floating Ring
Bearing
(FRB)
• Economic
• Longer life span
• Prone to
subsynchronous whirl
GT2009-59108 Turbocharger: Engine Induced Excitations
Literature Review
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 floatingring speed behavior, isothermal analysis is incorrect
ENGINE INDUCED Vibrations:
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 shaft motion
Measured shaft motion
Measured Steady-State Waterfall / Y Displacement
RBS with ODminIDmax / Oil Texaco-Havoile Energy 5W30, 150°C, 4bar
Predicted Steady-State Waterfall / Y Displacement
RBS with ODminIDmax / Oil Texaco-Havoline Energy 5W30, 150°C, 4bar
0.07
0.07
Subsynchronous Components
Subsynchronous Components
Synchronous Component
Synchronous Component
0.06
Normalized Nonlinear Response
0.06
Motion Amplitude
0.05
0.04
0.03
0.02
0.01
0.05
0.04
0.03
0.02
0.01
0
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
5500
6000
0
0
500
1000
Frequency (Hz)
1500
2000
2500
3000
3500
Frequency (Hz)
ASME DETC2007-34136
4000
4500
5000
5500
6000
GT2009-59108 Turbocharger: Engine Induced Excitations
Literature Review: San Andres and students
• 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
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. Tribology
IJTC 2006-12001
2007
ASME DETC2007-34136
Tools for shaft motion prediction with effect of engine
excitation needed –benchmarked by tests data
GT2009-59108 Turbocharger: Engine Induced Excitations
Objectives:
• 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
quantification of complex TC
behavior
TAMU-HTT publications show unique -one to onecomparisons between test data and nonlinear predictions
GT2009-59108 Turbocharger: Engine Induced Excitations
TC rotor & bearing system
Compressor
Turbine
Spacer
126.44 mm
RBS with Semi Floating Bearing
2 shaft model
GT2009-59108 Turbocharger: Engine Induced Excitations
Rotor finite element model:
2 shaft model
Shaft measurements (STN 3)
& predictions
0.04
0.03
Shaft Radius, meters
Thrust Collar
Rotor
C.G.
0.02
0.01Shaft1
1
5
10
15
Shaft2
45
20
49
54
Shaft2
58
35
40
Shaft1
44
30
25
0
-0.01
-0.02
Compressor
-0.03
SFRB
Turbine
u
-0.04
0
0.02
C
0.04
T
0.06
0.08
Axial Location, meters
0.1
0.12
Validate
rotor
model with
measurem
ents of
free-fee
modes
(room
Temp)
Rotor: 6Y gram
SFRB: Y gram
Static gravity load distribution
Compressor Side: Z
Turbine Side: 5Z
Shaft Radius, me
0.01
GT2009-59108 Turbocharger: Engine Induced Excitations
0
-0.01
Compressor
End
-0.02
Free-free mode natural frequency & shapes:
-0.03
Turbine End
-0.04
0
0.02
0.04
0.06
0.08
0.1
0.12
Axial Location, meters
0.04
Predicted (Freq = 1.823 kHz)
0.02
0.01
0
-0.01
Compressor
End
-0.02
-0.03
Turbine End
-0.04
Measured (Freq = 4.938 kHz)
Second mode
Predicted (Freq = 4.559 kHz)
0.03
Shaft Radius, meters
0.03
Shaft Radius, meters
0.04
Measured (Freq = 1.799 kHz)
First mode
0.02
0.01
0
-0.01
measured
prediction
-0.02
-0.03
-0.04
0
0.02
0.04
0.06
0.08
0.1
0.12
0
0.02
0.04
Axial Location, meters
0.04
0.08
0.1
0.12
Axial Location, meters
Measured (Freq = 4.938 kHz)
Second mode
measured
Predicted (Freq = 4.559 kHz)
0.03
Shaft Radius, meters
0.06
Predicted
% diff
KHz
KHz
-
First
1.799
1.823
1.3
Second
4.938
4.559
7.7
0.02
0.01
0
-0.01
measured
prediction
and
predicted
-0.02
Measured
free-free natural frequencies and
mode shapes agree: rotor model validation
-0.03
-0.04
0
0.02
0.04
0.06
0.08
Axial Location, meters
0.1
0.12
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
Operating conditions from test data:
– 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
accelerations are collected with three-axis accelerometers.
Engine
Engine
Compressor Housing
Compressor Housing
Proximity
Probes
Proximity
Probes (X, Y)
Air Inlet
Air Inlet
(X, Y)
TC Engine Test Facility Stand
GT2009-59108 Turbocharger: Engine Induced Excitations
(S)FRB Predictions :
Maximum temperature (C)
100% Engine Load - Inner Film
50% Engine Load - Inner Film
25% Engine Load - Inner Film
Lubricant Supply Temperature
Peak film temperatures
100% Engine Load - Outer Film
50% Engine Load - Outer Film
25% Engine Load - Outer Film
170
Inner film
160
150
Outer film
140
130
Supply
temperature
120
110
100
90
0
20000
40000
60000
80000 100000 120000 140000 160000 180000
Shaft speed (rpm)
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
(S)FRB Predictions :
100% Engine Load - Inner Film
50% Engine Load - Inner Film
25% Engine Load - Inner Film
Oil effective viscosity
100% Engine Load - Outer Film
50% Engine Load - Outer Film
25% Engine Load - Outer Film
Effective viscosity (cP)
7
Lubricant type:
SAE 15W - 40
6
outer film
5
4
Inner film
3
2
1
0
0
20000
40000
60000
80000 100000 120000 140000 160000 180000
Shaft speed (rpm)
Supply
Viscosity: 8.4 cP
LUB: SAE 15W-40
Increased film temperatures determine lower
lubricant viscosities. Operation parameters
independent of engine load
GT2009-59108 Turbocharger: Engine Induced Excitations
(S)FRB Predictions :
100% Engine Load - Inner Film
50% Engine Load - Inner Film
25% Engine Load - Inner Film
1.20
Film clearances
100% Engine Load - Outer Film
50% Engine Load - Outer Film
25% Engine Load - Outer Film
Film clearance
Cold clearance
1.15
Inner film
1.10
1.05
nominal
clearance
1.00
0.95
0.90
outer film
0.85
0.80
0
20000
40000
60000
80000 100000 120000 140000 160000 180000
Shaft speed (rpm)
Clearance thermal growth
relative to nominal inner or outer
cold radial clearance
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
TCaccelerations
housing
acceleration
measurements:
are collected
with three-axis accelerometers.
Engine
Compressor Housing
Proximity Probes (X, Y)
Air Inlet
Fig. 4 Turbocharger Engine Test Facility Stand
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
GT2009-59108 Turbocharger: Engine Induced Excitations
TC housing acceleration analysis:
Center Housing
Δt
Max
Time
#
points
in
FFT
Δf
Max
FFT
freq.
[μs]
[s]
--
[Hz]
[Hz]
200
3.0
2,048
2.44
2,500
m/s2
~570 Hz
Amplitude
300
200
100% engine load
100
0
0
100
200
Comp. Housing
300
400
500 600
700
Excitation frequency [Hz]
~300 Hz
m/s2
300
800
900
1000
Combined manifold
& TC system natural
frequencies
Amplitude
3600 rpm
200
100
0
1000 rpm
0
100
200
300
400
500 600
700
Excitation frequency [Hz]
800
900
1000
Last 2,048 (out of 15,000)
time data points converted
to frequency spectrum via
Fast Fourier
Transformations (FFTs)
GT2009-59108 Turbocharger: Engine Induced Excitations
TC housing acceleration analysis:
100% engine load
Center Housing
Amplitude
m/s2
300
~570 Hz
2, 4, and 6
times engine
(e) main
frequency
contribute
significantly
200
100
0
0
2
4
6
8
10
12
14
Order of engine frequency
~300 Hz
Comp. Housing
m/s2
Amplitude
300
16
18
20
Combined manifold
& TC system natural
frequencies
3600 rpm
200
100
0
0
2
4
6
8
10
12
14
Order of engine frequency
16
18
20
1000 rpm
1e order
frequency
does not
appear
GT2009-59108 Turbocharger: Engine Induced Excitations
TC housing total acceleration 100% engine load
500
Acceleration pk-pk (m/sec^2)
Compressor housing
Center Housing Acceleration
Compressor Housing Acceleration
450
400
m/s2
350
300
250
Center housing
200
150
100
50
0
0
500
1000
1500
2000
2500
3000
3500
4000
Engine Speed (rpm)
Center and compressor housings do not vibrate as
a rigid body
GT2009-59108 Turbocharger: Engine Induced Excitations
Integration of housing accelerations
into rotordynamics model
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
Note: TC Housing accelerations and TC shaft motions NOT recorded
simultaneously
GT2009-59108 Turbocharger: Engine Induced Excitations
Housing accelerations into model
Connection to engine mount
Accelerometer
Compressor
housing
Center Housing
Specified housing
motion
due to engine
Semi Floating Ring
Bearing Assembly
Eddy current
sensor
Compressor
Turbine
Shaft
Axial
Bearing
Assembly
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
M Z + (D  G ) Z + K Z  FB(t )  Fext (t )
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
FBX ,Y 
f X ,Y  , R , xS , yS , xS , yS , xR  xB , yR  yB , xR  xB , yR  yB 
Shaft motion
(ring motion – base motion)
GT2009-59108 Turbocharger: Engine Induced Excitations
Housing accelerations into model
Connection to engine mount
Accelerometer
Compressor
housing
Center Housing
Specified housing
motion
due to engine
Semi Floating Ring
Bearing Assembly
Eddy current
sensor
Fourier coefficient decomposition
of housing acceleration time data
0
a(t )  A0 
Compressor
Turbine
NF
 A cos  n t   
n
n 1
Shaft
e
n
Double time
integration
Axial
Bearing
Assembly
NF
x(t )   
n 1
An
 ne 
2
cos  net  n 
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
1st elastic mode
3000
Damped natural frequency (Hz)
100% engine load
cyl. turb. bear. ringing mode
f=2025.2 Hz
d=.1408 zeta
N=80000 rpm
Critical speed
1X
f=621. Hz
d=.5294 zeta
N=80000 rpm
2500
2000
cyl. comp. ringing mode
1500
f=546.5 Hz
d=.2492 zeta
N=80000 rpm
1000
500
conical mode
0
0
20000
40000 60000
80000 100000 120000 140000 160000 180000
Shaft speed (rpm)
f=99.5 Hz
d=.3161 zeta
N=80000 rpm
GT2009-59108 Turbocharger: Engine Induced Excitations
RBS response to imbalance
100% engine load
0.09
Test Data
Test Data
Test data
Nonlinear Pred. - No Housing Motion (1X)
0.08
Nonlinear Pred. Relative to Comp. Housing (1X)
Amplitude 0-pk (-)
0.07
Linear Pred. (1X)
0.06
0.05
0.04
Linear Pred.
0.03
NL pred.
0.02
0.01
Nonlinear Pred.
Differences
between
predictions
and test data
attributed to
inaccurate
knowledge of
imbalance
distribution
u
0.00
0
40000
80000
120000
160000
200000
Shaft Speed (rpm)
C
T
GT2009-59108 Turbocharger: Engine Induced Excitations
Transient time NL rotor response
XLTRC2® Nonlinear numerical integration of equation of motion (timemarching ) 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 direction
shown relative to maximum conical motion at the compressor
shaft end
GT2009-59108 Turbocharger: Engine Induced Excitations
Waterfalls of shaft motion at compressor end 100% engine load
0.25
0.25
Test Data
Predictions with Housing Acceleration
0.2
TC synchronous response
0.15
3.6 krpm
0.1
0.05
Amplitude 0-pk (-)
Amplitude 0-pk (-)
0.2
TC synchronous response
0.15
0.05
1.0 krpm
0
0
500
1000
1500
2000
2500
3000
3500
4000
500
1000
1500
2000
2500
3000
3500
4000
Frequency (Hz)
0.25
Predictions without Housing Acceleration
0.2
TC synchronous response
0.15
1.0 krpm
0
0
Frequency (Hz)
Amplitude 0-pk (-)
3.6 krpm
0.1
3600 rpm
Housing accelerations
induce broad range, low
frequency shaft whirl
motions
3.6 krpm
0.1
0.05
1.0 krpm
0
0
500
1000
1500
2000
2500
Frequency (Hz)
3000
3500
4000
1000 rpm
Test data shows broad
frequency response at low
frequencies (engine
speeds)
GT2009-59108 Turbocharger: Engine Induced Excitations
Total shaft motion at compressor end (amplitude)
0.50
Test Data
pk-pk (-)
Amplitude
Amplitude pk-pk (-)
0.45
Nonlinear Predictions
0.40
Good
correlation
with test data
for all shaft
speeds
Test data
0.35
0.30
0.25
0.20
NL pred.
0.15
0.10
0.05
0.00
0
500
1000
1500
2000
2500
Shaft speed
Rotor
speed(rpm)
(RPM)
100% engine load
3000
3500
4000
GT2009-59108 Turbocharger: Engine Induced Excitations
Subsynchronous amplitudes vs engine speed
Test Data
Test Data Peak Value
Nonlinear Predictions
Predicted Peak Value
0.14
0-pk(-)(-)
Amplitude
Amplitude 0-pk
0.12
Good
agreement
b/w
predictions
and test data
from 1750 –
2750 rpm
0.10
0.08
0.06
0.04
0.02
0.00
0
500
1000
1500
2000
2500
Engine
Engine
speedspeed
(RPM)(rpm)
100% engine load
3000
3500
4000
GT2009-59108 Turbocharger: Engine Induced Excitations
Subsynchronous amplitudes vs engine orders
Test Data
Amplitude
0-pk (-)
0-pk
(-)
Amplitude
0.14
Nonlinear Predictions
2e and 4e
orders
engine
frequency
contribute
the most to
shaft
motions
TC shaft selfexcited freq.
0.12
0.10
0.08
0.06
0.04
0.02
0.00
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Orders
of main
enginespeed
speed
Orders
of main
engine
Fig. 13. Predicted and measured subsynchronous shaft
motion amplitudes versus orders of engine speed
100%
engine nose,
load vertical direction)
(compressor
14e order is
due to shaft
self-excited
vibration
(whirl from
bearings)
GT2009-59108 Turbocharger: Engine Induced Excitations
Sub Synchronousfrequency
Frequency [Hz]
(Hz)
Subsynchronous
Subsynchronous frequency vs. rotor speed
2e frequency shown
Test Data
Nonlinear Predictions
conical mode
cylindrical (comp. bearing ring) mode
cylindrical (turb. bearing ring) mode
1000
800
in test data and
preds
4e frequency tracks
rotor conical mode
1X
600
Group 3 (4C)
~570 Hz
System (manifold & TC)
natural frequency ranges
Subsynchronous
frequencies ~ superharmonics of conical
mode
Group 2 (2C)
400
~300 Hz
4e order
freq.
200
Group 1 (0.5 C)
2e order
freq.
0
0
40000
80000
120000
Shaftspeed
speed(RPM)
(rpm)
Rotor
160000
200000
GT2009-59108 Turbocharger: Engine Induced Excitations
order engine frequencies, most likely due to the engine
Subsynchronous
freq. vs. IC engine speed
firing
(Hz)
frequency
Subsynchronous
Frequency
[Hz]
600
prediction
Nonlinear Predictions
measured
12e 11e 10e
Test Data
550
500
9e
8e
Test
450
7e
TC shaft selfexcited freqs.
400
6e
350
300
5e
250
4e
200
3e
150
100
2e
50
NL1e
0
0
250
500
750
1000 1250 1500 1750 2000 2250 2500 2750 3000 3250 3500 3750 4000
Engine speed (rpm)
Engine speed (RPM)
Subsynch.
freqs. are
multiples of
IC engine
frequency
Higher
engine
order
frequencies
not
predicted
Fig. 15. Predicted and measured subsynchronous whirl
frequencies
TC manifold nat freq.
100% engine load
GT2009-59108 Turbocharger: Engine Induced Excitations
Conclusions
• 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
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
Honeywell Turbocharging Technologies
(2000-2008)
TAMU Turbomachinery Laboratory
Turbomachinery Research Consortium
(XLTRC2®)
Learn more at http://phn.tamu/edu/TRIBgroup
Questions?