dynamic modeling of supersonic propulsion systems for aeropropulsoservoelasticity analysis€¦ ·...
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George Kopasakis
NASA Glenn Research Center
Cleveland, Ohio
AeroServoElasticity - AeroPropulsoServoElasticity Fundamental Aeronautics – High Speed Project
Propulsion Control and Diagnostics (PCD) Workshop
Cleveland OH, Dec. 11 – 12, 2013
Dynamic Modeling of Supersonic Propulsion Systems for AeroPropulsoServoElasticity Analysis
Integrated APSE Model
APSE Task Objective
Develop appropriate vehicle models and controls to study the dynamic
performance of supersonic vehicles
Team:
NASA Langley – Develop the structural vehicle models
NASA Glenn – Develop the propulsion system models
Controls and Dynamics Branch (RHC): George Kopasakis, Joseph Connolly
Inlet and Nozzle Branch (RTE): David Friedlander
Multidisciplinary Design Analysis Optimization Branch (RTM): Jonathan Seidel, Jeff Chin
Antenna and Optical Systems Branch (RHA): Noulie Theofylaktos
Thermal Systems Branch (DET): Xiao-Yen Wang
University of Colorado: PhD Research Kyle Woolwine
Ohio State University: PhD Research Joseph Connolly
Both – Develop integrated model and perform
APSE studies
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Fre
eSt
rea
m
Inle
t
Du
ct1
Fan
Spli
tte
r
Du
ctC
ore
HP
C
Du
ct3
Co
mb
ust
or
Du
ct4
0
HP
T
LPT
Du
ct7
Mix
er
DuctBypass
No
zzle
Fre
eE
nd
ShaftHP
ShaftLP
0 1 200 21 22
241 242
221 31 32 4 40 5
shaft_HPC
shaft_Fan shaft_LPT
shaft_HPT
6 7 8 9
Du
ct2
12
Fuel Fuel1
Ble
ed
s3
Bleed_HPC2
Bleed_HPC1 Bleed_LPT2
Bleed_LPT1
4142
45
49
CustBleed
Bleed_Srce2
Bleed_Srce1
Bleed_HPT2
Bleed_HPT1
Bleed_Cust
Overboard
VC
ESp
litt
er
Du
ct4
2
Duct1a200a
VCEFan VCEBypass VCENozzle VCEFreeEnd
222 42a
300 301 302 303
sha
ft_
VC
EFa
n
Variable Cycle Engine 1D Component Dynamic Model & NPSS Cycle Model
Feedback Controls GUI tool & Control Schedules
Parallel Flow Path modeling – 2D Dynamics
10-2
10-1
100
101
102
-10
0
10
20
30
40
frequency, Hz
acou
stic
wav
e ve
loci
ty s
pect
ral,
dB((
m/s
ec/H
z)
von Karman, eddy dissap.=5e-4
TF fit, eddy dissap.=5e-4
von Karman, eddy dissap.=8.5e-5
TF fit, eddy dissap.=8.5e-5
Atmospheric Turbulence Modeling
Shaker
Engines
Wing
APSE System Interfaces – analytical & by testing
Vehicle Structure – CFL3D, FUN3D & State Space
Integrated APSE
APSE
pre
ssu
re [
pa]
Nozzle Modeling – 1D & 2D for Dynamics
Note: Pictures manipulated to remove controlled information
External Compression Inlet CFD Modeling for Dynamics
0 0.5 1 1.50
0.2
0.4
0.6
0.8
1
nozzle length (m)
norm
alized a
rea &
density
nozzle area
final density
initial density
0 0.5 1 1.50
0.2
0.4
0.6
0.8
1
nozzle length (m)
norm
alized a
rea &
density
nozzle area
final density
initial density
0 0.5 1 1.50
0.2
0.4
0.6
0.8
1
nozzle length (m)
norm
alized a
rea &
density
nozzle area
final density
initial density
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Compressor/Fan Test-Bed SIM for Derivation of Control Schedules
Variable Area Dynamic Compressor
SIM
Compressor Plug-Nozzle
SIM
Inlet Conditions As f(N)
P, T, M
𝑊
Compressor Inlet
Conditions
Vs. N
(for Plug Design)
Isolated Compressor Rig SIM - Variable Guide Vane angle as a function of rotor speed
Dynamic Engine SIM
4 Note: Pictures manipulated to remove controlled information
-- Purpose of new control design GUI is to maximize control system performance (stability vs. disturbance rejection & response time).
-- Only information needed is plant transfer function and how fast the plant is driven (plant actuation system response)
-- Robust feedback control designs obtained with couple clicks (normally in the first try) – Robustness also due to auto GUI design of 2 dominant natural controller frequencies. --- Low natural frequency for stability/robustness & for high disturbance rejection in mid frequency range
--- High natural frequency for fast response & for high disturbance rejection
-- GUI control design more tolerable to unmodeled dynamics and tighter stability margins
Feedback Control Design GUI
Step response of CMAPPS fan control system
designed using the GUI
Low natural freq. of control system High natural freq.
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Nozzle Dynamic Characterization
Objective: Develop a dynamically accurate nozzle model to integrate with the rest of the propulsion system
Approach:
-- Develop CFD model to capture shock dynamics
-- Determine the minimum grid resolution necessary for dynamic
accuracy based on developed dynamic accuracy criteria
Nozzle CFD flow field
Nozzle frequency domain response characterization
Note: Pictures manipulated to remove controlled information
Flow
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Integrated AeroPropulsoServoElastic (APSE) Model
Early assessments indicate that closed loop coupling of propulsion and vehicle AeroServoElastic dynamics could be significant enough, that it may not be possible to ignore.
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Assessments of Compressor Stability Margin – realistic dynamics of stall
Test-bed to validate engine Cycle Deck designs, geometry sensitivity due to flow impedances and compressor/turbine dynamic feedback loop, and choked dynamics.
Test-bed to derive exit nozzle area control schedule and design controls to stabilize exit nozzle feedback loop
Test-bed for isolated compressor/plug system to derive compressor IGV control schedules
Perform assessments of the effect of flow distortion on dynamics
Using dynamic engine models as test-beds can substantially reduce costs by performing early design validation studies and by reducing test time of real engine hardware
Dynamic Propulsion System Modeling and Other Potential Applications
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Future Work
Increasingly develop more detailed APSE simulations towards developing in the near future dynamic test-beds in simulation of component systems and a complete integrated vehicle model to conduct APSE performance studies such as ride quality, flight dynamics and vehicle stability, and flight efficiency.
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