IVEELV
Created byMichael Berglund
1
A Thermal Hydraulic Modelfor Expendable Launch
Vehicles
Michael Berglund
Delta IV Launch Vehicle Development
May 16-17, 2000
IVEELV
Created byMichael Berglund
2
Outline
Point 1 - Correlation with Test DataRocketdyneThermal analysisDT-1 RCN
Point 2 - Design Tool, Test Transient ConditionsPoint 3 - Common Modeling System
RocketdyneControls group
Point 4 - Good Customer SupportNew Parts Specified
Modeling Hydraulic Systems Using EASY5Summary of EASY5 Process
IVEELV
Created byMichael Berglund
3
Easy5 Model of RS-68 Hydraulic System Heat Transfer Analysis: EJ Reott
ACTUATOR
VERIFICATION
VM fluid output temp
TF2VM FO fluid output temp
(corrected)
TF2
Matches MHI Data
(error +/- 3.7%)
IVEELV
Created byMichael Berglund
4
Easy5 Model of RS-68 Hydraulic System Heat Transfer Analysis: EJ Reott
LINE SEGMENT
VERIFICATION Heat transfer from fluid to
wall (BTUH)
QFPI Heat transfer from fluid to
wall (corrected)
QFPI11 Wall temp
TWPI Wall temp (corrected)
TWPI11 Matches Calculation
(error +/- 0.4%)
IVEELV
Created byMichael Berglund
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Fluid Temp Rise Across OrificeTVC1, TVC2, RCN
EASY5 model: oil temp rise across orifice results:
T = 76°F Hand Calculations: Oil
temp rise across orifice (same conditions) results:
T = 75.9°F
IVEELV
Created byMichael Berglund
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Fluid Temperature Rise In Flight
IVEELV
Created byMichael Berglund
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Development Test Models (major assumptions)
Development Test Models DT_RCN (boundary conditions, spring force)
DT_TVC (boundary conditions, spring + constant force)
DT_Breadboard (valves simulating flow demand for all actuators, single valve representing all 4 engine valves)
DT_System (TVC, RCN actuators included, single valve representing all 4 engine valves)
Hydraulic_System (same as DT_System but with engine valves from Rocketdyne)
IVEELV
Created byMichael Berglund
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EASY5 DT-1 RCN Model
IVEELV
Created byMichael Berglund
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RCN Velocity and Stroke
Stroke & Velocity vs. Time
-20.0
-15.0
-10.0
-5.0
0.0
5.0
10.0
15.0
20.0
0.0 0.5 1.0 1.5 2.0 2.5
Time (sec)
Stro
ke-in
, Vel
ocity
-in/s
ec
Velocity Transducer
LVDT-in.
Calculated LVDT
DT-1 RCN EASY5
IVEELV
Created byMichael Berglund
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Force Data
-3000
-2000
-1000
0
1000
2000
3000
0.0 0.5 1.0 1.5 2.0 2.5Time (sec)
Forc
e (lb
)
Force
DT-1 RCN EASY5
IVEELV
Created byMichael Berglund
11
DT-1 RCN & Model Correlation
Stroke vs. Time
-10.00
-5.00
0.00
5.00
10.00
0.0 0.5 1.0 1.5 2.0 2.5
Time (sec)
Stro
ke-in
, V
elo
city-in
/sec
LVDT-in.
Spring Characteristicsof Air Spring
-3000
-2000
-1000
0
1000
2000
3000
-6.0 -5.0 -4.0 -3.0 -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 5.0
Stroke (in)
Fo
rce (lb
s)
Force Data
-3000
-2000
-1000
0
1000
2000
3000
0.0 0.5 1.0 1.5 2.0 2.5Time (sec)
Fo
rc
e (lb
)
Force
DT-1 RCN EASY5
IVEELV
Created byMichael Berglund
12
Common Modeling System
Rocketdyne Received and integrated
Rocketdyne’s EASY5 model into CBC EASY5 model
Controls Group
IVEELV
Created byMichael Berglund
13
New Components
Found in New EASY5 Library AD (accumulator with an inlet and outlet), Qin, Qout for
both fluid and gas, EFX heat flux PI - Pipe with heat flux VO - Volumes with heat flux
IVEELV
Created byMichael Berglund
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New Accumulator
IVEELV
Created byMichael Berglund
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EASY5 New Components
New Parameters: EFX and QIN EFX defines additional energy
flux into the volume wall. EFX units are BTUH/in2.
QIN defines additional heat generated internally within the fluid. QIN units are BTUH
IVEELV
Created byMichael Berglund
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Conclusions
EASY5 Test correlation Design tool, test transient conditions Common modeling system New parts specified
Recommendation: Continue to use EASY5 to model hydraulic system
IVEELV
Created byMichael Berglund
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Modeling Hydraulic Systems Using EASY5
EASY5 ProcessBuilding a Model
IVEELV
Created byMichael Berglund
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EASY5 Process
Define system and the EASY5 model objective Build Model by Placing and Linking the
Components in the Correct Sequence (use only default or port connection method)
Create an Executable File Find an Initial Operating Point (All Time
Derivatives = Zero) If the Model Equations Converge, Run a
Simulation Plot Any Output As a Function of Time
IVEELV
Created byMichael Berglund
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Building the Model
Start with simple foundation model, ie, valves for actuators, volumes instead of accumulators, no tabular functions, average values
Run to see if results make sense, check with other team members (in the ball park values)
Build on model, make more complex if preliminary model checks out
Make thermodynamic model as simple as reasonably possible because of potentially large simulation times
IVEELV
Created byMichael Berglund
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Actuators Approximated byMetering Valves
Similar to Breadboard Development Testset-up
IVEELV
Created byMichael Berglund
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Model of TVC Actuator
IVEELV
Created byMichael Berglund
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IVEELV
Created byMichael Berglund
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IVEELV
Created byMichael Berglund
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