IV EELV Created by Michael Berglund 1 A Thermal Hydraulic Model for Expendable Launch Vehicles Michael Berglund Delta IV Launch Vehicle Development May 16-17, 2000

IV EELV Created by Michael Berglund 2 Outline  Point 1 - Correlation with Test Data  Rocketdyne  Thermal analysis  DT-1 RCN  Point 2 - Design Tool, Test Transient Conditions  Point 3 - Common Modeling System  Rocketdyne  Controls group  Point 4 - Good Customer Support  New Parts Specified  Modeling Hydraulic Systems Using EASY5  Summary of EASY5 Process

IV EELV Created by Michael 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%)

IV EELV Created by Michael 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%)

IV EELV Created by Michael Berglund 5 Fluid Temp Rise Across Orifice TVC1, 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

IV EELV Created by Michael Berglund 6 Fluid Temperature Rise In Flight

IV EELV Created by Michael Berglund 7 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)

IV EELV Created by Michael Berglund 8 EASY5 DT-1 RCN Model

IV EELV Created by Michael Berglund 9 RCN Velocity and Stroke DT-1 RCN EASY5

IV EELV Created by Michael Berglund 10 DT-1 RCNEASY5

IV EELV Created by Michael Berglund 11 DT-1 RCN & Model Correlation DT-1 RCN EASY5

IV EELV Created by Michael Berglund 12 Common Modeling System  Rocketdyne  Received and integrated Rocketdyne’s EASY5 model into CBC EASY5 model  Controls Group

IV EELV Created by Michael 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

IV EELV Created by Michael Berglund 14 New Accumulator

IV EELV Created by Michael Berglund 15 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

IV EELV Created by Michael Berglund 16 Conclusions  EASY5  Test correlation  Design tool, test transient conditions  Common modeling system  New parts specified  Recommendation: Continue to use EASY5 to model hydraulic system

IV EELV Created by Michael Berglund 17 Modeling Hydraulic Systems Using EASY5  EASY5 Process  Building a Model

IV EELV Created by Michael Berglund 18 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

IV EELV Created by Michael Berglund 19 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

IV EELV Created by Michael Berglund 20 Actuators Approximated by Metering Valves Similar to Breadboard Development Test set-up

IV EELV Created by Michael Berglund 21 Model of TVC Actuator

IV EELV Created by Michael Berglund 22

IV EELV Created by Michael Berglund 23

IV EELV Created by Michael Berglund 24