1. Projects Overview Air Bag Inflator Bonfire Test
Air Bag Inflator Weld Study
Compact Heat Exchanger for Aircraft
Fuel Cooled Oil Cooler Fire Test
Halogen Light Fixture
Solar Water Heater
Radiative Heating of Aircraft Strut by Hot Exhaust Pipe
Electronics Board
Pinckney Engineering International
(480)

2. Air Bag Inflator Bonfire Test
Pinckney Consulting
(480)

3. 400 OC Boundary conditions on bottom surfaces of pressurized inflator
400 OC Boundary conditions on bottom surfaces of pressurized inflator. Gas pressure increases until burst disk ruptures.
Air is modeled as a single node
Contact Segments used to connect air node and inside walls of inflator
Gas pressure is calculated as heat is added until burst disk ruptures
Convection is increased during venting
Sonic and subsonic flow regimes are modeled

4. Graph capturing rupture of burst disk and temperatures at locations within the pressure vessel at time of bursting.
Output interval is decreased during venting

5. Air Bag Inflator Weld Process Study
John Pinckney
(480)

6. Find Temperatures in Areas that Contain the Propellant
During the Welding Process
Cap Welded to Bottle
Propellant
Location

7. Apply Weld Heat to Nodes on Edge of Cap

8. Turn On Conductors Between Cap and Bottle as Weld Progresses

14. Transient Thermal Analysis of Compact Cross Flow Heat Exchanger for Aviation Application
Pulsed hot air operation
Modeled using innovative technique of applying fin equations within SINDA/G for Femap
Results used for performance and thermal stress analysis
By John Pinckney
(480)

15. Super Fin sections modeled as three nodes with two conductors and two heat terms.
See: Fundamentals of Heat Exchanger Design. Ramesh K. Shah, Dusan P. Sekulic. John Wiley & Sons, Hobeken, New Jersey. 2003
is difference in temperatures between air stream and fin location.

16. The fin equations are necessary because large errors will result in the convective heat transfer calculations otherwise. It is impractical to mesh fins fine enough to accurately capture the fin temperature profile.
A fin temperature profile.

17. Convection conductors (shown in red) from air streams to parting plates were constructed by using the Contact Segments Algorithm.

18. Initial temperatures are steady state with steady flow.

19. Letter of Appreciation for Phase 1

20. Fuel Cooled Oil Cooler Fire Test
John Pinckney
(480)

21. Goals
Find fluid and wall temperatures after 15 minutes under conditions of onboard fire.
Wall temperature to be < 380 oC.
Recommend any design changes.
Boundary Conditions:
Heat flux of 120,000 watts/m2 is the assumed fire conditions.
Fuel and oil inlet temperatures are 20 oC and 95 respectively oC.

22. Heat Exchanger Efficiency used in SINDA/G Model to Calculate Outlet Temperatures
Convection coefficient is calculated using correlation.
NTU method is used for calculating heat exchanger efficiency.
Efficiency used to compute fluid outlet temperatures.
Efficiency for cross-flow heat exchanger.

23. Results
The wall temperatures greatly exceeded the adverse service specifications.
Consider convection enhancement of adding pin fins.

24. Use correlation to compute convection coefficient from the pins.
Compute pin efficiency and overall efficiency.

25. 300 pin fins to the surface of the cover plates would be sufficient to meet adverse service temperature specifications.

26. Thermal Analysis of Recessed Halogen Light Fixture
John Pinckney
(480)

27. Halogen Light Fixture Model
View factors computed using Nevada.
McAdams relations update convection conductors.

28. Temperature Results with Convection
Reflector
(oC)
Bulb
Lens
Schematic
192
989
123
Nevada/Femap
193
991
115

29. Solar Water Heater Study
Day in the life of a solar water heater in Phoenix Arizona on Dec 21st .
One-way conductors are used for water flow.
Radiation to the sky and convection to ambient air is accounted for.
Pinckney Engineering International
(480)

30. Convection Correlation Used to Compute Convection from Collector to Air.
SINDA/G User’s Guide, Network Analysis Copyright © 2005

32. Radiative Heating of Aircraft Strut by Hot Exhaust Pipe
Pinckney Engineering International
(480)

33. Native CAD Geometry is Overly Complex
The CAD geometry is too complex to model for current Monte Carlo radiation solvers. A fully meshed strut contains almost 48,000 elements. Ray tracing from all the element faces would take days. The geometry must be simplified before exporting to a radiation solver.

34. A preliminary model can be constructed in Nevada
A preliminary model can be constructed in Nevada. The model contains all the essential features. Here the pipe is modeled as a straight cylinder.
The radiation conductors between surfaces are computed by Nevada and the thermal results obtained by SINDA/G.

35. New geometry in constructed in Femap using the basic dimensions of the strut.

36. The simplified geometry was meshed and model analyzed.

37. The results of the two models compared.

38. Add a radiation shield to the pipe.

39. The effect of the radiation shield on temperatures.

40. Thermal Analysis of Electronics Board
Pinckney Engineering International
(480)

41. Surfaces for component footprints are placed on the board.
Powers are assigned to components on the board.
Top and bottom of board set to card guide temperatures of chassis, 71.2 OC and 74.7 OC, respectively.

42. Model is analyzed and temperatures plotted.

43. A slightly different board layout is considered.
Components are easily moved on the board since they are represented by independent surfaces.

44. The new layout is analyzed.

45. A Component Report is generated.
Part #
Location
Power
ThetaCB
ThetaJC
Tboard
Tjunction
TjMax
SMargin
LM1336 C1
0.65
9.6 20
88.7
107.94
125
-17.06 C2
87.9
107.14
-17.86 C3
90.7
109.94
-15.06
LM1398 C4
0.56
11.2 30
84.7
LMC140A C6
0.22
87.2
96.264 C8
92.1
C10
90.6
99.664
The average of absolute value of SMargin is increased by 40% with new board layout.