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Miltope is using Coolit to validate the thermal design characteristics
of the In-Flight Entertainment Control Panel. The results have been
used to more accurately model new designs to meet both thermal and
pressure drop requirements.
The control panel was designed to not only efficiently cool internal
components but to keep the enclosure surfaces at or below "touch
temperature requirements". Because the aluminum enclosure was used
as a heat sink to cool many components, the surface temperatures
were above the requirements. The final design incorporated two small
internal fans to pull ambient air from one side of the enclosure
and exhaust out the opposite side.
Coolit was used to model the control panel, both with and without
fans. The initial model, without fans, showed that the enclosure
surfaces were too hot and would require active cooling. The model
was then changed with the addition of fans. The fans were modeled
with pressure drop vs. CFM data obtained from the manufacturer.
Lab data was then used to properly model intake and exhaust vent
flow characteristics (i.e. pressure drops). Once the proper vent
parameters were used, Coolit found the amount of CFM of air moved
by the fans and solved for temperatures. The results matched very
well with the actual lab measurements.
|
Coolit prediction (deg. C) |
Measured (deg. C) |
| Exhaust vent air temperature |
36.0 |
38.1 |
| CPU temperature |
48.7 |
50.2 |
| Back surface temperature |
38.7 |
39.0 |
Many enclosures on aircraft are cooled by a central plenum, which
is common to other equipment. This requires the enclosures to meet
temperature requirements at a specified pressure drop and CFM of
cooling air. The information learned from modeling the Control Panel
has been valuable in designing new enclosures. Proper vent sizing
and arrangement, and fan sizing can be more easily optimized using
Coolit.
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