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When developing mission-critical equipment, military contractors
demand quick reliable answers to thermal problems. To deliver these
answers, thermal consulting firm, Byrd Technology Group, LLC relies
on Coolit analysis.
Byrd worked with power supply manufacturer, Granite Power
Technologies to develop a vehicle-based power supply headed for
Iraq. The unit is mounted in a sealed cast aluminum housing along
with classified electronics that the military would
identify only by its size and location in the housing and the
power output. To protect against sand and other elements, the
housing is sealed and cooled by natural convection while
operating in a 60C environment.
The power supply is constructed with encapsulated Vicor modules, 2
EMI filter modules feeding 2 DC-DC Converter modules, with integral
heat plates and two PC boards. An aluminum block is sandwiched
vertically between the boards and bolted to them, while the block
base is bolted to the cast housing to complete the path from boards
to ambient.
To build the simulation, Byrd modeled the classified electronics as
a block of equivalent size, shape and power dissipation, but modeled
the power supply in detail. Coolit analysis predicted that the
supply was within its thermal design limits. However, Granite wanted
to quickly assess the accuracy of the CFD model without waiting for
testing under actual conditions.
Byrd suggested benchmarking the model in the lab and edited the
Coolit model to reflect the lab conditions and reran the analysis.
The results impressed Granite; prediction and actuals came within
1C of the measured temp. of 70C on one of the module
baseplates. Interestingly, the analysis identified that the lead
contractor's classified electronics were in thermal trouble and
the contractor was notified.
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