Thermal Design of Standard Avionic Enclosures

This paper details the development of standardized avionic enclosures for Naval aircraft, with particular emphasis on the package’s thermal design. The packaging system is unique in that it can accommodate modules of two different standardized sizes (ISEM-2A and 1/2 ATR), and modules having three different cooling modes -conduction cooled, flow-through cooled, and heat pipe cooled. The three module cooling modes, together with required package dissipation rates of 125 watts/MCU and pressure drops below 2.8 mm mercury create a great deal of complexity in the optimization of the thermal system. A computerized optimization program was therefore utilized to achieve specific designs, with results reported for various module mixes and heat exchanger designs.