Advanced cooling techniques comparison for airborne electronic circuits

A comparison of the performances of four different cooling techniques of modular avionics modules (233×150 mm) has been conducted. The cooling methods which have been investigated are conduction through a metallic (aluminum) core embedded in the module and Air Flow Through (AFT) module on one part, using theoretical evaluations, Liquid Flow Through (LFT) module and heat pipe using test results on the other part. The comparison yields the following conclusions. Conduction and AFT modules are limited to a maximum power dissipation in the range of 50 W. Heat pipes allow power dissipations in the range of 150 to 200 W but depending on the technology, their performances can be greatly decreased by gravity, vibrations and acceleration effects; moreover, the market for flat heat pipes of the kind necessary for modular avionics modules is not strong enough yet to support a substantial industrial production. LFT is the best cooling technique since it can allow power dissipations of more than 600 W, which covers more than foreseen needs for modular avionics modules