Cooling techniques and thermal analysis of circuit board mounted electronic equipment

Computer analysis based on resistance networks have been performed to determine temperature distribution from circuit board mounted electronic components to the ultimate heat sink. All of the thermal resistances, starting from the component mounting base to the heat sink, have been included into the heat flow path. Comparisons of temperature level and distribution have been made between application of conduction paths and heat pipes. Air and liquid have been considered as the ultimate heat sinks. The analytical results indicate that the application of heat pipes can reduce temperature gradients along the circuit board and can reduce equipment temperature significantly. The use of heat pipes, therefore, can simultaneously increase avionics reliability and decrease aircraft TOGW relative to current avionic thermal control technology. Further improvements can be achieved by using liquid instead of air coolants.