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Advanced electrical power conditioning systems for the More Electric Aircraft Initiative involve high currents and high voltages with the attendant waste heat generation and cooling problems. The use of solid state switching devices such as MCTs for these systems will result in power dissipation of several hundred Watts per square centimeter. Conventional forced air or low velocity single phase fluid cooling is inadequate to handle the waste heat dissipation of these high power devices. More advanced and innovative methods of cooling which can use fluids available in the aircraft and also easy to package are sought. A new approach called “venturi flow cooling concept” is described. It is shown that localized cooling up to 200 W/cm2 is possible at the venturi throat region where the MCTs can be mounted. PAO coolant with Pr = 56 at 40°C can be conveniently used in aircraft.

Experiments were performed to investigate the convective heat transfer from a two-dimensional slot jet of the dielectric liquid PAO to a smooth 15.2 mm by 9.5 mm film resistor surface. The effects of nozzle width, nozzle-to-plate distance, impinging velocity, and liquid properties have been examined. Heat transfer correlations and a discussion of relative parametric effects are provided.

Boiling heat transfer in a water heat pipe is investigated with the objective of relating heat flux and temperature drop across the evaporator. Nucleate boiling has been postulated as the heat transfer mechanism at and near the wall. A correlation has been obtained that relates evaporator heat flux and temperature drop to various screen-wick and working fluid properties. It is shown to agree well with other available experimental data.