Passive Two-Phase FADEC Cooling System

Rejecting heat from a FADEC unit 2m away over a temperature differential of only 13oC results in a very challenging problem for a LHP cycle, especially when considering the body forces expected on an aircraft. An ideal LHP cycle with only hydrostatic pressure head considerations shows that ammonia is the only fluid that could potentially provide 2m of coolant transport. Even with ammonia, a combination of heat leak to the compensation chamber, high ambient environment, high internal pressure, high g maneuver and low temperature budget makes it unlikely that a LHP can transport heat from the FADEC to the heat sink. RTI proposes to instead use their innovative Liquid Retention Evaporator for a Loop Thermosyphon which rightly suits the needs of this cooling problem. The Loop Thermosyphon offers a passive long-distance/low-temperature-differential cooling application which when combined with the Liquid Retention Evaporator can offer a huge cooling buffer for transient high g periods, lasting minutes.