EXPERIMENTAL COMPARISON OF LOOP HEAT PIPE PERFORMANCE WITH VARIOUS EVAPORATOR DESIGNS

In order to dissipate the heat generated by electronic boxes for avionic applications, a series of cylindrical copper-methanol LHPs were fabricated and tested at steady-state. Several evaporators were designed, having or not a bayonet or a secondary wick. The test parameters were the heat input, the fluid fill charge, and the elevation of the condenser above the evaporator. The performance of the various LHPs was evaluated in terms of minimum starting heat, maximum heat for which the evaporator reaches the maximum allowable temperature, and total thermal resistance. The results show the great effect of the fluid fill charge and of the orientation on the LHP performance and on its thermal behavior, stable or oscillatory.