Passive Oscillatory Heat Transport Systems

Abstract. An underdeveloped class of oscillatory passive heat transport cycles are discussed that have the potential to transport significantly higher heat loads than current heat pipes. Prototype cycles employing inferior working fluids have demonstrated transport of higher heat loads over significantly greater distances than similarly sized heat pipes (including CPLs and LHPs) employing ammonia. Most of the proposed cycles do not require capillary forces to circulate the working fluid. They are also relatively insensitive to gravity and might best be compared to thermal systems using mechanical pumps. The history of development to date of such cycles is presented in relation to other approaches under consideration for various semi/passive thermal control applications. Specific operational characteristics of a select loop are presented. The obvious pros and cons of these systems are discussed as well as potential applications—particularly as regards electronics cooling. REVIEW The extrapolated challenges for advanced electronics thermal control have been well articulated (Mudawar 2000). As the spectrum of cooling requirements continues to widen, designers are forced to remain receptive to new approaches with unique or niche performance advantages over existing and/or competing systems. From small- to large-scale systems, traditional heat pipes (including CPLs and LHPs), thermosyphons, and mechanically pumped loops represent the majority share of the phase-change thermal control/transport solutions