Flat plate pulsating heat pipes: A review on the thermohydraulic principles, thermal performances and open issues

Thermal management of modern micro- and high-power electronic systems has become a progressively challenging problem due to current trends in miniaturization increased heat generation. Conventional cooling methods, such as natural force convection, have insufficient meet new challenges electronics industries, transport space applications where thermal system size, mass, autonomy, high density overall reliability play crucial role. Unlike active technologies, pipes are passive transfer devices without moving mechanisms which lead greater reliability, even though they limited by capillary, viscous and/or gravity factors. In contrast, the Pulsating Heat Pipe (also called Oscillating Pipe) recently source increasing interest: first, fascination for complexity internal two-phase phenomena; secondly, novel applications, rapidly Technology Readiness Level this device, both ground environments. pipe manufacturing can be divided into two categories: classical tubular pulsating pipe, flat plate pipe. While former is manufactured developed from single tube enrolled like serpentine around cold sources, latter obtained metallic including an engraved channel, hermetically closed on its top side second plate. These concepts differences operating behavior that worth noting order better understand functioning devices. This paper presents review recent scientific experimental studies flow behaviors pipes, present particular interest their structural dissimilarity compared leading different thermo-hydrodynamic behaviors. The dissimilarities largely explained square or rectangular channels, capillary pumping corners, spreading effect associated with geometrical continuity Local self-induced evaporation demonstrated faster process channels versus circular ones, was confirmed later comparison tests channel shapes FPPHPs. Furthermore, FPPHPs tested horizontal orientation more often subject dry-out evaporator zone than ones. Based these considerations, literature overview local hydrodynamic visualizations physical analyses presented first fully phenomenological aspects, will help analyze following sections on: most influential parameters (channel dimension, fluid/material, conditions); performances attempts at significant improvements and, finally, potentially promising fields application processes applied manufacture pipes. Synthesis appendix highlights effective conductivities many papers flux evaporator, figures Merit hydraulic-diameter-to-capillary-length ratio, showing trend diameter. Lastly, table gathers all available material characteristics conditions literature.