State of the Art on Pulsating Heat Pipes

In recent years, thermal management of microelectronics is becoming a major feasibility bottleneck and has shown the limitations and shortcomings of conventional solutions. Market expetations are posing a simultaneous challenge of increased power levels coupled with high heat fluxes. Active and passive systems incorporating mini-/micro channel flows are gaining ground to meet the challenges. Both single phase and two-phase flows are under consideration with the latter proving to be better alternatives. Inline with these developments are the Pulsating Heat Pipes (PHPs), which are very attractive entrants in the family of closed passive two-phase heat transfer systems. Research activity in this area has steadily increased after their introduction. These apparently simple looking cooling devices have offered considerable challenges in phenomenological and theoretical understanding. These devices have already shown very high promise for terrestrial applications. They also have a potential for thermal control applications for space. Yet, complete design rules and optimization procedures are still not available. This paper highlights major progress and milestones achieved in the development of this promising technology of pulsating heat pipes in the last decade. A comprehensive review of design rules and modeling strategies available so far is presented. All the influence parameters affecting the thermal performance are explained in detail. Some recommendations for future research are also made.