Experimental investigation of the thermal management of flat-plate closed-loop pulsating heat pipes with interconnecting channels

A desired circulatory flow in flat-plate closed-loop pulsating heat pipes (FP-CLPHPs), which may ameliorate electronic thermal management, was achieved by using the new idea of interconnecting channels (ICs) to decrease flow resistance in one direction and increase the total heat transfer of fluid. In order to experimentally investigate the effects of the IC, two aluminum flat-plate thermal spreaders-one with ICs (IC-FP-CLPHP) and one without them-were fabricated. The FP-CLPHPs were charged with ethanol as working fluid with filling ratios of 35%, 50%, 65%, and 80% by volume. Performance of interconnecting channels in different heat inputs was explored, and the results demonstrated the higher performance of pulsating heat pipes with ICs in comparison with heat pipes without them in a wide range of heat inputs and filling ratios. It has been observed that the most efficient performance of IC-FP-CLPHP occurred at the filling ratio of 65%. Flow visualization indicated that interconnecting channels affect the flow regime and enhance flow circulation and heat transfer in CLPHPs. In furtherance of investigating the viability of the idea, a numerical procedure has been followed on a single-phase liquid to show the role of interconnecting channels in achieving one-way flow.