Characterization of polypropylene pulsating heat stripes: Effects of orientation, heat transfer fluid, and loop geometry

A parametric analysis of the thermal performance of flat polypropylene pulsating heat pipes (PHPs) is presented. In particular, the thermal performance was characterized for pulsating heat pipes with different number of turns of the serpentine channel, different orientations with respect to gravity, and containing different heat transfer fluids. The dependence of polymeric PHPs performance on design parameters is poorly understood to date. The development of polymeric PHPs characterized by high mechanical flexibility will have significant impact on thermal management of smartphones, portable electronics, and deployable systems such as cube satellites. Several prototype PHPs with different number of turns of the serpentine channel were fabricated bonding together three polypropylene sheets by selective transmission laser welding, after cutting out a serpentine channel in the central sheet. The thermal performance of the devices was characterized by supplying an ascending/descending stepped thermal power ramp to the evaporator, and measuring the corresponding equivalent thermal resistance between the evaporator and the condenser.