A novel antiparallel flat plate pulsating heat pipe for thermal management of electronics

Thermal management is an intrinsic aspect of the electronics industry, and a flat plate pulsating heat pipe (FPPHP) consisting of multiple capillary channels machined on a flat plate, sealed using another plate, and filled with a working fluid is an ideal choice for flat heat sources. Typically, the FPPHP plate is divided into the evaporator section, where the heat source is attached, and a condenser section, where heat is dissipated all on the same side of the plate. In the present work, the studied FPPHPs have evaporator and condenser sections arranged in a novel antiparallel manner, with the former attached to the bottom half of the FPPHP plate and the latter on the upper half of the cover plate, suitable for many commercial compact electronic housings having space constraints. Two FPPHP configurations are investigated for thermal performance, one with a gasket (Configuration 1) and the other with O-rings (Configuration 2) between the FPPHP and the cover plates for tight sealing between the channels. The condenser section is air-cooled with multiple fins, and the optimum fin length is investigated for maximum thermal performance. A resistance model is presented with the overall thermal resistance between the evaporator and condenser section comprising plate resistance, fluid resistance, condenser resistance, and gasket/O-rings resistance. Configuration 1 has a lesser fluid resistance of a minimum of 55% at 100 W than Configuration 2, as it can hold a larger working fluid volume. However, the overall thermal resistance is lesser in Configuration 2 by 16% over Configuration 1 at higher heat inputs because of better working fluid pulsation. Further superhydrophilic treatment of the FPPHP surface decreases the thermal resistance by 16%, and the impact of the FPPHP material's thermal conductivity, that is, aluminum FPPHP has a decreased thermal resistance of 20% over copper FPPHP, is reported.