A study of thermal performance in novel radial pulsating heat-pipe systems

As technology becomes increasingly miniaturized, extremely localized heat dissipation (so called hot-spot) leads to the challenge of how to keep devices from overheating. Heat dissipation from advanced power and military electronics is expected to be on the order of 1 kW/cm2, while conventional cooling techniques can only cool up to <10 W/cm2 with forced air convection cooling and <500 W/cm2 with advanced microchannel liquid cooling. In the present study, we propose and investigate a novel radial pulsating heat-pipe (RPHP), which is tailored for effective “spreading of heat” from a local high heat-flux hot-spot. An experimental system for RPHP was constructed with a 110 mm diameter circular brass plate with 1 mm depth and 1 mm width primary channels. The primary channels are enclosed using a polycarbonate cover that is equipped with an internal working fluid charging port. The diameters of the boiling chamber (or evaporator section) and the condenser section were 10 mm and 60 mm, respectively. Thermocouples were installed to measure the temperatures of RPHP surface and the working fluid. The pressure of the fluid in the boiling chamber (evaporator section) was measured using an absolute pressure transducer. The measured data was used to evaluate the thermal performance of the RPHP in terms of thermal resistance with respect to working fluid fill ratio and power input.