Novel radial pulsating heat-pipe for high heat-flux thermal spreading

•Novel radial pulsating heat-pipe (RPHP) has been proposed as a thermal spreader.•The feasibility and the underlying thermal performance of the proposed RPHP was experimentally investigated.•RPHP successfully spread heat and dropped the hot-spot temperature compared to its pure conduction.•Further studies on boiling chamber heat transfer and fluid pulsating enhancements are required. As technology becomes increasingly miniaturized, extremely localized heat dissipation (so called hot-spots) leads to the challenge of how to keep these 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 heat source. 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 was measured using an absolute pressure transducer. The measured data was used to evaluate the thermal performance of the RPHP in terms of convective heat transfer coefficient and thermal resistance with respect to working fluid fill ratio and power input. The study showed that the system was effective at spreading locally concentrated heat; in the study the heater temperature was dropped by 23 °C compared to that of pure heat conduction through the RPHP body in 30 W heater power case.