Additive-manufactured flat-plate copper pulsating heat pipe for three-dimensional heat spreader

A typical thermal management solution for miniaturized electronic devices with high heat flux values is integrating the heat spreader. Taking advantage of the thin and wickless simple structure of Pulsating Heat Pipes (PHPs), several studies proposed flat-plate PHPs for this application. In most PHP studies, the evaporator and the condenser are located at both ends of the PHP. However, in the practical use, the PHP should spread a centrally located heat source in a three-dimensional direction, achieving high-temperature uniformity in a limited space. In the present study, to investigate this configuration with the evaporator in the center, a flat-plate PHP is proposed for spreading heat of electronic devices with high heat flux up to 50 W/cm2, and its thermal performance was experimentally investigated. The PHP was fabricated using additive manufacturing to create spiral-shaped channels with a 2.4 × 2.4 mm² cross-sectional area. Pure copper was selected as the material for the PHP due to its high thermal conductivity and ease of brazing, although additively manufactured copper PHPs have rarely been reported. Methanol was used as the working fluid. By varying the filling ratio, the optimal range was determined to be between 39% and 59%. The thermal performance was evaluated within four orientations. The thermal resistance in every orientation was less than one-half of that of the empty PHP. The results shown in this work contribute to improving the thermal management of electronics that generate high heat flux by proposing an innovative heat spreader.

Iwata, N., Dupont, V., Accorinti, F., Bozzoli, F., and de Ryckel, A.

Journal of Thermal Science and Engineering Applications, 18(11), 2024. DOI: 10.1115/1.4070528