As the electronic technology becomes increasingly integrated and miniaturized, thermal management has become a major challenge for electronic device applications. A heat pipe is a highly efficient two-phase heat transfer device. Due to its simple structure, high thermal conductivity and good temperature uniformity, it has been used in many different industrial fields. A novel aluminum flat heat pipe, with micro-grooves, has in the present work been designed and fabricated by using a 3D printing technology. Aluminum powder was used as a raw material, which was selectively melted and solidified to form the shape of the heat pipe. The sintered aluminum powder increased the roughness of the inner surface of the heat pipe, and the designed micro-grooves further enhanced the capillary forces induced by the wick structure. The wettability, for the working fluid (acetone), was excellent and the capillary forces were sufficient for the working fluid to flow back in the pipe. The effects of working fluid filling ratio, on the heat transfer performance of the heat pipe, was also investigated. It was shown that a filling ratio of 10% gave the best heat transfer performance with the lowest thermal resistance. The 3D-printed flat heat pipe was, therefore, also tested for the thermal management of a LED. The temperature of the LED could be kept within 40 °C and its service life became prolonged.
Mono suspensions of either nanoparticles or microencapsulated phase change material (MPCM) capsules (microcapsules) have shown superior thermophysical properties and heat transfer performance for thermal management. In this study, hybrid suspensions of nanoparticles and MPCM particles were prepared to integrate the advantages of both materials. The properties of hybrid MPCM/nanoparticle suspensions were investigated in terms of dispersion stability and thermal conductivity , and the cooling performance of the hybrid suspensions on thermal management of light-emitting diodes (LED) were studied. The experimental results show that the addition of graphene oxide , titanium dioxide (TiO 2 ), and aluminum oxide (Al 2 O 3 ) nanoparticles effectively improved the dispersion stability of the MPCM suspension (MPCMS). The thermal conductivity of the MPCMS was enhanced by the TiO 2 and Al 2 O 3 nanoparticles. The hybrid MPCM/Al 2 O 3 suspensions, which exhibited remarkable improvement in both dispersion stability and thermal conductivity, were applied to an LED thermal management system. The results show that the cooling performance of the hybrid suspensions was enhanced compared with that of the mono suspensions of MPCM or nanoparticles. The optimal concentration of the hybrid suspension was obtained. The effects of inlet temperature of the hybrid suspensions on the cooling performance were studied.
危险品化学品经营许可证（带存储）