Enhanced heat transfer performance in vapor chambers via fabrication of novel regular composite porous wick structures using selective laser melting

The composite structure wick has been proven to significantly enhance the heat transfer performance of vapor chambers. Aluminum vapor chambers offer advantages such as being lightweight and cost-effective, meeting the requirements for lightweight cooling in fields like aviation. This study presented two novel composite porous wick structures with regular-shaped pores, designed and controlled via selective laser melting (SLM): the vertical square pore composite wick structure and the round-vertical square pore composite wick structure. A water-cooling test platform was built to investigate the effects of parameters such as wick structure thickness, round pore diameter, and round pore depth on the heat transfer performance and thermal resistance of the vapor chambers. The results indicate that the optimal thickness for the vertical square pore composite wick structure was 1.5 mm, yielding a minimum thermal resistance of 0.04 K/W. When the thickness was below 1.5 mm, it caused a reduction in the density of the vaporized core and insufficient liquid transport capacity. Conversely, when the thickness exceeded 1.5 mm, the primary limiting factor for heat transfer shifts to vapor-liquid flow resistance. Furthermore, the round-vertical square pore composite wick structure can provide further improvements in vapor-liquid transport within the structure.