Micro-/Nanohierarchical Surfaces for Enhanced Pool Boiling in Large-Area Silicon Multichips

With the rising demand for data centers, the need for an efficient thermal management approach becomes increasingly critical. This study examines the enhancement in pool boiling heat transfer on a customized multichip module, designed to mimic artificial intelligence chip layouts for high-performance computing. Experiments are conducted on smooth surfaces and hierarchical structures integrating micropillars and porous copper, specifically copper inverse opal (CuIO) and copper nanowire (NW). The results demonstrate significant enhancements in critical heat flux (CHF) and heat transfer coefficient (HTC) through these hierarchical structures. Notably, the NW-CuIO-integrated hierarchical structure exhibits the highest CHF (234 W cm-2), achieving a 166% enhancement over smooth silicon. The HTC enhancement is more pronounced for the CuIO-integrated hierarchical structure; this structure achieves an HTC of 70.3 kW m-2 K-1, which represents a 166% improvement. The heater layout, engineered surfaces, and their synergistic effects are analyzed through visualization. The observed boiling inversion phenomena further underscore the importance of sequential activation of nucleation sites in improving boiling performance. This study provides valuable insights into the mechanisms governing the enhancement of boiling heat transfer and offers practical guidance for developing efficient thermal management solutions for data centers.