Transient thermal behavior of various PCM-based heat sinks subjected to pulsed heat flux

The low thermal conductivity of phase change materials (PCMs) constrains cooling performance of PCM-based heat sinks for electronic devices subjected to pulsed operational conditions. In this study, we design and assess four types of heat sinks: paraffin-based heat sink, low melting point alloy (LMPA)-based heat sink, as well as their counterparts with structured porous materials (SPMs). The role of SPMs in augmenting thermal performance of PCM-based heat sink is comprehensively assessed via experiments under three heating loads (10W, 20W, and 30W) and two operational modes (60s on/60s off and 60s on/180s off). Thermal imaging and melting visualization are utilized to compare temperature uniformity and melting characteristics among different configurations. The results demonstrate that SPM integration significantly reduces peak temperatures, achieving reductions of up to 20°C compared to non-SPM configurations. Paraffin-based heat sinks with SPMs demonstrate superior thermal management at lower power inputs, e.g., maintaining base temperature below 60°C at 10W in Mode 2. Conversely, LMPA-based heat sinks with SPMs effectively prolong operating time at higher power levels. These findings highlight the potential of SPMs for improving thermal management performance of heat sinks, offering critical insights for the optimization of advanced passive cooling systems.