Topology optimization of liquid metal phase change heat sink with enhanced gradient thermal management for 100 W/cm² heat flux

Abstract

High-power optoelectronic devices, such as high-power lasers and X-ray sources, can generate substantial heat over short durations. Traditional phase change heat sinks are inadequate for managing extreme heat dissipation due to the poor thermal conductivity and low melting enthalpy of phase change materials and the ineffective design of their fin structures. To effectively address the heat flux of up to 100 W/cm², this study introduces a liquid metal phase change heat sink that incorporates topology optimization alongside a gradient phase change structure. The topological fins display a coral-like structure that completely encases the heat sink base, while many branched fins characterize the upper layer. In contrast to traditional straight fins, this coral-like structure effectively reduces heat accumulation in the phase change material located at the base, thereby preventing the formation of localized hotspots. This optimization strategy effectively reduces the temperature at the base of heat sink. Additionally, the innovative application of gradient phase-change material significantly enhances heat dissipation capabilities. This structure enhances the proportion of simultaneous phase changes, facilitating greater heat absorption by the phase-change material through latent heat. Numerical results indicate that the liquid metal phase change heat sink, which features topological fins and a gradient phase-change structure, exhibits significantly better thermal management performance. Specifically, the maximum temperature is 30.23°C lower than conventional straight fins with a heat duration of 10 seconds. The reduction in temperature significantly increases the operational lifespan of electronic chips, presenting an effective solution for high-power devices that necessitate efficient heat dissipation.