Multi-material topology optimization of innovative microchannel heat sinks equipped with metal foams

Microchannel heat sinks (MCHSs) play a pivotal role in numerous fields, including electronics cooling, chemical processing, and biomedical applications. Conventional design approaches for MCHSs often rely on predefined geometries or empirical trial-and-error methods, limiting the exploration of the design space and leading to suboptimal performance. Density-based topology optimization (TO), on the other hand, leverages gradient-based procedure to systematically explore and optimize the material distribution within MCHSs. On these premises, this work aims to study the combined use of porous materials like metal foams and TO in a multi-material topology optimization (MMTO) to improve MCHS thermo-fluid dynamic performance. Starting from a baseline design, a 2D numerical model has been developed with a conjugate heat transfer formulation, i.e., the governing equations of heat conduction inside solid material, and forced convection inside fluid/foam domains. For the multi-material topology optimization, the solid isotropic material with penalization (SIMP) model with two pseudo densities is used to handle the three phases problem. By strategically placing solid and foam materials, the aim is to balance the trade-off between low-pressure drop and high heat transfer rate. Overall, the optimized designs, i.e., TO and MMTO-based, turn out to be nonintuitive and show significantly higher thermo-fluid dynamic performance when both compared to a baseline case, with a reduction in the required pumping power up to 88 % at constrained inlet velocity. The MMTO microchannel, compared to the one developed with topology optimization, improves the performance evaluation criteria (PEC) of about 59–84 % at different fixed pressure drop and inlet velocities. Moreover, the weight saving – with respect to the baseline case – is assessed to range from 80 % to 83 %. This newly-designed devices might be really helpful to improve the thermal performance of available microchannel heat sinks.