Topology Optimized Aluminum Heat Sinks for Steady-State and Transient Operation

This study reports the use of numerical topology optimization schemes to design heat sinks for steady-state and transient operation. Using COMSOL 5.6, a circular heat sink design space is considered to model temperature as a function of design fill factor. An initial parameterization of Helmholtz filter (minimum feature size) from 125 to 2000μm and penalization factor from 2 to 7, shows that smaller feature size improves performance. Using a moderate selective laser melting tolerance of 250μm, we perform solid-isotropic-material-with-penalization (SIMP) simulations to show the impact of heat transfer coefficient (from 5 to 100 Wm
^-2
K
^-1
) on fill factor. Intuitively, higher heat transfer coefficient requires less aluminum fin material for a given design point. The transient results are less intuitive and represent a unique progression from a preference for larger quantities of material near the heat source with sparse or nonexistent fins to designs that converge to steady state solutions at large times. It is found that the transient approach is preferred over steady state, particularly for low time steps, where significant weight savings can be realized. These results demonstrate the benefits of transient topology optimization approaches using COMSOL 5.6 and set the stage for future numerical transient mitigation approaches.