Multiscale thermal analysis of diamond/Cu composites for thermal management applications by combining lattice Boltzmann and finite element methods

Abstract

To meet the cooling demands of high-power electronic devices, diamond/Cu composites (D/Cu) have attracted extensive attention as next-generation thermal management materials. However, the heat transfer mechanism of D/Cu across micro-nano and macro scales remains unclear. This study establishes a physical geometric model of D/Cu and investigates the impact of micro-nano scale diamond particles on thermal conductivity by integrating the mesoscopic lattice Boltzmann method with macroscopic finite element method. The results show that the sharp edges of the particles tend to reflect and scatter phonons, thereby influencing heat transfer. The thermal conductivity of the composite increases with the diamond particle size and exhibits a particle size threshold; diamond particles contribute to the improvement of thermal conductivity only when their size exceeds 22 μm. Additionally, secondary diamond particles effectively enhance thermal conductivity; on the other hand, the interfacial area introduced cannot be ignored. For a fixed diamond volume fraction, smaller particle size ratio of bimodal diamond particles lead to greater improvements in thermal performance.