Heat transfer of graphene foams and carbon nanotube forests under forced convection

Abstract

The effective dissipation of heat from electronic devices is essential to enable their long-term operation and their further miniaturization. Graphene foams (GF) and carbon nanotube (CNT) forests are promising materials for thermal applications, including heat dissipation, due to their excellent thermal conduction and low thermal interface resistance. Here, we study the heat transfer characteristics of these two materials under forced convection. We applied controlled airflow to heated samples of GF and CNT forests while recording their temperature using infrared micro-thermography. Then, we analyzed the samples using finite-element simulations in conjunction with a genetic optimization algorithm, and we extracted their heat fluxes in both the horizontal and vertical directions. We found that boundary layers have a profound impact on the heat transfer characteristics of our samples, as they reduce the heat transfer in the horizontal direction. The heat transfer in the vertical direction, on the other hand, is dominated by the material conduction and is much higher than the horizontal heat transfer. Accordingly, we uncover the fundamental thermal behavior of GF and CNT forests, paving the way toward their successful integration into thermal applications, including cooling devices.