Simulation study on flow dependent thermal conductivity of PC/MWCNTs nanocomposites considering interface topography

Abstract A representative-volume-element based numerical investigation was performed to study the thermal conductivity of the polycarbonate/multiwall-carbon-nanotubes (PC/MWCNTs) nanocomposites. The matrix/filler interface topography was modeled using the Cooper–Mikic–Yovanovich (CMY) correlation to consider its effect on the thermal conductivity. The effectiveness of the proposed numerical method was verified with the existing experimental results. Specifically, the flow induced factors were studied in terms of their influence on the nanocomposite's thermal conductivity. Furthermore, the response surface method was applied to identify the importance of the selected factors as well as their interactions. The interfacial thermal conductance was obtained in a broad range of 10 5 ~10 9  W/(m 2 ⋅K) depending on the contact pressure. In addition, the MWCNT orientation and contact pressure were identified as influential factors, and increasing contact pressure had equivalent effect of increasing the MWCNT content. There was an optimum contact pressure producing maximal thermal conductivity with a given MWCNT length and orientation. The thermal conductivity in flow direction exceeded five-fold of that in cross-flow directions for nanocomposites with perfectly oriented MWCNTs, indicating the existence of large thermal conductivity anisotropism.