A Numerical Analysis of Conductive Heat Transfer in Cylindrical Thermal Energy Storage Composites

Abstract

Composite thermal energy storage (TES) materials comprised of highly thermally conductive and thermally capacitive constituent phases have been shown to act as highly responsive thermal heatsinks. Such materials are advantageous for applications involving non-steady heat generation by rapidly transporting heat away from a hot interface, thereby reducing transient hot spots at that interface. Previous research into composite TES materials has been limited to the case of conductive heat transfer in lamellar composites within a Cartesian coordinate system. In contrast, both time-dependent conductive heat transfer, as well as the optimal volume fraction and distribution of constituent phases in TES composites in cylindrical and spherical coordinate systems are poorly understood. Here, we use a finite difference method to investigate time-dependent conductive heat transfer in TES composites for cylindrical geometries with different constituent phase fraction, geometries, and distribution of phases, to investigate time-dependent conductive heat transfer in TES composites for cylindrical geometries. Numerical simulations are completed with varying geometric designs and with a constant heat flux or constant temperature boundary condition. We also identify characteristic behavior under these different boundary conditions and geometries and discuss the length scales over which different behaviors are observed.