Modeling and Heat Storage Mechanism of Thermal Management Systems Equipped with Paraffin/expanded Graphite Composite

Paraffin waxes are intrinsically reliable latent heat-based thermal reservoirs. However, low thermal transport properties restrict their applications in various systems. In order to overcome these issues, expanded graphite (EG) has been intermingled with paraffin to obtain paraffin/EG composites (PEC) through the chemical impregnation method. PEC has been characterized via differential scanning calorimetry, repeated heating/cooling cycles under thermal shock devices, as well as heat diffusion analysis. Besides, mathematical modeling of heat equations has been proposed, and the heat storage mechanism of thermal management systems has been understood through numerical analysis using ANSYS Fluent. Under energy conservation laws, as-derived phase change heat equation sufficiently describes the simultaneous heat conduction, heat storage, and temperature distributions in thermal management systems. Results show that, after 400 thermal cycles (repeated heating/cooling), heat diffusion of PEC has been slightly reduced, depicting that PEC has great thermal reliability and long life.