Modelling transient heat conduction of granular materials by numerical manifold method

Modelling heat conduction is of significant importance for evaluating temperature effects of granular materials. Since the randomness of the grain structure and the heat resistance characteristics of grain interfaces, to realistically modelling the heat conduction of granular materials, the heat interactive among these random-shaped grains should be correctly reflected. In this study, the numerical manifold method (NMM) is extended to model the transient heat conduction of granular materials. The random-shaped grain structure of granular materials is represented with Voronoi polygons. The heat interactive among grains is realistically simulated by inserting heat conductive cohesive elements between grain boundaries. Besides, an interfacial heat conductivity is defined for the cohesive element to better represent the heat conduct capacity of grain interfaces. As a result, the temperature jumps at grain interfaces are naturally captured due to the dual cover systems of the NMM, while the heat fluxes across the interfaces are assumed to be continuous. To validate the developed numerical method, a benchmark test is carried out. At last, effects of the grain characteristics and interfacial heat resistance on the temperature field as well as the effective heat conductivity (EHC) of a plane consists of granular material are investigated by the developed NMM.