Three-dimensional finite discrete element-based contact heat transfer model considering thermal cracking in continuous–discontinuous media

Abstract

This paper proposes a three-dimensional heat transfer model that considers contact heat transfer and thermal cracking in continuous–discontinuous media. The 3D heat transfer model comprises the heat conduction model inside the continuum and the contact heat transfer model between discrete blocks. The model is combined with the 3D Finite Discrete Element (FDEM) for coupled thermo-mechanical calculation, which includes the following three parts: the temperature distribution of the system is obtained by the 3D heat transfer model considering contact heat transfer; then, the thermal stress caused by the temperature is applied to the system equation to perform the mechanical fracture calculation; finally, the heat exchange coefficient of the newly generated broken joint element is updated for heat transfer calculation at the next time. Some examples are given to verify the 3D contact heat transfer model with analytical solutions. Moreover, the influence of the heat exchange coefficient of the joint element and the contact heat transfer coefficient is discussed. Finally, examples of contact heat conduction in 3D granular assemblage, and thermal cracking caused by contact heat transfer are demonstrated. These examples demonstrated excellent capacity of the model in simulating contact heat transfer and thermal cracking in continuous–discontinuous media.