Abstract A pore scale numerical method dedicated to the simulation of heat transfer and associated thermo–hydro-mechanical couplings in granular media is described. The proposed thermo–hydro-mechanical approach builds on an existing hydro-mechanical model that employs the discrete element method for simulating the mechanical behavior of dense sphere packings and combines it with the finite volume method for simulating pore space fluid flow and the resulting hydro-mechanical coupling. Within the hydro-mechanical framework, the pore space is discretized as a tetrahedral network whose geometry is defined by the triangulation of discrete element method (DEM) particle centers. It is this discretization of DEM particle contacts and tetrahedral pore spaces that enables the efficient conductive and advective heat transfer models proposed herein. In particular, conductive heat transfer is modeled explicitly between and within solid and fluid phases: across DEM particle contacts, between adjacent tetrahedral pores, and between pores and incident particles. Meanwhile, advective heat transfer is added to the existing implicit fluid flow scheme by estimating mass–energy–flux from pressure induced fluid fluxes. In addition to the heat transfer model, a thermo-mechanical coupling is implemented by considering volume changes based on the thermal expansion of particles and fluid. The conduction and advection models are verified by presenting comparisons to an analytical solution for conduction and a fully resolved numerical solution for conduction and advection. Finally, the relevance of the fully coupled thermo–hydro-mechanical model is illustrated by simulating an experiment where a saturated porous rock sample is subjected to a cyclic temperature loading.

中文翻译：

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颗粒系统的孔隙尺度热-水-力学模型

摘要 描述了一种专门用于模拟颗粒介质中传热和相关热-水-机械耦合的孔隙尺度数值方法。所提出的热-流体-力学方法建立在现有的流体-力学模型的基础上，该模型采用离散元方法来模拟致密球填料的力学行为，并将其与有限体积方法相结合，用于模拟孔隙空间流体流动和由此产生的流体-机械耦合。在流体力学框架内，孔隙空间被离散化为四面体网络，其几何形状由离散元方法 (DEM) 粒子中心的三角剖分定义。正是这种 DEM 粒子接触和四面体孔隙空间的离散化，使得本文提出的有效传导和对流传热模型成为可能。特别是，在固相和流体相之间和内部对传导传热进行了明确建模：跨 DEM 粒子接触、相邻四面体孔之间以及孔和入射粒子之间。同时，通过估计压力引起的流体通量的质量-能量-通量，将平流传热添加到现有的隐式流体流动方案中。除了传热模型外，还通过考虑基于颗粒和流体热膨胀的体积变化来实现热机械耦合。传导和对流模型通过比较传导的解析解和完全解析的传导和平流的数值解来验证。最后，