A novel three-dimensional transient model for subsurface heat exchange in enhanced geothermal systems
A novel three-dimensional transient model for subsurface heat exchange in enhanced geothermal systems
复制标题
增强地热系统中地下热交换的新型三维瞬态模型
DOI：
10.1016/j.icheatmasstransfer.2012.11.003
复制
发表时间：
2013-02-01
影响因子：
7
通讯作者：
Chen, Jiliang
中科院分区：
文献类型：
--
作者：
Jiang, Fangming;Luo, Liang;Chen, Jiliang
了解强化型地热系统（EGS）地下热交换过程对提高地热资源的采热效率和地热资源的可持续利用至关重要。在目前的工作中，我们开发了一种新的三维瞬态模型的地下EGS热交换过程的研究。这个模型的新奇体现在几个显著的特征上。首先，感兴趣的几何形状在物理上由多个域组成：用于注入和生产威尔斯井的开放通道、人工热储层和包围热储层的岩石，而在计算上，我们将其视为与不同特征属性（孔隙度和渗透率等）相关联的多个子区域的单域。这就避免了传统多域方法中子域间边界条件匹配的典型困难，便于数值实现和模拟完整的地下热交换过程。其次，将热储层等效为单一孔隙度的多孔介质，考虑了固液组分之间的热不平衡性，引入了两组传热方程，分别描述了流体在岩石孔隙中的热对流和热传导以及岩石基质中的热传导，从而能够模拟和分析岩石基质与在孔中流动的流体之间的对流热交换。以一个虚拟的EGS为例，验证了该模型的有效性。(C)2012爱思唯尔有限公司保留所有权利。
Understanding the subsurface heat exchange process in enhanced geothermal systems (EGS) is crucial to the efficiency of heat extraction and the sustainable utilization of geothermal reservoir. In the present work we develop a novel three-dimensional transient model for the study of the subsurface heat exchange process in EGS. The novelty of this model is embodied by a couple of salient features. First, the geometry of interest physically consists of multiple domains: open channels for injection and production wells, the artificial heat reservoir, and the rock enclosing the heat reservoir, while computationally we treat it as a single-domain of multiple sub-regions associated with different sets of characteristic properties (porosity and permeability etc.). This circumvents typical difficulties about matching boundary conditions between sub-domains in traditional multi-domain approaches and facilitates numerical implementation and simulation of the complete subsurface heat exchange process. Second, the heat reservoir is treated as an equivalent porous medium of a single porosity, while we consider thermal non-equilibrium between solid and fluid components and introduce two sets of heat transfer equations to describe the heat advection and conduction for fluid in rock apertures and the heat conduction in rock matrix, respectively, thus enabling the simulation and analysis of convective heat exchange between rock matrix and fluid flowing in the apertures. Case study with respect to an imaginary EGS demonstrates the validity and capability of the developed model. (C) 2012 Elsevier Ltd. All rights reserved.