A 3D space-marching analytical model for geothermal borehole systems with multiple heat exchangers
A 3D space-marching analytical model for geothermal borehole systems with multiple heat exchangers
复制标题
具有多个热交换器的地热钻孔系统的 3D 空间推进分析模型
DOI：
10.1016/j.applthermaleng.2022.119027
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发表时间：
2022
影响因子：
6.4
通讯作者：
A. Sasmito
中科院分区：
文献类型：
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作者：
M. Hefni;Minghan Xu;Ahmad F. Zueter;F. Hassani;M. A. Eltaher;H. M. Ahmed;H. Saleem;H. Ahmed;Gamal S. A. Hassan;Khaled I. Ahmed;Essam B. Moustafa;E. Ghandourah;A. Sasmito
我们提出了一种新颖的三维（3D）空间推进分析框架，可以准确预测和评估具有单个或多个n × n热交换器的地热钻孔系统的热性能。这个与这项工作的关键创新有关的模型的程序有三个方面。首先，通过使用格林函数的精确解来求解单个井眼布置中的径向温度分布。在井壁周围规定了随时间变化的对流边界。其次，通过空间推进算法计算单孔的轴向温度分布，该算法通过能量平衡获得传热流体（HTF）温度，从而更新每个深度的对流边界。第三，根据每个井眼的位置，通过代数方程的热叠加，将二维的单个井眼扩展到三维的n × n排列。利用有限元方法对所建立的三维模型进行了数值验证，并与文献中有关HTF温度的现场实验数据进行了验证。进一步研究了井眼距离、地面导热系数和质量流率对高温射流的影响。可以得出结论，该三维空间推进分析框架能够以准确且计算高效的方式预测受时间依赖边界影响的任意n × n地热钻孔的瞬态温度分布，从而促进地热系统的热设计和能源提取。
We present a novel, three-dimensional (3D), space-marching analytical framework that accurately predicts and evaluates the thermal performance of a geothermal borehole system with single or multiple N-by-N heat exchangers. The procedure for this model which is associated with the key novelties of this work is threefold. First, a radial temperature profile in a single borehole arrangement is solved through an exact solution using the Green’s function. A time-dependent convective boundary is prescribed around the borehole wall. Second, an axial temperature distribution in this single borehole is calculated by a space-marching algorithm, which updates the convective boundary at every depth by obtaining the heat transfer fluid (HTF) temperature via an energy balance. Third, the single borehole in 2D is extended to a N-by-N arrangement in 3D by the thermal superposition with algebraic equation based on each borehole’s location. The developed 3D model is verified with numerical results using the finite element method and validated against a field-scaled experimental data in the literature in regards to the HTF temperature. Further, the influences of borehole distance, ground thermal conductivity and mass flow rate of the HTF are studied. It can be concluded that this 3D space-marching analytical framework is capable of predicting transient temperature profile of any N-by-N geothermal boreholes subjected to a time-dependent boundary in an accurate and computationally efficient manner, which in turn facilitates the thermal design and implementation of geothermal systems for energy extraction.