基于复合单元法建立了裂隙岩体渗流-传热耦合的复合单元模型。该模型前处理简便快捷，网格剖分不受限制，可依据裂隙的真实信息自动将其离散在单元内。其次，采用交叉迭代算法，对裂隙岩体的渗流场和温度场进行耦合分析，耦合算法不仅考虑了温度对流体运动黏度的影响，而且可计算裂隙中流体与相邻岩块间渗流-传热过程以及两者间的渗流量和热量交换。通过与已有近似解析解相比较，验证了复合单元耦合算法的可靠性。算例分析表明，渗流-传热耦合作用对裂隙岩体的渗流场和温度场均有一定的影响。分析了不同岩块热传导系数和裂隙开度对热能提取效率的影响，结果显示，岩块热传导系数越大、裂隙开度越大，低温流体从高温岩块中吸取的热能会较多，出口处流体温度下降得较快。

A composite element model is developed for the coupled seepage-heat transfer of fractured rock mass based on the composite element method (CEM). The proposed model has simple and convenient preprocessing function, an unrestricted mesh generating system, and the automatic simulation of fractures in term of their real information in the elements. In addition, the iterative algorithm is employed to perform the coupling analysis of seepage field and temperature field. The influence of thermal on the dynamic viscosity of fluid is considered, and the fluid flow, heat transfer, flow and heat exchange between fractures and the neighboring rock blocks can also be calculated by the iterative algorithm. Moreover, the proposed method is validated by approximately analytical solutions. Numerical examples show that both fluid flow and heat transfer are influenced by the coupling effect of seepage and thermal fields. It is also found that the thermal conductivity coefficients of different rock blocks and fracture aperture affect the effectiveness of heat extraction significantly, and even have direct impact on the outflow temperature. The results demonstrate that the greater fracture aperture is caused by the higher thermal conductivity. Furthermore, the absorbed energy is increased to great extent when the cool fluid flows through the hot rock blocks, but the temperature of the fluid at the outlet decreases quickly.