地下储气库热力耦合数值分析动态边界条件研究

Study of dynamic boundary conditions for thermo-mechanical coupling analysis of underground gas storage cavern

为获取地下储气库围岩热力耦合效应数值分析的边界条件,基于压缩空气质量和能量守恒方程,提出了利用FLAC3D软件求解压缩空气热力学过程及储气库围岩热力耦合数值分析边界条件的确定方法,通过算例验证了压缩空气热力学过程计算方法的正确性。采用数值分析方法研究了充放气条件下的储气库洞壁边界条件的变化特点,分析了围岩初始温度、对流换热系数以及热传导系数对边界条件变化过程的影响。研究表明:地下储气库力学及传热分析边界在运行过程中具有十分显著的动态变化特点,并与压缩空气的状态、洞壁表面热交换特性及围岩热传导特性密切相关。

To obtain the boundary conditions for coupling thermo-mechanical simulation of underground caverns for compressed gas storage, based on the mass and energy conservation equations of compressed air, a calculation method for the solution of thermodynamic process analysis of compressed air and determination of boundary conditions of coupling thermo-mechanical simulation was proposed in software FLAC3 D. The calculation method for thermodynamic process analysis of compressed gas was also validated by an example cited in the paper. The variation characteristics of boundary conditions acting on the cavern wall under the situation of charging and discharging were explored with numerical simulation method. The influences of the initial temperature,the convective heat transfer coefficient and the thermal conductivity of the surrounding rock on the boundary conditions of the cavern wall were also analyzed. The research results show that the boundary of mechanics and heat transfer analysis of underground gas storage cavern has a remarkable dynamic change during operation, which is closely related to the state of compressed air, the heat exchange characteristics of cavern wall surface and the heat conduction characteristics of surrounding rock.