花岗岩双裂隙热-流耦合参数敏感性

Sensitivity of Thermal-Fluid Coupling Parameters of Granite Double Fractures

为研究岩体热物性参数对渗流传热结果的影响,本文基于离散元3DEC软件,建立了平行双裂隙的热-流耦合数值模型,通过与解析方法进行对照,验证了数值模型的准确性。基于数值模型,研究了不同参数下岩体温度场的分布特征。结合正交试验法,对影响热-流耦合的各参数进行了敏感性分析。结果表明:数值解与解析解的最大误差为3.45%,在合理区间内,表明用该模型研究裂隙中的水流传热问题结果准确可靠。模型运行24 h后,不同方案下裂隙进水口和出水口的温度有所不同,说明不同参数对渗流传热的影响不同。沿裂隙流体流动方向,模型温度对试验参数的敏感程度呈减小趋势,其中裂隙进水口(B点)处岩体比热容、流体速率和裂隙开度极差值分别为10.25、13.80、13.25,说明岩体比热容、流体速率和裂隙开度是影响热-流耦合模型温度的主要因素;而岩体热传导率和流体-岩石传热系数极差值分别为6.53和4.66,表明岩体热传导率和流体-岩石传热系数对模型温度的影响较小。

To study the influence of thermal physical parameters of rock mass on seepage heat transfer results,based on discrete element 3 DEC software,the heat-flow coupling numerical model of granite with parallel double fractures was established,and the model was verified by comparing with the analytical solution.Based on the numerical model,the distribution characteristics of the rock mass temperature field under different parameters were studied.Combined with the orthogonal experiment method,the sensitivity analysis of the parameters affecting the heat-fluid coupling was carried out.The results showed that the maximum error between the numerical solution and the analytical solution was 3.45%,which indicated that the model is accurate and reliable in studying the heat transfer problem of water flow in fractures.After the model runs for 24 h,the temperature of the inlet and outlet of the fracture is different under different schemes,which indicates that different parameters have different effects on the seepage heat transfer.Along the flow direction of fracture fluid,the sensitivity of model temperature to test parameters tends to decrease.The range values of specific heat capacity of rock mass,fluid velocity and fracture opening at the fracture inlet(point B)are 10.25,13.80 and 13.25 respectively.The specific heat capacity of rock mass,fluid velocity and fracture opening were the main factors affecting the temperature of heat flow coupled model.The extreme difference values of rock mass heat conductivity and fluid rock heat transfer coefficient were 6.53 and 4.66,respectively.The rock mass heat conductivity and fluid rock heat transfer coefficient had little influence on the model temperature.