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为了研究高放射性核废物地下处置库近场的水流-传热耦合问题,采用国内高放废物地下处置库预选场址——甘肃北山地区的花岗岩石块体,加工组合成米尺度的规则裂隙岩体模型,设置边界热源和裂隙水流,试验模拟裂隙水水流与传热之间的相互作用。作为该室内模型试验的前期理论研究,采用等效孔隙介质数值模型,着重分析了裂隙开度、裂隙流量和热源功率对流场和温度场的影响。在设定条件下,计算分析表明:热传导和裂隙水水流由热源作用初期的不耦合很快转化为耦合;不流动的裂隙水主要表现为热存储和热传导,而流动的裂隙水还引起流动传热和水与岩石之间的对流换热,使岩体温度场明显不同于单纯热传导的情况;如果保持裂隙水流量不变,则裂隙开度的变化对水流-传热影响不大;如果保持裂隙水流速不变,则裂隙开度的变化对水流-传热影响显著;热源功率越大,通过裂隙水的热流量越大,裂隙水压强越大,而当温度超过100℃时,裂隙水会因汽化而压强显著增大;加热7 d时,热量的输入和输出几乎相等,裂隙水流带走的热量接近热源供给的热量,模型系统基本达到了热平衡。
In order to study the water flow-heat transfer coupling in the near field of the underground repository for high-level radionuclide waste, the granite blocks in the Beishan area of Gansu, the pre-selected site of the underground high-level waste repository, are grouped into the regular scale- Body model, boundary heat source and fissure flow were set up to simulate the interaction between fissure water flow and heat transfer. As an early theoretical study of the indoor model test, the equivalent porous media numerical model is used to analyze the influence of the crack opening, fracture flow and heat source power on the flow field and the temperature field. Under the set conditions, the calculation and analysis show that the thermal conduction and the fissure water flow are quickly converted into the coupling by the uncoupling of the initial heat source effect. The fissure water does not flow mainly as heat storage and heat conduction, and the flowing fissure water also causes the flow transfer The convective heat transfer between heat and water and rock make the temperature field of rock mass obviously different from that of pure heat conduction. If the flow of fissure water is kept constant, the change of fissure opening has little effect on water flow and heat transfer. Fissure water flow rate is constant, then the change of fissure opening has a significant effect on water flow-heat transfer. The larger the heat source power, the larger the heat flux through fissure water, the greater the water pressure of fissure, and when the temperature exceeds 100 ℃, The pressure will increase significantly due to vaporization. At 7 days of heating, the input and output of heat are almost equal. The heat of fissure water flow is close to the heat supplied by the heat source, and the model system basically reaches the thermal equilibrium.