结合化学反应方程式,并应用多孔多相介质溶混污染物输运过程的数值模型,对多孔多相介质中含均相/非均相化学反应传质过程进行了数值模拟。化学反应主要包含均相快速/慢速和非均相快速/慢速等5种化学反应过程,溶质输运行为的控制机制主要考虑对流、扩散及降解、吸附等。基于原有的隐式特征线Galerkin离散化的有限元方法,求解模型控制方程的边值初值问题,求解过程中把均相化学反应物质中按照反应物和生成物分开,非均相反应物质按照固相和液相分开,对均相反应物及非均相液相物质浓度耦合求解,而均相生成物和非均相固相物质独立求解。使方程组按照其不同类型进行分类,同时可减少未知数的个数。对于含有非线性内状态变量的右端项进行迭代求解。数值例题结果验证了所提出的数值方法的有效性、计算精度和稳定性。
A framework for numerical modelling of miscible contaminant transport contained homogeneous/heterogeneous chemical reactions in porous media is presented. The mathematical model of the chemical-reacting processes integrates the homogeneous fast/slow and heteroneneous fast/slow governing phenomena. The transport behaviors of governing processes mainly include: convection, diffusion and degradation, adsorption etc. A finite element method based on the implicit characteristic Galerkin discretization is used to numerically solve the initial and boundary value problem for the model governing equations. The solving process separates the reactants and products in the homogeneous chemical reactions and the material in liquid and solid phases in heterogeneous reactions. The reactants in homogeneous reactions and chemical cations in liquid phase of heterogeneous reactions are simulated as the basic unknowns. The products in homogeneous reactions and the chemical cations in solid phase of heterogeneous reactions are solved individually. The different governing equations, then, can be classified as its intrinsic nature. The unknowns are also decreased by such treatments. The iterative operation is performed for the reason of the nonlinear right side contained the internal state variables. The numerical results and the stability analysis of the algorithm validate good performance of the present model and efficiency, accuracy and stability of the present numerical method.