A Pore-Scale Computational Model for the Simulation of Mass Transfer From Nonaqueous Phase Liquids

本研究将对多流体多孔介质中的传质过程进行物理描述。通过建立一个孔隙尺度的混相运移模型，并将其与现有的流体-流体驱替的孔隙尺度模型相耦合，可以得到毛细管驱油、流体运动、相间传质和混相污染物运移的完整和自洽的数学描述。利用该模型，传质系数将被预测为界面面积的函数，这将直接与流体饱和有关。模型结果与一些报道的涉及非水相液体(NAPL)溶解的实验室实验的比较将被用来验证该模型。将探索预测的传质系数与毛细压力-饱和度-相对渗透率关系之间的相关性。该模型将被用来研究分散度和流体饱和度之间的函数依赖关系，包括检查可能的滞后。最后，将探讨材料非均质性的影响，重点是有效传质系数和宏观分散度的确定。通过将孔尺度模型预测的连续介质尺度输运性质与更传统的连续介质尺度多相模拟器相耦合，将证明结果的实用价值。

This study will provide a physically-based description of the mass transfer process in multi-fluid porous media. By developing a pore-scale miscible transport model and coupling it with existing pore-scale models for fluid-fluid displacement, a complete and self-consistent mathematical description of capillary displacement, fluid motion, interphase mass transfer, and miscible contaminant transport will be obtained. With this model, mass transfer coefficients will be predicted as functions of interfacial areas, which will be directly related to fluid saturations. comparison of model results to a number of reported laboratory experiments involving non-aqueous phase liquid (NAPL) dissolution will be used to validate the model. Correlations between predicted mass transfer coefficients and capillary pressure-saturation-relative permeability relations will be explored. The model will be used to investigate the functional dependence between dispersivities and fluid saturations, including examination of possible hysteresis. Finally, the influence of material heterogeneity will be explored, with an emphasis on determination of effective mass transfer coefficients and macrodispersivities. The practical utility of the results will be demonstrated by coupling the continuum-scale transport properties predicted by the pore-scale models to more traditional continuum-scale multi-phase simulators.