Zhong Hua, Ouni Asma El, Lin Dan, Wang Bingguo, Brusseau Mark L
Soil, Water, and Environmental Science Department, School of Earth and Environmental Sciences, University of Arizona, Tucson, AZ 85721.
School of Environmental Studies, China University of Geosciences, Wuhan, Hubei, China.
Water Resour Res. 2016 Jul;52(7):5506-5515. doi: 10.1002/2016WR018783. Epub 2016 Jul 24.
Interfacial areas between nonwetting-wetting (NW-W) liquids in natural porous media were measured using a modified version of the interfacial partitioning tracer test (IPTT) method that employed simultaneous two-phase flow conditions, which allowed measurement at NW saturations higher than trapped residual saturation. Measurements were conducted over a range of saturations for a well-sorted quartz sand under three wetting scenarios of primary drainage (PD), secondary imbibition (SI), and secondary drainage (SD). Limited sets of experiments were also conducted for a model glass-bead medium and for a soil. The measured interfacial areas were compared to interfacial areas measured using the standard IPTT method for liquid-liquid systems, which employs residual NW saturations. In addition, the theoretical maximum interfacial areas estimated from the measured data are compared to specific solid surface areas measured with the N/BET method and estimated based on geometrical calculations for smooth spheres. Interfacial areas increase linearly with decreasing water saturation over the range of saturations employed. The maximum interfacial areas determined for the glass beads, which have no surface roughness, are 32±4 and 36±5 cm for PD and SI cycles, respectively. The values are similar to the geometric specific solid surface area (31±2 cm) and the N/BET solid surface area (28±2 cm). The maximum interfacial areas are 274±38, 235±27, and 581±160 cm for the sand for PD, SI, and SD cycles, respectively, and ~7625 cm for the soil for PD and SI. The maximum interfacial areas for the sand and soil are significantly larger than the estimated smooth-sphere specific solid surface areas (107±8 cm and 152±8 cm, respectively), but much smaller than the N/BET solid surface area (1387±92 cm and 55224 cm, respectively). The NW-W interfacial areas measured with the two-phase flow method compare well to values measured using the standard IPTT method.
采用界面分配示踪试验（IPTT）方法的改进版本，在天然多孔介质中测量非湿-湿（NW-W）液体之间的界面面积，该方法采用同时两相流条件，从而能够在高于捕集残余饱和度的NW饱和度下进行测量。在三种润湿情形下，即初次排水（PD）、二次吸水（SI）和二次排水（SD），对分选良好的石英砂在一系列饱和度范围内进行了测量。还针对模型玻璃珠介质和土壤进行了有限组实验。将测得的界面面积与使用标准IPTT方法（用于液-液系统，采用残余NW饱和度）测得的界面面积进行比较。此外，将根据测量数据估算的理论最大界面面积与用N/BET方法测量并基于光滑球体几何计算估算的比固体表面积进行比较。在所采用的饱和度范围内，界面面积随水饱和度降低呈线性增加。对于无表面粗糙度的玻璃珠，PD和SI循环确定的最大界面面积分别为32±4和36±5 cm。这些值与几何比固体表面积（31±2 cm）和N/BET固体表面积（28±2 cm）相似。对于砂，PD、SI和SD循环的最大界面面积分别为274±38、235±27和581±160 cm，对于土壤，PD和SI的最大界面面积约为7625 cm。砂和土壤的最大界面面积明显大于估算的光滑球体比固体表面积（分别为107±8 cm和152±8 cm），但远小于N/BET固体表面积（分别为1387±92 cm和55224 cm）。用两相流方法测得的NW-W界面面积与使用标准IPTT方法测得的值比较吻合。
