Zahid Syed, Halkarni Surfarazhussain S
Department of Mechanical Engineering SRM University-AP Andhra Pradesh 522 240, India.
Department of Mathematics SRM University-AP Andhra Pradesh 522 240, India.
Heliyon. 2023 Mar 15;9(3):e14480. doi: 10.1016/j.heliyon.2023.e14480. eCollection 2023 Mar.
The effect of a sinusoidal injection on the fingering instability in a miscible displacement in the application of liquid chromatography, pollutant contamination in aquifers, etc., is investigated. The injection velocity, is characterized by its amplitude of and time-period of . The solute transport, flow in porous media, and mass conservation in a two-dimensional porous media is modeled by the convection-diffusion equation, Darcy's equation, and the continuity equation, respectively. The numerical simulation is performed in COMSOL Multiphysics utilizing a finite-element based approach. The fingering dynamics for various time-period have been studied for two scenarios namely, injection-extraction and extraction-injection ( ). The onset of fingers and vigorous mixing is observed for , whereas for , the onset gets delayed. The viscosity contrast between the sample and the surrounding fluid is characterized by the log-mobility ratio . When the rare interface becomes unstable, while for the frontal interface deformed. In the case of the extraction-injection process attenuates the fingering dynamics, which is beneficial in chromatographic separations or pollutant dispersion in underground aquifers. The injection-extraction process is observed to have a longer mixing length, indicating early interaction between both interfaces. The degree of mixing is more pronounced for injection-extraction scenario and least for extraction-injection . The average convective forces are more dominant for till the deformed rare interface interact with diffusive frontal interface. The average diffusive forces are significant for which can be helpful in separation of chemicals in chromatography. This study therefore provided new insights into the role of alternate injection-extraction injections in altering the fingering dynamics of the miscible sample.
研究了在液相色谱应用、含水层污染物污染等混相驱替中正弦注入对指进不稳定性的影响。注入速度由其振幅 和周期 来表征。溶质传输、多孔介质中的流动以及二维多孔介质中的质量守恒分别由对流扩散方程、达西方程和连续性方程建模。数值模拟在COMSOL Multiphysics中采用基于有限元的方法进行。针对两种情况，即注入 - 提取 和提取 - 注入（ ），研究了不同周期下的指进动力学。对于 ，观察到指状物的出现和剧烈混合，而对于 ，指状物的出现会延迟。样品与周围流体之间的粘度对比由对数迁移率比 来表征。当 时，稀有界面变得不稳定，而当 时，前沿界面变形。在 的情况下，提取 - 注入过程会减弱指进动力学，这在色谱分离或地下含水层中的污染物扩散中是有益的。观察到注入 - 提取过程具有更长的混合长度，表明两个界面之间的早期相互作用。混合程度在注入 - 提取情况下更为明显，在提取 - 注入 情况下最小。对于 ，直到变形的稀有界面与扩散前沿界面相互作用之前，平均对流力更为占主导。对于 ，平均扩散力很显著，这在色谱中化学物质的分离中可能是有帮助的。因此，本研究为交替注入 - 提取注入在改变混相样品指进动力学中的作用提供了新的见解。
