Electromagnetohydrodynamic two-phase flow of immiscible electrolytes through an undulating hydrophobic microchannel

The article investigates the complex interplay of electromagnetohydrodynamic (EMHD) forces in a two-phase flow system, focusing on the behavior of immiscible electrolytes within a hydrophobic microchannel with undulating surfaces. It highlights the significant role of surface roughness, which arises from various microfabrication processes, in influencing the performance of microfluidic devices. The study reveals how roughness promotes mixing, interfacial contact, and coalescence-induced separation, crucial for efficient liquid-liquid extraction and separation processes. The geometry of the channel, including irregular walls or bends, is shown to create eddies and vortices that enhance mixing, a phenomenon vital for applications in microfluidics, chemical engineering, and materials sciences. The article delves into the electroosmotic phenomenon, characterized by the movement of electrolyte liquid under an applied electric field, and its quantification through electroosmotic mobility. It explores the impact of magnetic fields on electroosmotic flow (EOF), demonstrating the potential to control EOF for enhanced performance in microfluidic devices. The analytical solutions derived using perturbation techniques provide insights into the effects of roughness on applied potential, electric double layer (EDL) potential, EMHD flow, and volumetric flow rate. The study also examines the boundary layer thickness, offering a comprehensive understanding of fluid flow dynamics in rough microchannels. The findings underscore the importance of considering surface roughness in the design and optimization of microfluidic devices, particularly in applications requiring precise control of fluid flow and separation efficiency.