Electromagnetohydrodynamic Control and Energy Conversion in Narrow Fluidic Devices: A Theoretical Perspective

Abstract

In recent years, electromagnetohydrodynamically modulated control and hydroelectric energy conversion through narrow fluidic devices have emerged as promising means for controlling and manipulating liquid flows in diverse applications. Such processes include development of smart sensors, micrototal analysis systems (μTAS), capillary electrophoresis, electrochromatography, mixing, flow cytometry, DNA hybridization and analysis, cell manipulation, cell patterning, immunoassay, enzymatic reactions, and molecular detection, etc. Accordingly, in the present chapter, we discuss the fundamental theories and elucidate the semi analytical and numerical approaches for analysis of the electromagnetohydrodynamic forces and their effect on thermofluidic control and energy transfer characteristics in narrow fluidic confinements. The consequences of electromagnetohydrodynamic forces and interfacial slip on the streaming potential development has been discussed in detail for pressure driven flows in a narrow fluidic confinement. It has been inferred that wall slip activated electro-magnetohydrodynamic transport can enhance the induced streaming potential and intensifies the convective heat transfer rate. Furthermore, we have also shown an analysis for combined electroosmotic and pressure-driven flows through narrow confinements, subjected to spatially varying non-uniform magnetic field. It is revealed that one can augment heat transfer rate for such a situation by judiciously choosing the spatially varying magnetic field strength. Next, we highlight the collective interaction of the fluid rheology, kinematics, volumetric effects of ionic species (steric effect), and the electrodynamics leading to giant augmentations in the energy conversion efficiency. For all the studies reported above, exergy analysis can indicate the route for optimal designs of process and the reduction in the thermodynamic irreversibility. Finally, the specific points emerging out from the research are concluded and relevant application areas have been discussed.