Enhanced mixing in dual-mode cylindrical magneto-hydrodynamic (MHD) micromixer

Abstract

The proposed cylindrical magneto-hydrodynamic (MHD) micromixer developed in this study was a geometrically modified conventional T-micromixer combining the characteristics of passive and active micromixers. Characterization was achieved by observing the mixing efficiencies of NaCl solution (1% concentration) based on supplied electrical potential and inlet flow rates. The design mainly aimed to utilize the pumping capability of the magneto-hydrodynamic principle as a secondary element to give counter pumping energy towards inlet flows, such that perturbation of fluid increased mixing performance. NaCl solution was mixed by advection through the stretching and folding by micro-vortices generated in the mixing reservoir. The cylindrical MHD micromixer achieved its highest mixing index of 99.42% at Re = 40 with 3 V of direct-current potential (VDC) supplied to the electrodes. Mixing efficiency increased in a considerably similar and linear pattern for Re = 5, 10, 20, and 40 within the electrical potential range of 0.5 ≤ V ≤ 3.0. Control was gained by manipulating the external electrical potential source which only required a smaller capacity of direct-current voltage sources. Overall, the proposed cylindrical MHD micromixer, which emphasizes the use of inexpensive material and simple design, has been experimentally proven to be practical as compared to the passive and active micromixers found in the literature.

Characterization of a Sub‐Atmospheric Pressure‐Inducing Micropump Based on Flow Rate and Gauge Pressure Measurements

“…The fabricated SAP micropump was tested using three different microfluidic channels, namely, conventional T-shape [27][28][29][30], magneto-hydrodynamic (MHD) [31][32][33], and Tesla microchannels [34][35][36]. The microchannels (Fig.…”

“…Two inlets and one outlet port with a diameter of 3.5 mm were cut through for direct attachment of the inlet and outlet tubing. The engraved sheet was then fixed to another PMMA sheet of the same size [33], and (c) multistage Tesla microchannels [36].…”

“…The mean flow rates measured during attachment with the T-shape [29,30], cylindrical MHD [33], and multistage Tesla microchannels [36] are shown in Tab. 3.…”

Magneto‐hydrodynamic mixing: A new technique for preparing carbomer hydrogels

“…Experimental observations reveal that the magnetic field is responsible for additional shear, electrostatic, tensile, and oscillatory forces. [20][21][22][23] Pairing of turbulent flow with electromagnetic forces creates powerful conditions for dispersing powders, enhancing fragmentation, de-agglomeration, hydration, and solubilization. 24 These mixing conditions can be advantageous to emulsification, scale prevention, dispersion, crystallization, and catalyst preparation processes.…”

“…The impact of a permanent magnetic field on turbulent flowing colloidal system is very complex, 17–19 and even today there is no comprehensive scientific description of the phenomena. Experimental observations reveal that the magnetic field is responsible for additional shear, electrostatic, tensile, and oscillatory forces 20–23 . Pairing of turbulent flow with electromagnetic forces creates powerful conditions for dispersing powders, enhancing fragmentation, de‐agglomeration, hydration, and solubilization 24 .…”