Hydrodynamic and mass transfer simulation of two immiscible phases in Y-Y and Spiral microchannels

Microfluidic is a science and technology that studies fluid in volumes of 10-9 to 10-18 liters using channels with dimensions on a micro-scale. One of the most critical applications of this technology is fluid flow analysis. Separation processes in microfluidic devices have received much attention in the last two decades. Among the various separation processes, liquid-liquid extraction has advantages such as low molecular diffusion distance and high interface-specific surface area, leading to efficient mass transfer in microfluidic devices. Stable isotopes are valuable tools for research into mineral availability and metabolism. Stable isotope applications as radiation-free detectors, Diagnosis of the disease, and nuclear imaging can also be used as the primary material or raw material for the production of radiopharmaceuticals, Nuclear imaging, Biochemical analysis, and radiotherapy. Due to the very low abundance of some isotopes, it is essential to separate and concentrate them. This research combines liquid-liquid extraction and microfluidic technology to extract and separate calcium ions as a new method.  In this study, to evaluate the possibility of performing calcium ion extraction simulations, in the studied microfluidic system, the ratio of two-phase velocities was selected so that the current inside the microchannel was flowing in parallel. First, the exact location of the interface was determined by the level set method, then the amount of mass transfer from the aqueous to organic phase was measured using the transport of diluted species method. The microchannel geometry was changed to a spiral geometry, and the extraction rate was investigated to study the effect of geometry on the extraction rate. In the Y-Y microchannel, the extraction efficiency was 60.062%, while in the spiral microchannel, the yield was 71.97%. in other words, by changing the microchannel geometry from Y-Y to the spiral, the mass transfer rate is improved by 11.9%.