NUMERICAL ANALYSIS OF MIXING PERFORMANCE IN A SPIRAL PASSIVE MICROMIXER

Abstract

This research work possesses a mathematical analysis and contrasting of mixing characteristic and flow behavior inside microchannels with different geometries: Simple T shape and Spiral/Helical shape (with and without nanofluid). Micromixing has become very popular and useful contemporarily. The flow analysis is carried out using Navier-Stokes equations and mixing performance of two fluids, namely; water and dye is numerically calculated. The dye is infused with 1% Al2O3 in the case of a spiral T shape micromixer with nanofluid. The boundary conditions are specified in terms of suitable velocity at the two inlets and the pressure is set as zero static at the micromixer outlet. The mixing performance is calculated concerning mixing index or efficiency of mixing. The spiral T shape mixer creates the vortices and makes the swirling flows even at low Reynolds numbers in comparison to a basic T shape mixer. The circular cross-section at the beginning of mixing spiral microchannel enhances the contact surface area of the fluid by widening the flow. The proposed spiral microchannel is found to be efficient in mixing fluids at a vast range of Reynolds numbers. The three micromixers are observed, analyzed and their mixing index is finally observed at different Reynolds number, namely 5, 45, 165, and 350. This suggested mixer is easy to design and fabricate and provides a wide control for the mixing index based on Reynolds number. The results possess that the mixing in a spiral microchannel is very subtle to the input variables, exhibiting different characteristics at different Reynolds numbers. This research is helpful in the biomedical and biochemical sciences, and their applications in fields such as cell storage, screening, cancer detection techniques, DNA analysis, dynamic cell separators, etc.