The numerical investigation of the flow regimes in the T-shaped microchannels with different width-to-height aspect ratios of mixing channel was carried out. In the first case, the mixing channel width was varied from 200 m to 1000 m while its height was constant; in the second case, the mixing channel height was varied from 100 m to 2000 m, while its width was constant. The Reynolds number was varied from 5 to 700. The dependences of fluids mixing efficiency and the pressure drop on the Reynolds number at different width-to-height aspect ratios of mixing channel were numerically established. The correlations to determine the critical Reynolds number, as well as the friction factor at different widths and heights of the mixing channel, were proposed. The mixing efficiency, reduced to the pressure drop and the volume unit was analyzed for the first time. The optimal range of parameters in terms of the working efficiency of the micromixer was determined.

Microreaction engineering enables new strategies in process intensification. A precise analysis of local mass transfer and hydrodynamics in micromixers for different flow regimes are strongly needed for a complete understanding the processes occurring. One of the simplest in the manufacture, but at the same time, quite effective T-shaped micromixer was used for numerical investigation and analyzing the mixing quality and flow regimes as well as the influence of different fluids properties on this parameters. It was numerically revealed that the viscosities and the densities, as well as the initial temperatures and the rheology of mixing fluids have significant effects on the flow regimes and the mixing efficiency of two fluids. In this study viscosities and densities ratios of mixing fluids ranged from 1 to 2; the coefficient n in power-law model of non-Newtonian fluids ranged from 0.3 to 1; the initial temperatures difference of two fluids was varied up to 40ºC. Mixture components concentration as well as pressure and velocity fields distribution in the micromixer was obtained. The dependence of fluids mixing efficiency and the pressure drop, as well as a map of flow regimes and mixing modes on the Reynolds number and properties of miscible fluids was numerically established.

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