A Numerical Study of the Effects of Narrow Channel Dimensions on Pressure Drop and Mass Transfer Performance of a Mixer Device

The numerical study in this paper investigates the effect of inlet and outlet areas of micromixer channels on fluid flow behavior and mass transfer performance. The ratio of the outlet to the junction area is varied from 0.6−2 while the ratio of the inlet to junction area is from 0.6−1.4. The flow patterns obtained for various mixers indicate that vortices or recirculation zones are created as the two fluids turn and enter the outlet channel. The formation of recirculation regions results in enhanced mixing rates. The micromixers are evaluated in terms of mixing quality, pressure drop, and mixing effectiveness parameters. The mixing quality increases up to 10 times when the outlet area ratio increases from 0.6 to 2. The rise in pressure drop due to the increased outlet area is about 50%. The inlet area also influences the mixing rate and pressure drop. The mixing quality first increases and then decreases with an increase in area. The pressure drop, whereas, continuously decreases when the inlet area ratio increases from 0.6 to 1.4.  Suitable dimensions of micromixers are suggested based on mixing effectiveness. A mixer device with an outlet/junction area ratio of 1.2 and an inlet/junction area ratio 0.8−1 is found to provide better performance.