Numerical and experimental study of passive fluids mixing in micro-channels of different configurations

This paper represents a numerical and experimental investigation of fluids mixing in straight and serpentine micro-channels. These microchannels are fabricated with the help of soft lithography technique. The width of straight and serpentine micro-channels after fabrication is obtained around 335 and 282 µm respectively. Numerical simulations of fluids mixing in micro-channels are performed by solving momentum, continuity and mass diffusion equations. Mixing performance has been evaluated in three average inlet velocities such as 0.001, 0.007 and 0.0167 m/s. The numerical results show that in serpentine micro-channel, an effective mixing has been achieved in almost all the flow conditions whereas in straight channel that is achieved for 0.001 m/s velocity only. Water and water-KMnO₄ solution are used as working fluids in this study. The experimental results show that the mixing efficiency of around 95.5, 70.20, and 48.54% has been achieved for straight channel at inlet velocities 0.001, 0.007 and 0.0167 m/s respectively. However, in serpentine micro-channel, the mixing efficiency has been achieved around 97.12, 95.10, and 65.21% at inlet velocities 0.007, 0.0167 and 0.03 m/s respectively. Moreover, the experimental results are compared with the numerical results where it has been observed that the results are quite identical to each other.