Investigations into mixing of fluids in microchannels with lateral obstructions
- 706 Downloads
This work presents a study of a passive micromixer with lateral obstructions along a microchannel. The mixing process is simulated by solving the continuity, momentum and diffusion equations. The mixing performance is quantified in terms of a parameter called ‘mixing efficiency’. A comparison of mixing efficiencies with and without obstructions clearly indicates the benefit of having obstructions along the microchannel. The numerical model was validated by comparing simulation results with experimental results for a micromixer. An extensive parametric study was carried out to investigate the influence of the geometrical and operational parameters in terms of the mixing efficiency and pressure drop, which are two important criteria for the design of micromixers. A very interesting observation reveals that there exists a critical Reynolds number (Re cr ~ 100) below which the mixing process is diffusion dominated and thus the mixing efficiency is reduced with increase in Re and above which the mixing process is advection dominated and mixing efficiency increases with increase in Re. Microchannels with symmetric and staggered protrusion arrangements were studied and compared. The mixing performance of the staggered arrangement was comparable with that of symmetric arrangement but the pressure drop was lower in the case of staggered arrangements making it more suitable.
KeywordsPressure Drop Microfluidic Chip Critical Reynolds Number Active Mixer Symmetric Arrangement
The authors would like to acknowledge the Science and Engineering Research Council (SERC), Department of Science and Technology (DST), India for providing financial support for the project.
- Evans J, Liepmann D, Pisano AP (1997) Planar laminar mixer. Proceedings of the 10th IEEE international workshop on micro electro mechanical systems (MEMS’97), Nagoya, Japan, pp 96–101 Google Scholar
- Howell PB, Mott DR, Golden JP, Ligler FS (2004) Design and evaluation of a Dean vortex-based micromixer Miniaturisation for Chemistry. Biol Bioeng 4:663–669Google Scholar
- Lee YK, Deval J, Ho CM, Tabeling P (2001) Chaotic mixing in electrokinetically and pressure driven micro flows. Proc. MEMS’01, 14th IEEE Int. workshop micro electromechanical system (Interlaken, Switzerland) 483–486Google Scholar
- Miyake R, Lammerink TSJ, Elwenspoek M, Fluitman JHJ (1993) Micro mixer with fast diffusion. Proceedings of the 6th IEEE int workshop on MEMS’93. Fort Lauderdale, Florida, pp 248–253Google Scholar