A Passive Micromixer with Koch Snowflakes Fractal Obstacle in Microchannel

Document Type : Regular Article


1 Departement of Physics Education, Universitas Pendidikan Indonesia, Bandung, Jawa Barat, 40154, Indonesia

2 Departement of Electrical Engineering Education, Universitas Pendidikan Indonesia, Bandung, Jawa Barat, 40154, Indonesia

3 Engineering Physics, Institut Teknologi Bandung, Bandung, Jawa Barat, 40132, Indonesia

4 Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia (UKM), Bangi, Selangor, 43600, Malaysia



The passive micromixer is one of the essential devices that can be integrated into the Lab on Chip (LoC) system. Micromixer is needed to increase mixing efficiency. In this paper, two Koch fractal obstacle-based micromixer models of Secondary Snowflakes Fractal Micromixer (SSFM) and Tertiary Snowflakes Fractal Micromixer (TSFM) were designed. The effect of the Koch fractal resistance angles (15o, 30o, 45o, 315o, 330o, 345o) and the influence of the inlet (T and T-vortex) were studied in this paper using COMSOL Multiphysics numerical simulations. The results showed that the TSFM structure with a 30o angle on the T-vortex inlet is optimal. The deflection phenomena generated by the TSFM obstacle enhance the contact area between the two fluids and chaotic convection can be increased at Reynolds Number (Re) 0.05 and Re 100. This paper examines concentration curves along the channel ranging from 1 mol/L to 5 mol/L. This clearly shows that the fluid flow direction changes within the microchannel. This work provides a new design for the micromixer.


Ansari, M. A., K. Y. Kim, K. Anwar and S. M. Kim (2012). Vortex Micro T-mixer with Non-Aligned Inputs. Chemical Engineering Journal 181, 846-850.##
Bahrami, D., A. A. Nadooshan and M. Bayareh (2020). Numerical Study on the Effect of Planar Normal and Halbach Magnet Arrays on Micromixing. International Journal of Chemical Reactor Engineering 18(9).##
Balasubramaniam, L., R. Arayanarakool, S. D. Marshall, B. Li, P. S. Lee and P. C. Chen (2017). Impact of Cross-Sectional Geometry on Mixing Performance of Spiral Microfluidic Channels Characterized by Swirling Strength of Dean-Vortices. Journal of Micromechanics and Microengineering 27(9), 095016.##
Bayareh, M. (2021). Artificial Diffusion in the Simulation of Micromixers: a Review. Journal of Mechanical Engineering Science 235(21), 5288-5296.##
Bayareh, M., A. Usefian and A. A. Nadooshan (2019). Rapid Mixing of Newtonian and non-Newtonian Fluids in a Three-Dimensional Micromixer Using Non-Uniform Magnetic Field. Journal of Heat and Mass Transfer Research 6(1), 55-61.##
Bayareh, M., M. N. Ashani and A. Usefian (2020). Active and Passive Micromixers: A Comprehensive Review. Chemical Engineering and Processing-Process Intensification 147, 107771.##
Bazaz, S. R., A. A. Mejrizi and S. M. Javid (2016). Canadian Society for Mechanical Engineering (CSME) International Conference, Canada, June##
Borgohain P., J. Arumughan, A. Dalal and G. Natarajan (2018). Design and Performance of a Three-Dimensional Micromixer with Curved Ribs Chemical engineering research and design 136, 761–775.##
Cai, G., L. Xue, H. Zhang and J. Lin (2017). A Review on Micromixers. Micromachines 8(9), 274.##
Chen, X. and S. Zhang (2018). 3D Micromixers Based on Koch Fractal Principle. Microsystem Technologies 24(6), 2627-2636.##
Chen, X. and T. Li (2017). A Novel Passive Micromixer Designed by Applying an Optimization Algorithm to the Zigzag Microchannel. Chemical Engineering Journal 313, 1406-1414.##
Chen, X. and Z. Zhao (2017). Numerical Investigation on Layout Optimization of Obstacles in A Three-Dimensional Passive Micromixer. Analytica chimica acta 964, 142-149.##
Chen, X., S. Liu, Y. Chen and S. Wang (2021). A Review on Species Mixing in Droplets Using Passive and Active Micromixers. International Journal of Environmental Analytical Chemistry 101(3), 422-432.##
Chen, X., S. Zhang, Z. Wu and Y. Zheng (2019). A Novel Koch Fractal Micromixer with Rounding Corners Structure. Microsystem Technologies 25(7), 2751-2758.##
Chen, Y. and C. N. Kim (2018). Numerical Analysis of the Mixing of Two Electrolyte Solutions in an Electromagnetic Rectangular Micromixer. Journal of industrial and engineering chemistry 60, 377-389.##
Chen, Y., X. Chen and S. Liu (2020). Numerical and Experimental Investigations of Novel Passive Micromixers with Fractal-Like Tree Structures. Chemical Physics Letters 747, 137330.##
Fatimah, N., B. Mulyanti, R. E. Pawinanto and A. B. Pantjawati (2020). 2020 3rd International Conference on Computer and Informatics Engineering (IC2IE), Yogyakarta, Indonesia, December##
Hama, B., G. Mahajan, P. S. Fodor, M. Kaufman and C. R. Kothapalli (2018). Evolution of Mixing in a Microfluidic Reverse-Staggered Herringbone Micromixer. Microfluidics and Nanofluidics 22(5), 1-14.##
Huang, C. Y., Y. H. Hu, S. A. Wan and H. Nagai (2020). Application of Pressure-Sensitive Paint for The Characterization of Mixing with Various Gases in T-Type Micromixers. International Journal of Heat and Mass Transfer 156, 119710.##
Keçili, R., F. Ghorbani-Bidkorbeh, I. Dolak, İ and C. M. Hussain (2020). Era of Nano-Lab-on-a-Chip (LOC). Elsevier, 1-17.##
Liu, G., X. Ma, C. Wang, X. Sun and C. Tang (2018). Piezoelectric Driven Self-Circulation Micromixer with High-Frequency Vibration. Journal of Micromechanics and Microengineering 28(8), 085010.##
Lv, H. and X. Chen (2021). New insights into the mechanism of fluid mixing in the micromixer based on alternating current electric heating with film heaters. International Journal of Heat and Mass Transfer 181, 121902.##
Lv, H., X. Chen and X. Zeng (2021). Optimization of micromixer with Cantor fractal baffle based on simulated annealing algorithm. Chaos, Solitons & Fractals 148, 111048.##
Mehrdel, P., S. Karimi, J. Farré-Lladós, and J. Casals-Terré (2018). Novel Variable Radius Spiral–Shaped Micromixer: From Numerical Analysis to Experimental Validation. Micromachines 9(11), 552.##
Mondal, B., S. K. Mehta, P. K. Patowari and S. Pati (2019). Numerical Study of Mixing in Wavy Micromixers: Comparison Between Raccoon and Serpentine Mixer. Chemical Engineering and Processing-Process Intensification 136, 44-61.##
Pawinanto, R. E., J. Yunas and A. M. Hashim (2020). Micropillar Based Active Microfluidic Mixer for The Detection of Glucose Concentration. Microelectronic Engineering 234, 111452.##
Rafeie, M., M. Welleweerd, A. Hassanzadeh-Barforoushi, M. Asadnia, W. Olthuis and M. E.  Warkiani (2017). An Easily Fabricated Three-Dimensional Threaded Lemniscate-Shaped Micromixer for a Wide Range of Flow Rates. Biomicrofluidics 11, 1.##
Raza, W. and K. Y. Kim (2020). Unbalanced Split and Recombine Micromixer with Three-Dimensional Steps. Industrial & Engineering Chemistry Research 59(9), 3744-3756.##
Rohman, A. S., B. Mulyanti, R. E. Pawinanto and A. B. Pantjawati (2020). 2020 3rd International Conference on Computer and Informatics Engineering (IC2IE), Yogyakarta, Indonesia, December##
Sarma, P. and P. K. Patowari (2016). Design and Analysis of Passive Y-Type Micromixers for Enhanced Mixing Performance for Biomedical and Microreactor Application. Journal of Advanced Manufacturing Systems 15(03), 161-172.##
Shi, X., L. Wang, S. Huang and F. Li (2021). A Novel Passive Micromixer with Array of Koch Fractal Obstacles in Microchannel. Journal of Dispersion Science and Technology 42(2), 236-247.##
Thiermann, R., R. Bleul and M. Maskos (2017). Kinetic Control of Block Copolymer Self‐Assembly in a Micromixing Device–Mechanistical Insight into Vesicle Formation Process. Macromolecular Chemistry and Physics 218(2), 1600347.##
Usefian, A.and M. Bayareh (2019). Numerical and Experimental Study on Mixing Performance of a Novel Electro-Osmotic Micro-Mixer. Meccanica 54(8) 1149–1162.##
Wu, Z. and X. Chen (2019). A Novel Design for Passive Micromixer Based on Cantor Fractal Structure. Microsystem Technologies 25(3), 985-996.##
Zhang, S., X. Chen, Z. Wu and Y. Zheng (2019). Numerical Study on Stagger Koch Fractal Baffles Micromixer. International Journal of Heat and Mass Transfer 133, 1065-1073.##