AUTHORS: Joanne Zi En Soh, Eko Supriyanto
Download as PDF
ABSTRACT: Micro-scaled Coiled Flow Inverter (MCFI) is a scaled down version of a Coiled Flow Inverter (CFI) which utilizes the principle of flow inversion for process intensification. MCFI is constructed with tubing less than 1.0mm. The microfluidic nature of MCFI caused by low Reynolds number (Re) laminar flow posed as a challenge to achieve effective mixing. Simulation was implemented with Computational Fluid Dynamics (CFD) software FLUENT to visualize the mixing of MCFI with different diameters. Fluid flow of the mixing of two water bodies was simulated. Geometry of the MCFI was designed with tubing diameters of 1.0mm, 0.8mm, 0.6mm and 0.5mm to investigate the effect of cross-sectional diameter towards mixing efficiency. The curvature ratio (λ) was fixed at 10 to reduce the complexity of the system. Fluid flow rate was calculated and adjusted to obtain Re 250 for each tubing size. Velocity profile of tubing within the range of diameter investigated showed negligible difference. Simulation results showed a parabolic velocity profile for straight tube, while skewed velocity profiles were observed within the straight coil and MCFI. MCFI with the tubing diameter of 0.5 mm achieved complete mixing at normalized tube length of 0.69, equivalent to 175mm. MCFI with ID 1.0 mm showed 54.5% mixing, while MCFI with ID 0.8 mm and 0.6 mm showed 69.6% and 78.9% mixing respectively at the outlet. Similarly, fluid in straight tube and straight coil had also failed to achieve complete mixing. Results obtained suggested smaller tubing diameter indeed led to better mixing process in MCFI, in expense of an increase in pressure
KEYWORDS: Computational Fluid Dynamics (CFD), Coiled Flow Inverter (CFI), Micro-Coiled Flow Inverter (MCFI), Reynolds number, Laminar Flow, Diffusive Mixing
REFERENCES:
[1] V. Kumar, M. Aggarwal, and K. D. P. Nigam. 'Mixing in curved tubes.' Chemical Engineering Science. 2006; 61(17): 5742-5753.
[2] M. Mridha, and K.D Nigam. “Coiled flow inverter as an inline mixer.” Chemical Engineering Science. 2008 Mar; 63(6):1724-32.
[3] V. Kumar, M. Mridha, A.K. Gupta, and K. D. Nigam . “Coiled flow inverter as a heat exchanger.” Chemical Engineering Science. 2007 May; 62(9):2386-96.
[4] V. Kumar, and K.D. Nigam “Numerical simulation of steady flow fields in coiled flow inverter”. International journal of heat and mass transfer. 2005 Nov; 48(23):4811-28.
[5] M.M. Mandal, V. Kumar, and K. D. P. Nigam. 'Augmentation of heat transfer performance in coiled flow inverter vis-à-vis conventional heat exchanger.' Chemical Engineering Science 65, no. 2 (2010): 999-1007.
[6] M.M Mandal, P. Aggarwal, K.D. Nigam . “Liquid–liquid mixing in coiled flow inverter.” Industrial & Engineering Chemistry Research. 2011 Jul; 50(23):13230-5.
[7] M.M. Mandal, C. Serra, Y. Hoarau, and K. D. P. Nigam. 'Numerical modeling of polystyrene synthesis in coiled flow inverter.' Microfluidics and nanofluidics 10, no. 2 (2011): 415-423.
[8] J. Singh, N. Kockmann, K.D. Nigam . “Novel three-dimensional microfluidic device for process intensification.” Chemical Engineering and Processing: Process Intensification. 2014 Dec; 86:78-89.
[9] S.K. Kurt, M.G. Gelhausen, N. Kockmann. “Axial dispersion and heat transfer in a milli/microstructured coiled flow inverter for narrow residence time distribution at laminar flow.” Chemical Engineering & Technology. 2015 Jul; 38(7):1122-30.
[10] S.K. Kurt, I.V Gürsel, V. Hessel, K.D. Nigam, and N. Kockmann. “Liquid–liquid extraction system with microstructured coiled flow inverter and other capillary setups for single-stage extraction applications.” Chemical Engineering Journal. 2016 Jan 15; 284:764-77.
[11] L. Sharma, K. D. P. Nigam, and S. Roy. 'Single phase mixing in coiled tubes and coiled flow inverters in different flow regimes.' Chemical Engineering Science. 2017;160: 227- 235.
[12] López-Guajardo, Enrique, et al. 'Coiled flow inverter as a novel alternative for the intensification of a liquid-liquid reaction.' Chemical Engineering Science. 2017, https://doi.org/10.1016/j.ces.2017.01.016.
[13] Gürsel, Iris Vural, S. K. Kurt, J. Aalders, Q. Wang, T. Noël, K. D. P. Nigam, N. Kockmann, and V. Hessel. 'Utilization of milli-scale coiled flow inverter in combination with phase separator for continuous flow liquid–liquid extraction processes.' Chemical Engineering Journal 283 (2016): 855-868.
[14] A.K. Sharma, H. Agarwal, M. Pathak, K. D.P. Nigam, and A. S. Rathore. 'Continuous refolding of a biotech therapeutic in a novel Coiled Flow Inverter Reactor.' Chemical Engineering Science 140 (2016): 153-160.