On the performance of static mixers: A quantitative comparison

Abstract

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. b s t r a c tThe performance of industrially relevant static mixers that work via chaotic advection in the Stokes regime for highly viscous fluids, flowing at low Reynolds numbers, like the Kenics, the Ross Low-Pressure Drop (LPD) and Low-Low-Pressure Drop (LLPD), the standard Sulzer SMX, and the recently developed new design series of the SMX, denoted as SMX(n) (n, N p , N x ) = (n, 2n − 1, 3n), is compared using as criteria both energy consumption, measured in terms of the dimensionless pressure drop, and compactness, measured as the dimensionless length. Results are generally according to expectations: open mixers are most energy efficient, giving the lowest pressure drop, but this goes at the cost of length, while the most compact mixers require large pressure gradients to drive the flow. In compactness, the new series SMX(n), like the SMX(n = 3) (3, 5, 9) design, outperform all other devices with at least a factor 2. An interesting result is that in terms of energy efficiency the simple SMX (1, 1, 4, Â = 135 • ) outperforms the Kenics RL 180• , which was the standard in low pressure drop mixing, and gives results identical to the optimized Kenics RL 140• . This makes the versatile "X"-designs, based on crossing bars, superior in all respects.

Numerical study of fluid mixing at different inlet flow-rate ratios in Tear-drop and Chain micromixers compared to a new H-C passive micromixer

“…The use of microfluidic devices permit a reduction in the size and cost of laboratory equipment, diminishing the consumption of specimens and increasing the speed and reliability of analysis (Solehati, Bae, & Sasmito, 2014). Micromixers are broadly applied in various industrial processes such as polymer mixing, chemical reaction and food processing, in cosmetics and pharmaceutics, and also in waste-water treatment (Alam, Afzal, & Kim, 2014;Hossain, Husain, & Kim, 2011;Meijer, Singh, & Patrick, 2012). Convection and diffusion are the basic mechanisms which permit fluid mixing in mixers (Liu, Deng, Zhang, Liu, & Wu, 2013).…”

Spectral analysis of mixing in chaotic flows via the mapping matrix formalism: Inclusion of molecular diffusion and quantitative eigenvalue estimate in the purely convective limit

“…The mapping method, 8,9 based on the distribution matrices, offers an efficient way to investigate the kinematics of mixing for generic mixing protocols in time and spatial periodic flows. A variety of two-and three-dimensional prototypes of flows and mixers has been studied by using the mapping method, 10 including the Kenics and other static mixers, [11][12][13] the rotated arc mixer, 14 micromixers, 15 various extruders, 16 etc. In these works, the evolution of a scalar field is studied by the iterative application of the the mapping matrix to the vector describing the initial/inlet concentration distribution.…”

The Effect of Inertia on the Flow and Mixing Characteristics of a Chaotic Serpentine Mixer

“…In this figure, the ordinate is the dimensionless pressure p * , defined by p * = p/∆p 1 , where ∆p 1 is the pressure drop in a single periodic unit of each channel geometry at a reference Reynolds number Re = 1. As reported in [35], the performance of a mixer can be evaluated using two different criteria, energy consumption measured by the pressure drop and its compactness measured by the length of the mixer. In microfluidic applications where length becomes a major issue, mixing in a short length at the expense of higher pressure drop is an option if the compactness of a microfluidic device is of great importance.…”