scholarly journals Numerical investigation of the mixing efficiency of fluids in the micromixer with a cylindrical section of a swirl flow

2020 ◽  
Author(s):  
A. S. Lobasov ◽  
A. A. Shebeleva ◽  
A. V. Shebelev ◽  
A. V. Minakov
Keyword(s):  
Numerical Investigation ◽  
Swirl Flow ◽  
Mixing Efficiency ◽  
Cylindrical Section

Three Dimensional Triangle Chaotic Micromixer

2014 ◽  
Vol 875-877 ◽  
pp. 1189-1193 ◽  
Author(s):  
Lin Li ◽  
Qing De Chen ◽  
C.T. Tsai
Keyword(s):  
Numerical Investigation ◽  
Three Dimensional ◽  
Microfluidic System ◽  
Chaotic Advection ◽  
Mixing Efficiency ◽  
Mixing Index ◽  
Ansys Fluent ◽  
Essential Component ◽  
Highly Efficient

Micromixer is essential component of microfluidic system which has wide application in the field of chemistry and biochemistry. A highly efficient and easily fabricated three dimensional micromixer based on chaotic advection is proposed and investigated. The depth of 25μm for each layer of micromixer and two kinds of fluids, which have viscosities of 0.00097kgm-1s-1and 0.186kgm-1s-1with Re number from 0.001 to 150, are adopted for numerical investigation of mixing efficiency by using ANSYS-Fluent. High mixing index of more than 90% can be obtained by using less than 300μm of length under Re number of 0.01 for mixing Fluid 1. However, it requires 850μm to achieve mixing index of more than 90% for hard-to-mix Fluid 2.

scholarly journals Numerical Investigation of Liquid–Liquid Mixing in Modified T Mixer with 3D Obstacles

2021 ◽  
pp. 25-32
Author(s):  
Md. Readul Mahmud
Keyword(s):  
Numerical Investigation ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Channel Length ◽  
Navier Stokes ◽  
Mixing Efficiency ◽  
Mixing Performance ◽  
Wide Range

The fluids inside passive micromixers are laminar in nature and mixing depends primarily on diffusion. Hence mixing efficiency is generally low, and requires a long channel length and longtime compare to active mixers. Various designs of complex channel structures with/without obstacles and three-dimensional geometries have been investigated in the past to obtain an efficient mixing in passive mixers. This work presents a design of a modified T mixer. To enhance the mixing performance, circular and hexagonal obstacles are introduced inside the modified T mixer. Numerical investigation on mixing and flow characteristics in microchannels is carried out using the computational fluid dynamics (CFD) software ANSYS 15. Mixing in the channels has been analyzed by using Navier–Stokes equations with water-water for a wide range of the Reynolds numbers from 1 to 500. The results show that the modified T mixer with circular obstacles has far better mixing performance than the modified T mixer without obstacles. The reason is that fluids' path length becomes longer due to the presence of obstacles which gives fluids more time to diffuse. For all cases, the modified T mixer with circular obstacle yields the best mixing efficiency (more than 60%) at all examined Reynolds numbers. It is also clear that efficiency increase with axial length. Efficiency can be simply improved by adding extra mixing units to provide adequate mixing. The value of the pressure drop is the lowest for the modified T mixer because there is no obstacle inside the channel. Modified T mixer and modified T mixer with circular obstacle have the lowest and highest mixing cost, respectively. Therefore, the current design of modified T with circular obstacles can act as an effective and simple passive mixing device for various micromixing applications.

Numerical investigation of mixing efficiency of helical ribbons

AIChE Journal ◽  
1998 ◽  
Vol 44 (4) ◽  
pp. 972-977 ◽  
Author(s):  
J. de la Villéon ◽  
F. Bertrand ◽  
P. A. Tanguy ◽  
R. Labrie ◽  
J. Bousquet ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Mixing Efficiency

Impact of Swirl Flow on Combustor Liner Heat Transfer and Cooling: A Numerical Investigation With Hybrid RANS-LES Models

2015 ◽  
Author(s):  
L. Mazzei ◽  
A. Andreini ◽  
B. Facchini ◽  
F. Turrini
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Numerical Investigation ◽  
Film Cooling ◽  
Swirling Flow ◽  
Cooling System ◽  
Swirl Flow ◽  
Opening Angle ◽  
Lean Burn ◽  
Combustor Liner

This paper reports the main findings of a numerical investigation aimed at characterizing the flow field and the wall heat transfer resulting from the interaction of a swirling flow provided by lean burn injectors and a slot cooling system, which generates film cooling in the first part of the combustor liner. In order to overcome some well-known limitations of RANS approach, e.g. the underestimation of mixing, the simulations were performed with hybrid RANS-LES models, namely SAS-SST and DES-SST, which are proving to be a viable approach to resolve the main structures of the flow field. The numerical results were compared to experimental data obtained on a non-reactive three sector planar rig developed in the context of the EU project LEMCOTEC. The analysis of the flow field has highlighted a generally good agreement against PIV measurements, especially for the SAS-SST model, whereas DES-SST returns some discrepancies in the opening angle of the swirling flow, altering the location of the corner vortex. Also the assessment in terms of Nu/Nu0 distribution confirms the overall accuracy of SAS-SST, where a constant over-prediction in the magnitude of the heat transfer is shown by DES-SST, even though potential improvements with mesh refinement are pointed out.

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