Modeling of Newtonian droplet formation in power-law non-Newtonian fluids in a flow-focusing device

2020 ◽  
Vol 56 (9) ◽  
pp. 2711-2723
Author(s):  
Qi Chen ◽  
Jingkun Li ◽  
Yu Song ◽  
David M Christopher ◽  
Xuefang Li
Keyword(s):  
Power Law ◽  
Droplet Formation ◽  
Newtonian Fluids ◽  
Flow Focusing

scholarly journals Coating Flows of Power-Law Non-Newtonian Fluids in Slot Coating

2010 ◽  
Vol 38 (4/5) ◽  
pp. 223-230 ◽  
Author(s):  
Takeaki Tsuda
Keyword(s):  
Power Law ◽  
Newtonian Fluids ◽  
Coating Flows ◽  
Slot Coating

scholarly journals Analyzing Impacts of Interfacial Instabilities on the Sweeping Power of Newtonian Fluids to Immiscibly Displace Power-Law Materials

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 742
Author(s):  
Morteza Esmaeilpour ◽  
Maziar Gholami Korzani
Keyword(s):  
Power Law ◽  
Computational Cost ◽  
Initial Section ◽  
Wall Layer ◽  
Newtonian Fluids ◽  
Displacement Efficiency ◽  
Interfacial Instabilities ◽  
Compatibility Factor ◽  
Boltzmann Method ◽  
Power Law Index

Injection of Newtonian fluids to displace pseudoplastic and dilatant fluids, governed by the power-law viscosity relationship, is common in many industrial processes. In these applications, changing the viscosity of the displaced fluid through velocity alteration can regulate interfacial instabilities, displacement efficiency, the thickness of the static wall layer, and the injected fluid’s tendency to move toward particular parts of the channel. The dynamic behavior of the fluid–fluid interface in the case of immiscibility is highly complicated and complex. In this study, a code was developed that utilizes a multi-component model of the lattice Boltzmann method to decrease the computational cost and accurately model these problems. Accordingly, a 2D inclined channel, filled with a stagnant incompressible Newtonian fluid in the initial section followed by a power-law material, was modeled for numerous scenarios. In conclusion, the results indicate that reducing the power-law index can regulate interfacial instabilities leading to dynamic deformation of static wall layers at the top and the bottom of the channel. However, it does not guarantee a reduction in the thickness of these layers, which is crucial to improve displacement efficiency. The impacts of the compatibility factor and power-law index variations on the filling pattern and finger structure were intensively evaluated.

Effect of nanoparticle surfactants on droplet formation in a flow-focusing microchannel

2021 ◽  
Vol 33 (11) ◽  
pp. 112008
Author(s):  
Jie Qi ◽  
Zheng Liang Yu ◽  
Guo Peng Liao ◽  
Zheng Yuan Luo ◽  
Bo Feng Bai
Keyword(s):  
Droplet Formation ◽  
Flow Focusing

scholarly journals Breakup Dynamics of Semi-dilute Polymer Solutions in a Microfluidic Flow-focusing Device

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 406
Author(s):  
Chun-Dong Xue ◽  
Xiao-Dong Chen ◽  
Yong-Jiang Li ◽  
Guo-Qing Hu ◽  
Tun Cao ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Polymer Solutions ◽  
Newtonian Fluids ◽  
Droplet Microfluidics ◽  
Droplet Generation ◽  
Flow Focusing ◽  
Polymeric Fluids ◽  
Practical Applications ◽  
Dilute Polymer Solutions ◽  
Microfluidic Flow

Droplet microfluidics involving non-Newtonian fluids is of great importance in both fundamental mechanisms and practical applications. In the present study, breakup dynamics in droplet generation of semi-dilute polymer solutions in a microfluidic flow-focusing device were experimentally investigated. We found that the filament thinning experiences a transition from a flow-driven to a capillary-driven regime, analogous to that of purely elastic fluids, while the highly elevated viscosity and complex network structures in the semi-dilute polymer solutions induce the breakup stages with a smaller power-law exponent and extensional relaxation time. It is elucidated that the elevated viscosity of the semi-dilute solution decelerates filament thinning in the flow-driven regime and the incomplete stretch of polymer molecules results in the smaller extensional relaxation time in the capillary-driven regime. These results extend the understanding of breakup dynamics in droplet generation of non-Newtonian fluids and provide guidance for microfluidic synthesis applications involving dense polymeric fluids.

Modeling droplet formation in microfluidic flow-focusing devices using the two-phases level set method

2020 ◽  
Author(s):  
D. Hernández-Cid ◽  
V.H. Pérez-González ◽  
R.C. Gallo-Villanueva ◽  
J. González-Valdez ◽  
M.A. Mata-Gómez
Keyword(s):  
Level Set Method ◽  
Level Set ◽  
Droplet Formation ◽  
Flow Focusing ◽  
Microfluidic Flow ◽  
Two Phases

Gas–liquid flow stability and bubble formation in non-Newtonian fluids in microfluidic flow-focusing devices

2010 ◽  
Vol 10 (5) ◽  
pp. 1135-1140 ◽  
Author(s):  
Taotao Fu ◽  
Youguang Ma ◽  
Denis Funfschilling ◽  
Huai Z. Li
Keyword(s):  
Liquid Flow ◽  
Bubble Formation ◽  
Flow Stability ◽  
Newtonian Fluids ◽  
Flow Focusing ◽  
Microfluidic Flow ◽  
Gas Liquid Flow

Droplet Formation and Fission in Shear-Thinning/Newtonian Multiphase System Using Bilayer Bifurcating Microchannel

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Yong Ren ◽  
Kai Seng Koh ◽  
Jit Kai Chin ◽  
Jing Wang ◽  
Conghua Wen ◽  
...  
Keyword(s):  
Shear Thinning ◽  
Droplet Formation ◽  
Newtonian Fluids ◽  
Model Systems ◽  
Multiphase System ◽  
Blood Capillaries ◽  
Two Systems ◽  
Flow Through ◽  
Newtonian System ◽  
Droplet Fission

With a novel platform of bilayer polydimethylsiloxane microchannel formed by bifurcating junction, we aim to investigate droplet formation and fission in a multiphase system with complex three-dimensional (3D) structure and understand the variations in mechanism associated with droplet formation and fission in the microstructure between shear-thinning/Newtonian system versus Newtonian/Newtonian system. The investigation concentrates on shear-thinning fluid because it is one of the most ubiquitous rheological properties of non-Newtonian fluids. Sodium carboxymethyl cellulose (CMC) solution and silicone oil have been used as model fluids and numerical model has been established to characterize the shear-thinning effect in formation of CMC-in-oil emulsions, as well as breakup dynamics when droplets flow through 3D bifurcating junction. The droplet volume and generation rate have been compared between two systems at the same Weber number and capillary number. Variation in droplet fission has been found between two systems, demonstrating that the shear-thinning property and confining geometric boundaries significantly affect the deformation and breakup of each mother droplet into two daughter droplets at bifurcating junction. The understanding of the droplet fission in the novel microstructure will enable more versatile control over the emulsion formation and fission when non-Newtonian fluids are involved. The model systems in the study can be further developed to investigate the mechanical property of emulsion templated particles such as drug encapsulated microcapsules when they flow through complex media structures, such as blood capillaries or the porous tissue structure, which feature with bifurcating junction.

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