scholarly journals High Mixing Efficiency by Modulating Inlet Frequency of Viscoelastic Fluid in Simplified Pore Structure

Processes ◽  
2018 ◽  
Vol 6 (11) ◽  
pp. 210 ◽  
Author(s):  
Meng Zhang ◽  
Yunfeng Cui ◽  
Weihua Cai ◽  
Zhengwei Wu ◽  
Yongyao Li ◽  
...  
Keyword(s):  
Viscoelastic Fluid ◽  
Essential Role ◽  
Fluid Flows ◽  
Fluid Mixing ◽  
Modulation Method ◽  
Mixing Efficiency ◽  
Microscale Flow ◽  
Pressure Modulation ◽  
Active Mixing ◽  
Junction Structure

Fluid mixing plays an essential role in microscale flow systems. Here, we propose an active mixing approach which enhances the mixing of viscoelastic fluid flow in a simplified pore T-junction structure. Mixing is actively controlled by modulating the driving pressure with a sinusoidal signal at the two inlets of the T-junction. The mixing effect is numerically investigated for both Newtonian and viscoelastic fluid flows under different pressure modulation conditions. The result shows that a degree of mixing as high as 0.9 is achieved in viscoelastic fluid flows through the T-junction mixer when the phase difference between the modulated pressures at the two inlets is 180°. This modulation method can also be used in other fluid mixing devices.

scholarly journals Comparison of Micro-Mixing in Time Pulsed Newtonian Fluid and Viscoelastic Fluid

Micromachines ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 262 ◽  
Author(s):  
Zhang ◽  
Zhang ◽  
Wu ◽  
Shen ◽  
Chen ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Newtonian Fluid ◽  
Viscoelastic Fluid ◽  
Flow Rate ◽  
Essential Role ◽  
Weissenberg Number ◽  
The Other ◽  
Fluid Mixing ◽  
Constant Flow ◽  
Constant Flow Rate

Fluid mixing plays an essential role in many microfluidic applications. Here, we compare the mixing in time pulsing flows for both a Newtonian fluid and a viscoelastic fluid at different pulsing frequencies. In general, the mixing degree in the viscoelastic fluid is higher than that in the Newtonian fluid. Particularly, the mixing in Newtonian fluid with time pulsing is decreased when the Reynolds number Re is between 0.002 and 0.01, while it is enhanced when Re is between 0.1 and 0.2 compared with that at a constant flow rate. In the viscoelastic fluid, on the other hand, the time pulsing does not change the mixing degree when the Weissenberg number Wi ≤ 20, while a larger mixing degree is realized at a higher pulsing frequency when Wi = 50.

An implicit scheme for simulation of free surface non-Newtonian fluid flows on dynamically adapted grids

2021 ◽  
Vol 36 (3) ◽  
pp. 165-176
Author(s):  
Kirill Nikitin ◽  
Yuri Vassilevski ◽  
Ruslan Yanbarisov
Keyword(s):  
Free Surface ◽  
Numerical Model ◽  
Newtonian Fluid ◽  
Viscoelastic Fluid ◽  
Fluid Flows ◽  
Numerical Results ◽  
Implicit Scheme ◽  
New Approach

Abstract This work presents a new approach to modelling of free surface non-Newtonian (viscoplastic or viscoelastic) fluid flows on dynamically adapted octree grids. The numerical model is based on the implicit formulation and the staggered location of governing variables. We verify our model by comparing simulations with experimental and numerical results known from the literature.

Fluid Mixing Control Inside a Y-Shaped Microchannel by Using Electrokinetic Instability

2007 ◽  
Author(s):  
Zheyan Jin ◽  
Hui Hu
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Fluid Mixing ◽  
Critical Voltage ◽  
Mixing Efficiency ◽  
Mixing Process ◽  
Static Electric Field ◽  
Electrokinetic Instability ◽  
Mixing Control ◽  
Static Electric Fields

An experimental study was conducted to further our understanding about the fundamental physics of electrokinetic instability (EKI) and to explore the effectiveness to enhance fluid mixing inside a Y-shaped microchannel by manipulating convective EKI waves. The dependence of the critical voltage of applied static electric field to trig EKI to generate convective EKI waves on the conductivity ratio of the two adjacent streams was quantified at first. The effect of the strength of the applied static electric field on the evolution of the convective EKI waves and fluid mixing process were assessed in terms of scalar concentration fields, shedding frequency of the convective EKI waves and scalar mixing efficiency. The effectiveness of manipulating the convective EKI waves by introducing alternative electric perturbations to the applied static electric fields was also explored for the further enhancement of the fluid mixing process inside the Y-shaped microchannel.

Elimination of Clogging in PMMA Microchannels Using Water Assisted CO2 Laser Micromachining

2015 ◽  
Vol 799-800 ◽  
pp. 407-412 ◽  
Author(s):  
Mohamed O. Helmy ◽  
Ahmed M. Fath El-Bab ◽  
Hassan El-Hofy
Keyword(s):  
Thin Layer ◽  
Heat Affected Zone ◽  
Scanning Speed ◽  
Fluid Mixing ◽  
Mixing Efficiency ◽  
Water Cooling ◽  
Quick Method ◽  
Lab On Chip ◽  
On Chip

The accuracy and clogging of microchannels are important for assessing the quality of lab on chip (L-O-C) devices. The clogging affects the fluid mixing efficiency and influences the bonding of substrate. In this paper, inexpensive and quick method for microchannel fabrication in polymethyl methacrylate (PMMA) while reducing the thermal damage is introduced. Accordingly, the substrate was covered with a thin layer of water during CO2laser ablation. The effect of water cooling on the clogging formation, heat affected zone and the microchannel geometry in terms of depth and width is investigated. Clogging formation mechanism in the intersection of Y-channel is studied to improve its quality for microfluidics applications. During the experimental work, the CO2laser power was varied from 2.4 to 6 W at scanning speed from 5 to 12.5 mm/s. The results showed that covering the PMMA substrate with a thin layer of water prevented clogging formation and reduced the heat affected zone.

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