scholarly journals Mixing in the NETmix Reactor

2021 ◽  
Vol 3 ◽  
Author(s):  
Joana Matos ◽  
Ricardo J. Santos ◽  
Madalena M. Dias ◽  
José Carlos B. Lopes
Keyword(s):  
Channel Width ◽  
Width Ratio ◽  
Perfect Mixing ◽  
Mixing Chambers ◽  
Chamber Diameter

NETmix is a static mixing reactor composed of a network of mixing chambers interconnected by channels. The repetitive mixing pattern inside the reactor enables the use of reduced geometries to represent the NETmix network, such as the ExtendedNUB model, used in this work. Mixing in NETmix is based on the impingement of jets, issuing from channels. Inside the chambers, the jets are engulfed by dynamic vortices which can be quantified using Lagrangian techniques. Batch Lagrangian Mixing Simulation (BLMS) is based on successive injections of particles to measure the fraction of the fluids at the outlet of the mixing chambers. The distribution of the outlet fraction of particles indicates that it is possible to have nearly perfect mixing inside the NETmix chambers, depending on the dimensions of the channels and chambers. The NETmix design is here optimized in relation to the chamber diameter to channel width ratio, D/d. Results from BLMS show that best performance in NETmix occurs for 6.65≤D/d≤6.85.

scholarly journals Tributary Channel Width Effect on the Flow Behavior in Trapezoidal and Rectangular Channel Confluences

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1344
Author(s):  
Aliasghar Azma ◽  
Yongxiang Zhang
Keyword(s):  
Recirculation Zone ◽  
Flow Behavior ◽  
Rectangular Channel ◽  
Maximum Velocity ◽  
Main Channel ◽  
Channel Width ◽  
Width Ratio ◽  
Geometrical Shape ◽  
Eddy Simulation ◽  
Flow Parameters

Channel confluences happen commonly in water transport networks and natural rivers. Utilizing a 3D CFD code, a series of numerical simulations were performed using a large eddy simulation turbulence model to investigate the effect of the variations in tributary channel width and the transverse geometrical shape of the main channel on the flow parameters and vertical structure in a T-shape confluence. The code was calibrated using the experimental data from the literature. Flow parameters were considered in ratios of tributary width to the main channel width in trapezoidal and rectangular channels. Results indicate that decreasing the width ratio of the tributary channel to the main channel significantly affects the flow structure in the confluence. Generally, it increases the width and length of the main recirculation zone. It also increases the maximum velocity near the bed, especially in cases with a trapezoidal shape. Besides, it highly affects the structure and formation of the recirculation zone in trapezoidal channels.

Numerical study on micromixers with smart-rhombic structure

2018 ◽  
Vol 32 (27) ◽  
pp. 1850301 ◽  
Author(s):  
Jiajia Xu ◽  
Xueye Chen ◽  
Yanlin Liu ◽  
Zhen Yao
Keyword(s):  
Numerical Simulation ◽  
High Throughput ◽  
Numerical Study ◽  
Considerable Effect ◽  
Geometric Parameters ◽  
Channel Width ◽  
Variable Method ◽  
Mixing Efficiency ◽  
Width Ratio ◽  
Chaotic Convection

In this paper, we have designed a rhombic microchannel plane micromixer (RMPM). The RMPM uses the principle of converging and diverging to improve the mixing efficiency. We improved the mixing efficiency by changing the rhombic angles and the rhombic channel width ratios. The influence of geometric parameters on mixing efficiency is analyzed by control of the variable method. Through the analysis of the numerical simulation, the RMPM can help increase the chaotic convection between different concentrations of fluids. The results of the study show that the rhombic angle and the width ratio of a microchannel can have a considerable effect on the mixing efficiency. The micromixer can be potentially useful in the future applications of rapid and high throughput mixing.

Slug Formation Analysis of Liquid–Liquid Two-Phase Flow in T-Junction Microchannels

2019 ◽  
Vol 11 (5) ◽  
Author(s):  
Jin-yuan Qian ◽  
Xiao-juan Li ◽  
Zan Wu ◽  
Zhi-jiang Jin ◽  
Junhui Zhang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Rate Ratio ◽  
Two Phase Flow ◽  
Continuous Phase ◽  
Channel Width ◽  
Flow Rate Ratio ◽  
Width Ratio ◽  
Phase Flow ◽  
Channel Depth ◽  
Two Phase

Slug flow is a common flow pattern in the liquid–liquid two-phase flow in microchannels. It is an ideal pattern for mass transfer enhancement. Many factors influence the slug formation such as the channel geometries (channel widths, channel depth), flow rates of the two phase, and physical properties. In this paper, in order to investigate the liquid–liquid two-phase slug formation in a T-junction microchannel quantitatively, the volume of fluid (VOF) method is adopted to simulate the whole slug formation process. With the validated model, the effects of the disperse phase channel width, channel depth, and two-phase flow rate ratio on slug formation frequency and slug size (slug volume and slug length) are analyzed with dimensionless parameters. Dimensionless parameters include the disperse-to-continuous phase channel width ratio, height-to-width ratio, and two-phase flow rate ratio. Results show that both the channel geometry and two-phase flow rate ratio have a significant influence on slug formation. Compared with the conventional slug formation stages, a new stage called the lag stage emerges when the disperse phase channel width decreases to half of the continuous phase channel width. When the channel depth decreases to one third of the continuous phase channel width, the flow patterns become unstable and vary with the two-phase flow rate ratio. Moreover, empirical correlations are proposed to predict the slug formation frequency. The correlation between slug formation frequency and slug volume is quantified.

scholarly journals High Yielding Microbubble Production Method

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Joe Fiabane ◽  
Paul Prentice ◽  
Ketan Pancholi
Keyword(s):  
High Velocity ◽  
Production Method ◽  
Polydispersity Index ◽  
Channel Width ◽  
Liquid Jet ◽  
Width Ratio ◽  
Micro Channel ◽  
High Susceptibility ◽  
Nitrogen Gas ◽  
Mean Diameter

Microfluidic approaches to microbubble production are generally disadvantaged by low yield and high susceptibility to (micro)channel blockages. This paper presents an alternative method of producing microbubbles of 2.6 μm mean diameter at concentrations in excess of 30 × 106 mL−1. In this method, the nitrogen gas flowing inside the liquid jet is disintegrated into spray of microbubble when air surrounding this coflowing nitrogen gas-liquid jet passes through a 100 μm orifice at high velocity. Resulting microbubble foam has the polydispersity index of 16%. Moreover, a ratio of mean microbubble diameter to channel width ratio was found to be less than 0.025, which substantially alleviates the occurrence of blockages during production.

Numerical Study on the Cathode Channel Width Ratio for Improving Performance of a Passive Air Cooled PEMFC

2020 ◽  
Vol 23 (1) ◽  
pp. 40-48
Author(s):  
Jaeseung Lee ◽  
Nammin Lee ◽  
Kisung Lim ◽  
Jaeyoo Choi ◽  
Hyunchul Ju
Keyword(s):  
Numerical Study ◽  
Channel Width ◽  
Width Ratio

The Hydrofoil with Finite Cavity in a Solid-Wall Channel

1971 ◽  
Vol 15 (02) ◽  
pp. 125-140
Author(s):  
Steven H. Schot
Keyword(s):  
Cavity Length ◽  
Solid Wall ◽  
Lift Coefficient ◽  
Cavitation Number ◽  
Channel Width ◽  
Width Ratio ◽  
Third Order ◽  
Choked Flow ◽  
Method Of Solution ◽  
Correction Terms

The asymmetrical fully cavitating linearized flow about an arbitrarily shaped slender hydrofoil placed anywhere in a solid-wall channel is considered as a doubly connected region problem. The method of solution involves conformal mapping and a generalization of the Plemeli formulas to doubly periodic functions. The velocity field is expressed in terms of Jacobi's that a functions with the nome q of these functions related directly to the cavity-length/channel-width ratio. Explicit results are obtained for a fully cavitating flat plate at small angles of attack in a midchannel position. For small q, simple wall effect correction terms are obtained for the cavity length and the lift coefficient as a function of cavitation number. These correction terms are correct up to and including third order in q and require no quadratures. For large values of the cavity-length/channel-width ratio (q close to unity) the asymptotic choked flow solution is used to compute the blockage cavitation number and the lift coefficient for the choked flow.

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