Fluid dynamic gauging: a new technique for studying membrane fouling

2007 ◽  
Vol 7 (5-6) ◽  
pp. 175-184 ◽  
Author(s):  
Y.M.J. Chew ◽  
W.R. Paterson ◽  
D.I. Wilson
Keyword(s):  
Fluid Dynamics ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Fluid Dynamic ◽  
Navier Stokes ◽  
Permeate Flux ◽  
Continuity Equations ◽  
Glass Spheres ◽  
Microfiltration Membranes ◽  
A New Technique

The deposition of fouling layers on porous surfaces such as those experienced in membrane/filtration systems has been investigated using the technique of fluid dynamic gauging (FDG). In this work, dead end microfiltration was simulated using polymeric microfiltration membranes and Sphericel (hollow glass spheres) suspensions. FDG was used to track, in situ and in real time, the build-up of a Sphericel cake during the filtration process. The permeate flux through the membrane was also simultaneously monitored. Computational fluid dynamics (CFD) studies were also performed to illuminate the fluid dynamics of FDG, with particular focus on the flow patterns and on the stresses imposed on the porous surface. The governing Navier-Stokes, Darcy's and continuity equations were solved using the commercial partial differential equation solver, Fastflo™. Simulations of gauging flow with a permeable gauged surface were then conducted and comparison with filtration experiments showed excellent agreement.

scholarly journals Computational Analysis to Factor Wind into the Design of an Architectural Environment

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Hassam Nasarullah Chaudhry ◽  
John Kaiser Calautit ◽  
Ben Richard Hughes
Keyword(s):  
Fluid Dynamics ◽  
Power Generation ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Numerical Data ◽  
Navier Stokes ◽  
Windward Side ◽  
Average Value ◽  
Continuity Equations ◽  
Prevailing Wind Direction

The effect of wind distribution on the architectural domain of the Bahrain Trade Centre was numerically analysed using computational fluid dynamics (CFD). Using the numerical data, the power generation potential of the building-integrated wind turbines was determined in response to the prevailing wind direction. The three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations along with the momentum and continuity equations were solved for obtaining the velocity and pressure field. Simulating a reference wind speed of 6 m/s, the findings from the study quantified an estimate power generation of 6.4 kW indicating a capacity factor of 2.9% for the benchmark model. At the windward side of the building, it was observed that the layers of turbulence intensified in inverse proportion to the height of the building with an average value of 0.45 J/kg. The air velocity was found to gradually increase in direct proportion to the elevation with the turbine located at higher altitude receiving maximum exposure to incoming wind. This work highlighted the potential of using advanced computational fluid dynamics in order to factor wind into the design of any architectural environment.

scholarly journals Airflow inside the nasal cavity: visualization using computational fluid dynamics

2010 ◽  
Vol 4 (4) ◽  
pp. 657-661 ◽  
Author(s):  
Mohammed Zubair ◽  
Vizy Nazira Riazuddin ◽  
Mohammed Zulkifly Abdullah ◽  
Rushdan Ismail ◽  
Ibrahim Lutfi Shuaib ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Nasal Cavity ◽  
Three Dimensional ◽  
Clinical Importance ◽  
Navier Stokes ◽  
Tomographic Images ◽  
Computed Tomographic ◽  
Continuity Equations ◽  
Cfd Method

Abstract Background: It is of clinical importance to examine the nasal cavity pre-operatively on surgical treatments. However, there is no simple and easy way to measure airflow in the nasal cavity. Objectives: Visualize the flow features inside the nasal cavity using computational fluid dynamics (CFD) method, and study the effect of different breathing rates on nasal function. Method: A three-dimensional nasal cavity model was reconstructed based on computed tomographic images of a healthy Malaysian adult nose. Navier-Stokes and continuity equations for steady airflow were solved numerically to examine the inspiratory nasal flow. Results: The flow resistance obtained varied from 0.026 to 0.124 Pa.s/mL at flow-rate from 7.5 L/min to 40 L/min. Flow rates by breathing had significant influence on airflow velocity and wall shear-stress in the vestibule and nasal valve region. Conclusion: Airflow simulations based on CFD is most useful for better understanding of flow phenomenon inside the nasal cavity.

A Fluid Dynamics Study of a Modified Low-Reynolds-Number Flapping Motion

2010 ◽  
Author(s):  
M. R. Amiralaei ◽  
H. Alighanbari ◽  
S. M. Hashemi
Keyword(s):  
Fluid Dynamics ◽  
Reynolds Number ◽  
Phase Angle ◽  
Fluid Dynamic ◽  
Low Reynolds Number ◽  
Dynamic Performance ◽  
Navier Stokes ◽  
Fluid Forces ◽  
Low Reynolds ◽  
Volume Method

The objective of the present study is to investigate the low Reynolds number (LRN) fluid dynamics of an elliptic airfoil performing a novel figure-eight-like motion. To this mean, the influence of phase angle between the pitching and translational (heaving and lagging) motions and the amplitude of translational motions on the fluid flow is simulated. Navier-Stokes (NS) equations with Finite Volume Method (FVM) are used and the instantaneous force coefficients and the fluid dynamics performance, as well as the corresponding vortical structures are analyzed. Both the phase angle and the amplitudes of horizontal and vertical motions are of great importance to the fluid dynamic characteristics of the model as they are shown to change the peaks of the fluid forces, fluid dynamic performance, and the vortical patterns around the model.

Temporally and Spatially Resolved Flow in a Two-Stage Axial Compressor: Part 1—Experiment

1991 ◽  
Vol 113 (2) ◽  
pp. 219-225 ◽  
Author(s):  
R. C. Stauter ◽  
R. P. Dring ◽  
F. O. Carta
Keyword(s):  
Fluid Dynamics ◽  
Fluid Dynamic ◽  
Axial Compressor ◽  
Spatial Variations ◽  
Navier Stokes ◽  
Dense Matrix ◽  
Two Stage ◽  
Data Set ◽  
Spatially Resolved ◽  
Interactive Nature

The fluid dynamics of turbomachines are extremely complex, due in part to the aerodynamic interactions between rotors and stators. It is necessary to acquire fluid dynamic data that reflect the interactive nature of a turbomachine to correlate with the fluid dynamics predicted from modern analyses. The temporal and spatial variations in the midspan aerodynamics of the second stage of a two-stage compressor have been studied with a two-component LDV system. Spatial variations were examined by traversing the LDV probe volume through a dense matrix of both axial and circumferential positions, while temporal resolution was achieved by acquiring all data as a function of the instantaneous rotor position. Hence, the data set reveals rotor and stator wake structure and decay in both the stationary and rotating frames of reference. The data also compared very favorably with extensive pneumatic measurements previously acquired in this compressor. In Part 2 of the paper, the data are used in the assessment of a prediction of the flow in the compressor using a time-accurate, thin-layer, two-dimensional Navier–Stokes analysis.

scholarly journals Performance of a novel recycling magnetic flocculation membrane filtration process for tetracycline-polluted surface water treatment

2017 ◽  
Vol 76 (2) ◽  
pp. 490-500 ◽  
Author(s):  
Yufei Wang ◽  
Hui Jia ◽  
Hongwei Zhang ◽  
Jie Wang ◽  
Wenjin Liu
Keyword(s):  
Surface Water ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Average Particle Size ◽  
Quality Parameters ◽  
Average Particle ◽  
Permeate Flux ◽  
Personal Care Product ◽  
Surface Water Treatment ◽  
Scale Experiment

A recycling magnetic flocculation membrane filtration (RMFMF) process integrating circulating coagulation, magnetic enhanced flocculation and membrane filtration was investigated for the treatment of surface water micro-polluted by tetracycline, a typical pharmaceutical and personal care product. A bench-scale experiment was conducted and several water quality parameters including turbidity, ultraviolet absorbance at 254 nm (UV254), total organic carbon and tetracycline concentration were evaluated, taking coagulation membrane filtration and magnetic flocculation membrane filtration processes as reference treatments. The experimental results showed that at the optimum doses of 20 mg·L−1 ferric chloride (FeCl3), 4 mg·L−1 magnetite (Fe3O4) and 6 mg·L−1 reclaimed magnetic flocs in RMFMF processes, removal efficiencies of above evaluated parameters ranged from 55.8% to 92.9%, which performed best. Simultaneously, the largest average particle size of 484.71 μm and the highest fractal dimension of 1.37 of flocs were achieved, which did not only present the best coagulation effect helpful in enhancing the performance of removing multiple contaminants, but also lead to the generation of loose and porous cake layers favouring reduced permeate flux decline and membrane fouling.

scholarly journals In-Situ Ultrasound-Assisted Control of Polymeric Membrane Fouling

2021 ◽  
Author(s):  
Westphalen Dornelas Camara Heloisa
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Separation ◽  
Feed Solution ◽  
Solution Concentration ◽  
Polymeric Membrane ◽  
Permeate Flux ◽  
Latex Paint ◽  
Water And Wastewater Treatment ◽  
Maximum Increase

Membrane separation processes have been more widely applied to industrial activities, especially in water and wastewater treatment. However, there are still challenges associated to the use of membranes. Concentration polarization and fouling can cause significant permeate flux decay during the filtration process, hindering its efficiency and increasing cost. Among many strategies, the combination of membrane filtration with ultrasound (US) application has shown promising results in reducing membrane fouling. The main goal of this research was to identify the effect of US frequency, US power intensity and feed solution concentration on permeate flux during ultrafiltration of simulated latex paint effluent. Maximum increase in permeate flux of 19.7% was obtained by applying 20 kHz and 0.29 W.cm-2 to feed solution with 0.075 wt.% of solid concentration. The effect of feed flow rate was analyzed showing that an increase in feed flowrate is not beneficial to the fouling minimization process. Overall, the application of US improves permeate flux by reducing fouling of ultrafiltration polymeric membrane.

scholarly journals Application of Coagulation–Membrane Rotation to Improve Ultrafiltration Performance in Drinking Water Treatment

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 643
Author(s):  
Hongjian Yu ◽  
Weipeng Huang ◽  
Huachen Liu ◽  
Tian Li ◽  
Nianping Chi ◽  
...  
Keyword(s):  
Shear Stress ◽  
Drinking Water ◽  
Water Treatment ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Drinking Water Treatment ◽  
Permeate Flux ◽  
Organic Removal ◽  
Cake Layer ◽  
The Impact

The combination of conventional and advanced water treatment is now widely used in drinking water treatment. However, membrane fouling is still the main obstacle to extend its application. In this study, the impact of the combination of coagulation and ultrafiltration (UF) membrane rotation on both fouling control and organic removal of macro (sodium alginate, SA) and micro organic matters (tannic acid, TA) was studied comprehensively to evaluate its applicability in drinking water treatment. The results indicated that membrane rotation could generate shear stress and vortex, thus effectively reducing membrane fouling of both SA and TA solutions, especially for macro SA organics. With additional coagulation, the membrane fouling could be further reduced through the aggregation of mediate and macro organic substances into flocs and elimination by membrane retention. For example, with the membrane rotation speed of 60 r/min, the permeate flux increased by 90% and the organic removal by 35% in SA solution, with 40 mg/L coagulant dosage, with an additional 70% increase of flux and 5% increment of organic removal to 80% obtained. However, too much shear stress could intensify the potential of fiber breakage at the potting, destroying the flocs and resulting in the reduction of permeate flux and deterioration of effluent quality. Finally, the combination of coagulation and membrane rotation would lead to the shaking of the cake layer, which is beneficial for fouling mitigation and prolongation of membrane filtration lifetime. This study provides useful information on applying the combined process of conventional coagulation and the hydrodynamic shear force for drinking water treatment, which can be further explored in the future.

scholarly journals Assessing Enzyme Immobilization on Reverse Asymmetric Membranes and Biocatalytic Reactor Performance

2021 ◽  
Author(s):  
Amirah Syakirah Zahirulain ◽  
Fauziah Marpani ◽  
Syazana Mohamad Pauzi ◽  
'Azzah Nazihah Che Abd Rahim ◽  
Hang Thi Thuy Cao ◽  
...  
Keyword(s):  
Enzyme Immobilization ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Separation ◽  
Permeate Flux ◽  
Reactor Performance ◽  
Membrane Performance ◽  
Reverse Mode ◽  
Substrate Conversion ◽  
Product Separation

Abstract Integration of membrane filtration and biocatalysis has appealing benefits in terms of simultaneous substrate conversion and product separation in one reactor. Nevertheless, the interaction between enzymes and membrane is complex and the mechanism of enzyme docking on membrane is similar to membrane fouling. In this study, focus is given on the assessment of enzyme immobilization mechanism on reverse asymmetric polymer membrane based on the permeate flux data during the procedure. Evaluation of membrane performance in terms of its permeability, fouling mechanisms, enzyme loading, enzyme reusability and biocatalytic productivity were also conducted. Alcohol Dehydrogenase (EC 1.1.1.1), able to catalyze formaldehyde to methanol with subsequent oxidation of NADH to NAD was selected as the model enzyme. Two commercial, asymmetric, flat sheet polymer membranes (PES and PVDF) were immobilized with the enzyme in the reverse mode. Combination of concentration polarization phenomenon and pressure driven filtration successfully immobilized almost 100% of the enzymes in the feed solutions. The biocatalytic membrane reactor recorded more than 90% conversion, stable permeate flux with no enzyme leaching even after 5 cycles. The technique showing promising results to be expanded to continuous membrane separation setup for repeated use of enzymes.

Application of MIEX® pre-treatment for ultrafiltration membrane process for NOM removal and fouling reduction

2005 ◽  
Vol 5 (5) ◽  
pp. 15-24 ◽  
Author(s):  
H.J. Son ◽  
Y.D. Hwang ◽  
J.S. Roh ◽  
K.W. Ji ◽  
P.S. Sin ◽  
...  
Keyword(s):  
Organic Matter ◽  
Removal Efficiency ◽  
Membrane Fouling ◽  
Membrane Filtration ◽  
Reduction Rate ◽  
Chemical Characteristics ◽  
Permeate Flux ◽  
Physical Chemical ◽  
Sample Water ◽  
Original Water

In this study, pretreatment of organic matters with MIEX® was evaluated using bench-scale experimental procedures on three organic matters to determine its effect on subsequent UF or MF membrane filtration. For comparison, a coagulation process was also used as a pretreatment of UF or MF membrane filtration. Moreover, the membrane fouling potential was identified using different fractions and molecular weights (MW) of organic matter. From the removal property of MW organic matter by the coagulation process for the sample water NOM and AOM, the removal efficiencies of high MW organic matter were much higher than those of low MW organic matter. It was shown that the removal efficiency of high MW organic matter (more than 10 kDa) was lower than that of low MW organic matter for the MIEX® process. For the change of permeate flux by the pretreatment process, the MIEX®-UF process showed high removal efficiency of organic matter compared with the coagulation-UF processes, but a high reduction rate of permeate flux was presented through the reduction of removal efficiency of high MW organic matter. From sequential filtration test results to examine the effect of MW of organic matter on membrane fouling, we found that the membrane fouling occurred with high MW organic matter, and the DOC of organic matter less than 0.5 mg/L was acting as the membrane foulant. In sample water composed of low MW organic matter (less than 10 kDa), because the low MW organic matter of less than 10 kDa has a high removal efficiency by MIEX®, a low reduction rate of permeate flux is obtained compared with the coagulation-UF processes. In summary, research on the physical/chemical characteristics of original water is needed before a membrane pretreatment process is selected, and a pertinent pretreatment process should be used based on the physical/chemical characteristics of the original water.

scholarly journals In-Situ Ultrasound-Assisted Control of Polymeric Membrane Fouling

2021 ◽  
Author(s):  
Westphalen Dornelas Camara Heloisa
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Separation ◽  
Feed Solution ◽  
Solution Concentration ◽  
Polymeric Membrane ◽  
Permeate Flux ◽  
Latex Paint ◽  
Water And Wastewater Treatment ◽  
Maximum Increase

Membrane separation processes have been more widely applied to industrial activities, especially in water and wastewater treatment. However, there are still challenges associated to the use of membranes. Concentration polarization and fouling can cause significant permeate flux decay during the filtration process, hindering its efficiency and increasing cost. Among many strategies, the combination of membrane filtration with ultrasound (US) application has shown promising results in reducing membrane fouling. The main goal of this research was to identify the effect of US frequency, US power intensity and feed solution concentration on permeate flux during ultrafiltration of simulated latex paint effluent. Maximum increase in permeate flux of 19.7% was obtained by applying 20 kHz and 0.29 W.cm-2 to feed solution with 0.075 wt.% of solid concentration. The effect of feed flow rate was analyzed showing that an increase in feed flowrate is not beneficial to the fouling minimization process. Overall, the application of US improves permeate flux by reducing fouling of ultrafiltration polymeric membrane.

Sign in / Sign up

Export Citation Format

Share Document