CFD modeling of gypsum scaling in cross-flow RO filters using moments of particle population balance

2020 ◽  
Vol 8 (5) ◽  
pp. 104151
Author(s):  
Ashish Uppu ◽  
Abhijit Chaudhuri ◽  
Shyama Prasad Das ◽  
Nitikesh Prakash
Keyword(s):  
Cross Flow ◽  
Population Balance ◽  
Cfd Modeling ◽  
Particle Population ◽  
Gypsum Scaling

scholarly journals An improved particle population balance equation in the continuum-slip regime

2016 ◽  
Vol 20 (3) ◽  
pp. 921-926 ◽  
Author(s):  
Mingliang Xie ◽  
Jin Li ◽  
Tingting Kong ◽  
Qing He
Keyword(s):  
Asymptotic Behavior ◽  
Correction Factor ◽  
Balance Equation ◽  
Present Model ◽  
Population Balance ◽  
Population Balance Equation ◽  
Brownian Coagulation ◽  
Slip Regime ◽  
Particle Population ◽  
The Continuum

An improved moment model is proposed to solve the population balance equation for Brownian coagulation in the continuum-slip regime, and it reduces to a known one in open literature when the non-linear terms in the slip correction factor are ignored. The present model shows same asymptotic behavior as that in the continuum regime.

Simulation of Forward Osmosis Flow in a Two-Dimensional Asymmetric Membrane Channel With Draw Channel Circular Baffle Implementation

2015 ◽  
Author(s):  
James R. L. Koch ◽  
Ramesh K. Agarwal
Keyword(s):  
Osmotic Pressure ◽  
Pressure Loss ◽  
Membrane Filtration ◽  
Concentration Polarization ◽  
Fluid Dynamic ◽  
Forward Osmosis ◽  
Cross Flow ◽  
Cfd Modeling ◽  
Asymmetric Membrane ◽  
Asymmetric Membranes

Forward Osmosis (FO) driven asymmetric membrane filtration is a developing technology which shows promise for seawater desalination and wastewater treatment. Due to the fact that asymmetric membranes are widely used in conjunction with this technology, internal concentration polarization (ICP), a flow-entrainment effect occurring within such membranes, is a significant if not dominant source of overall osmotic pressure loss across the membrane. Accurate modeling of ICP effects is therefore very critical for accurate Computational Fluid Dynamic (CFD) modeling of asymmetric membranes. A related, dilutive effect known as external concentration polarization (ECP) also develops on both the rejection and draw sides of the membrane, further contributing to osmotic pressure loss. In order to increase the overall water flux, circular spacers can be implemented within the draw channel of FO cross-flow membrane exchange units to decrease the effects of ICP and draw ECP. The drawback of spacer inclusions is an increased pressure loss across the length of the feed channel. The system efficiency gained by the decrease in ECP must therefore be weighed against the energy cost of hydraulically making up lost channel pressure. To model the geometry of a FO cross-flow channel, the open source CFD package OpenFOAM is used. A compressible flow model with explicit boundary conditions is developed to simulate the flux transfer and ICP effects present within an asymmetric membrane when exposed to a NaCl solution. Results are validated by comparison with the numerical data generated by earlier models of asymmetric membranes implemented by other investigators using similar simulation conditions.

A predictor–corrector algorithm for the coupling of stiff ODEs to a particle population balance

2009 ◽  
Vol 228 (8) ◽  
pp. 2758-2769 ◽  
Author(s):  
Matthew Celnik ◽  
Robert Patterson ◽  
Markus Kraft ◽  
Wolfgang Wagner
Keyword(s):  
Population Balance ◽  
Particle Population ◽  
Stiff Odes ◽  
Predictor Corrector

Simulation of Forward Osmosis Flow in a Two-Dimensional Asymmetric Membrane Channel With Draw Channel Circular Baffle Implementation

2016 ◽  
Author(s):  
James R. L. Koch ◽  
Ramesh K. Agarwal
Keyword(s):  
Osmotic Pressure ◽  
Pressure Loss ◽  
Membrane Filtration ◽  
Concentration Polarization ◽  
Fluid Dynamic ◽  
Forward Osmosis ◽  
Cross Flow ◽  
Cfd Modeling ◽  
Asymmetric Membrane ◽  
Asymmetric Membranes

Forward Osmosis (FO) driven asymmetric membrane filtration is a developing technology which shows promise for seawater desalination and wastewater treatment. Due to the fact that asymmetric membranes are widely used in conjunction with this technology, internal concentration polarization (ICP), a flow-entrainment effect occurring within such membranes, is a significant if not dominant source of overall osmotic pressure loss across the membrane. Accurate modeling of ICP effects is therefore very critical for accurate Computational Fluid Dynamic (CFD) modeling of asymmetric membranes. A related, dilutive effect known as external concentration polarization (ECP) also develops on both the rejection and draw sides of the membrane, further contributing to osmotic pressure loss. In order to increase the overall water flux, circular spacers can be implemented within the draw channel of FO cross-flow membrane exchange units to decrease the effects of ICP and draw ECP. The drawback of spacer inclusions is an increased pressure loss across the length of the feed channel. The system efficiency gained by the decrease in ECP must therefore be weighed against the energy cost of hydraulically making up lost channel pressure. To model the geometry of a FO cross-flow channel, the open source CFD package OpenFOAM is used. A compressible flow model with explicit boundary conditions is developed to simulate the flux transfer and ICP effects present within an asymmetric membrane when exposed to a NaCl solution. Results are validated by comparison with the numerical data generated by earlier models of asymmetric membranes implemented by other investigators using similar simulation conditions.

Measurement of Combustion Air to a Typical Cyclone Burner With a Common Wind Box and Pressure Loss Effects on the Cyclone Due to Inlet Configuration

2009 ◽  
Author(s):  
Robert O. Brandt
Keyword(s):  
Pressure Loss ◽  
Cross Flow ◽  
Flow Distribution ◽  
Cfd Modeling ◽  
Width Ratio ◽  
Worst Case ◽  
Air Inlet ◽  
Large Length ◽  
Coal Flow ◽  
Case Condition

To maintain proper fuel air ratio and minimize NOx during combustion, air and coal flow into a cyclone burner must be measured. Due to the large length to width ratio of the air inlet to some burners, often greater than 7, accurate measurement has proven to be difficult; in fact, measurement with a ratio greater than 2 to 1 has proven to be difficult. A typical cyclone burner system was analyzed with a premium CFD modeling package, with particular attention being given to the location which would be considered “worst case”. If this location can be measured accurately, then we can assume that the less stringent locations will also be measured accurately. Additionally, a “best case” was also analyzed to compare pressure loss due to the measurement. The worst case location was chosen based on a cross flow condition of the air just going around the corner at the entrance, where the flow velocity is the highest. See Figure A. The “best case” condition was chosen as the air flow entering the inlet normal to the plane of the inlet, although this condition may not actually exist in the example wind box chosen. Three inlet configurations were analyzed, (1) three optimally designed Oval High Betas across the inlet, (2) two optimally designed Oval High Betas across the inlet and (3) the flow distribution across the inlet as is, with no method to break up the large length to width ratio. Of particular interest, once the analysis for both the “worst case” and “best case” were done for the three inlet configurations, one configuration, proved best for both measurement and pressure loss—condition (1), the three optimally designed Oval High Betas.

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