Numerical simulation of heat and mass transfer in direct membrane distillation in a hollow fiber module with laminar flow
The heat and mass transfer processes in direct contact membrane distillation (MD) under laminar flow conditions have been analyzed by computational fluid dynamics (CFD). A two-dimensional heat transfer model was developed by coupling the latent heat, which is generated during the MD process, into th...
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sg-ntu-dr.10356-1007782020-03-07T11:43:47Z Numerical simulation of heat and mass transfer in direct membrane distillation in a hollow fiber module with laminar flow Yu, Hui Yang, Xing Wang, Rong Fane, Anthony Gordon School of Civil and Environmental Engineering Singapore Membrane Technology Centre DRNTU::Engineering::Environmental engineering::Water treatment The heat and mass transfer processes in direct contact membrane distillation (MD) under laminar flow conditions have been analyzed by computational fluid dynamics (CFD). A two-dimensional heat transfer model was developed by coupling the latent heat, which is generated during the MD process, into the energy conservation equation. In combination with the Navies–Stokes equations, the thermal boundary layer build-up, membrane wall temperatures, temperature polarization coefficient (TPC), local heat transfer coefficients, local mass fluxes as well as the thermal efficiency, etc. were predicted under counter-current flow conditions. The overall performance predicted by the model, in terms of fluxes and temperatures, was verified by single hollow fiber experiments with feed in the shell and permeate in the lumen. Simulations using the model provide insights into counter-current direct contact MD. Based on the predicted temperature profiles, the local heat fluxes are found to increase and then decrease along the fiber length. The deviation of the membrane wall temperature from the fluid bulk phase on the feed and the permeate sides predicts the temperature polarization (TP) effect. The TP coefficient decreases initially and then increase along the fiber length. It is also found that the local Nusselt numbers (Nu) present the highest values at the entrances of the feed/permeate sides. Under the assumed operating conditions, the feed side heat transfer coefficients hf are typically half the hp in the permeate side, suggesting that the shell-side hydrodynamics play an important role in improving the heat transfer in this MD configuration. The model also shows how the mass transfer rate and the thermal efficiency are affected by the operating conditions. Operating the module at higher feed/permeate circulation velocities enhances transmembrane flux; however, the thermal efficiency decreases due to the greater heat loss at a higher permeate velocity. The current study suggests that the CFD simulations can provide qualitative predictions on the influences of various factors on MD performance, which can guide future work on the hollow fiber module design, module scale-up and process optimization to facilitate MD commercialization. Accepted version 2013-05-30T07:02:21Z 2019-12-06T20:28:03Z 2013-05-30T07:02:21Z 2019-12-06T20:28:03Z 2011 2011 Journal Article Yu, H., Yang, X., Wang, R., & Fane, A. G. (2011). Numerical simulation of heat and mass transfer in direct membrane distillation in a hollow fiber module with laminar flow. Journal of Membrane Science, 384(1–2), 107-116. 0376-7388 https://hdl.handle.net/10356/100778 http://hdl.handle.net/10220/10026 10.1016/j.memsci.2011.09.011 173023 en Journal of membrane science © 2011 Elsevier. This is the author created version of a work that has been peer reviewed and accepted for publication by Journal of Membrane Science, Elsevier B.V. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [DOI: http://dx.doi.org/10.1016/j.memsci.2011.09.011]. 10 p. application/pdf |
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DRNTU::Engineering::Environmental engineering::Water treatment Yu, Hui Yang, Xing Wang, Rong Fane, Anthony Gordon Numerical simulation of heat and mass transfer in direct membrane distillation in a hollow fiber module with laminar flow |
description |
The heat and mass transfer processes in direct contact membrane distillation (MD) under laminar flow
conditions have been analyzed by computational fluid dynamics (CFD). A two-dimensional heat transfer
model was developed by coupling the latent heat, which is generated during the MD process, into the
energy conservation equation. In combination with the Navies–Stokes equations, the thermal boundary
layer build-up, membrane wall temperatures, temperature polarization coefficient (TPC), local heat
transfer coefficients, local mass fluxes as well as the thermal efficiency, etc. were predicted under
counter-current flow conditions. The overall performance predicted by the model, in terms of fluxes
and temperatures, was verified by single hollow fiber experiments with feed in the shell and permeate
in the lumen.
Simulations using the model provide insights into counter-current direct contact MD. Based on the
predicted temperature profiles, the local heat fluxes are found to increase and then decrease along the
fiber length. The deviation of the membrane wall temperature from the fluid bulk phase on the feed and
the permeate sides predicts the temperature polarization (TP) effect. The TP coefficient decreases initially
and then increase along the fiber length. It is also found that the local Nusselt numbers (Nu) present the
highest values at the entrances of the feed/permeate sides. Under the assumed operating conditions,
the feed side heat transfer coefficients hf are typically half the hp in the permeate side, suggesting that
the shell-side hydrodynamics play an important role in improving the heat transfer in this MD configuration.
The model also shows how the mass transfer rate and the thermal efficiency are affected by
the operating conditions. Operating the module at higher feed/permeate circulation velocities enhances
transmembrane flux; however, the thermal efficiency decreases due to the greater heat loss at a higher
permeate velocity. The current study suggests that the CFD simulations can provide qualitative predictions
on the influences of various factors on MD performance, which can guide future work on the hollow
fiber module design, module scale-up and process optimization to facilitate MD commercialization. |
author2 |
School of Civil and Environmental Engineering |
author_facet |
School of Civil and Environmental Engineering Yu, Hui Yang, Xing Wang, Rong Fane, Anthony Gordon |
format |
Article |
author |
Yu, Hui Yang, Xing Wang, Rong Fane, Anthony Gordon |
author_sort |
Yu, Hui |
title |
Numerical simulation of heat and mass transfer in direct membrane distillation in a hollow fiber module with laminar flow |
title_short |
Numerical simulation of heat and mass transfer in direct membrane distillation in a hollow fiber module with laminar flow |
title_full |
Numerical simulation of heat and mass transfer in direct membrane distillation in a hollow fiber module with laminar flow |
title_fullStr |
Numerical simulation of heat and mass transfer in direct membrane distillation in a hollow fiber module with laminar flow |
title_full_unstemmed |
Numerical simulation of heat and mass transfer in direct membrane distillation in a hollow fiber module with laminar flow |
title_sort |
numerical simulation of heat and mass transfer in direct membrane distillation in a hollow fiber module with laminar flow |
publishDate |
2013 |
url |
https://hdl.handle.net/10356/100778 http://hdl.handle.net/10220/10026 |
_version_ |
1681038584335826944 |