RESEARCH ARTICLE

CFD simulation on membrane distillation of NaCl solution

  • Zhaoguang XU ,
  • Yanqiu PAN ,
  • Yalan YU
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  • School of Chemical Engineering, Dalian University of Technology, Dalian 116012, China

Received date: 17 Sep 2008

Accepted date: 22 Jan 2009

Published date: 05 Sep 2009

Copyright

2014 Higher Education Press and Springer-Verlag Berlin Heidelberg

Abstract

A computational fluid dynamics (CFD) simulation that coupled an established heat and mass transfer model was carried out for the air-gap membrane distillation (AGMD) of NaCl solution to predict mass and heat behaviors of the process. The effects of temperature and flowrate on fluxes were first simulated and compared with available experimental data to verify the approach. The profiles of temperature, temperature polarization factor, and mass flux adjacent to the tubular carbon membrane surface were then examined under different feed Reynolds number in the computational domain. Results show that the temperature polarization phenomena can be reduced, and mass flux can be enhanced with increase in the feed Reynolds number.

Cite this article

Zhaoguang XU , Yanqiu PAN , Yalan YU . CFD simulation on membrane distillation of NaCl solution[J]. Frontiers of Chemical Science and Engineering, 2009 , 3(3) : 293 -297 . DOI: 10.1007/s11705-009-0204-7

Acknowledgements

The authors are grateful to the Center of Membrane Science and Technology in Dalian University of Technology for providing the commercial CFD package FLUENT v6.
Nomenclature
Dinner diameter of the tubular carbon membrane
Hvlatent heat of evaporation
h1the condensation heat transfer coefficient
hcheat transfer coefficient at cooling plate
Jmass flux
kthermal conductivity
Llength of the tubular carbon membrane
Mwmolecular weight of water
Nmolar flux
Pavgaverage totoal pressure
pfmpartial pressure of water on the feed side
pmgpartial pressure of water on the membrane/air-gap interface
pvsaturation pressure
qheat flux
qcmconductive heat flux across the membrane
qvmvaporization heat flux across the membrane
Runiversal gas constant
ReReynolds number (Re= ρuD/μ)
r0the average pore radius of the membrane
Tavg,mthe average temperature of the membrane
Tfthe feed temperature at the inlet
Tfmthe feed temperature adjacent to membrane surface
Ufcoverall heat transfer coefficient
uaxial velocity
vradial velocity
xaxial coordinate
xNaClmolar fraction of the NaCl solution
yradial coordinate
Greeks letters
ΔPpressure difference beteween the membrane
αwthe activity coefficient of water
δthicknes
ϵporosity
μviscosity
Θtemperature polarization factor
ρdensity
τtortuosity
Subscripts
aair
ccoolant
fpcondensate film/cooling plate interface
gair-gap
gfair-gap/condensate film interface
mmembrane
mgmembrane/air-gap interface
pcooling plate
pccooling plate/coolant interface
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