NUMERICAL STUDY OF HEAT AND MASS TRANSFER DURING EVAPORATION OF A TURBULENT BINARY LIQUID FILM

Abstract

This paper deals with a computational study for analysing heat and mass exchanges in the evaporation of a turbulent binary liquid film (water-ethanol and water-methanol) along a vertical tube. The film is in co-current with the dry air and the tube wall is subjected to a uniform heat flux. The effect of gas-liquid phase coupling, variable thermophysical properties and film vaporization are considered in the analysis. The numerical method applied solves the coupled governing equations together with the boundary and interfacial conditions. The algebraic systems of equations obtained are solved using the Thomas algorithm. The results concern the effects of the inlet liquid Reynolds number and inlet film composition on the intensity of heat and mass transfer. In this study, results obtained show that heat transferred through the latent mode is more pronounced when the concentration of volatile components is higher in the liquid mixture .The comparisons of wall temperature and accumulated mass evaporation rate with the literature results are in good agreement.

Keywords

Dates

  • Submission Date2012-09-27
  • Revision Date2013-03-25
  • Acceptance Date2013-03-31
  • Online Date2013-04-13

DOI Reference

10.2298/TSCI120927025K

References

  1. Nusselt W., Die oberflachenkondensation des wasserdampfes. Zeitschr Ver Deutsch, (1916), 60: 541-546 and 569-575.
  2. Yan, W.M., Binary diffusion and heat transfer in mixed convection pipe flows with film evaporation, Int. J. Heat Mass Transfer, 36 (1993), pp. 2115-2123
  3. Feddaoui, M., Mir, A., Belahmidi, E., Co-current turbulent mixed convection heat and mass transfer in falling film of water inside a vertical heated tube , Int. J. Heat Mass Transfer, 46 (2003), pp. 3497-3509
  4. Feddaoui, M., Meftah, H., Mir, A., The numerical computation of the evaporative cooling of falling water film in turbulent mixed convection inside a vertical tube, Int Comm Heat Mass Transfer, 33 (2006), pp. 917-927
  5. Feddaoui, M., Mir, A., Turbulent mixed convection heat and mass exchanges in evaporating liquid film along a vertical tube. Int. J. Heat Exchangers, 8 (2007) pp. 15-13.
  6. Senhaji, S., Feddaoui, M., Mediouni, T., Mir, A., Simultaneous heat and mass transfer inside a vertical tube in evaporating a heated falling alcohols liquid film into a stream of dry air, Heat Mass Transfer, 45 (2009), pp. 663-371
  7. Baumann, WW., Thiele, WM., Heat and mass transfer in evaporating two-component liquid film flow , Int. J. Heat Mass Transfer, 33 (1990), pp. 267-273
  8. Cherif, A., Daif, A., Etude numérique de transfert de chaleur et de masse entre deux plaques plane verticales en présence d'un film liquide binaire ruisselant sur l'une des plaques chauffée, Int. J. Heat and mass transfer, 42 (1999), pp. 2399-2418
  9. Palen, J. W., Wang, Q., Chen, J. C., Falling Film Evaporation of Binary Mixtures, AIChE J., 40 (1994), pp. 207-214
  10. El Armouzi, M., Chesneau, X., Zeghmati, B., Numerical study of evaporation by mixed convection of a binary liquid film flowing down the wall of two coaxial cylinders, Heat and Mass Transfer, 41 (2005), pp. 375-386
  11. Nasr, A., Debbissi, C., Ben Nasrallah, S., Evaporation of a Thin Binary Liquid Film by Forced Convection into Air and Superheated Steam, J. Thermal Science, 19 (2010), pp. 346-356.
  12. Nasr, A., Debbissi, C., Ben Nasrallah, S., Evaporation of a Binary Liquid Film by Forced Convection, J. Thermal Science, 15 (2011), pp. 773-784.
  13. Nasr, A., Debbissi, C., Ben Nasrallah, S., Numerical study of evaporation by mixed convection of a binary liquid film, Energy, 36 (2011), pp. 2316-2327
  14. Yih, S., Liu, J., Prediction of heat transfer in turbulent falling liquid films with or without interfacial shear, AIChE J., 29 (1983), pp. 903-909
  15. Cebeci, T., Smith, A.M.O.., A finite difference method for calculating compressible and turbulent boundary layers, J. Basic Eng. Trans. ASME., 92 (1970), pp. 523-535
  16. Habib, I. S. Na, T. P., "Prediction of heat transfer in turbulent pipe flow with constant wall temperature", J. Heat Transfer, (1974), vol. 96, pp.253.
  17. Eckert, E.R.G., Drake, R.M., Analysis of heat and mass transfer, New York : McGraw-Hill, USA, 1972.
  18. Reid, R.C. , Sherwood, T.K. , The properties of gases and liquids, Mc. Graw Hill, New York, USA, 1984.
  19. Bird, R. B., Stewart, W. E., Lightfoot, E. N. , Transport Phenomena, Wiley, New York, 1960.
  20. Patankar, S. V., Numerical Heat Transfer and Fluid Flow, Hemisphere/Mc Graw-Hill, New York.Chap.6, 1980.
  21. Raithby, G.D., Schneider, G.E., Numerical solution of problems in incompressible fluid flow: treatment of the velocity pressure coupling, Num. Heat Transfer, 2 (1979), pp. 417-440
  22. . Ralston A., Rabinowitz P., A first course in numerical analysis. McGraw Hill Book Co, 1965.