Research Article Open Access

Analysis of Non-Equilibrium Phase Change in Transfers at Low Water Content by Considering the Film Flow

Marcel Bawindsom Kébré1, François Ouédraogo2, Bétaboalé Naon2, Fabien Cherblanc3 and François Zougmoré1
  • 1 Université Joseph KI-ZERBO, Burkina Faso
  • 2 Université Nazi BONI, Burkina Faso
  • 3 Université de Montpellier, France


In this study, we analyze the effect of non-equilibrium phase change on transfer at low water content in a sandy soil by considering the contribution of film flow in the motion of liquid water. Indeed, most of the non-equilibrium study methods use for hydraulic conductivity, the van Genuchten-Mualem (VGM) capillary model which does not consider the film flow occurred at low water contents. Thus, we conduct a theoretical study by using an unidirectional non-equilibrium two phase flow model to simulate water transfers by filtration of liquid water and diffusion of water vapour coupled by liquid/gas phase change. We then compare the results of the non-equilibrium with the classical model of VGM for hydraulic conductivity function and another model considering the film flows. The numerical simulation is based on a column of sandy soil exposed to a controlled atmosphere. We observe that the shapes of the profiles of fluxes (liquid water, liquid/vapour non-equilibrium phase change) simulated using the capillary model are very different from those obtained with the model considering the film flow. In this last case, the liquid/gas non-equilibrium is not noticeable as in the case of the capillary model. It seems that the film flows occult the water vapour diffusion by delaying the phase change process, therefore a lower concentration of water vapour into the soil than in the case where the capillary flow alone has been considered.

American Journal of Environmental Sciences
Volume 17 No. 1, 2021, 1-13


Submitted On: 30 December 2020 Published On: 1 June 2021

How to Cite: Kébré, M. B., Ouédraogo, F., Naon, B., Cherblanc, F. & Zougmoré, F. (2021). Analysis of Non-Equilibrium Phase Change in Transfers at Low Water Content by Considering the Film Flow. American Journal of Environmental Sciences, 17(1), 1-13.

  • 0 Citations



  • Sandy Soil
  • Low Water Content
  • Phase Change
  • Non-Equilibrium
  • Film Flow
  • Hydraulic Conductivity