Article
 

Effects of sodium chloride on constitutive relations in variably saturated porous media.pdf

Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/articles/8623hz39w

Descriptions

Attribute NameValues
Creator
Abstract
  • Though many arid and contaminated sites have high salinity, prediction of effects of salinity on water movement in soils has been based on dilute solution approximations. Here a sensitivity analysis compares predicted liquid and vapor pressure in variably saturated porous media found using both the dilute approximations and a more general formulation that is valid for salt concentrations from zero to saturation. Sodium chloride (NaCl) was selected as a representative salt of environmental importance. Salt-mineral interactions are not included in the analysis. The dilute approximations neglect the salt-related changes in specific volume, which translate into nonnegligible pressure effects (i.e., error >1%) under dry conditions, being more pronounced for finer media. The analysis shows that for silt textures, the dilute approximation to the vapor pressure constitutive relation is acceptable for water contents θ > 5%, for sand θ > 1%, and for loam θ > 2%. When computing gradients of vapor pressure resulting from gradients in salt concentration, volume correction is necessary for silt for θ < 10%. Gradients in vapor pressure with changes in water content require volume correction, except under dilute conditions (i.e., <0.5 molal). For concentrated solutions in silt, salt effect errors are not acceptable for prediction of liquid pressure, nor are the effects on gradients negligible. Errors for sand and loam are only marginally better, with acceptable errors generally occurring only for ionic strengths of less than 1 molal. An example of use of the constitutive relations to plot results from experiments is provided to illustrate how the theory may be used to determine which thermodynamic corrections must be incorporated into analyses of the experimental results. Here the volumetric effects of the salt on vapor depression were negligible, though volumetric effects may be nonnegligible for computation of gradients of both vapor and liquid pressures. The method of analysis of nonideal effects developed herein is general, and the resulting corrections to the dilute approximation may be easily implemented in numerical codes.
  • Keywords: Sodium chloride, Unsaturated, Brine, Salt, Thermodynamics
Resource Type
DOI
Date Available
Date Issued
Citation
  • Burns, E. R., J. S. Selker, J.-Y. Parlange, and R. B. Guenther (2006), Effects of sodium chloride on constitutive relations in variably saturated porous media, Water Resources Research, 42, W05405, doi:10.1029/2005WR004060.
Journal Title
Journal Volume
  • 42
Journal Issue/Number
  • W05405
Rights Statement
Funding Statement (additional comments about funding)
  • This work was funded under a U.S. EPA STAR (Science to Achieve Results) Fellowship.
Publisher
Peer Reviewed
Language
Replaces

Relationships

Parents:

This work has no parents.

Items

Thumbnail Title Date Uploaded Visibility Actions
file details SelkerJohnSChemicalBiologicalEnvironmentalEngineeringEffectsSodiumChloride.pdf 2017-07-08 Public Download