Accession Number:

ADA238532

Title:

The Impact of Interphase Mass-Transfer Rate and Equilibrium for Multiphase Groundwater Systems

Descriptive Note:

Final rept.,

Corporate Author:

NORTH CAROLINA UNIV AT CHAPEL HILL DEPT OF ENVIRONMENTAL SCIENCES AND ENGINEERING

Personal Author(s):

Report Date:

1991-04-29

Pagination or Media Count:

11.0

Abstract:

Ground water contamination by substances that are immiscible with water e.g., gasoline, jet fuels, chlorinated solvents is well-documented as a commonplace occurrence. The release of such nonaqueous phase liquids NAPLs leads to a multiphase system in which contaminants can exist in, move within, and be transport among NAPL phases, aqueous phases, gas or vapor phases, and solid phases. A common assumption until now is that each chemical species is in local equilibrium among all the phases present in a subsurface environment. This research project investigated the propriety of the local equilibrium assumption through conduct of fundamental laboratory studies and mathematical modeling of interphase mass transfer in multiphase porous media systems. The experimental results of this work were used to develop interphase mass transfer rate coefficient correlations for NAPL-aqueous and aqueous-vapor systems, and to determine correlations of NAPL morphology at residual saturation. The modeling portion of this study incorporated the experimental results into one dimensional and two dimensional multiphase flow and transport models-in order to investigate expected deviations from equilibrium conditions at the field scale. Experimental and modeling results showed that deviations from equilibrium are common for vapor-aqueous phase mass transfer and may be important for NAPL-aqueous phase mass transfer, especially in heterogeneous systems.

Subject Categories:

  • Hydrology, Limnology and Potamology
  • Fluid Mechanics
  • Water Pollution and Control

Distribution Statement:

APPROVED FOR PUBLIC RELEASE