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Title: Mass- and temperature-dependent diffusion coefficients for lightnoble gases for the TOUGH2-EOSN Model

Abstract

This report describes modifications made to the EOSN module(Shan and Pruess, 2003) of the nonisothermal multiphase flow simulatorTOUGH2 (Pruess, et al., 1999). The EOSN fluid property module simulatestransport of water, brine, air, and noble gases or CO2 in the subsurface.In the standard version of the EOSN module, diffusion coefficients can bespecified by the user, but there is no allowance for liquid-phasediffusion coefficients to change with temperature. Furthermore, usersmust specify radiogenic sources of heat and helium for each element indata block GENER, which can be a time-consuming task for models withlarge numbers of elements. Our modifications seek to increase thefunctionality and efficiency of using TOUGH2-EOSN by allowing for mass-and temperature-dependent liquid-phase diffusion coefficients for heliumand neon and specification of radiogenic heat and helium production as aproperty of a material. The modified version is based on TOUGH2-EOSN andthus requires familiarity with the capabilities and input formats of theTOUGH2 code (Pruess, et al., 1999) and the EOSN module (Shan and Pruess,2003). This report only details our modifications and how to properlyutilize them.

Authors:
; ;
Publication Date:
Research Org.:
COLLABORATION - U.Minnesota
OSTI Identifier:
927031
Report Number(s):
LBNL-62595
R&D Project: DSP005; BnR: YN0100000; TRN: US200810%%204
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54; AIR; DIFFUSION; EFFICIENCY; HELIUM; MODIFICATIONS; MULTIPHASE FLOW; NEON; PRODUCTION; RARE GASES; SIMULATORS; SPECIFICATIONS; TRANSPORT; WATER

Citation Formats

Andrews, J.L., Finsterle, S., and Saar, M.O. Mass- and temperature-dependent diffusion coefficients for lightnoble gases for the TOUGH2-EOSN Model. United States: N. p., 2007. Web. doi:10.2172/927031.
Andrews, J.L., Finsterle, S., & Saar, M.O. Mass- and temperature-dependent diffusion coefficients for lightnoble gases for the TOUGH2-EOSN Model. United States. doi:10.2172/927031.
Andrews, J.L., Finsterle, S., and Saar, M.O. Fri . "Mass- and temperature-dependent diffusion coefficients for lightnoble gases for the TOUGH2-EOSN Model". United States. doi:10.2172/927031. https://www.osti.gov/servlets/purl/927031.
@article{osti_927031,
title = {Mass- and temperature-dependent diffusion coefficients for lightnoble gases for the TOUGH2-EOSN Model},
author = {Andrews, J.L. and Finsterle, S. and Saar, M.O.},
abstractNote = {This report describes modifications made to the EOSN module(Shan and Pruess, 2003) of the nonisothermal multiphase flow simulatorTOUGH2 (Pruess, et al., 1999). The EOSN fluid property module simulatestransport of water, brine, air, and noble gases or CO2 in the subsurface.In the standard version of the EOSN module, diffusion coefficients can bespecified by the user, but there is no allowance for liquid-phasediffusion coefficients to change with temperature. Furthermore, usersmust specify radiogenic sources of heat and helium for each element indata block GENER, which can be a time-consuming task for models withlarge numbers of elements. Our modifications seek to increase thefunctionality and efficiency of using TOUGH2-EOSN by allowing for mass-and temperature-dependent liquid-phase diffusion coefficients for heliumand neon and specification of radiogenic heat and helium production as aproperty of a material. The modified version is based on TOUGH2-EOSN andthus requires familiarity with the capabilities and input formats of theTOUGH2 code (Pruess, et al., 1999) and the EOSN module (Shan and Pruess,2003). This report only details our modifications and how to properlyutilize them.},
doi = {10.2172/927031},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Apr 13 00:00:00 EDT 2007},
month = {Fri Apr 13 00:00:00 EDT 2007}
}

Technical Report:

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  • The temperature-dependent mass diffusion coefficient is computed using transition state theory. Ab initio supercell phonon calculations of the entire system provide the attempt frequency, the activation enthalpy, and the activation entropy as a function of temperature. Effects due to thermal lattice expansion are included and found to be significant. Numerical results for the case of hydrogen in nickel demonstrate a strong temperature dependence of the migration enthalpy and entropy. Trapping in local minima along the diffusion path has a pronounced effect especially at low temperatures. The computed diffusion coefficients with and without trapping bracket the available experimental values over themore » entire temperature range between 0 and 1400 K.« less
  • The GEO-SEQ Project is investigating methods for geological sequestration of CO{sub 2}. This project, which is directed by LBNL and includes a number of other industrial, university, and national laboratory partners, is evaluating computer simulation methods including TOUGH2 for this problem. The TOUGH2 code, which is a widely used code for flow and transport in porous and fractured media, includes simplified methods for gas diffusion based on a direct application of Fick's law. As shown by Webb (1998) and others, the Dusty Gas Model (DGM) is better than Fick's Law for modeling gas-phase diffusion in porous media. In order tomore » improve gas-phase diffusion modeling for the GEO-SEQ Project, the EOS7R module in the TOUGH2 code has been modified to include the Dusty Gas Model as documented in this report. In addition, the liquid diffusion model has been changed from a mass-based formulation to a mole-based model. Modifications for separate and coupled diffusion in the gas and liquid phases have also been completed. The results from the DGM are compared to the Fick's law behavior for TCE and PCE diffusion across a capillary fringe. The differences are small due to the relatively high permeability (k = 10{sup -11} m{sup 2}) of the problem and the small mole fraction of the gases. Additional comparisons for lower permeabilities and higher mole fractions may be useful.« less
  • The development of an analytical model for predicting the performance of HF lasers that result from the mixing of atomic fluorine with molecular hydrogen in continuously flowing systems is described. The model combines a temperature-dependent solution for a premixed laser system with laminar or turbulent flame-sheet mixing schemes to generate closed-form expressions for the two conditions of constant pressure (simulating a free jet) and constant density (simulating a partially confined flow). The various approximations, including a fully communicating cavity and characteristic reaction and deactivation lifetimes, are discussed. Scaling laws that relate power to the total pressure and nozzle parameters aremore » developed. Comparison with exact numerical treatments for a wide range of conditions reveals that the model is consistently accurate to about 10%. Finally, the sensitivity of the predictions to the kinetic rate package and the utility of the model for performing parameter studies are indicated.« less