Numerical model for fully coupled THM processes with multiphase flow and code validation
2009 (English)In: Chinese Journal of Rock Mechanics and Engineering, ISSN 1000-6915, Vol. 28, no 4, 649-665 p.Article in journal (Refereed) Published
A numerical model for fully coupled THM processes with multiphase flow in porous media was developed based on the momentum, mass and energy conservation laws of the continuum mechanics and the averaging approach of the mixture theory over a solid-liquid-gas three-phase system. To characterize multiphase THM coupling and to make the governing equations closed, complete and compatible, six processes and their coupling effects were considered, including stress-strain, water flow, gas flow, vapor flow, heat transport and porosity evolution processes. The physical phenomena such as phase transition, gas solubility in liquid, thermo-osmosis, moisture transfer and moisture swelling were modeled. As a result, the relative humidity of pore gas was defined on a sounder physical basis, avoiding the traditional definition as a negative exponential function of suction and absolute temperature. By selecting displacements, pore water pressure, pore gas pressure, pore vapor pressure, temperature and porosity as basic unknown variables, a finite element formulation was then established, and a three-dimensional computer code, THYME3D, was developed, with each node of 8 degrees of freedom. The bentonite THM Mock-up experiments performed by CEA were employed to validate the mathematical model and the software. The main coupling mechanisms involved in the experiments were satisfactorily simulated in the validation, and the effects of the governing equations, the constitutive relations and the parameters on the coupled THM processes were understood. The work developed enabled further in-depth research on fully coupled THM or THMC processes in porous media.
Place, publisher, year, edition, pages
2009. Vol. 28, no 4, 649-665 p.
Code validation, Moisture swelling, Multiphase flow transfer, Numerical simulation, Porous medium, Relative humidity, Rock mechanics, THM coupling
IdentifiersURN: urn:nbn:se:kth:diva-153617ScopusID: 2-s2.0-65449170115OAI: oai:DiVA.org:kth-153617DiVA: diva2:752806
QC 201410062014-10-062014-10-062014-10-06Bibliographically approved