Two Parallel Computing Methods for Coupled Thermohydromechanical Problems

Schrefler, Bernhard A.; Matteazzi, Renato; Gawin, Dariusz; Wang, X.

doi:10.1111/0885-9507.00182

Cited by 13 publications

(2 citation statements)

References 19 publications

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“…Among them, parallel computing provides the most powerful speed-up. Due to decreasing hardware cost in recent years, parallel computation is becoming very attractive for applied research [44,45,49,51]. …”

Section: Geothermal Modelingmentioning

confidence: 99%

Uncertainty analysis of thermo-hydro-mechanical coupled processes in heterogeneous porous media

et al. 2009

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In this paper we present an uncertainty analysis of thermo-hydro-mechanical (THM) coupled processes in a typical geothermal reservoir in crystalline rock. Fracture and matrix are treated conceptually as an equivalent porous medium, and the model is applied to available data from the Urach Spa and Falkenberg sites (Germany). The finite element method (FEM) is used for the numerical analysis of fully coupled THM processes, including thermal water flow, advective-diffusive heat transport, and thermoelasticity. Non-linearity in system behavior is introduced via temperature and pressure dependent fluid properties. Reservoir parameters are considered as spatially random variables and their realizations are generated using conditional Gaussian simulation. The related Monte-Carlo analysis of the coupled THM problem is computationally very expensive. To enhance computational efficiency, the parallel FEM based on domain decomposition technology using message passing interface (MPI) is utilized to conduct the numerous simulations. In the numerical analysis we considered two reservoir modes: undisturbed and stimulated. The uncertainty analysis we apply captures both the effects of heterogeneity and hydraulic stimulation near the injection borehole. The results show the influence of parameter ranges on reservoir evolution during long-term heat extraction, taking into account fully coupled thermo-hydro-mechanical processes. We found that the most significant factors in the analysis are permeability and heat capacity. The study demonstrates the importance of taking parameter uncertainties into account for geothermal reservoir evaluation in order to assess the viability of numerical modeling.

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Section: Geothermal Modelingmentioning

confidence: 99%

Uncertainty analysis of thermo-hydro-mechanical coupled processes in heterogeneous porous media

et al. 2009

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“…Efficient solution of THM coupled problems requires the use of parallel computing (Schrefler et al 2000;Wang et al 2009). …”

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confidence: 99%

Non-isothermal flow in low permeable porous media: a comparison of Richards’ and two-phase flow approaches

et al. 2010

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The present work compares the performance of two alternative flow models for the simulation of thermal-hydraulic coupled processes in low permeable porous media: non- isothermal Richards' and two-phase flow concepts. Both models take vaporization processes into account: however, the Richards' model neglects dynamic pressure variations and bulk flow of the gaseous phase. For the comparison of the two approaches first published data from a laboratory experiment is studied involving thermally driven moisture flow in a partially saturated bentonite sample. Then a benchmark test of longer-term thermal-hydraulic behavior in the engineered barrier system of a geological nuclear waste repository is analyzed (DECOVALEX project). It was found that both models can be used to reproduce the vaporization process if the intrinsic permeability is relative high. However, when a thermalhydraulic coupled problem has the same low intrinsic permeability for both the liquid and the gas phase, only the two-phase flow approach provides reasonable results.

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