Local thermal non-equilibrium in porous media with heat conduction

Gandomkar, Arjang; Gray, K. E.

doi:10.1016/j.ijheatmasstransfer.2018.04.011

Cited by 52 publications

(9 citation statements)

References 25 publications

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“…3a reveals that even under conventional thermo-poroelasticity (trivial thermo-osmosis), LTNE influences pore pressure and stress variations (maximum 3 MPa at 0.01 day). This observation is consistent with previous studies [30]. Lower pore pressures are generated under LTNE compared to LTE when ignoring the nontraditional thermal process.…”

Section: Ltne Results Versus Lte Resultssupporting

confidence: 93%

Impact of local thermal non-equilibrium on temporal thermo-hydro-mechanical processes in low permeable porous media

Zhai

Atefi-Monfared

2020

E3S Web Conf.

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The thermo-hydraulic-mechanical (THM) response of low permeable media is of crucial significance in thermal fracturing for production of unconventional shale oil, enhanced geothermal systems, and waste disposal. During such processes, pore pressures and stresses change in a spatiotemporal manner due to hydraulic and thermal loadings. From the viewpoint of the energy balance equation, the available theoretical studies can be classified as local thermal equilibrium (LTE), and local thermal non-equilibrium (LTNE) models. LTE models consider identical temperature for different phase of the porous system. LTNE models allow different temperature variations in solid and fluid phases of a porous medium. Current LTNE studies are weakly-coupled – not incorporating thermo-osmosis. This paper presents novel coupled LTNE thermo-poroelastic solutions in a transversely isotropic saturated porous medium, incorporating thermo- osmosis effect. Solutions are obtained for permeable and impermeable boundaries. Thermo-osmosis is found to have a very different effect in case of LTNE versus LTE, resulting in a fundamentally different THM response. LTNE effect analysis reveals different THM responses under different heat transfer properties at the solid-fluid interface in low permeable strata.

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Section: Ltne Results Versus Lte Resultssupporting

confidence: 93%

Impact of local thermal non-equilibrium on temporal thermo-hydro-mechanical processes in low permeable porous media

Zhai

Atefi-Monfared

2020

E3S Web Conf.

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“…where a m,ref is the reference specific surface area of the material of interest, while we use a m,max = 3.0 × 10 4 m −1 which is a typical value for coarse sands [108]. Although the interfacial heat transfer coefficient may not only depend on the pore space geometry but also the flow velocity, as we focus on low Reynolds number flow in both the bulk and crack regions, this study regards h m as an independent material parameter for simplicity, following [83,89].…”

Section: Thermal Responses and Heat Exchange Modelmentioning

confidence: 99%

“…Notice that Eqs. ( 88) and (89) hint that the set of vectors (ỹ sf and ysf ) span R N sf n . It implies that we have two sets of eigenvectors that correspond to the case where the eigenvalues are either γ sf = 0 or γ sf ̸ = 0, respectively, since they are orthogonal with respect to Ksf .…”

Section: Stability Of Mixed Time Integrationmentioning

confidence: 99%

Asynchronous phase field fracture model for porous media with thermally non-equilibrated constituents

Suh

Sun

2021

Computer Methods in Applied Mechanics and Engineering

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“…Gandomkar and Gray [54] solved analytically the transient LTE and LTNE models and calculated instant temperature profiles within a water-saturated non-metallic porous medium like sandstones or rocks in radial coordinates, using the Laplace transform technique together with the Stehfest algorithm for developing transient exact solutions. They concluded that the weighted average temperatures of the LTNE model are permanently larger than these of the classical theory LTE.…”

Section: In Forced Convectionmentioning

confidence: 99%

Legitimacy of the Local Thermal Equilibrium Hypothesis in Porous Media: A Comprehensive Review

et al. 2021

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Local thermal equilibrium (LTE) is a frequently-employed hypothesis when analysing convection heat transfer in porous media. However, investigation of the non-equilibrium phenomenon exhibits that such hypothesis is typically not true for many circumstances such as rapid cooling or heating, and in industrial applications involving immediate transient thermal response, leading to a lack of local thermal equilibrium (LTE). Therefore, for the sake of appropriately conduct the technological process, it has become necessary to examine the validity of the LTE assumption before deciding which energy model should be used. Indeed, the legitimacy of the LTE hypothesis has been widely investigated in different applications and different modes of heat transfer, and many criteria have been developed. This paper summarises the studies that investigated this hypothesis in forced, free, and mixed convection, and presents the appropriate circumstances that can make the LTE hypothesis to be valid. For example, in forced convection, the literature shows that this hypothesis is valid for lower Darcy number, lower Reynolds number, lower Prandtl number, and/or lower solid phase thermal conductivity; however, it becomes invalid for higher effective fluid thermal conductivity and/or lower interstitial heat transfer coefficient.

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Local thermal non-equilibrium in porous media with heat conduction

Cited by 52 publications

References 25 publications

Impact of local thermal non-equilibrium on temporal thermo-hydro-mechanical processes in low permeable porous media

Impact of local thermal non-equilibrium on temporal thermo-hydro-mechanical processes in low permeable porous media

Asynchronous phase field fracture model for porous media with thermally non-equilibrated constituents

Legitimacy of the Local Thermal Equilibrium Hypothesis in Porous Media: A Comprehensive Review

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