Pattern selection for Darcy-Bénard convection with local thermal nonequilibrium

Bidin, Biliana; Rees, D. Andrew S.

doi:10.1016/j.ijheatmasstransfer.2020.119539

Cited by 8 publications

(2 citation statements)

References 25 publications

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“…Recently many authors (Dehghan et al 2014, Chen and Tso 2011, Yi et al 2021, Rees 2011, Kuznetsov and Nield 2015, Bidin and Rees 2020, Parhizi et al 2021, and Rees et al 2008 discussed the LTNE effect for the duct which is filled and partially filled with porous substance respectively and presented the results based on general Biot number functions which contribute to the improvement of the novel porous material's thermal performance and their engineered characteristics.…”

Section: Introductionmentioning

confidence: 99%

A Numerical Study of the Effect of Magnetic field in the Entrance region of a Couette flow in a Duct Filled with Porous Material under the Local Thermal Non-Equilibrium

Bhargavi

Gupta

Narayana

2023

Preprint

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The effect of the magnetic field on Couette flow in a porous-filled duct under local thermal non-equilibrium (LTNE) is examined in the present analysis. The bottom plate is moving and experiencing isoflux boundary conditions, whereas the top plate is stationary and adiabatic. The porous region's unidirectional flow fits the Darcy Brinkman (DB) model. The investigations further quantify the impact of the thermal conductivity ratio (κ), Hartmann number (MH), and Biot number (BiH), on heat transfer enhancement. For the coupled energy equations, a successive accelerated replacement (SAR) method is used to generate numerical solutions. The present investigation gives the temperatures in the solid and, the fluid phases in dimensionless form, dimensionless temperature based on the bulk mean temperature and, the local Nusselt number profiles. In the Couette flow model, the magnetic field influences the temperature field in both phases. Additionally, for each Hartmann number, the temperature of the solid phase is greater than that of the fluid phase, validating LTNE. For the thermal field, the fully developed condition is validated in the LTNE model. This study is primarily concerned with modeling high-performance matrix heat exchangers.

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Section: Introductionmentioning

confidence: 99%

A Numerical Study of the Effect of Magnetic field in the Entrance region of a Couette flow in a Duct Filled with Porous Material under the Local Thermal Non-Equilibrium

Bhargavi

Gupta

Narayana

2023

Preprint

View full text Add to dashboard Cite

show abstract

“…This investigation is usually performed by means of a weakly nonlinear analysis, since the interaction between the single modes must be taken into account 24 . Such an approach has indeed been used to investigate the effect of local thermal non-equilibrium on the pattern formation for mixed convection in porous media 25 . In the present analysis, however, only the linear pattern selection is discussed.…”

Section: Introductionmentioning

confidence: 99%

The effect of local thermal non-equilibrium on the onset of thermal instability for a metallic foam

Freitas¹,

Brandão

Alves³

et al. 2022

Physics of Fluids

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Mixed convection in metallic foams modeled with Darcy's law under local thermal non-equilibrium conditions is investigated, where the solid phase thermal conductivity is assumed to be infinitely larger than its fluid phase counterpart. A linear and modal stability analysis was employed to evaluate the convective and absolute instability thresholds as well as their respective cell patterns. This analysis indicates that local thermal non-equilibrium always has a stabilizing effect and the spanwise uniform mode is always the most unstable. At the onset of convective instability, however, the number of equally unstable cell patterns increases with both the aspect ratio and the local thermal non-equilibrium strength.

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Sharp Instability Estimates for Bidisperse Convection with Local Thermal Non-equilibrium

Franchi,

Nibbi,

Straughan

2023

Transp Porous Med

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We analyse a theory for thermal convection in a Darcy porous material where the skeletal structure is one with macropores, but also cracks or fissures, giving rise to a series of micropores. This is thus thermal convection in a bidisperse, or double porosity, porous body. The theory allows for non-equilibrium thermal conditions in that the temperature of the solid skeleton is allowed to be different from that of the fluid in the macro- or micropores. The model does, however, allow for independent velocities and pressures of the fluid in the macro- and micropores. The threshold for linear instability is shown to be the same as that for global nonlinear stability. This is a key result because it shows that one may employ linearized theory to ensure that the key physics of the thermal convection problem has been captured. It is important to realize that this has not been shown for other theories of bidisperse media where the temperatures in the macro- and micropores may be different. An analytical expression is obtained for the critical Rayleigh number and numerical results are presented employing realistic parameters for the physical values which arise. Article Highlights A two-temperature regime for a bidisperse Darcy porous medium is proposed to study the thermal convection problem. The optimal result of coincidence between the linear instability and nonlinear stability critical thresholds is proven. Numerical analysis enhances that the scaled heat transfer coefficient between the fluid and solid and the porosity-weighted conductivity ratio stabilize the problem significantly.

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Pattern selection for Darcy-Bénard convection with local thermal nonequilibrium

Cited by 8 publications

References 25 publications

A Numerical Study of the Effect of Magnetic field in the Entrance region of a Couette flow in a Duct Filled with Porous Material under the Local Thermal Non-Equilibrium

A Numerical Study of the Effect of Magnetic field in the Entrance region of a Couette flow in a Duct Filled with Porous Material under the Local Thermal Non-Equilibrium

The effect of local thermal non-equilibrium on the onset of thermal instability for a metallic foam

Sharp Instability Estimates for Bidisperse Convection with Local Thermal Non-equilibrium

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