Propagation of Reaction Front in Porous Media with Natural Convection

This paper examines the influence of convective instability on the reaction front propagation in porous media. The model includes heat and concentration equations and motion equations under Boussinesq approximation. The non-stationary Darcy equation is adopted and the fluid is supposed to be incompressible. Numerical results are performed via the dispersion relation. The simulations show that the propogating reaction front loses stability as Vadasz number increase, it shows also more stability is gained when Zeldovich number increased.

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A Meshfree Method for Heat Explosion Problems with Natural Convection in Inclined Porous Media

MATEC Web of Conferences ◽

10.1051/matecconf/201824101019 ◽

2018 ◽

Vol 241 ◽

pp. 01019 ◽

Cited By ~ 1

Author(s):

Abdoulhafar Halassi ◽

Youssef Joundy ◽

Loubna Salhi ◽

Ahmed Taik

Keyword(s):

Porous Media ◽

Natural Convection ◽

Vertical Direction ◽

Meshfree Method ◽

Boussinesq Approximation ◽

Complex Behaviour ◽

Meshless Collocation ◽

Darcy Equations ◽

Small Inclination ◽

Good Agreement

This paper investigates the interaction between natural convection and heat explosion in porous media. A meshless collocation method based on multiquadric radial basis functions has been applied to study the problem in an inclined two-dimensional porous media. The governing equations consist of coupling the Darcy equations in the Boussinesq approximation of low density variations to the heat equation with a nonlinear chemical source term. The numerical results obtained are in good agreement with some previous studies that consider the vertical direction. A complex behaviour of solutions is observed, including periodic and aperiodic oscillations. We have shown that a small inclination of the container stabilizes the reactive fluid and can prevent thermal explosion.

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Natural Convection in a Horizontal Cavity Partially Occupied by a Porous Media Saturated by a Coolant Liquid

Volume 1: Symposia, Parts A and B ◽

10.1115/fedsm2006-98236 ◽

2006 ◽

Author(s):

Fakhreddine S. Oueslati ◽

Rachid Bennacer ◽

Habib Sammouda ◽

Ali Belghith

Keyword(s):

Heat Transfer ◽

Porous Media ◽

Natural Convection ◽

Flow Structure ◽

Boussinesq Approximation ◽

Density Variation ◽

Heat Fluxes ◽

Complex Flow ◽

Coupled Equations ◽

Complex Flow Structure

The natural convection is studied in a cavity witch the lower half is filled with a porous media that is saturated with a first fluid (liquid), and the upper is filled with a second fluid (gas). The horizontal borders are heated and cooled by uniform heat fluxes and vertical ones are adiabatic. The formulation of the problem is based on the Darcy-Brinkman model. The density variation is taken into account by the Boussinesq approximation. The system of the coupled equations is resolved by the classic finite volume method. The numerical results show that the variation of the conductivity of the porous media influences strongly the flow structure and the heat transfer as well as in upper that in the lower zones. The effect of conductivity is conditioned by the porosity which plays a very significant roll on the heat transfer. The structures of this flow show that this kind of problem with specific boundary conditions generates a complex flow structure of several contra-rotating two to two cells, in the upper half of the cavity.

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