Interaction between chemical reaction and natural convection in porous media

Gatica, Jorge E.; Viljoen, Hendrik J.; Hlaváček, Vladimír

doi:10.1016/0009-2509(89)85127-9

Cited by 59 publications

(29 citation statements)

References 43 publications

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“…The focus of the gravity-related studies was on intrasample effects [gas-solid reactions, where natural convection affects gas flow in the sample], but the conjugate flow problem [where natural convection outside the sample affects the combustion] has been largely overlooked. The interaction between natural convection and chemical reaction has been extensively studied for porous and homogeneous media [Viljoen and Hlavacek, 1988;Gatica et al, 1989;Viljoen et al, 1989Viljoen et al, , 1990, investigating the influence of natural convection on ignition and induction periods. Matkowsky and coworkers [1997a,b] did a comprehensive study of natural convection in the realm of filtration combustion.…”

Section: S E Whitney H J Viljoenmentioning

confidence: 99%

Natural convection and solid phase combustion

Whitney

Viljoen

2003

Chemical Engineering Communications

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Self-propagating high-temperature synthesis [SHS] is a combustion process involving two or more solid reactants. The typical SHS configuration consists of a cylindrical preform of mixed powders, placed in an inert gas chamber, and ignited at one end. In past studies, interaction between the solid phase and the ambient gas phase has been limited to heat losses from the solid; the influence of natural convection on the solid phase has never been considered. In this study, computational fluid dynamics [CFD] is used, and it is shown that intense convection flow develops in the proximity of the combustion front. Gas flows adjacent to reacted solid material, heats up, and when it reaches the unreacted solid heat is transferred from the gas to the solid phase, which aids solid phase thermal conduction in preheating the material. The effect is stronger than expected, and it could stabilize the combustion of structured reactants like roll-ups of foils and wires. Combustion parallel and antiparallel to gravity is investigated for different burning velocities. At low propagation velocities, the natural convection cell forms a torus that is seated above the combustion front. At high propagation velocities, the convection flow cannot track the combustion front, and Tollmien-Schlichting waves form. Constant front propagation and planar oscillations of the combustion front lead to increasingly complex flows. Finally, the heat exchange between the gas and solid for constant front propagation is compared to analytical solutions.

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Section: S E Whitney H J Viljoenmentioning

confidence: 99%

Natural convection and solid phase combustion

Whitney

Viljoen

2003

Chemical Engineering Communications

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“…The use of such an approximation has been the subject of several analyses and modifications; the details can be found elsewhere. [14] For a fluid that obeys Boussinesq's approximations, and for low infiltration velocities, the momentum equation becomes…”

Section: Model Equations and Assumptionsmentioning

confidence: 99%

Dynamic analysis of unidirectional pressure infiltration of porous preforms by pure metals

Biswas¹,

Gatica

Tewari

1998

Metall Mater Trans A

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“…The first study on the reactive convection in porous media was due to Steinberg and Brand [22,23]. More studies were carried out by Gatica et al [24,25], Viljoen et al [26] and Malashetty and Gaikwad [27]. Pritchard and Richardson [28] figured out a model similar to that of Steinberg and Brand [22,23].…”

Section: Introductionmentioning

confidence: 96%

The non-linear energy stability of Brinkman thermosolutal convection with reaction

Al-Sulaimi

2016

Ricerche mat

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We use the energy method to obtain the non-linear stability threshold for thermosolutal convection porous media of Brinkman type with reaction. The obtained non-linear boundaries for different values of the reaction terms are compared with the relevant linear instability boundaries obtained by Wang and Tan (Phys Lett A 373:776-780, 2009). Using the energy theory we obtain the non-linear stability threshold below which the solution is globally stable. The compound matrix numerical technique is implemented to solve the associated system of equations with the corresponding boundary conditions. Two systems are investigated, the heated below salted above case and the heated below salted below case. The effect of the reaction terms and Brinkman term on the Rayleigh number is discussed and presented graphically.

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Interaction between chemical reaction and natural convection in porous media

Cited by 59 publications

References 43 publications

Natural convection and solid phase combustion

Natural convection and solid phase combustion

Dynamic analysis of unidirectional pressure infiltration of porous preforms by pure metals

The non-linear energy stability of Brinkman thermosolutal convection with reaction

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