New solutions for axial flow convection in porous and partly porous cylindrical domains

Arpino, Fausto; Carotenuto, A.; Massarotti, Nicola; Mauro, Alessandro

doi:10.1016/j.ijheatmasstransfer.2012.10.030

Cited by 33 publications

(28 citation statements)

References 44 publications

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“…(28) when h N which is the entropy generation rate due to heat transfer can be calculated from integration over the specific boundary for the first terms of Eq. (26a), the first and second terms of Eq.…”

Section: Entropy Generationmentioning

confidence: 99%

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Heat transfer and second law analyses of forced convection in a channel partially filled by porous media and featuring internal heat sources

Torabi

Karimi

Zhang

2015

Energy

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This paper provides a comprehensive study on the heat transfer and entropy generation rates in a channel partially filled with a porous medium and under constant wall heat flux. The porous inserts are attached to the walls of the channel and the system features internal heat sources due to exothermic or endothermic physical or physicochemical processes. Darcy-Brinkman model is used for modelling the transport of momentum and an analytical study on the basis of local thermal non-equilibrium (LTNE) condition is conducted. Further analysis through considering the simplifying, local thermal equilibrium (LTE) model is also presented. Analytical solutions are, first, developed for the velocity and temperature fields. These are subsequently incorporated into the fundamental equations of entropy generation and both local and total entropy generation rates are investigated for a number of cases. It is argued that, comparing with LTE, the LTNE approach yields more accurate results on the temperature distribution within the system and therefore reveals more realistic Nusselt number and entropy generation rates. In keeping with the previous investigations, bifurcation phenomena are observed in the temperature field and rates of entropy generation. It is, further, demonstrated that partial filling of the channel leads to a substantial reduction of the total entropy generation. The results also show that the exothermicity or endothermicity characteristics of the system have significant impacts on the temperature fields, Nusselt number and entropy generation rates.

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Section: Entropy Generationmentioning

confidence: 99%

“…Partial filling is an effective avenue to circumvent significant pressure drops in a porous system [28].…”

Section: Introductionmentioning

confidence: 99%

Heat transfer and second law analyses of forced convection in a channel partially filled by porous media and featuring internal heat sources

Torabi

Karimi

Zhang

2015

Energy

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“…These experimental data have then been used in a numerical simulation code, based on finite elements, in order to reproduce the transient behavior of a typical building structure, characterized by a 3D field of the quantities of interest, defined as thermal bridge. This novel paper integrates the experiences of the authors belonging to research groups, working in two research areas: materials sciences [7][8][9][10]23,25,29,33] and thermal sciences [43][44][45][46][47][48].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Analysis of Thermal and Hygrometric Characteristics of Building Structures Employing Recycled Plastic Aggregates and Geopolymer Concrete

et al. 2013

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Abstract:The correct estimation of building energy consumptions is assuming an always increasing importance, and a detailed reproduction of building structures, with all the single components involved, is necessary to achieve this aim. In addition, the current ecological development tries to limit the use of natural raw materials as building components, in favor of alternative (waste) materials, which ensure significant advantages from the economic, energetic and environmental point of views. In this work, dynamic heat and vapor transport in a typical three-dimensional (3D) building structure, involving different types of environmental-friendly concrete mixtures, have been simulated by using finite elements. In particular, the authors propose to substitute part of the aggregates with plastic waste and to use a fly ash based geopolymeric binder for the production of low conductivity concrete, to be employed in eco-efficient buildings. Concrete produced with natural limestone aggregates has been considered as the reference benchmark. The whole characterization of the different types of concrete tested in the present work has been obtained through laboratory experiments. The structure taken into account in the simulations is a 3D thermal bridge, typical of building envelopes. The thermal and hygrometric transient behavior of this structure, employing plastic waste in different percentages and geopolymer concrete, has been analyzed by the authors.

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“…Details on this are available in ref. [27]. The code has been successfully validated through a comparison with experimental data available in scientific literature for steady state and transient natural convection in porous cylindrical domain; details about code validation can be found in ref.…”

Section: Numerical Modelmentioning

confidence: 99%

“…Moreover, all these works are based on simplifying hypothesis; in fact, only few works referring to square cavities [14] or infinite domains [15] refer to very specific conditions, such as nonBoussinesq convection [14] or non-Newtonian viscoelastic fluids [15]. As regards thermal analysis of partially porous cavities, while laminar free convection in partially porous square and rectangular domains has been extensively analyzed both in steady [16][17][18][19][20] and transient conditions [21][22][23], few works concerning natural convection in partially vertical cylindrical cavities are available in scientific literature [24][25][26][27][28][29]. Moreover, only few papers [28][29] did not overlook transient regime, despite many engineering applications of the enclosure problem are related to real systems operating in dynamic mode.…”

Section: Introductionmentioning

confidence: 99%

Transient Natural Convection in Partially Porous Vertical Annuli

Arpino¹,

Carotenuto²,

Ciccolella³

et al. 2016

IJHT

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The numerical modeling of natural convection in partially porous annuli is a topic of rising interest, due to its practical applications for the provisional analyses of several engineering applications such as geothermal down-hole heat exchangers, chemical reactors, etc. Though a large number of papers focused on the modeling of this phenomenon under steady-state conditions, only few works consider its transient thermal evolution and no works are available referred to partially porous annular cavities. However, most of the real technical applications operate in dynamic mode, for this reason, this paper focuses on the transient numerical analysis of heat transfer in partially porous annular enclosures, where natural convection occurs. A fully explicit version of the CBS algorithm is employed here to solve the generalized porous medium model which describes both the sub-domains of the cavity using only one equations set; a dual time stepping technique is employed for transient analyses. Several cases have been analyzed, by changing the cavity aspect ratio and thermo-physical parameters of the fluid. Several results have been presented by changing both porous medium's properties and geometrical characteristics of the domain. The obtained results highlight that both the properties and the position of porous layer, inserted into the computational domain, strongly influence the thermal behavior of the cavity.

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New solutions for axial flow convection in porous and partly porous cylindrical domains

Cited by 33 publications

References 44 publications

Heat transfer and second law analyses of forced convection in a channel partially filled by porous media and featuring internal heat sources

Heat transfer and second law analyses of forced convection in a channel partially filled by porous media and featuring internal heat sources

Experimental and Numerical Analysis of Thermal and Hygrometric Characteristics of Building Structures Employing Recycled Plastic Aggregates and Geopolymer Concrete

Transient Natural Convection in Partially Porous Vertical Annuli

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