Combined Heat and Mass Transfer by Natural Convection in a Vertical Enclosure

Trevisan, Osvair Vidal; Bejan, Adrian

doi:10.1115/1.3248027

Cited by 143 publications

(65 citation statements)

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“…Then, the massline concept was proposed for convective mass transfer problems [2]. Morega and Bejan [3] and Nield and Bejan [4] visualized heatlines in forced convection laminar boundary layers and in porous media, respectively.…”

Section: Introductionmentioning

confidence: 99%

Visualization of diffusion and convection heat transport in a square cavity with natural convection

Mobedi

Özkol

Sundén

2010

International Journal of Heat and Mass Transfer

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a b s t r a c tIn this study, the total heatfunction equation which includes diffusion and convection transport is divided into the corresponding heatfunction equations. The superposition rule is used to obtain the mathematical definitions of diffusion and convection heatfunctions and corresponding boundary conditions. It is observed that the separate visualization of diffusion and convection heatlines provides significant information on understanding of the mechanism of heat transfer in a convective flow. The direction of the diffusion and convection heat transport as well as the strength of convection compared to the conduction in entire or in a portion of a domain can be visualized. The diffusion heatlines demonstrate a potential flow like behavior while convective heat flow rotates due to the source term of the convection heatfunction equation, similar to the rotation of fluid flow generated by fluid flow vorticity. The similarity between the streamfunction and the total heatfunction yields a concept of heat flow vorticity, X t . The obtained results show that the maximum absolute value of the convection heatfunction may be an appropriate parameter for determination of the convection strength. The diffusion and convection heatfunction equations for natural convection in a differentially heated square cavity for four different length of the heated surface on the right vertical wall as s p = L/4, L/2, 3L/4 and L and a fixed length of the cooled surface on the right vertical wall as L/4 are obtained and corresponding heatlines are drawn. The values of the conduction heatfunction are positive while the sign of convection heatfunction values is negative for the studied cases. Based on the distribution of total heatlines, two regions are detected in the cavity, an active region with the positive values of heatlines signifying dominant conduction heat transfer and a passive region with the negative heatfunction values in where convection heat flow is dominant and heat only rotates in a closed contour pattern. The variations of average Nusselt number, average of heat flow vorticity, maximum absolute values of convection heatfunction and streamfunction at different Rayleigh numbers and lengths of the heated surface are presented.

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Section: Introductionmentioning

confidence: 99%

Visualization of diffusion and convection heat transport in a square cavity with natural convection

Mobedi

Özkol

Sundén

2010

International Journal of Heat and Mass Transfer

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“…In these studies the critical Rayleigh numbers for the onset of convective flows are predicted. The theoretical and numerical study of heat and mass transfer affected by a high Rayleigh number Benard convection in a porous layer heated from below is obtained in [6]. The numerical results and a scale analysis of the flow in a porous medium are presented, where the buoyancy effect is due entirely to temperature gradients.…”

Section: Introductionmentioning

confidence: 99%

Boundary Element Method for double diffusive natural convection in a horizontal porous layer

Kramer¹,

Jecl²,

Skerget³

2007

WIT Transactions on Modelling and Simulation, Vol 44

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A numerical study of double-diffusive natural convection in porous media using the Boundary Element Method is presented. The studied configuration is a horizontal layer filled with fluid saturated porous media, where different temperature and concentration values are applied on the horizontal walls, while the vertical walls are adiabatic and impermeable. Transport phenomena in porous media are described with the use of modified Navier-Stokes equations in the form of conservation laws for mass, momentum, energy and species. The results for different governing parameters (Rayleigh number, Darcy number, buoyancy ratio and Lewis number) are presented and compared with those in published studies.

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“…Brand and Steinberg [8] studied numerically the convective instabilities of two miscible fluids in a porous medium with the Soret effect. Trevisan and Bejan [9] developed a double-diffusive convective model including both Soret and Dufour effects to predict heat transfer into a rectangular slot with uniform heat flux along the vertical sides. Nithyadevi and Yang [10] analyzed the effect of various parameters on double-diffusive convection of water in a partially heated enclosure with Soret and Dufour effects.…”

Section: Introductionmentioning

confidence: 99%

Unsteady Double Diffusive Natural Convection with Dufour and Soret Effects

Niche¹,

Bouabdallah²,

Ghernaout³

et al. 2016

IJHT

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Transient double diffusive natural convection in a square cavity is numerically investigated. The enclosure is heated and cooled along the vertical walls with thermal and solutal gradients, the two horizontal walls of the enclosure are adiabatic and impermeable, the Dufour and Soret effects are considered. The governing equations are solved by using control volume method and SIMPLER algorithm. The main focus of this work is to identify the flow regime for thermal and solutal dominated flows. The flow pattern and heat and mass transfer and the effect of various parameters are analyzed (thermal Rayleigh number, Buoyancy ratio, Soret and Dufour coefficients). Comprehensive Nusselt and Sherwood numbers data are presented as functions of the governing parameters. The results showed that both heat and mass transfer increased in the presence of Dufour coefficient, and the Soret coefficient had great effect on the flow structure.

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Combined Heat and Mass Transfer by Natural Convection in a Vertical Enclosure

Cited by 143 publications

References 0 publications

Visualization of diffusion and convection heat transport in a square cavity with natural convection

Visualization of diffusion and convection heat transport in a square cavity with natural convection

Boundary Element Method for double diffusive natural convection in a horizontal porous layer

Unsteady Double Diffusive Natural Convection with Dufour and Soret Effects

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