Numerical heat flow visualization analysis on enhanced thermal processing for various shapes of containers during thermal convection

Lukose, Leo; Basak, Tanmay

doi:10.1108/hff-05-2019-0376

Cited by 13 publications

(12 citation statements)

References 84 publications

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“…A comprehensive review of the fundamental aspects of thermal convection in curved geometries and surfaces in the presence of porous media and nanofluids has been reported by Shenoy et al (2016). To understand the thermo-fluid phenomena, many researchers have studied the thermal convective phenomena in different geometries adopting curved, corrugated, sinusoidal, irregular or other wavy surfaces considering coupled multiphysical situations (Dalal, and Das, 2006; Abu-Nada and Oztop, 2011; Rahimi et al , 2018; Manna et al , 2019; Lukose and Basak, 2021).…”

Section: Introductionmentioning

confidence: 99%

Magnetohydrodynamic thermal characteristics of water-based hybrid nanofluid-filled non-Darcian porous wavy enclosure: effect of undulation

Biswas

Mandal²,

Manna

et al. 2021

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Purpose The aims of this study is to numerically investigate the thermal phenomena during magnetohydrodynamic (MHD) free convection in an oblique enclosure filled with porous media saturated with Cu–Al2O3/water hybrid nanofluid and heated at the left wavy wall. The thermophysical phenomena are explored thoroughly by varying the amplitude (λ) and undulation (n) of the wavy wall and the inclination of the enclosure (γ) along with other pertinent physical parameters. Darcy–Rayleigh number (Ram), Darcy number (Da), Hartmann number (Ha) and nanoparticle volumetric fraction (ϕ). The effect of all parameters has been analyzed and represented by using heatlines, isotherms, streamlines, average Nusselt number and local Nusselt number. Design/methodology/approach The finite volume method is used to work out the transport equations coupled with velocity, pressure and temperature subjected to non-uniform staggered grid structure after grid-sensitivity analysis by an indigenous computing code and the semi-implicit method for pressure linked equations (SIMPLE) algorithm. The solution process is initiated following an iterative approach through the alternate direction implicit sweep technique and the tridiagonal matrix algorithm (TDMA) algorithm. The iterative process is continued until successive minimization of the residuals (<1e-8) for the governing equations. Findings This study reveals that the increase in the heating surface area does not always favor heat transfer. An increase in the undulation amplitude enhances the heat transfer; however, there is an optimum value of undulation of the wavy wall for this. The heat transfer enhancement because of the wall curvature is revealed at higher Ram, lower Da and Ha and lower volume fraction of nanoparticles. In general, this augmentation is optimum for four undulations of the wavy wall with an amplitude of λ = 0.3. The heat transfer enhancement can be more at the cavity inclination γ = 45°. Research limitations/implications The technique of this investigation could be used in other multiphysical areas involving partial porous layers, conducting objects, different heating conditions, wall motion, etc. Practical implications This study is to address MHD thermo-fluid phenomena of Cu–Al2O3/water-based hybrid nanofluid flow through a non-Darcian porous wavy cavity at different inclinations. The amplitude and number of undulations of the wavy wall, permeability of the porous medium, magnetic field intensity, nanoparticle volumetric fraction and inclinations of the enclosure play a significant role in the heat transfer process. This analysis and the findings of this work can be useful for the design and control of similar thermal systems/devices. Originality/value Many researchers have examined the problem of buoyancy-induced free convection in a wavy-porous cavity packed with regular fluids or nanofluids. However, the effect of magnetic fields along with the amplitude (λ) at different undulations (n) of the heated wavy wall of an inclined enclosure is not attended so far to understand the transport mechanisms. Most often, the evolutions of the thermo-fluid phenomena in such complex geometries invoking different multiphysics are very intricate. Numerical implementations for simulations and subsequent post-processing of the results are also challenging.

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Section: Introductionmentioning

confidence: 99%

Magnetohydrodynamic thermal characteristics of water-based hybrid nanofluid-filled non-Darcian porous wavy enclosure: effect of undulation

Biswas

Mandal²,

Manna

et al. 2021

HFF

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“…The state of the art of natural convection numerical studies, in the most diverse applications and methodologies of modeling and solution, is broadly represented by the references (Salari et al , 2017) in the three-dimensional study of turbulent/transitional natural convection with different turbulence/transition models in trapezoidal enclosures (Dash and Dash, 2020). In the analysis of conjugate heat transfer by natural convection and thermal radiation in a horizontal cylinder that is suspended in the air; (Lukose and Basak, 2020) in the study of natural convection through the Galerkin finite element method in nine different shapes of containers, with the same surface area and identical isothermal heat input at the bottom wall; (Henniche and Korichi, 2020) in the study and numerical simulation (using the software OpenFOAM®) of enhanced mixed convection heat transfer in a vertical channel with staggered inclined baffles; Raizah (2020) in the application of the ISPH method for the study of natural convection with copper-water nanofluid inside cavities with cross blades or circular cylinder cylinder; Alshomrani et al (2020) in the three-dimensional study of the influence of different locations of cooler and the tilting angles of a cavity on natural convection heat transfer in a laminar regime; Aghighi et al (2020) in obtaining solutions, through the Galerkin’s weighted residual finite element method, of the natural convection of Casson fluid in a square enclosure, under conditions of differentially heated side walls; Sasidharan and Dutta (2020) in the study of the thermal performance of a hybrid tubular and cavity solar thermal receiver; Ullah et al (2021) in the two-dimensional study of natural convection of micropolar nanofluid in a rectangular vertical container, heated on the lower wall to generate the internal flow; Lukose and Basak (2021) in the extensive literature review on the mixed convection and the proposition of 10 unified models in different physical–numerical conditions; and Nishad et al (2021) in the two-dimensional study of natural convection inside a wavy enclosure with Cu-water nanofluid under magnetic field and using the element-free Galerkin method (EFGM) with parallel algorithm.…”

Section: Introductionmentioning

confidence: 99%

Physical–numerical parameters in laminar simulations of natural convection on three-dimensional square plates

Júnior¹,

Scalon

Oliveira

2021

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Purpose The purpose of this study is to analyze the influence of the main physical–numerical parameters in the computational evaluation of natural convection heat transfer rates in isothermal flat square plates in the laminar regime. Moreover by experimentally validate the results of the numerical models and define the best parameter settings for the problem situation studied. Design/methodology/approach The present work is an extension of the study by Verderio Junior et al. (2021), differing in the modeling, results analysis and conclusions for the laminar flow regime with Rade=1×105. The analysis of the influence and precision of the physical–numerical parameters: boundary conditions, degree of mesh refinement, refinement layers and κ – ω SST and κ – ε turbulence models, occurred from the results from 48 numerical models, which were simulated using the OpenFOAM® software. Comparing the experimental mean Nusselt number with the numerical values obtained in the simulations and the analysis of the relative errors were used in the evaluation of the advantages, restrictions and selection of the most adequate parameters to the studied problem situation. Findings The numerical results of the simulations were validated, with excellent precision, from the experimental reference by Kitamura et al. (2015). The application of the κ – ω SST and κ – ε turbulence models and the boundary conditions (with and without wall functions) were also physically validated. The use of the κ – ω SST and κ – ε turbulence models, in terms of cost-benefit and precision, proved to be inefficient in the problem situation studied. Simulations without turbulence models proved to be the best option for the physical model for the studies developed. The use of refinement layers, especially in applications with wall functions and turbulence models, proved unfeasible. Practical implications Use of the physical–numerical parameters studied and validated, and application of the modeling and analysis methodology developed in projects and optimizations of natural convection thermal systems in a laminar flow regime. Just like, reduce costs and the dependence on the construction of experimental apparatus to obtain experimental results and in the numerical-experimental validation process. Social implications Exclusive use of free and open-source computational tools as an alternative to feasible research in the computational fluid dynamics area in conditions of budget constraints and lack of higher value-added infrastructure, with applicability in the academic and industrial areas. Originality/value The results and discussions presented are original and new for the applied study of laminar natural convection in isothermal flat plate, with analysis and validation of the main physical and numerical influence parameters.

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“…GFEM had been used extensively in earlier studies for CFD simulations (Basak et al , 2006; Anandalakshmi and Basak, 2015; Biswal and Basak, 2018; Das et al , 2019; Lukose and Basak, 2019; Rafiei et al , 2019). The current work employs GFEM to solve equations (7)–(9) with velocity and different thermal boundary conditions at the walls (equation (10)).…”

Section: Model Formulation Numerical Methodology Finite Element Logistics and Post-processingmentioning

confidence: 99%

“…Earlier works in literature concluded that fluid flow during natural convection is mainly dependent on the dimensionless parameters, Ra and Pr . However, a recent work (Lukose and Basak, 2019) established that in addition to the dimensionless parameters, Ra and Pr , the shape of containers also plays an important role on the fluid flow, energy flow and thermal distribution during natural convection to achieve enhanced thermal processing. In contrast to the earlier works on entropy generation (as discussed in the previous paragraphs), the role of straight wall (square, triangle, rhombic, trapezoidal) vs curved wall (convex, concave, triangle with curved hypotenuse) on entropy generation due to fluid friction and heat transfer with identical area and heat input during natural convection within various shapes of configurations is yet to appear in literature.…”

Section: Introductionmentioning

confidence: 99%

Can the shape influence entropy generation for thermal convection of identical fluid mass with identical heating? A finite element introspection

Lukose

Basak

2020

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Purpose This paper aims to investigate the role of shapes of containers (nine different containers) on entropy generation minimization involving identical cross-sectional area (1 sq. unit) in the presence of identical heating (isothermal). The nine containers are categorized into three classes based on their geometric similarities (Class 1: square, tilted square and parallelogram; Class 2: trapezoidal type 1, trapezoidal type 2 and triangular; Class 3: convex, concave and curved triangular). Design/methodology/approach Galerkin finite element method is used to solve the governing equations for a representative fluid (engine oil: Pr = 155) at Ra = 103–105. In addition, finite element method is used to solve the streamfunction equation and evaluate the entropy generation terms (Sψ and Sθ). Average Nusselt number ( Nub¯) and average dimensionless spatial temperature ( θ^) are also evaluated via the finite element basis sets. Findings Based on larger Nub¯, larger θ^ and optimal Stotal values, containers from each class are preferred as follows: Class 1: parallelogrammic and square, Class 2: trapezoidal type 1 and Class 3: convex (larger θ^, optimum Stotal) and concave (larger Nub¯). Containers with curved walls lead to enhance the thermal performance or efficiency of convection processes. Practical implications Comparison of entropy generation, intensity of thermal mixing ( θ^) and average heat transfer rate give a clear picture for choosing the appropriate containers for processing of fluids at various ranges of Ra. The results based on this study may be useful to select a container (belonging to a specific class or containers with curved or plane walls), which can give optimal thermal performance from the given heat input, thereby leading to energy savings. Originality/value This study depicts that entropy generation associated with the convection process can be reduced via altering the shapes of containers to improve the thermal performance or efficiency for processing of identical mass with identical heat input. The comparative study of nine containers elucidates that the values of local maxima of Sψ (Sψ,max), Sθ (Sθ,max) and magnitude of Stotal vary with change in shapes of the containers (Classes 1–3) at fixed Pr and Ra. Such a comparative study based on entropy generation minimization on optimal heating during convection of fluid is yet to appear in the literature. The outcome of this study depicts that containers with curved walls are instrumental to optimize entropy generation with reasonable thermal processing rates.

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Numerical heat flow visualization analysis on enhanced thermal processing for various shapes of containers during thermal convection

Cited by 13 publications

References 84 publications

Magnetohydrodynamic thermal characteristics of water-based hybrid nanofluid-filled non-Darcian porous wavy enclosure: effect of undulation

Magnetohydrodynamic thermal characteristics of water-based hybrid nanofluid-filled non-Darcian porous wavy enclosure: effect of undulation

Physical–numerical parameters in laminar simulations of natural convection on three-dimensional square plates

Can the shape influence entropy generation for thermal convection of identical fluid mass with identical heating? A finite element introspection

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