Role of multiple discrete heaters to minimize entropy generation during natural convection in fluid filled square and triangular enclosures

“…A few studies associated with entropy generation in trapezoidal (Basak et al , 2012; Mahmoudi et al , 2013; Selimefendigil et al , 2016; Shirvan et al , 2017) and triangular (Basak et al , 2013; Bondareva et al , 2017; Das and Basak, 2017; Das et al , 2018) enclosures are discussed next. Basak et al (2012) performed analysis on entropy generation in trapezoidal enclosures subjected to isothermal/non-isothermal heating of the bottom wall.…”

Section: Introductionmentioning

confidence: 99%

“…Das and Basak (2017) analyzed the role of discrete heater on entropy generation in square, regular and inverted triangular enclosures. The work (Das and Basak, 2017) was further extended in the presence of double discrete heaters (Das et al , 2018) within square and triangular enclosures. It was reported that double discrete heaters depict higher heat transfer rate and lower entropy generation compared to single discrete heater.…”

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

HFF

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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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“…In this study, it has been found that the channel walls and the surface of the bluff body have higher temperatures than the incoming flow and the mixed convection kick off periodicity and irregularity in the wake at a lower Re than forced convection alone.Role of numerous discrete warmers to find out lower entropy invention through natural convection in fluid filled square and triangular cavities was learnt by Das etal. [8].Das and Basak [9] also performed heated discretely porous square and triangular enclosures by natural convection. The pattern of heat flow inside the cavities for a variety of parameters is imagined by the heatline method.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation on Heat Flow for Mixed Convection Within a Triangular Enclosure

Hossain

Billah

Bangalee

et al. 2019

GANIT: J. Bangladesh Math. Soc.

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Heat flow for laminar mixed convection in a triangular enclosure with uniformly heated bottom wall is solved using Galerkin weighted residual method of finite element formulation. A fluid with Prandtl number (Pr = 0.71) is also used to investigate the effects of heat flow for Reynolds number(40 ≤ Re ≤ 110) varying Rayleigh number (10 3 ≤ Ra ≤ 10 4 ) in that enclosure. In the enclosure, the left wall is considered cold; bottom wall is uniformly heated while the other inclined wall is insulated. The geometry of physical problems is represented mathematically by different sets of governing equations along with appropriate boundary conditions. Results are shown in terms of streamlines, isotherms, average Nusselt number and average temperature of the fluid in the cavity for uniform heating of bottom wall. It is seen that heat transfer rate from the heat source is higher for increasing value of Re. On the other hand, average bulk temperature declines significantly. It is also indicated that for fixed Prandtl number and various Ra, the buoyancy force and heat transfer rate inside the enclosure are increased for the greater value of Re.

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Role of multiple discrete heaters to minimize entropy generation during natural convection in fluid filled square and triangular enclosures

Cited by 19 publications

References 36 publications

Presenting a novel higher-order bounded convection scheme for simulation of multiphase flows and convection heat transfer

Presenting a novel higher-order bounded convection scheme for simulation of multiphase flows and convection heat transfer

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

Numerical Simulation on Heat Flow for Mixed Convection Within a Triangular Enclosure

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