Influence of Heater Aspect Ratio on Natural Convection in a Rectangular Enclosure

Biswas, Nirmalendu; Mahapatra, Pallab Sinha; Manna, Nirmal K.; Roy, Prasanta

doi:10.1080/01457632.2015.1044392

Cited by 53 publications

(45 citation statements)

References 29 publications

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“…As comparison of eqs. (11) and 12  and considerations relating to the more restrictive situation in which the temperature gradient is parallel to gravity (heating from below effect). For such condition, relevant data about the inertial wavenumber region located between the energy containing and the dissipative ranges have been presented in the very recent study by De et al, 98 .…”

Section: Mesh Assessment Against the Kolmogorov Length Scalementioning

confidence: 99%

“…Many other variants can be found in the specific field of energy production, where configurations with multiple sources of buoyancy are a characteristic feature of thermal discharges from nuclear and fossil-fueled electricity generation plants (Martineau et al,7 ; Lee and Asce 8 ; Fregni et al, 9 ). They can also exist at a smaller scale in typical problems relating to the cooling of computer mother boards and related CPUs and memories (Sun and Jaluria 10 ; Biswas et al, 11 ) or in combustion chambers as a result of the presence of holes or orifices for fuel injection and dilution (Issac and Jakubowski 12 ; Baltasar et al, 13 ). Similar concepts also apply to the manufacturing industry, where gas furnaces are commonly used for the heat treatment of metals (Viskanta 14 ).…”

Section: Introductionmentioning

confidence: 99%

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On the highly unsteady dynamics of multiple thermal buoyant jets in cross flows

Lappa

2019

Physics of Fluids

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Thermal plumes of small scale generated by spatially separated heat sources can form, like atoms in a chemical compound, complex structures of different kind and with distinct behaviors. The situation becomes even more complex if plumes can interact with imposed vertical shear (a horizontal wind). In this analysis a 'minimal framework' based on the application of a filtering process to the governing balance equations for mass, momentum and energy (falling under the general heading of 'Large Eddy Simulation' approach), is used together with Direct Numerical Simulation to inquiry about the relative importance of buoyancy and vertical shear effects in determining the patterning scenario when highly unsteady dynamics are established (turbulent flow). Emerging patterns range from the flow dominated by a static rising jet produced by the aggregation of plumes, which are pushed by horizontal leftwards and rightwards winds towards the center of the physical domain, to convective systems with disconnected thermal pillars of smaller scale, which travel in the same direction of the prevailing wind. The classical sheltering effect, which for flows that are steady 'in mean' simply consists of an increased deflection of the leading buoyant jet with respect to the trailing ones, is taken over by a variety of new phenomena, including (but not limited to) fast plume removal-rebirth mechanisms (with local increase in the velocity frequency and shrinkage in the related amplitude), 'bubble' formation-rupture and local departure of the frequency spectrum from the Kolmogorov similarity law.

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Section: Mesh Assessment Against the Kolmogorov Length Scalementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On the highly unsteady dynamics of multiple thermal buoyant jets in cross flows

Lappa

2019

Physics of Fluids

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“…1 had been studied numerically by various researchers due to its importance in energy related applications. Some of these studies were [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Ghasemi et al [2] investigated numerically the influence of the magnetic field on buoyancy driven fluid flow in a square nanofluid enclosure filled with Al2O3-water.…”

Section: Simple Enclosuresmentioning

confidence: 99%

“…They concluded that heat source had a crucial impact on heat transfer. For more details about the previous works, the reader can be referring to [8][9][10][11][12][13][14][15]. Wang et al [16] presented a comparison between the impact of Al2O3-H2O and Ga-H2O and the radius under different Rayleigh numbers of heat transfer using a two-phase lattice Boltzmann method.…”

Section: Simple Enclosuresmentioning

confidence: 99%

Comprehensive Review of Natural Convection Heat Transfer in Annulus Complex Enclosures

Abdulkadhim

Al‐Farhany

Abed

et al. 2020

QJES

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The natural convection heat transfer has many applications in engineering like solar collectors, cooling of electronic equipment and geothermal engineering. The present work demonstrates the recent publications in the last ten years in this specific subject for a body located in complex shapes like rhombic, wavy, trapezoidal, elliptical and Parallelogrammic enclosure. Many parameters like Ra, Nu, number of undulations, the position of the inner body had been addressed and discuss to draw the main conclusions and recommendations. It is worthy to mention that wavy enclosure had been investigated less than the other simple enclosure shapes due to its complexity. Beside that entropy generation should be included in the future studies in complex shapes of enclosure as this will helps the researchers to extended their studies. The inner bodies inside trapezoidal, parallelogrammic enclosure are very limited and more investigation should be done.

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“…They found that when the heat sources are close to each other the unification of thermal plume appears at an early stage of the flow evolution. Biswas et al [10] numerically and experimentally investigated natural convection inside a rectangular enclosure with protruding a heat source. They observed, heat transfer increases with the increase of aspect ratio of heater at higher Rayleigh number, whereas, the opposite trend is observed at lower Rayleigh number mainly due to the change in the thermal boundary layer thickness.…”

Section: Introductionmentioning

confidence: 99%

CFD Simulation of Natural Convection Flow and Heat Transfer Process in Rectangular Cavity

Harish

2019

IJEAT

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In this paper we investigate the natural convective heat transfer process inside a ventilated rectangular cavity with a projected heat source. The heat source block is mounted on the bottom wall and a horizontal vent is provided on the top wall of the rectangular cavity. The flow is induced due to the density difference which arises due to the variations in temperature between the heat source block and the surrounding ambient fluid. A FORTRAN 90 CFD solver is developed to simulate the natural convection phenomena by solving the Navier-stokes equation, energy equation coupled with Realizable k-ε turbulence model. The transient flow behavior inside the cavity is simulated by varying the heat source aspect ratios, Grashof number and the heat source locations. It is found that the heat source aspect ratio and its locations significantly influences the flow and heat transfer characteristics inside the cavity. The bidirectional exchange rate across the horizontal opening increases linearly with Grashof number and heat source aspect ratio. A chaotic flow behavior pattern is observed across the opening and the strength of the instabilities increases linearly with heat source aspect ratio. It is identified that by varying the aspect ratio 0.1 ≤ β ≤ 3, the average Nusselt number and mass flow rates are increased by 28% and 43% respectively.

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Influence of Heater Aspect Ratio on Natural Convection in a Rectangular Enclosure

Cited by 53 publications

References 29 publications

On the highly unsteady dynamics of multiple thermal buoyant jets in cross flows

On the highly unsteady dynamics of multiple thermal buoyant jets in cross flows

Comprehensive Review of Natural Convection Heat Transfer in Annulus Complex Enclosures

CFD Simulation of Natural Convection Flow and Heat Transfer Process in Rectangular Cavity

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