Forced convection in power-law fluids from an asymmetrically confined heated circular cylinder

Nirmalkar, Neelkanth; Chhabra, R.P.

doi:10.1016/j.ijheatmasstransfer.2011.09.008

Cited by 22 publications

(7 citation statements)

References 42 publications

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“…The entire domain independence test was done taking grid G1 with the minimum dimensionless grid size of 0.01. These distances are also consistent with the literature [5][6][7][8]17,19,21,23].…”

Section: Selection Of Numerical Parameterssupporting

confidence: 92%

“…In [15][16][17][18] a heated circular cylinder is symmetrically placed (gap ratio γ = 1) in a channel and forced convection (Richardson number Ri = 0) is assumed. Progress in research on the forced convection can also be found for the asymmetrical placement of a circular cylinder in the confined domain [19][20][21][22][23]. Mettu et al [19] explored flow around and forced convection from a circular cylinder placed asymmetrically in a planar channel for Reynolds number Re ranging from 10 to 500, blockage ratio β from 0.1 to 0.4, gap ratio γ from 0.125 to 1 and Prandtl number Pr = 0.744.…”

Section: Current Status Of Literaturementioning

confidence: 99%

“…The heat transfer was observed to increase with the blockage ratio when Dirichlet condition was used, while an inverse relation was obtained for the Neumann condition. Investigating symmetrical versus asymmetrical confinement, Nirmalkar and Chhabra [21] studied the momentum and heat transfer characteristics from the power-law fluid flow past a heated cylinder in asymmetric confinement for Re ranging from 0.1 to 100, Pr from 1 to 100, β from 0.2 to 0.4 and γ from 0.25 to 1. They found that Nusselt number did not follow any trend with respect to the asymmetry in the placement of the cylinder.…”

Section: Current Status Of Literaturementioning

confidence: 99%

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Cross-buoyancy mixed convection from a heated cylinder placed asymmetrically in a channel

Dhiman

Gupta

Baranyi

2018

International Communications in Heat and Mass Transfer

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Mixed convection heat transfer from a heated circular cylinder asymmetrically placed in a horizontal channel was studied for incompressible Newtonian fluid. A systematic investigation using two-dimensional numerical simulation (Ansys Fluent) was performed for the following control parameters: Reynolds number Re = 50, 100, 150, Richardson number Ri = 0, 1, 2, blockage ratio β = 0.2, 0.3, 0.4, gap ratio γ = 0.25, 0.5, 1 and Prandtl number of air Pr = 0.7. Upon changing these parameters, steady and time periodic regimes were identified. The strongest influence on heat transfer (average Nusselt number) was identified when changing the Reynolds number (a 94% increase between the minimum and maximum Re investigated, with other parameters held constant), followed by Richardson number (+18%) and blockage ratio (+16%); the effect of asymmetric placement (γ) was almost negligible (+1%). The time-mean of the drag coefficient was most influenced by blockage ratio (a 150% increase), followed by Richardson number (+91%), gap ratio (+19%), and Re (+10%).

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Section: Selection Of Numerical Parameterssupporting

confidence: 92%

Section: Current Status Of Literaturementioning

confidence: 99%

Section: Current Status Of Literaturementioning

confidence: 99%

See 1 more Smart Citation

Cross-buoyancy mixed convection from a heated cylinder placed asymmetrically in a channel

Dhiman

Gupta

Baranyi

2018

International Communications in Heat and Mass Transfer

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“…Flow pattern and its characteristics around immersed bluff bodies have been studied by many researches because of the complexities and practical importance of these flows, the principle issues of classical flow configuration are wake formation, flow separation, the external forces acting on the body (drag and lift), and especially the heat transfer rate changing among the fluid-flow and the immersed body. The results show that the flow over a cylinder depends on large number of parameters and geometrical shapes such as type of fluid-flow (compressible or incompressible, Newtonian or Non Newtonian) [1][2][3][4], confined or unconfined cylinder [5,6], and symmetrically or asymmetrically confined cylinder [7][8][9]. Forced convection and fluid-flows over circular cylinder arise in many micro-channels, nuclear.…”

Section: Introductionmentioning

confidence: 98%

Mixed convection in poiseuille fluid from an asymmetrically confined heated circular cylinder

Laidoudi

Bouzit

2018

THERM SCI

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This paper examines the effects of thermal buoyancy on momentum and heat transfer characteristics of symmetrically and asymmetrically confined cylinder submerged in incompressible Poiseuille liquid. The detailed flow and temperature fields are visualized in term of streamlines and isotherm contours. The numerical results have been presented and discussed for the range of conditions as 10 ≤ Re ≤ ≤ 40, Richardson number 0 ≤ Ri ≤ 4, and eccentricity factor 0 ≤ ε ≤ 0.7 at Prandtl number Pr = 1, and blockage ratio B = 20%. The representative streamlines and isotherm patterns are presented to interpret the flow and thermal transport visualization. When the buoyancy is added, it is observed that the flow separation diminishes gradually and at some critical value of the thermal buoyancy parameter it completely disappears resulting a creeping flow. Additionally, it is observed that the down vortex requires more heating in comparison to upper vortex in order to be suppressed. In the range 1.5 ≤ Ri ≤ 4, two counter rotating regions appear above the cylinder and on the down channel wall behind the cylinder. The total drag coefficient, C D , increases with increasing Richardson number at (ε = 0). Moreover, an increase in eccentricity factor from 0 to 0.3 increases C D by 37% at Re = 10, and 30% at Re = 20 for Ri = 4. An increase in eccentricity factor form 0 to 0.4 increases local Nusselt number by 20.4% at Re = 10, and 18.6% at Re = 30 for Ri = 4.

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“…In some cases, the separation flow behind objects is an undesirable and detrimental flow phenomena, principally causes increase of hydrodynamic forces (lift, drag) [1], and loss flowing power .Whereas it is an desirable purpose in other cases, partially improves the heat transfer rate behind the obstacles [2]. For the completed application range, experimental and numerical researches have indicated that the formation of flow separation depends on its flow conditions (Re, Pr, n) [3] as well as geometrical parameters (cross-sectional shape, channel blockage) [4,5] in those works, there is some detailed information exists on the flow field and heat transfer around (circular, square cylinder).…”

Section: Introductionmentioning

confidence: 99%

Non-Newtonian Power-Law Flows around Circular Cylinder under Aiding/Opposing Thermal Buoyancy

Laidoudi

Bouzit

2018

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This paper presents a comprehensive computational work on hydrodynamic and thermal phenomena of upward flow separation around a confined circular cylinder by aiding/opposing thermal buoyancy. For that purpose, let us consider a confined flow of Non-Newtonian power-law fluid around a heated/cooled circular cylinder in a two-dimensional vertical channel. The effects of thermal buoyancy and power-Law index on the flow separation and the average Nusselt number are studied for the conditions: (10 ≤ Re ≤ 40), (0.4≤ n ≤ 1.2), (-0.5 ≤ Ri ≤ 0.8), Pr = 50 and blockage ratio β = 0.2. In the steady flow regime the results show that the augmentation of the power-law index in the absence of thermal buoyancy causes a separation to grow. The adding buoyancy effect delays the separation in different power-law indices gradually and at some critical value of the buoyancy parameter it completely disappears resulting a stuck flow around a cylinder, whereas the opposing buoyancy effect causes an earlier wake behind cylinder. Moreover, the recirculation length is calculated to support the above finding. The decrease in the power-Law index increases the heat transfer rate. The Nusselt numbers are computed to predict the heat transfer rates of power-law fluids under the aiding/opposing thermal buoyancy condition.

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Forced convection in power-law fluids from an asymmetrically confined heated circular cylinder

Cited by 22 publications

References 42 publications

Cross-buoyancy mixed convection from a heated cylinder placed asymmetrically in a channel

Cross-buoyancy mixed convection from a heated cylinder placed asymmetrically in a channel

Mixed convection in poiseuille fluid from an asymmetrically confined heated circular cylinder

Non-Newtonian Power-Law Flows around Circular Cylinder under Aiding/Opposing Thermal Buoyancy

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