Optimum natural convection from square cylinder in vertical channel

Khodary, Khaled; Bhattacharyya, T.K.

doi:10.1016/j.ijheatfluidflow.2005.04.007

Cited by 16 publications

(7 citation statements)

References 14 publications

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“…5. The existence of such asymptotes is commonly found in heat and mass transfer problems, and it is reported in literature like Elenbass [60], Raithby and Hollands [61], Martin et al [62], and Khodary and Battacharrya [63]. In the present configuration, the lower asymptote can be correlated as Nu 1.0 and is applicable for values of Ra < 1000.…”

Section: A Results For Enclosure Filled With Pure Fluidsupporting

confidence: 63%

Thermophysical Properties-Based Evaluation of Nanofluids Laminar Natural Convection Inside Square Enclosure

Esmaeil

2015

Journal of Thermophysics and Heat Transfer

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The effect of thermophysical properties on laminar natural convection inside a differentially heated enclosure filled with nanofluids is numerically investigated. Expressions for minimum, average, and maximum values of nanofluid viscosity and thermal conductivity are deduced for an Al 2 O 3 ∕water-based nanofluid. The configuration is mathematically simulated using four nonhomogeneous governing field equations: two mass balance equations (one for each phase), a momentum equation, and an energy equation. Brownian motion and thermophoresis are considered as the physical transport mechanisms for the nanoparticles. A numerical finite difference scheme is developed to solve the governing equations. The results of the Nusselt numbers for pure water and nanofluids are found to increase monotonously versus the Rayleigh number in a typical characteristic curve between two asymptotes. Correlations for the Nusselt number are developed. A parametric analysis of the results indicates that the heat transfer effectiveness of nanofluids is highly dependent on the nanofluid viscosity, whereas the nanofluid thermal conductivity has a secondary effect. The minimum values of nanofluid viscosity always lead to heat transfer augmentation, whereas maximum values mostly lead to heat transfer degradation, except for the observed augmentation in very high Grashof number values. Comparative examinations of the results as well as contours for streamlines, isotherms, void fraction distribution, and local apparent Reynolds number are presented.

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Section: A Results For Enclosure Filled With Pure Fluidsupporting

confidence: 63%

Thermophysical Properties-Based Evaluation of Nanofluids Laminar Natural Convection Inside Square Enclosure

Esmaeil

2015

Journal of Thermophysics and Heat Transfer

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“…The heated square cylinder is placed at the middle of the channel width and height. The present predicted variation of the average Nusselt number over the four faces of the heater with Grashof number is compared to that of Khodary et al [24] in To find out the grid size for grid independent solutions, the present problem is solved on grids of sizes (N x × N y × N z ) 65 × 39 × 39, 98 × 46 × 46, 110 × 46 × 46 and 127 × 61 × 61 for baseline configuration (Gr = 8 × 10 7 ) and the predicted average Nusselt number over all the inner cylinder faces is monitored. Here, N x , N y and N z are numbers of grids in x, y, and z directions, respectively.…”

Section: Code Validation and Grid Sensitivity Testsmentioning

confidence: 85%

“…The code is used to solve natural convection about an isothermal heated square rib placed in an adiabatic parallel plate vertical channel, for which the solutions are available in the literature [24]. The heated square cylinder is placed at the middle of the channel width and height.…”

Section: Code Validation and Grid Sensitivity Testsmentioning

confidence: 99%

Study of conjugate natural convection between vertical coaxial rectangular cylinders

Gavara

Kanna

2012

International Communications in Heat and Mass Transfer

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“…The author found that the drag coefficient decreases while the Strouhal number increases with increasing Grashof number. Khodary and Bhattacharyya (2006) studied natural convection from a horizontal isothermal square cylinder inside a vertical adiabatic channel. Theirs results indicate that the laminar natural convection is significantly affected by the aspect ratio and the lateral position of the obstacle.…”

Section: Introductionmentioning

confidence: 99%

Aided Mixed Convection past a Heated Square Cylinder at Low Blockage Ratio

Moulai

Korichi

Polidori

2016

JAFM

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This paper investigates numerically the flow and heat transfer in air (Pr=0.71) by mixed convection past a heated square cylinder under aiding buoyancy effect in a confined channel. The numerical simulations are performed in the range of parameters 20≤Re≤45 and 1.61x10 3 ≤Gr≤6.33x10 3 for a fixed blockage ratio D/L of 0.1. The combination in the present study of these two Re and Gr parameters is reduced so that the Richarson number varies from 0,8 to 8, in order to neglect neither free convection (Ri<0.1) nor forced convection (Ri>10). The steady two-dimensional governing equations are solved by the finite volume formulation using the open source OpenFoam® code. The representative flow structure, isotherm patterns and local Nusselt number evolution are presented and discussed. The effect of both the Reynolds number and the buoyancy parameter on the fluid flow and the heat transfer are also analyzed. It is found that the wake region size strongly depends on both Reynolds and Grashof numbers and this region is shown to increase in size increasing the Reynolds number and/or decreasing the Grashof number. Moreover, increasing the Reynolds number leads to a heat transfer enhancement more pronounced on the front face of the obstacle, whereas increasing the Grashof number leads to a heat transfer enhancement more pronounced on the side faces.

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Optimum natural convection from square cylinder in vertical channel

Cited by 16 publications

References 14 publications

Thermophysical Properties-Based Evaluation of Nanofluids Laminar Natural Convection Inside Square Enclosure

Thermophysical Properties-Based Evaluation of Nanofluids Laminar Natural Convection Inside Square Enclosure

Study of conjugate natural convection between vertical coaxial rectangular cylinders

Aided Mixed Convection past a Heated Square Cylinder at Low Blockage Ratio

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