Numerical investigation of the laminar natural convection heat transfer from two horizontally attached horizontal cylinders

Liu, Jie; Liu, Huan; Qi, Zhen; Lu, Weiyue

doi:10.1016/j.ijheatmasstransfer.2016.08.075

Cited by 25 publications

(9 citation statements)

References 50 publications

(140 reference statements)

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“…The temperature distribution was calculated in several directions according to the fringe-order number difference, and the Nu was determined from Equation (15). Figure 6A compares Nu loc of the present results and the previous results of Corcione, 12 Saitoh et al, 26 Wang et al, 27 and Kuehn and Goldstein.…”

Section: Validation Of Resultsmentioning

confidence: 73%

“…The results showed that the Nu ave was growing with Ra and the strongest heat transfer was at an inclination angle of 90°. Liu 15 numerically simulated two horizontally contacting cylinders and pointed out two recirculating vortices in the wake area. In the same year, their team simulated two vertically contacting cylinders in the same way and pointed out that the heat transfer rate of the two cylinders was reduced by more than 87.5% 16 .…”

Section: Introductionmentioning

confidence: 99%

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Natural convection heat transfer from two horizontal cylinders using a large lateral shearing interferometer

Zhu

Wang

et al. 2020

Heat Trans

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Natural convection heat transfer from two horizontal cylinders in the air was investigated experimentally and numerically. Two cylinders were spaced at 1.3, 1.8, and 2.7 cylinder diameters horizontally. The experiments were carried out by large lateral shear interferometry (LSI) for various Rayleigh numbers in the range of 103 to 104. Large LSI is common path interferometry with the advantages of simple structure, strong antivibration, and fewer required optical components. It is not necessary for LSI to perform a complex algorithm to restore wavefront with a large shear amount. Simple and infinite fringe interferograms of the cylinders heated from ambient temperature 282.15 to 723.15 K were obtained. A numerical simulation was carried out with ANSYS‐Fluent 18.0. The influence of two factors, the distance between the cylinders, and the Rayleigh number, on the heat transfer of two horizontal cylinders was examined. The average Nusselt number and local Nusselt number were determined from the experimental results and numerical results, respectively, and the two results were in good agreement. The rising direction for the plume flow pattern of each horizontal cylinder was no longer simply vertically upward but was inclined toward the central symmetry axis of the two cylinders. In addition, the heat transfer from a cylinder increased with the cylinder spacing at any Rayleigh number.

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Section: Validation Of Resultsmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Natural convection heat transfer from two horizontal cylinders using a large lateral shearing interferometer

Zhu

Wang

et al. 2020

Heat Trans

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“…Comparison of average Nusselt number of the present work with the numerical study of Liu at al [28]. for S/D = 0, Pr = 0.71 and n = 1 left half) and normalized pressure contours (right half) at Gr = 10 and 10 3 , respectively.…”

mentioning

confidence: 74%

“…Attached cylinders of three, six and ten in numbers were arranged in a triangular manner to form different stacks for their study in both laminar and turbulent regimes. Natural convection from a pair of two horizontally attached cylinders in air has been investigated numerically by Liu et al [28] and it has been found that the overall heat transfer degraded with compared to that of a single cylinder due to the interaction of their thermal plumes. In addition, two recirculation zones were seen to form in their work when the two plumes merged and the size of these vortices was found to grow with the increase in Rayleigh number.…”

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confidence: 99%

Effect of Horizontal Spacing on Natural Convection to Power-Law Fluids from Two Horizontally Aligned Cylinders

Rath

Dash

2020

Heat Transfer Engineering

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Laminar natural convection from two horizontally aligned isothermal cylinders in unconfined Power-law fluids has been investigated numerically. The effect of horizontal spacing (0 S / D 20)  on both momentum and heat transfer characteristics has been delineated under the following pertinent parameters: Grashof number 5 (10 Gr 10 )  , Prandtl number (0.71 Pr 100)  , and Power-law index (0.4 n 1.6)  . The heat transfer characteristics are elucidated in terms of isotherms, local Nusselt number (Nu) distributions and average Nusselt number values, whereas the flow characteristics are interpreted in terms of streamlines, pressure contours, local distribution of the pressure drag and skin-friction drag coefficients along with the total drag coefficient values. The average Nusselt number shows a positive dependence on both Gr and Pr whereas it shows an adverse dependence on Power-law index (n). Overall, shear-thinning (n<1) fluid behavior promotes the convection whereas shear-thickening (n>1) behavior impedes it with reference to a Newtonian fluid (n=1). Furthermore, owing to the formation of a chimney effect, the heat transfer increases with decrease in horizontal spacing (S/D) and reaches a maximum value corresponding to the optimal spacing whereas the heat transfer drops significantly with further decrease in S/D. Finally, a correlationfor Nu has been developed, which can be useful to academic researchers and practicing engineers.

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“…Hence, the purposed Bejan's approach [20] is applied in the present study to reduce the size of the domain to a great extent. This approach was also implemented subsequently by Liu et al [18,19]. The flow is expected to be steady and symmetric about the vertical center line between the square cylinders hence, computations have been conducted only for a half (right half) of the domain and called as computational domain.…”

Section: Physical Descriptionmentioning

confidence: 99%

Effect of horizontal spacing and tilt angle on thermo-buoyant natural convection from two horizontally aligned square cylinders

Rath

Dash

2019

International Journal of Thermal Sciences

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Laminar natural convection heat transfer from two horizontally aligned square cylinders has been investigated numerically using a finite-volume method (FVM) approach. Computations were performed to delineate the momentum and heat transfer characteristics under the following ranges of parameters: horizontal spacing between the cylinders (0 ≤ S/W ≤ 10), tilt angle of the square cylinder (0 0 ≤ δ ≤ 60 0 ), and Grashof number (10 ≤ Gr ≤ 10 5 ) for some specific Newtonian fluids having Prandtl number (0.71 ≤ Pr ≤ 7). The comprehensive results are represented in terms of temperature contours and streamlines, velocity and temperature profiles, the mass flow rate in the passage between the cylinders, local and average Nu, and the drag coefficient. Owing to the development of a chimney effect, the heat transfer increases with decrease in the horizontal spacing up to a certain limit, whereas it significantly degrades with a further decrease in the spacing. The square cylinder having δ = 45 0 shows a higher heat transfer, whereas it is least for δ = 0 0 . At higher Gr and Pr, the average Nu is found to be in excess of 22% at δ = 45 0 compared to at δ = 0 0 . Overall, the average Nu has a strong dependence on both Gr and Pr, whereas it is a weak function of S/W and δ. Furthermore, the entropy generation is reproduced non-dimensionally in terms of the Bejan number. Finally, a correlation for the average Nu has been developed, which can be useful for the engineering calculations.

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Numerical investigation of the laminar natural convection heat transfer from two horizontally attached horizontal cylinders

Cited by 25 publications

References 50 publications

Natural convection heat transfer from two horizontal cylinders using a large lateral shearing interferometer

Natural convection heat transfer from two horizontal cylinders using a large lateral shearing interferometer

Effect of Horizontal Spacing on Natural Convection to Power-Law Fluids from Two Horizontally Aligned Cylinders

Effect of horizontal spacing and tilt angle on thermo-buoyant natural convection from two horizontally aligned square cylinders

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