Forced Convection Heat Transfer Analysis through Dimpled Surfaces with Different Arrangements

Sardar, Hasibur Rahman; Kaladgi, Abdul Razak

doi:10.11648/j.ajee.20150303.12

Cited by 10 publications

(2 citation statements)

References 8 publications

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“…It can also be seen that the variation in the Nusselt number is almost gradual with orientation as expected [12,13]. It can be seen that as expected the Nusselt number, heat transfer coefficient 'h' and heat transfer rate 'Q' follows the same trend as for the copper plate [16] but with a little lower value because of the low thermal conductivity of aluminum plates as compared to copper plate. It is obvious that 'h' increases as compared to flat plates because the dimple arrangement causes delay in the development of the thermal boundary layer & hence increases the local heat transfer in the reattachment region and increases the heat transfer coefficient [1].It can also be seen that 'Q' increases with decrease in orientation angle of dimples.…”

Section: Resultssupporting

confidence: 77%

“…It can be seen that as expected the Nusselt number, and heat transfer coefficient 'h' curve for aluminum plate follows the same trend as for the copper plate [16] but with a little lower value because of the low thermal conductivity of aluminum plates. Nusselt number 'Nu' and heat transfer coefficient 'h' are higher for low angle orientation of dimples because at low angles the dimples are close to each other hence a pronounce effect of dimples is felt which is obvious from the figure.…”

Section: Resultssupporting

confidence: 72%

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An Experimental Study on Heat Transfer Enhancement of Flat Plates Using Dimples

Khan¹

2015

EPES

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Dimples play a very important role in heat transfer enhancement of electronic cooling systems. In the current paper, the fluid flow and heat transfer characteristics of spherical dimples at different angle of orientation from the centre with apex facing the inlet were investigated. The experiment was carried out for laminar Natural convection conditions with air as a working fluid. The overall Nusselt numbers and heat transfer coefficient at different orientation angle of dimples were obtained. From the obtained results, it was observed that the Nusselt numbers and heat transfer coefficient increases with decrease in the orientation angle of dimples.

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Section: Resultssupporting

confidence: 77%

Section: Resultssupporting

confidence: 72%

An Experimental Study on Heat Transfer Enhancement of Flat Plates Using Dimples

Khan¹

2015

EPES

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Analysis of the flow field, thermal performance, and heat transfer augmentation in circular tube using different dimple geometrical configurations with internal twisted‐tape insert

Al‐Obaidi

2020

Heat Trans

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In this study, a numerical investigation for the fluid flow field analysis using different configuration dimple parameters in conjunction with an internal type insert in pipe is carried out. The effects of the dimple diameters with a center twisted tape on the flow pattern, pressure drop, friction factor, and heat transfer characteristics are investigated. The influence of the latter device on heat performance and thermal-hydraulic performance evaluation factor (PEF) were carried out in a pipe for fully developed flow with range for fully developed flow with range of Reynolds number (Re) of 1573 and 23 592. Experiments with numerical models are performed using different dimpled dimeters by inserting twisted tapes. The outcomes observe that the qualitative analysis for flow fields such as static pressure, dynamic pressure, velocity magnitude, wall shear stress, and turbulent kinetic energy as well as the quantities analysis for pressure drop, heat transfer coefficient friction factor, and Nu number in dimpled pipe fitted with twisted tape are greater than plain pipe. This is because using these devices cause more secondary flow, swirl flow, and flow mixing that lead to higher turbulence, which, in turn, enhance the overall heat transfer. The results indicated that the lower and higher values of thermal PEF are about 0.78 and 1.6, respectively, at the dimple dimmers of 1 mm.

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Study the influence of concavity shapes on augmentation of heat‐transfer performance, pressure field, and fluid pattern in three‐dimensional pipe

Al‐Obaidi

2021

Heat Trans

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In this current study, the heat‐transfer augmentation mechanism and pressure drop with flow field structures over different dimple arrays in turbulent flow of three‐dimensional circular tube are investigated based on computational fluid dynamics numerical methods using the standard k − e turbulent model. The water is the working fluid over the range of Reynolds numbers from 1500 to 24,000, with three different tubes dimpling arrangements are analyzed. The numerical simulation results are validated through available experimental data, and they show good agreement results between them. The numerical analysis results showed that the flow fields are symmetric within the middle cross‐sectional direction in the pipe with and without dimples. Also, the flow near or close to the dimples is chaotic and including small vortexes and eddies. The results found that the temperature difference in the dimple tube with 2 mm diameter at low flow range 0.56 L/min was higher than that of smooth pipe, dimple tube 0.75 and 1.5 mm by 26.8%, 10.57%, and 3.68%, respectively. It can be concluded that using dimples in heat‐exchanger tubes can provide rates of heat transfer that is higher than that without dimpled tubes at the same operating conditions. Hence, this is an important enhancement in process industries for the energy conversion applications.

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Forced Convection Heat Transfer Analysis through Dimpled Surfaces with Different Arrangements

Cited by 10 publications

References 8 publications

An Experimental Study on Heat Transfer Enhancement of Flat Plates Using Dimples

An Experimental Study on Heat Transfer Enhancement of Flat Plates Using Dimples

Analysis of the flow field, thermal performance, and heat transfer augmentation in circular tube using different dimple geometrical configurations with internal twisted‐tape insert

Study the influence of concavity shapes on augmentation of heat‐transfer performance, pressure field, and fluid pattern in three‐dimensional pipe

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