Flow characteristics along and above dimpled surfaces with three different dimple depths within a channel

Won, Se Youl; Ligrani, Phil

doi:10.1007/bf03177447

Cited by 14 publications

(3 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The deeper dimple was subject to flow separation different from the shallowest ones. Won et al [20] examined how dimple depth caused the flow pattern in a duct. When the dimple depth was large, it generated greater main vortex pairs with larger turbulence extents.…”

Section: Introductionmentioning

confidence: 99%

Influence of Dimple Height on Turbulent Heat Transfer of Fin Array with Alternate Convex/Concave Dimples

Chen

Kelana

et al. 2020

Inventions

View full text Add to dashboard Cite

This study analyzes transient turbulent modeling of three-dimensional multiple dimpled fin array using large eddy simulation (LES). The Navier–Stokes equations as well as the energy equation were constructed by the finite volume method and then discretized to form algebraic equations, which were solved by semi-implicit method for pressure-linked equation (SIMPLE). The solutions of temperature and velocity were obtained by iterating computation until it converged within each step. This simulation places nine fins on the bottom surface of a channel and changes the height of the dimple (0.4, 0.8, and 1.2 mm) with three different levels of Reynolds number (Re) (3500, 5000, and 6500) to investigate the temperature and flow field without gravity in forced convection. The results indicate that the dimpled fin array can generate vortices between the convex/concave dimples and the fin base and increase the influences of the height of the dimple on the flow field around the fin array. The averaged time-mean of the Nusselt number (Nu) for the dimple height of 0.8 mm is higher than that of the no-dimple case up to 14.4%, while the averaged time-mean Nu for the dimple height of 1.2 mm is lower than that of the no-dimple case up to 11.6%.

show abstract

Section: Introductionmentioning

confidence: 99%

Influence of Dimple Height on Turbulent Heat Transfer of Fin Array with Alternate Convex/Concave Dimples

Chen

Kelana

et al. 2020

Inventions

View full text Add to dashboard Cite

show abstract

“…Experimental results further indicated the deep dimples increased in the strengths and intensity of vortices and increases in the magnitudes of 3-D turbulence production and turbulence transport. The effect of inlet turbulent intensity level, dimple depth and shape on the flow, and heat transfer of a dimpled surface was also investigated in [5][6][7][8]. The heat transfer augment increases with the dimple depth when the Reynolds number varies from 9540 to 74800 and the local Nusselt number shows slightly decrease as the inlet turbulent intensity increases.…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical investigation of thermal performance of channels with staggered array-based dimples

Xie¹,

Shen²,

Liu³

et al. 2015

THERM SCI

View full text Add to dashboard Cite

Numerical simulation coupled with experimental method was carried out to study the flow and heat transfer characteristics in rectangular channel with staggered array-based dimples. The effect of different dimple depths and Reynolds number were investigated using the shear stress transport turbulent model coupled with gamma-theta transition model. The results indicated that heat transfer and flow resistance of the dimpled surface increases with the increase of dimple depth. Moreover, the thermal performance is sensitive to the flow transition. Heat transfer in each single dimple region increases monotonously in the streamwise direction with Reynolds number increasing. Heat transfer characteristics almost remain the same when the flow is under fully laminar or turbulent but increases greatly when the flow is transited from laminar condition to turbulent condition. Besides, the variations of friction coefficients and thermal performance coefficients are quite similar to those of heat transfer enhancement coefficients, which firstly increases then decreases with the increase of Reynolds number. By comparing the experimental and numerical results, it is found that staggered array-based dimples with δ/D = 0.2 was the most effective structure from the aspect of thermal performance.

show abstract

“…The flow structure of a channel with a dimpled surface on one wall, both with and without protrusions on the other wall (ℎ/ = 0.5, / = 0.2, Re ℎ = 380-30000), was studied by Ligrani et al [4]. The effect of inlet turbulent intensity level, dimple depth, and shape on the flow and heat transfer of a dimpled surface was also investigated by Ligrani et al [5][6][7][8][9]. The heat transfer augment increases with the dimple depth when the Reynolds number varies from 9540 to 74800 and the local Nusselt Heat transfer and pressure drop in different sets of dimpled fin channels including protrusion-dimple channel, dimple-dimple channel, and protrusion-protrusion channel (ℎ/ = 1.0, / = 0.3, Re ℎ = 1500-11000) were experimentally examined by Chang et al [10].…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Flow and Heat Transfer in a Dimpled Channel among Transitional Reynolds Numbers

Shen

Xie

2013

Mathematical Problems in Engineering

View full text Add to dashboard Cite

The SST turbulent model coupled with Gamma-Theta transition model was adopted in the investigation of the flow and heat transfer characteristics of a rectangular channel with arrays of dimples among transitional Reynolds number. The results show that the velocity gets plumper along streamwise direction which indicates that the flow is transited from laminar flow to turbulent flow, which is also confirmed by the turbulence intermittency distribution. The dual vortex inside the dimple becomes asymmetrical when Reynolds number increases. The averaged Nusselt number decreases monotonously in the streamwise direction when the flow is under laminar condition while it increases monotonously when the flow is under turbulent condition. The heat transfer is enhanced by the dimple when the flow is turbulent and it increases with the dimple depth. However, the heat transfer is worsened by the dimple when the flow is laminar. The friction factor increases when the dimple depth increases. The overall thermal performance increases with Reynolds number. The dimple arrays with depth ratio equal to 0.2 show the best overall thermal performance.

show abstract

Flow characteristics along and above dimpled surfaces with three different dimple depths within a channel

Cited by 14 publications

References 14 publications

Influence of Dimple Height on Turbulent Heat Transfer of Fin Array with Alternate Convex/Concave Dimples

Influence of Dimple Height on Turbulent Heat Transfer of Fin Array with Alternate Convex/Concave Dimples

Experimental and numerical investigation of thermal performance of channels with staggered array-based dimples

Numerical Investigation of Flow and Heat Transfer in a Dimpled Channel among Transitional Reynolds Numbers

Contact Info

Product

Resources

About