Heat transfer and friction in turbulent vortex flow

Kreith, Frank; Margolis, D. P.

doi:10.1007/bf00411769

Cited by 149 publications

(41 citation statements)

References 13 publications

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“…Following the reconstruction procedure of Hinz [12], we identify these invalid data points with a criterion based on the associated standard error (20) of the local axial mean velocity (17). We define as admissible threshold value for standard errors.…”

Section: Reconstruction Of Velocity Profilesmentioning

confidence: 99%

“…Koch [16], Kreith and Margolis [17], and Smithberg and Landis [30] investigate effects of swirl on skin friction and heat transfer, finding that the surface heat transfer coefficients in swirling flow are at least four times as large as in purely axial flow and highly dependent on the swirling intensity, the fluid density, and the temperature gradient. Similarly, Migay and Golubev [19] investigate the possibility of increasing the heat transfer rate by adding swirl and Algifri et al [2] test empirical approximations to predict associated heat transfer coefficients.…”

Section: Introductionmentioning

confidence: 99%

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Downstream relaxation of velocity profiles in pipe-flow with swirl disturbances

Graner¹,

Hinz²,

Breitsamter

2016

Tm - Technisches Messen

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Abstract:We study characteristic flow patterns downstream of a standardized swirl disturbance generator using laser-Doppler velocimetry (LDV). To investigate the spatial development of flow patterns, we conduct LDV measurements in cross-sections located at various distances downstream from the swirl disturbance generator. Focusing on velocity profiles, decay of swirl, and performance indicators used to describe the characteristic shape of the velocity profiles, we systematically compare the experimental results with available references and various theories for decay of swirl disturbances. We find that the standardized swirl disturbance generator provides exponentially decaying swirling flow that is best captured by the theory of Steenbergen and Voskamp¹. In addition, deviations from the axial reference profile caused by the swirl disturber persist for long downstream distances. In particular, our results suggest that the peakness factor relaxes linearly towards the fully-developed state.Keywords: Laser-Doppler velocimetry, swirl disturbance generator, swirling pipe-flow, performance indicators, downstream relaxation.

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Section: Reconstruction Of Velocity Profilesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Downstream relaxation of velocity profiles in pipe-flow with swirl disturbances

Graner¹,

Hinz²,

Breitsamter

2016

Tm - Technisches Messen

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“…The investigations which were conducted by Evans and Sarjant [12], Kreith and Margolis [13], Ibragimov et al [14], and Lopina and Bergles [15] are some of the early works on experimental works on heat transfer enhancement in turbulent flow in tubes induced with twisted tape. An enhancement of up to 50% above that in the plain tube was obtained in all these investigations.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of heat transfer and fluid flow of water through a circular tube induced with divers' tape inserts

Oni

Paul

2016

Applied Thermal Engineering

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An investigation was carried out to analyse numerically heat transfer and flow characteristics of water through a circular tube induced with different twisted tapes. The aim is to know which of the tube designs gives the best performance when compared with a plain tube. Turbulent flow was considered, the walls of the tubes were under uniform wall heat flux, Reynolds number was between 5000 and 20000, and RNG κ-ε model was selected for the simulations. The shape of cuts on the tapes has effects on the performance of the induced tubes. The tube fitted with alternate-axis triangular cut twisted tape has the best performance as its Nusselt number and friction factor are 1.63 -2.18 and 2.60 -3.15 times respectively that of the tube fitted with plain twisted tape while its thermal performance factor is 1.35 -1.43 times that of the tube with plain twisted tape. New correlations were developed for the Nusselt number and friction factors, and reveal that the Nusselt number obtained from the new correlation agrees well with the correlation proposed by Thianpong et al. with a discrepancy of 2.21%. For the friction factor, the discrepancy is 3.01%.

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“…Special role of centrifugal forces in intensification of convective heat exchange of swirled turbulent flow was marked also in [125,126]. Analysis of experimental data [126] shows that turbulent self-similar flow in swirled conditions appears at much smaller Re values, than at direct-flow liquid motion in cylindrical pipe.…”

Section: Wwwintechopencommentioning

confidence: 99%

Actual Problems of Hydrodynamics at Internal Not-Isothermal Flows in Fields of Mass Forces

Kharlamov¹

2012

Hydrodynamics - Theory and Model

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Heat transfer and friction in turbulent vortex flow

Cited by 149 publications

References 13 publications

Downstream relaxation of velocity profiles in pipe-flow with swirl disturbances

Downstream relaxation of velocity profiles in pipe-flow with swirl disturbances

Numerical investigation of heat transfer and fluid flow of water through a circular tube induced with divers' tape inserts

Actual Problems of Hydrodynamics at Internal Not-Isothermal Flows in Fields of Mass Forces

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