Performance comparison of some tube inserts

Wang, Lieke; Sundén, Bengt

doi:10.1016/s0735-1933(01)00323-2

Cited by 184 publications

(60 citation statements)

References 6 publications

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“…We can see that the friction factor decreases as the Reynolds number increases before reaching a relatively constant rate. This is explained by the fact that when Re increases, the thickness of the viscous sublayer decreases, leading to the generation of more vortices that are responsible for energy loss [26]. We also notice that our results are relatively close to those obtained by Chaube et al [19].…”

Section: Validation Casesupporting

confidence: 90%

“…For transverse ribs, growth in the friction factor is almost twice the increase in heat transfer. The best performance was recorded for ribs with rectangular section in the range of the studied parameters [11,19,26]. Another important criterion, which has not been investigated enough, is that the rib height should not a ect the ow out of the laminar sublayer [6,19].…”

Section: E Ect Of the Cross Section Of The Roughnessmentioning

confidence: 99%

“…In Figure 18, we plot the global thermohydraulic performance parameter curve presented by many authors [19,20,26]:…”

Section: Heat Transfer Analysismentioning

confidence: 99%

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Comparative Study of the Effect of Two Type of Ribs on Thermal Performance of Solar Air Heaters

2017

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Abstract. This paper aims to analyze uid ow characteristics and heat transfer augmentation in the air duct of a solar air heater using CFD techniques. The air duct has a rectangular section, the top wall is the glazing and the bottom one is the absorber provided with transverse rectangular or squared ribs. The simulations are performed in the turbulent regime and RANS formulation is used to model the ow and resolve mass, momentum, and energy equations using Finite Volumes method. The air ow analysis shows that the velocity pro le is not disturbed by the ribs outside the laminar sublayer. Heat transfer analysis based on the calculation of Nusselt Number, friction factor, and thermo-hydraulic performance highlights the heat transfer enhancement and no big friction losses are recorded. A comparative study between two rib shapes (square and rectangular) is performed, which shows better thermohydraulic performance of the rectangular ribs.

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Section: Validation Casesupporting

confidence: 90%

Section: E Ect Of the Cross Section Of The Roughnessmentioning

confidence: 99%

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Comparative Study of the Effect of Two Type of Ribs on Thermal Performance of Solar Air Heaters

2017

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“…The production of these heat exchangers involves huge investments for capital and operation costs [1][2][3]. In view of the need to reduce the financial resources spent on producing thermal energy, it has become important to devise heat exchanger that is more efficient in performance [4,5] and also save cost and energy [6,7]. To achieve this, enhancement of heat transfer becomes applicable and important.…”

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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“…( Kim et al 2001 visualized the flow pattern, void fraction and slug rise velocity on the counter-current two-phase flow in a vertical round tube with coil-wire inserts. ( Wang and Sund, 2002 ) studied the heat transfer enhancement technology in the heat exchanger. ( Rahai and Wong, 2002 ) experimentally studied the turbulent jets from round tubes with coil inserts.…”

Section: Introductionmentioning

confidence: 99%

CFD Analysis of Enhancement of Turbulent Flow Heat Transfer in a Horizontal Circular Tube with Twisted Tape Inserts

Gaddem¹

2018

IJRASET

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The present work includes the results of Cfd analysis of enhancement of turbulent flow heat transfer in a horizontal circular tube with twisted tape inserts with air as working fluid. The Reynolds number ranged from 6000 to 14000. It is observed that enhancement of heat transfer as compared to the conventional bare tube at the same mass flow rate was found to be a factor of 3 to 5 times, were as the friction factor rise was about a factor of 5 times for different tube inserts. Finally we compared results with theoretical values (Dittus-Boelter Equation)by using tool of package of ANSYS-Fluent. Geometries for plain tube, and tube with different inserts is developed in ICEM CFD (3D) with fine meshing and exported to Ansys-Fluent, then suitable boundary conditions are applied to these models and solved energy, momentum and turbulence equations and results obtained are discussed.

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Performance comparison of some tube inserts

Cited by 184 publications

References 6 publications

Comparative Study of the Effect of Two Type of Ribs on Thermal Performance of Solar Air Heaters

Comparative Study of the Effect of Two Type of Ribs on Thermal Performance of Solar Air Heaters

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

CFD Analysis of Enhancement of Turbulent Flow Heat Transfer in a Horizontal Circular Tube with Twisted Tape Inserts

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