Heat transfer coefficients of laminar, transitional, quasi-turbulent and turbulent flow in circular tubes

Meyer, Josua P.; Everts, Marilize; Coetzee, Nicole; Grote, Kersten; Steyn, Madder

doi:10.1016/j.icheatmasstransfer.2019.03.016

Cited by 78 publications

(42 citation statements)

References 67 publications

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“…The results obtained for the smooth tube for the Nusselt number and friction factor are validated with the well-established correlations of the Dittus-Boelter correlation [81], the Meyer et al [82] correlation was used for the Nusselt number and Blasius Correlation [82] for the friction factor.…”

Section: Resultsmentioning

confidence: 58%

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Heat and Fluid Flow Analysis and ANN-Based Prediction of A Novel Spring Corrugated Tape

et al. 2021

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A circular tube fitted with novel corrugated spring tape inserts has been investigated. Air was used as the working fluid. A thorough literature review has been done and this geometry has not been studied previously, neither experimentally nor theoretically. A novel experimental investigation of this enhanced geometry can, therefore, be treated as a new substantial contribution in the open literature. Three different spring ratio and depth ratio has been used in this study. Increase in thermal energy transport coefficient is noticed with increase in depth ratio. Corrugated spring tape shows promising results towards heat transfer enhancement. This geometry performs significantly better (60% to 75% increase in heat duty at constant pumping power and 20% to 31% reduction in pumping power at constant heat duty) than simple spring tape. This paper also presented a statistical analysis of the heat transfer and fluid flow by developing an artificial neural network (ANN)-based machine learning (ML) model. The model is evaluated to have an accuracy of 98.00% on unknown test data. These models will help the researchers working in heat transfer enhancement-based experiments to understand and predict the output. As a result, the time and cost of the experiments will reduce. The results of this investigation can be used in designing heat exchangers.

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Section: Resultsmentioning

confidence: 58%

“…Range: 3000 < Re < 10 6 ; 0.7 < Pr < 120 Moreover, Meyer et al [82] correlated the Nusselt number as follows:…”

Section: Resultsmentioning

confidence: 99%

Heat and Fluid Flow Analysis and ANN-Based Prediction of A Novel Spring Corrugated Tape

et al. 2021

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“…The Nusselt number is obtained inside the U-tube HEX by the following equations [55] for the laminar and turbulent flow behavior:…”

Section: Governing Equationsmentioning

confidence: 99%

Experimental and Numerical Study on Energy Piles with Phase Change Materials

2020

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Phase change materials (PCM) utilization in energy storage systems represents a point of interest and attraction for the researchers to reduce greenhouse gas emissions. PCM have been used widely on the interior or exterior walls of the building application to optimize the energy consumption during heating and cooling periods. Meanwhile, ground source heat pump (GSHP) gained its popularity because of the high coefficient of performance (COP) and low running cost of the system. However, GSHP system requires a stand-by heat pump during peak loads. This study will present a new concept of energy piles that used PCM in the form of enclosed tube containers. A lab-scaled foundation pile was developed to examine the performance of the present energy pile, where three layers of insulation replaced the underground soil to focus on the effect of PCM. The investigation was conducted experimentally and numerically on two identical piles with and without PCM. Moreover, a flow rate parametric study was conducted to study the effect of the working fluid flow rate on the amount of energy stored and released at each model. Finally, a comprehensive Computational fluid dynamic (CFD) model was developed and compared with the experimental results. There was a good agreement between the experimental measurements and the numerical predictions. The results revealed that the presence of PCM inside the piles increased not only the charging and discharging capacity but also the storage efficiency of the piles. It was found that PCM enhances the thermal response of the concrete during cooling and heating processes. Although increasing the flow rate increased charging and discharging capacity, the percentage of energy stored/released was insignificant compared to the flow rate increasing percentage.

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“…Nusselt number inside the U loop HEX is obtained as follows 31 : In the above equations, ρ s is the density of solid layers (eg, concrete), c ps is the specific heat of solid, U (u, v, w) is the velocity field vector, T is the temperature, k s is the thermal conductivity of solid, Nu D is the Nusselt number, Re D is the Reynolds number, Pr is the Prandtl Number, and n is a constant given to be 0.4 for cooling and 0.3 for heating.…”

Section: Governing Equationsmentioning

confidence: 99%

“…Nusselt number inside the U loop HEX is obtained as follows 31 :

{Nu}_{D} = 0.023 {Re}_{D}^{4 / 5} . P r^{n} (Turbulent Flow)

{Nu}_{D} = 3.66 (Laminar Flow)

…”

Section: Numerical Model Descriptionmentioning

confidence: 99%

Underground energy storage utilizing concrete building foundation: Experimental and numerical approach

Mousa

Bayomy

Wang³

et al. 2020

Int J Energy Res

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Space heating and cooling represent 63% of total building energy demand. In the present study, the concept of concrete foundation piles was used as an underground storage medium. This system requires no additional drilling costs or space, unlike conventional boreholes. A laboratory-scaled experiment facility was designed to experimentally investigate the thermal response of a concrete pile during the charging and discharging processes. The amount of energy stored and released during each process was evaluated. A flow rate parametric study was also conducted to explore the effect of the laminar and turbulent flow behavior. In order to complement the experimental study, an extensive CFD model was developed and compared with the experimental data. There was good agreement between the numerical and experimental results for each process at different flow rates. The results revealed that increasing the flow rate increases not only the heat rejection and extraction but also the storage efficiency.

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Heat transfer coefficients of laminar, transitional, quasi-turbulent and turbulent flow in circular tubes

Cited by 78 publications

References 67 publications

Heat and Fluid Flow Analysis and ANN-Based Prediction of A Novel Spring Corrugated Tape

Heat and Fluid Flow Analysis and ANN-Based Prediction of A Novel Spring Corrugated Tape

Experimental and Numerical Study on Energy Piles with Phase Change Materials

Underground energy storage utilizing concrete building foundation: Experimental and numerical approach

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