Heat transfer performance evaluation in circular tubes via internal repeated ribs with entropy and exergy analysis

Ahmed, Saeed; Ibrahim, El-Nobi A.; Ibrahim, Mukdad; Essa, Mohamed A.; Abdelatief, Mohamed A.; El-Sayed, Mohamed N.

doi:10.1016/j.applthermaleng.2018.09.018

Cited by 45 publications

(8 citation statements)

References 40 publications

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“…With the advent of high power computers and well-tested CFD solvers, a considerable amount of numerical investigations on heat transfer enhancement techniques has been taken place in the last two decades. Some of the investigations 53,55,63 used in-house solvers, whereas the majority of the others [42][43][44][45][46][47][48][49][50][51][52]54,[56][57][58][59][60][61][62] used commercially available CFD solvers. Fluid flow governing mass, momentum and energy equations were solved by discretizing the computational domain using numerical techniques such as finite difference method, finite volume method etc.…”

Section: Heat Transfer Enhancement In Heat Exchangers Employed With C...mentioning

confidence: 99%

“…A higher pressure drop in comparison to an unenhanced heat exchanger like a smooth tube or smooth plate heat exchanger requires a larger pump and higher pumping power. In most cases, the power input costs to the pump considerably outweigh the heat transfer enhancement Variable twist ra�o twisted tape heat exchanger [6] Rib roughened helical insert [11] Discrete double inclined rib tubes [17] Double TT with helical ribs [21] Double counter TT with porosity [25] Hair pin heat exchanger with U bend [36] Mul�ple co TT and solid rings inserts [38] Internal Finned Tube [39] TT with axial perfora�on [40] Helical corrugated tube [39] Helical corrugated tube [69] Square duct with v finned inserts [43] Tunes with internal repeated ribs [61] Double TT with co & counter swirl [92] Triple and quadruple TT inser�on [55] PEC benefit. Hence, most engineers reduce the mass flow rate to reduce the pressure drop while also simultaneously lowering the heat transfer rate and overall effectiveness of the heat exchanger.…”

Section: Heat Transfer Enhancement In Heat Exchangers Employed With U...mentioning

confidence: 99%

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Design and testing of energy-efficient heat exchangers for Newtonian and non-Newtonian fluids – A review

Jayesh

Mukkamala

John

2021

Proceedings of the Institution of Mechanical Engineers, Part A:

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Heat transfer enhancement, pumping power and weight minimization in enhanced heat exchangers has long been achieved by deploying tubes with internal surface modifications like microgrooves, ribs, fins, knurls, and dimples with and without tube inserts. This article presents a very extensive review of experimental and computational studies on heat transfer enhancement, which covers convectional and unconventional working fluids under different fluid flow conditions. Compound augmentation with tube surface modifications and inserts has yielded enhancements in the overall heat transfer coefficient of over 116% in the fully developed turbulent flow regime. Exotic fluids like nano-coolants deployed in spiral grooved mircofin tubes yielded 196% enhancement in tube side heat transfer rate for concentrations as low as 0.5% by volume, while the thermal efficiency index measuring the overall enhancement in relation to the pumping power was 75%. However, reviews that address the combined effect of unconventional fluids, surface modifications and tube inserts on the overall thermo-hydraulic performance of annular heat exchangers seem to be limited. Further, nano-coolants aren’t frequently used in the process industry. The goal of this study is to document and evaluate the impact of cost-effective and energy-saving passive enhancement techniques such as tube surface modifications, tube inserts, and annular enhancement techniques on annular heat exchangers used in the process industries with Newtonian and non-Newtonian fluids. This review should be useful to engineers, academics and medical professionals working with non-Newtonian fluids and enhanced heat exchangers.

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Section: Heat Transfer Enhancement In Heat Exchangers Employed With C...mentioning

confidence: 99%

Section: Heat Transfer Enhancement In Heat Exchangers Employed With U...mentioning

confidence: 99%

Design and testing of energy-efficient heat exchangers for Newtonian and non-Newtonian fluids – A review

Jayesh

Mukkamala

John

2021

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…The velocity of the restart pressure wave along the pipe is shown in Table 4. [26][27][28] It is known from the table that with the same shutdown duration, the propagation of the pressure wave continuously accelerates as the pressure decreases more along the pipe. Effected by crude oil's compressibility, the longer the duration of shutdown is, the faster the pressure wave within the pipe is.…”

Section: The Restart Process Of the Pipe In Summermentioning

confidence: 99%

Thermal–hydraulic coupling model and operating conditions analysis of waxy crude oil pipeline restart process after shutdown

Cheng

Yang

Liu

et al. 2020

Advances in Mechanical Engineering

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To realize the safe and economic operation of a waxy crude oil pipeline, a thermal–hydraulic model in an unsteady state was established for the restart process of waxy crude oil. The model is based on the thermodynamic and hydraulic characteristics of crude oil within a pipeline intercoupling with media outside the pipeline during the restart process of the crude oil pipeline. The characteristics of waxy crude oil are considered, and the model includes the continuity equation, momentum conservation equation, and energy conservation equation. This article suggests a method for developing the model based on shockwave theory combined with the characteristic line method, numerically simulates the restart process of a certain buried oil pipe in summer and winter, and analyzes how the oil temperature at the beginning and terminal of the pipeline and the pressure at the beginning of the pipeline change during restart. In addition, this article confirms the safe duration of shutdown in two seasons for a waxy oil pipe, which are 37 h in summer and 33 h in winter.

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“…Internal repeated ring ribs [6] CFD Air 3600 ≤ Re ≤ 16,500 0.29 ≤ P f /D i ≤ 4.35 0.025 ≤ e/D i ≤ 0.069 D i = 13.8 mm Highest Nu was obtained using ring type ribs as compared to other rib geometries.…”

Section: Introductionmentioning

confidence: 98%

Numerical Analysis of Heat Transfer and Pressure Drop in Helically Micro-Finned Tubes

et al. 2021

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In this study, the pressure drop and heat transfer characteristics of smooth tube and internal helically micro-finned tubes with two different fin-to-fin height ratios i.e., equal fin height and alternating fin height, are computationally analysed. The tube with alternating fin height is analysed for proof of concept of pressure drop reduction. A single phase steady turbulent flow model is used with a Reynolds number ranging from 12,000 to 54,000. Water is used as working fluid with inlet temperature of 55 °C and constant wall temperature of 20 °C is applied. Friction factor, heat transfer coefficient, Nusselt number, and Thermal Performance Index are evaluated and analysed. The numerical results are validated by comparison with the experimental and numerical data from literature. The results showed that the thermal performance is enhanced due to helically finned tube for a range of Reynolds numbers, but at the expense of increased pressure drop as compared to a smooth tube. The helically finned tube with alternating fin heights showed a 5% decrease in friction factor and <1% decrease in heat transfer coefficient when compared with the equal fin heights tube, making it a suitable choice for heat transfer applications.

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Heat transfer performance evaluation in circular tubes via internal repeated ribs with entropy and exergy analysis

Cited by 45 publications

References 40 publications

Design and testing of energy-efficient heat exchangers for Newtonian and non-Newtonian fluids – A review

Design and testing of energy-efficient heat exchangers for Newtonian and non-Newtonian fluids – A review

Thermal–hydraulic coupling model and operating conditions analysis of waxy crude oil pipeline restart process after shutdown

Numerical Analysis of Heat Transfer and Pressure Drop in Helically Micro-Finned Tubes

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