Energies

Editorial

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7 pages, 227 KiB

Open AccessEditorial

Numerical Heat Transfer and Fluid Flow: New Advances

by Artur S. Bartosik

Energies 2023, 16(14), 5528; https://doi.org/10.3390/en16145528 - 21 Jul 2023

Cited by 1 | Viewed by 1545

Abstract

This Special Issue, titled ‘Numerical Heat Transfer and Fluid Flow 2022’, presents articles addressed to Energies and is a continuation of the 2021 edition [...] Full article

(This article belongs to the Special Issue Numerical Heat Transfer and Fluid Flow 2022)

Research

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14 pages, 3141 KiB

Open AccessArticle

Analysis of the Heat Transfer in Electronic Radiator Filled with Metal Foam

by Xiaofang Shan, Bin Liu, Zongsheng Zhu, Rachid Bennacer, Rounan Wang and Panagiotis E. Theodorakis

Energies 2023, 16(10), 4224; https://doi.org/10.3390/en16104224 - 20 May 2023

Cited by 1 | Viewed by 1746

Abstract

The performance of an electronic radiator filled with metal foam with a porosity of 96% was studied. The effect of the factors including the flow rates, the pores per linear inch (PPI) and the numbers of fins was analyzed. The results show that [...] Read more.

The performance of an electronic radiator filled with metal foam with a porosity of 96% was studied. The effect of the factors including the flow rates, the pores per linear inch (PPI) and the numbers of fins was analyzed. The results show that the electronic radiator with metal foam reflects a stronger ability of the heat transfer compared to the electronic radiator without metal foam. With the increase in the flow rate between 10 L/h and 60 L/h, the heat transfer coefficient of both of the two electronic radiators will be improved, but it is also dependent on the number of fins. In this study, we find that the heat transfer coefficient first increases and then decreases with the number of fins. The optimum number is three. As for the effect of the PPI, the higher the PPI, the larger the heat transfer coefficient, while the pressure drop always increases with the flow rates’ increase, the pores per linear inch (PPI) and the numbers of fins. Full article

(This article belongs to the Special Issue Numerical Heat Transfer and Fluid Flow 2022)

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21 pages, 10985 KiB

Open AccessArticle

Strongly Heated Turbulent Flow in a Channel with Pin Fins

by Chien-Shing Lee, Tom I. -P. Shih, Kenneth Mark Bryden, Richard P. Dalton and Richard A. Dennis

Energies 2023, 16(3), 1215; https://doi.org/10.3390/en16031215 - 22 Jan 2023

Cited by 4 | Viewed by 1415

Abstract

Large-eddy simulations (LES) were performed to study the turbulent flow in a channel of height H with a staggered array of pin fins with diameter D = H/2 as a function of heating loads that are relevant to the cooling of turbine blades [...] Read more.

Large-eddy simulations (LES) were performed to study the turbulent flow in a channel of height H with a staggered array of pin fins with diameter D = H/2 as a function of heating loads that are relevant to the cooling of turbine blades and vanes. The following three heating loads were investigated—wall-to-coolant temperatures of T_w/T_c = 1.01, 2.0, and 4.0—where the Reynolds number at the channel inlet was 10,000 and the back pressure at the channel outlet was 1 bar. For the LES, two different subgrid-scale models—the dynamic kinetic energy model (DKEM) and the wall-adapting local eddy-viscosity model (WALE)—were examined and compared. This study was validated by comparing with data from direct numerical simulation and experimental measurements. The results obtained show high heating loads to create wall jets next to all heated surfaces that significantly alter the structure of the turbulent flow. Results generated on effects of heat loads on the mean and fluctuating components of velocity and temperature, turbulent kinetic energy, the anisotropy of the Reynolds stresses, and velocity-temperature correlations can be used to improve existing RANS models. Full article

(This article belongs to the Special Issue Numerical Heat Transfer and Fluid Flow 2022)

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18 pages, 5352 KiB

Open AccessArticle

On the Simulations of Thermal Liquid Foams Using Lattice Boltzmann Method

by Mohammad Mobarak, Bernhard Gatternig and Antonio Delgado

Energies 2023, 16(1), 195; https://doi.org/10.3390/en16010195 - 24 Dec 2022

Cited by 1 | Viewed by 2084

Abstract

Liquid foams exist in a wide variety of chemical and industrial processes, and they can contaminate the end-product and cause time and economical losses. Understanding and simulating foam is not a straightforward task, due to the highly dispersed time and length scales where [...] Read more.

Liquid foams exist in a wide variety of chemical and industrial processes, and they can contaminate the end-product and cause time and economical losses. Understanding and simulating foam is not a straightforward task, due to the highly dispersed time and length scales where the physical phenomena occur. Surfactants’ or proteins’ length scales are far beyond the capability of macroscopic and even mesoscopic numerical fluid solvers, yet the macroscales are still required to be resolved. Meanwhile, the lattice Boltzmann method (LBM) has gained much attention and success as a mesoscopic approach which can deal with complex multiphase multicomponent systems. The aim of this study is to implement LBM to simulate liquid foams while considering the accompanying thermal effects. A coupled multiphase multicomponent thermal flow model and its selected add-ons from the literature are tuned and explained, limitations and future suggestions are fairly discussed. Validations and a final study case are shown as an example for the proposed model and its applicability in thermal liquid foams. Finally, a delicate treatment to back couple the effect of temperature on the surface tension is proposed, hence considering one aspect of the Marangoni effect. Initial results show promising behavior, which can be material for future investigations. Full article

(This article belongs to the Special Issue Numerical Heat Transfer and Fluid Flow 2022)

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18 pages, 5960 KiB

Open AccessArticle

Aerodynamic Performance of VAWT Airfoils: Comparison between Wind Tunnel Testing Using a New Three-Component Strain Gauge Balance and CFD Modelling

by Luis Santamaría, Mónica Galdo Vega, Adrián Pandal, José González Pérez, Sandra Velarde-Suárez and Jesús Manuel Fernández Oro

Energies 2022, 15(24), 9351; https://doi.org/10.3390/en15249351 - 10 Dec 2022

Cited by 5 | Viewed by 2541

Abstract

Vertical axis wind turbines are an emerging and in-development wind energy technology which are characterized by their complicated aerodynamics. Detached flow conditions, which are typically developed at operational tip speed ratios, demand a rigorous characterization of the airfoils for an accurate prediction of [...] Read more.

Vertical axis wind turbines are an emerging and in-development wind energy technology which are characterized by their complicated aerodynamics. Detached flow conditions, which are typically developed at operational tip speed ratios, demand a rigorous characterization of the airfoils for an accurate prediction of the turbine performance. In this work, a custom-built, three-component external strain gauge balance, specifically developed for airfoil testing, is validated. The physical reasons responsible for discrepancies with reference data are also analyzed. Two- and three-dimensional flat plates, as well as the DU06-W-200 airfoil, are tested in a wind tunnel. Lift and drag coefficients and pitching moments are obtained for a wide angular range at Re = 200,000. The results are compared with data from the bibliography and CFD simulations, performed with the recently developed GEKO (generalized k-omega) turbulence model, achieving remarkable agreement. Instantaneous forces are also analyzed with both experimental and CFD techniques, providing interesting results of the unsteady fluid dynamics. Finally, critical factors affecting the measurements are identified and enhancements are proposed for future works. In summary, a thorough evaluation of this new balance design is provided, showing its valuable potential for VAWT applications. Full article

(This article belongs to the Special Issue Numerical Heat Transfer and Fluid Flow 2022)

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22 pages, 10717 KiB

Open AccessArticle

Numerical Investigation of Flow Past Bio-Inspired Wavy Leading-Edge Cylinders

by Paulo Henrique Ferreira, Tiago Barbosa de Araújo, Eduardo Oliveira Carvalho, Lucas Dantas Fernandes and Rodrigo Costa Moura

Energies 2022, 15(23), 8993; https://doi.org/10.3390/en15238993 - 28 Nov 2022

Cited by 3 | Viewed by 1637

Abstract

A numerical investigation is proposed to explore the flow past a novel wavy circular cylinder as a passive flow control, whose shape is determined by a sinusoidal function applied to its leading edge line, similar to studies with wavy leading-edge airfoils. The latter [...] Read more.

A numerical investigation is proposed to explore the flow past a novel wavy circular cylinder as a passive flow control, whose shape is determined by a sinusoidal function applied to its leading edge line, similar to studies with wavy leading-edge airfoils. The latter are motivated by the wavy-shaped tubercles found in the flippers of humpback whales, which are believed to improve their maneuverability. Our attempt is, therefore, to assess the effects of leading-edge waviness now on a simpler and canonical geometry: circular cylinders. The present work relies on iLES simulations conducted with Nektar++ at a Reynolds number of 3900. Besides the straight cylinder, two wavy geometries are assessed, which are determined by a single wavelength of 37.5% for two amplitudes, 3% and 11%, based on the mean diameter of the wavy cylinder. Our results showed that, contrary to what is usually the case with traditional wavy cylinders at similar Reynolds numbers, waviness caused a reduction in the near-wake recirculation length and an increase in the mean near-wake turbulent kinetic energy compared to the straight cylinder. This was followed by a reduction in base pressure (up to about 36%) leading to a rise in lift oscillations and also to a significant increase in the mean drag coefficient of up to about 28%. An attempt to detail the flow phenomena is provided, evidencing the emergence of counter-rotating pairs of streamwise vortices between peaks. It is argued that the differences observed in recirculation length, turbulent kinetic energy, and force coefficients start even prior to the formation of these coherent structures and end up with interactions with the near wake. Full article

(This article belongs to the Special Issue Numerical Heat Transfer and Fluid Flow 2022)

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14 pages, 3581 KiB

Open AccessArticle

Settling of Mesoplastics in an Open-Channel Flow

by Luka Kevorkijan, Elvis Žic, Luka Lešnik and Ignacijo Biluš

Energies 2022, 15(23), 8786; https://doi.org/10.3390/en15238786 - 22 Nov 2022

Cited by 1 | Viewed by 1490

Abstract

Pollution of water by plastic contaminants has received increasing attention, owing to its negative effects on ecosystems. Small plastic particles propagate in water and can travel long distances from the source of pollution. In order to research the settling motion of particles in [...] Read more.

Pollution of water by plastic contaminants has received increasing attention, owing to its negative effects on ecosystems. Small plastic particles propagate in water and can travel long distances from the source of pollution. In order to research the settling motion of particles in water flow, a small-scale experiment was conducted, whereby spherical plastic particles of varying diameters were released in an open-channel flow. Three approaches were investigated to numerically simulate the motion of particles. The numerical simulation results were compared and validated with experimental data. The presented methods allow for deeper insight into particle motion in fluid flow and could be extended to a larger scale to predict the propagation of mesoplastics in natural environments. Full article

(This article belongs to the Special Issue Numerical Heat Transfer and Fluid Flow 2022)

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16 pages, 3961 KiB

Open AccessFeature PaperArticle

The Transient Thermal Disturbance in Surrounding Formation during Drilling Circulation

by Minsoo Jang, Troy S. Chun and Jaewoo An

Energies 2022, 15(21), 8052; https://doi.org/10.3390/en15218052 - 29 Oct 2022

Cited by 1 | Viewed by 1184

Abstract

The injecting drilling mud is typically at the ambient temperature, relatively much colder than the deep formation, inducing a cooling effect in the formation. Although the cooled formation temperature gradually returns to its original temperature after drilling circulation, the recovery speed is slow [...] Read more.

The injecting drilling mud is typically at the ambient temperature, relatively much colder than the deep formation, inducing a cooling effect in the formation. Although the cooled formation temperature gradually returns to its original temperature after drilling circulation, the recovery speed is slow due to low thermal diffusivity. Considering that any well tests begin in a short period after drilling ends, temperature recovery is not fully achieved before the tests. It means that the measured temperature of producing fluid is not that of the actual formation, significantly impairing the robustness of the subsequent thermal applications. Furthermore, there has been no quantified concept of thermal disturbance in the formation and its analysis. In this work, a proposed numerical transient heat transfer model computes the radial temperature in the drill pipe, annulus, and formation. The concept of quantifying thermal disturbance, named thermally disturbed radius (TDR), indicates how long the thermal disturbance occurs radially in the formation. The TDR increases with the more significant temperature difference between circulating fluid and formation. Thus, the TDR appears to be the largest at the bottom-hole depth. In the sensitivity of TDR of various operational parameters, circulation time (i.e., drilling time) is the most influential factor. Meanwhile, the other parameters do not significantly affect TDR: circulation rate, injecting mud temperature, and mud density. The sensitivity analysis concludes that as long as the operators control the drilling time, the uncertainty of the measured temperature after drilling can be manageable without limiting any other operational parameters. Full article

(This article belongs to the Special Issue Numerical Heat Transfer and Fluid Flow 2022)

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32 pages, 3768 KiB

Open AccessArticle

An Asymptotic Energy Equation for Modelling Thermo Fluid Dynamics in the Optical Fibre Drawing Process

by Giovanni Luzi, Seunghyeon Lee, Bernhard Gatternig and Antonio Delgado

Energies 2022, 15(21), 7922; https://doi.org/10.3390/en15217922 - 25 Oct 2022

Cited by 3 | Viewed by 1453

Abstract

Microstructured optical fibres (MOFs) are fibres that contain an array of air holes that runs through the whole fibre length. The hole pattern of these fibres can be customized to manufacture optical devices for different applications ranging from high-power energy transmission equipment to [...] Read more.

Microstructured optical fibres (MOFs) are fibres that contain an array of air holes that runs through the whole fibre length. The hole pattern of these fibres can be customized to manufacture optical devices for different applications ranging from high-power energy transmission equipment to telecommunications and optical sensors. During the drawing process, the size of the preform is greatly scaled down and the original hole pattern result might be modified, potentially leading to unwanted optical effects. Because only a few parameters can be controlled during the fabrication process, mathematical models that can accurately describe the fibre drawing process are highly desirable, being powerful predictive tools that are significantly cheaper than costly experiments. In this manuscript, we derive a new asymptotic energy equation for the drawing process of a single annular capillary and couple it with existing asymptotic mass, momentum, and evolution equations. The whole asymptotic model only exploits the small aspect ratio of a capillary and relies on neither a fitting procedure nor on any empirical adjustable parameters. The numerical results of the simplified model are in good accordance with experimental data available in the literature both without inner pressurization and when internal pressure is applied. Although valid only for annular capillaries, the present model can provide important insights towards understanding the MOF manufacturing process and improving less detailed approaches for more complicated geometries. Full article

(This article belongs to the Special Issue Numerical Heat Transfer and Fluid Flow 2022)

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17 pages, 1936 KiB

Open AccessArticle

Numerical Simulation of Flow and Heat Transfer of a Discontinuous Single Started Helically Ribbed Pipe

by Simon Kügele, Gino Omar Mathlouthi, Peter Renze and Thomas Grützner

Energies 2022, 15(19), 7096; https://doi.org/10.3390/en15197096 - 27 Sep 2022

Cited by 5 | Viewed by 1704

Abstract

In the present study, the turbulent flow field and the heat transfer in a single started helically ribbed pipe with a discontinuous rib are investigated. A large-eddy simulation (LES) technique is applied in a pipe section with cyclic boundary conditions. The aim of [...] Read more.

In the present study, the turbulent flow field and the heat transfer in a single started helically ribbed pipe with a discontinuous rib are investigated. A large-eddy simulation (LES) technique is applied in a pipe section with cyclic boundary conditions. The aim of this study is to explain and further analyze the findings from the heat transfer measurements at such complex structures with the help of detailed flow simulations. The simulation results are validated with measurements at a Reynolds number of Re = 21,100 and a Prandtl number of Pr = 7 with water as fluid. The comparison clearly shows that the current method delivers accurate results concerning average flow field, turbulence quantities and local heat transfer. The results demonstrate that the applied method is capable of correctly simulating flows with heat transfer in complex three-dimensional structures. The overall heat transfer performance of the helically ribbed pipe with a discontinuous rib is compared to a smooth pipe and a continuous rib configuration. The impact of the interruption of the rib structure on pressure drop and heat transfer are analyzed in detail. Full article

(This article belongs to the Special Issue Numerical Heat Transfer and Fluid Flow 2022)

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26 pages, 7687 KiB

Open AccessArticle

Cooling Modelling of an Electrically Heated Ceramic Heat Accumulator

by Dawid Taler, Jan Taler, Tomasz Sobota and Jarosław Tokarczyk

Energies 2022, 15(16), 6085; https://doi.org/10.3390/en15166085 - 22 Aug 2022

Cited by 2 | Viewed by 1870

Abstract

This paper presents a simple novel mathematical model of a heat accumulator with an arranged packing in the form of ceramic cylinders. The accumulator analysed in the paper can be heated with inexpensive electricity overnight or excess electricity from wind farms. It can [...] Read more.

This paper presents a simple novel mathematical model of a heat accumulator with an arranged packing in the form of ceramic cylinders. The accumulator analysed in the paper can be heated with inexpensive electricity overnight or excess electricity from wind farms. It can be used as a heat source in a hydronic heating system or for domestic hot water. The differential equations describing the transient temperature of the accumulator packing and flowing air were solved using the explicit Euler and Crank–Nicolson methods. The accuracy of both methods was assessed using exact analytical solutions and the superposition method for a uniform initial temperature and accounted for time changes in inlet air temperature. A numerical simulation of the accumulator cooled by flowing air was carried out. The correlation for the air-side Nusselt number was determined using the method of least squares based on experimental data. The calculated exit air temperature was compared with the measured data. The accumulator can operate as a heat source with dynamic discharge. The developed mathematical model of the accumulator can be used in a system to adjust the fan rotational speed so that the air temperature in the room is equal to the preset temperature. Full article

(This article belongs to the Special Issue Numerical Heat Transfer and Fluid Flow 2022)

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18 pages, 4770 KiB

Open AccessArticle

Identification of Transient Steam Temperature at the Inlet of the Pipeline Based on the Measured Steam Temperature at the Pipeline Outlet

by Karol Kaczmarski

Energies 2022, 15(16), 5804; https://doi.org/10.3390/en15165804 - 10 Aug 2022

Cited by 2 | Viewed by 1585

Abstract

A solution to the inverse heat transfer problem (IHP) occurring in steam pipelines is presented in the paper. The transient steam temperature at the pipeline inlet was determined from the steam temperature measured at the pipeline outlet. Temporary changes of steam temperature at [...] Read more.

A solution to the inverse heat transfer problem (IHP) occurring in steam pipelines is presented in the paper. The transient steam temperature at the pipeline inlet was determined from the steam temperature measured at the pipeline outlet. Temporary changes of steam temperature at the turbine inlet are set by the turbine manufacturer and result from the conditions of safe starting of the turbine and maintaining high durability of its components. The boiler start-up should be carried out so that the time-temperature changes at the boiler outlet equal the time-temperature changes determined using the inverse problem. In this paper, the inverse problem of heat transfer in the pipeline was solved by the finite volume method using data smoothing, future times steps, and Tikhonov regularization that stabilized the solution of the inverse problem. The determined transient steam temperature at the pipeline inlet was compared with the measured temperatures. The steam temperature at the inlet to the pipeline, which is the solution to the inverse problem, agrees very well with the measured temperature, as the absolute value of the relative difference

ε_{T}

between measured and calculated temperature is between 0.045% and 0.3%, and the root mean square error RMSE is within the range of 0.038 K to 0.322 K. Full article

(This article belongs to the Special Issue Numerical Heat Transfer and Fluid Flow 2022)

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20 pages, 828 KiB

Open AccessArticle

How to Improve an Offshore Wind Station

by João Paulo N. Torres, Ana Sofia De Jesus and Ricardo A. Marques Lameirinhas

Energies 2022, 15(13), 4873; https://doi.org/10.3390/en15134873 - 2 Jul 2022

Cited by 2 | Viewed by 1727

Abstract

The ocean is approximately 71% of the Earth’s surface and has a lot of resources available. Nowadays, human beings are looking for renewable ways to obtain energy. Offshore power can be obtained in several different ways. Offshore wind power is the most used [...] Read more.

The ocean is approximately 71% of the Earth’s surface and has a lot of resources available. Nowadays, human beings are looking for renewable ways to obtain energy. Offshore power can be obtained in several different ways. Offshore wind power is the most used renewable offshore energy. Since 2017, offshore wind power has a competitive price in comparison with conventional sources. In the 2010s, offshore wind power grew at over 30% per year. Although it has remained less than one percent of the overall world electricity generation, offshore wind power becomes quite relevant on the northern European countries from 2020. However, there are other ways to obtain energy offshore such as using tides and the sun. These types of farms are expensive and difficult to install and, therefore, we propose a combination of several renewable energies in one farm. The main ambition of this work is to try to reduce the installation and maintenance costs of the two types of offshore renewable energies by creating a structure capable of supporting the two types of turbines. To accomplish it, a theoretical study will be made, a brief state-of-the-art will be presented, the chosen items and the environment chosen for installation will be referred to, a prototype will be simulated using a multiphysics software and, finally, the results and conclusions will be presented, based on a Portuguese case study. How piezoelectric materials can enter offshore farms to increase efficiency is also referred to. The project proved to be possible of producing approximately 12.5 GWh of energy annually, more or less enough to supply 10 thousand homes. However, the installation of the piezoelectric materials did not prove to be viable as it is an expensive technology and does not produce a large amount of energy. Full article

(This article belongs to the Special Issue Numerical Heat Transfer and Fluid Flow 2022)

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12 pages, 1361 KiB

Open AccessArticle

Effect of Deflocculant Addition on Energy Savings in Hydrotransport in the Lime Production Process

by Beata Jaworska-Jóźwiak and Marek Dziubiński

Energies 2022, 15(11), 3869; https://doi.org/10.3390/en15113869 - 24 May 2022

Cited by 2 | Viewed by 1396

Abstract

The subject of the research was limestone hydromixture consisting of particles of a mean size of 45.5 μm conveyed by water in a pipeline of a total length of 632 m. In the paper, the results of rheological measurements of tested hydromixtures after [...] Read more.

The subject of the research was limestone hydromixture consisting of particles of a mean size of 45.5 μm conveyed by water in a pipeline of a total length of 632 m. In the paper, the results of rheological measurements of tested hydromixtures after the application of deflocculant consisting of waste product from the lime production process in the form of mineral particles and commonly known dispersant were presented. Calculations of pressure drop including hydromixtures with volume concentrations in the range of 21.30–50.00%, and density ranging from 1140–1410 kg/m³ in a pipeline of 200 mm diameter are presented. A decrease in friction losses in the flow in the pipeline of hydromixtures with different mass concentrations after the addition of deflocculant was observed. The study revealed that the addition of deflocculant resulted in a reduction of friction in the pipeline, enabling the pumping of hydromixtures with twice higher solids concentrations than originated from industrial installation, with a lower volumetric flow rate. This resulted in a decrease of the power consumption of the motor driving the pump, and obtained significant energy savings in the hydromixture transport process. The maximum energy saving achieved was equal to 58%. Full article

(This article belongs to the Special Issue Numerical Heat Transfer and Fluid Flow 2022)

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Review

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29 pages, 4721 KiB

Open AccessReview

Navier-Stokes Solutions for Accelerating Pipe Flow—A Review of Analytical Models

by Kamil Urbanowicz, Anton Bergant, Michał Stosiak, Adam Deptuła and Mykola Karpenko

Energies 2023, 16(3), 1407; https://doi.org/10.3390/en16031407 - 31 Jan 2023

Cited by 7 | Viewed by 3061

Abstract

This paper reviews analytical solutions for the accelerated flow of an incompressible Newtonian fluid in a pipeline. This problem can be solved in one of two ways according to the (1) imposed pressure gradient or (2) flow rate. Laminar accelerated flow solutions presented [...] Read more.

This paper reviews analytical solutions for the accelerated flow of an incompressible Newtonian fluid in a pipeline. This problem can be solved in one of two ways according to the (1) imposed pressure gradient or (2) flow rate. Laminar accelerated flow solutions presented in a number of publications concern cases where the two driving mechanisms are described by simple mathematical functions: (a) impulsive change; (b) constant change; (c) ramp change, etc. The adoption of a more complex and realistic description of the pressure gradient or flow rate will be associated with a profound mathematical complexity of the final solution. This is particularly visible with the help of the universal formula derived by several researchers over the years and discussed in this paper. In addition to the solutions strictly defined for laminar flow, an interesting extension of this theory is the theory of underlying laminar flow for the analysis of turbulent accelerated pipe flows (TULF model developed by García García and Alvariño). The TULF model extends the Pai model developed more than 60 years ago, which has been previously used for steady flows only. The discussed solutions extend the theory of analytical solutions of simplified two-dimensional Navier–Stokes equations and can be used not only to study the behavior of liquids during accelerating pipe flow but they can also be used to test the accuracy of commercial CFD codes. Full article

(This article belongs to the Special Issue Numerical Heat Transfer and Fluid Flow 2022)

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18 pages, 1604 KiB

Open AccessReview

Numerical Modelling of Forced Convection of Nanofluids in Smooth, Round Tubes: A Review

by Janusz T. Cieśliński

Energies 2022, 15(20), 7586; https://doi.org/10.3390/en15207586 - 14 Oct 2022

Cited by 4 | Viewed by 1370

Abstract

A comprehensive review of published works dealing with numerical modelling of forced convection heat transfer and hydrodynamics of nanofluids is presented. Due to the extensive literature, the review is limited to straight, smooth, circular tubes, as this is the basic geometry in shell-and-tube [...] Read more.

A comprehensive review of published works dealing with numerical modelling of forced convection heat transfer and hydrodynamics of nanofluids is presented. Due to the extensive literature, the review is limited to straight, smooth, circular tubes, as this is the basic geometry in shell-and-tube exchangers. Works on numerical modelling of forced convection in tubes are presented chronologically in the first part of the article. Particular attention was paid to the method of the solution of governing equations, geometry of the heating section, and boundary conditions assumed. Influence of nanoparticles on heat transfer and flow resistance are discussed. Basic information is summarized in tabular form, separately for single-phase approach and two-phase models. The second part of the article contains the correlation equations proposed in the presented papers for the calculation of the Nusselt (Nu) number or heat transfer coefficient, separately for laminar and turbulent flow. Details of the type of nanofluids, the concentration of nanoparticles, and the Reynolds (Re) number range are also presented. Finally, advantages and disadvantages of individual numerical approaches are discussed. Full article

(This article belongs to the Special Issue Numerical Heat Transfer and Fluid Flow 2022)

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