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17 pages, 8252 KiB

Open AccessArticle

Assessment of Hybrid RANS/LES Models in Heat and Fluid Flows around Staggered Pin-Fin Arrays

by Byeong-Cheon Kim and Kyoungsik Chang

Energies 2020, 13(14), 3752; https://doi.org/10.3390/en13143752 - 21 Jul 2020

Cited by 5 | Viewed by 3021

Abstract

In the present work, the three-dimensional heat and fluid flows around staggered pin-fin arrays are predicted using two hybrid RANS/LES models (an improved delayed detached eddy simulation (IDDES) model and a stress-blended eddy simulation (SBES) model), and one transitional unsteady Reynolds averaged Navier-Stokes [...] Read more.

In the present work, the three-dimensional heat and fluid flows around staggered pin-fin arrays are predicted using two hybrid RANS/LES models (an improved delayed detached eddy simulation (IDDES) model and a stress-blended eddy simulation (SBES) model), and one transitional unsteady Reynolds averaged Navier-Stokes (URANS) model, called k-ω SSTLM. The periodic segment geometry with a total of nine pins is considered with a channel height of 2D and a distance of 2.5D between each pin. The corresponding Reynolds number based on the pin diameter and the maximum velocity between pins is 10,000. The two hybrid RANS/LES results show the superior prediction of the mean velocity profiles around the pins, pressure distributions on the pin wall, and Nusselt number distributions. However, the transitional model, k-ω SSTLM, shows large discrepancies except in front of the pins where the flow is not fully developed. The vortical structures are well resolved by the two hybrid RANS/LES models. The SBES model is particularly adept at capturing the 3-D vortex structures after the pins. The effects of the blending function switching between RANS and LES mode of the two hybrid RANS/LES models are also investigated. Full article

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

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32 pages, 11228 KiB

Open AccessArticle

Systematic Frequency and Statistical Analysis Approach to Identify Different Gas–Liquid Flow Patterns Using Two Electrodes Capacitance Sensor: Experimental Evaluations

by Fayez M. Al-Alweet, Artur J. Jaworski, Yusif A. Alghamdi, Zeyad Almutairi and Jerzy Kołłątaj

Energies 2020, 13(11), 2932; https://doi.org/10.3390/en13112932 - 8 Jun 2020

Cited by 5 | Viewed by 2600

Abstract

This work proposes a method to distinguish between various flow patterns in a multiphase gas–liquid system. The complete discrimination between different flow patterns can be achieved by mapping the corresponding frequency and statistical parameters. These parameters are usually obtained from further analysis conducted [...] Read more.

This work proposes a method to distinguish between various flow patterns in a multiphase gas–liquid system. The complete discrimination between different flow patterns can be achieved by mapping the corresponding frequency and statistical parameters. These parameters are usually obtained from further analysis conducted on the signal data of the utilized sensor. The proposed technique is based on establishing interrelationships between these parameters, namely the mean (m), the standard deviation (

\bar{σ}

), power spectral density (PSD), the width of the characteristic frequency peaks (Δƒ), the skewness (

γ_{1}

) and the kurtosis (

γ_{2}

). Therefore, a relatively simple electrical capacitance sensor with two electrodes was designed and implemented on a two-phase flow apparatus with a circular pipe. The experimental operating conditions comprised of different combinations of air–water superficial velocities at three inclinations (i.e., horizontal, upward 15° and upward 30°). This research discusses in specific the analysis underlying flow patterns identification method and the rationale for selecting the proposed approach. The results showed that some parameters found to be more valuable than others such as m,

\bar{σ}

and Δƒ. Besides, combining two sets of these statistical graphs which are (a)

\bar{σ}

vs. Δƒ with Δƒ vs. m (or Δƒ vs. total power), (b) Δƒ vs. total power with

γ_{1}

vs.

\bar{σ}

(or

γ_{2}

vs.

\bar{σ}

), and (c)

\bar{σ}

vs. m with Δƒ vs. m (or Δƒ vs. total power), allowed all flow patterns field to be identified clearly at all inclinations. It is therefore concluded that for any gas–liquid multiphase flow system, the reported approach can be used reliably to discriminate between different generated flow patterns. Full article

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

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18 pages, 5834 KiB

Open AccessArticle

Study on Loose-Coupling Methods for Aircraft Thermal Anti-Icing System

by Xiaobin Shen, Qi Guo, Guiping Lin, Yu Zeng and Zhongliang Hu

Energies 2020, 13(6), 1463; https://doi.org/10.3390/en13061463 - 20 Mar 2020

Cited by 7 | Viewed by 2845

Abstract

To simulate aircraft thermal anti-icing systems and solve the conjugate heat transfer of air-droplet flow and solid skin, the heat and mass transfer model of the runback water on the anti-icing surface was combined with the heat conduction equation of the skin by [...] Read more.

To simulate aircraft thermal anti-icing systems and solve the conjugate heat transfer of air-droplet flow and solid skin, the heat and mass transfer model of the runback water on the anti-icing surface was combined with the heat conduction equation of the skin by loosely coupled methods. According to the boundary conditions used for the runback water conservation equations, two loose-coupling methods for the heat exchange between the runback water and the solid skin were developed based on surface heat flow and surface temperature, respectively. The anti-icing and ice accretion results of a NACA 0012 electro-thermal anti-icing system were obtained by the two loose-coupling methods. The heat flow-based method directly solves the thermodynamic model of the runback water without any extra assumptions, but the convergence rate is relatively slow. On the other hand, the temperature-based method achieves higher calculation speed, but the freezing point is extended to an artificial temperature range between water and ice phases. When the value of the artificial temperature range is small, the results obtained by the temperature-based method are consistent with those of the heat flow-based method, indicating that the effect of freezing point extension can be ignored for thermal anti-icing simulation. Furthermore, the solutions of the two methods are in acceptable and comparable agreement with the experimental and simulative results in the literature, confirming their feasibility and effectiveness. In addition, it is found that the ice thicknesses and ice shapes rise obviously near the runback water limits as a result of the transverse heat conduction of the solid skin. Full article

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

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9 pages, 2045 KiB

Open AccessArticle

Boiling Synchronization in Two Parallel Minichannels—Image Analysis

by Gabriela Rafałko, Iwona Zaborowska, Hubert Grzybowski and Romuald Mosdorf

Energies 2020, 13(6), 1409; https://doi.org/10.3390/en13061409 - 18 Mar 2020

Cited by 6 | Viewed by 1915

Abstract

In this paper, the boiling synchronization of two-phase flow patterns in two parallel minichannels of 1 mm in diameter with connected compressible volumes was analyzed. The analysis was performed using images recorded with a high-speed camera. The degree of synchronization between channels was [...] Read more.

In this paper, the boiling synchronization of two-phase flow patterns in two parallel minichannels of 1 mm in diameter with connected compressible volumes was analyzed. The analysis was performed using images recorded with a high-speed camera. The degree of synchronization between channels was evaluated by assessing the presence of liquid flow in the small part of the minichannels. It can be concluded that boiling is synchronized when small bubble flow or wavy annular flow occur in neighboring channels. The occurrence of slug flow in one channel causes the boiling in neighboring channels to become unsynchronized. The result of the image analysis shows that the correlation coefficient based on the evaluation of the presence of liquid flow in the small part of the minichannels over a long enough time period allows for the detection of boiling synchronization. Full article

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

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13 pages, 6802 KiB

Open AccessArticle

Effect of Secondary Vortex Flow Near Contact Point on Thermal Performance in the Plate Heat Exchanger with Different Corrugation Profiles

by Hyung Ju Lee and Seong Hyuk Lee

Energies 2020, 13(6), 1328; https://doi.org/10.3390/en13061328 - 12 Mar 2020

Cited by 9 | Viewed by 3283

Abstract

The present study numerically investigates thermal performance and turbulent flow characteristics of chevron-type plate heat exchangers with sinusoidal, trapezoidal, triangular, and elliptical corrugation profiles. The commercial code of ANSYS Fluent (v. 17.0) is used for computational fluid dynamics (CFD) simulation with the realizable [...] Read more.

The present study numerically investigates thermal performance and turbulent flow characteristics of chevron-type plate heat exchangers with sinusoidal, trapezoidal, triangular, and elliptical corrugation profiles. The commercial code of ANSYS Fluent (v. 17.0) is used for computational fluid dynamics (CFD) simulation with the realizable k-ε model. In particular, we focus on the influence of configuration shape on a substantial change in flow direction near the contact point, yielding local vorticity. As a result, secondary vortical motions are observed in the flow passage with vorticity that is distributed locally and which changes near the contact point. Higher flow mixing generated and distributed by the secondary vortical motions contributes to the increase of the Colburn j-factor as well as the friction factor. The highest Colburn j-factor and friction factor are obtained for an elliptical profile, compared to other shapes, because of the increase in the vortex strength near the contact point. Full article

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

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17 pages, 2980 KiB

Open AccessArticle

Experimental Investigation on Heat Transfer of Supercritical Water Flowing in the Subchannel with Grid Spacer in Supercritical Water-Cooled Reactor

by Weishu Wang, Lingwei Guo, Ge Zhu, Xiaojing Zhu and Qincheng Bi

Energies 2020, 13(5), 1016; https://doi.org/10.3390/en13051016 - 25 Feb 2020

Cited by 4 | Viewed by 2732

Abstract

Experimental investigations on the heat transfer performance of supercritical water flowing in the subchannel of supercritical water-cooled reactor (SCWR) simulated by a triangular channel were conducted at pressures of 23–28 MPa, mass flow rates of 700–1300 kg·m⁻²·s⁻¹, and inner [...] Read more.

Experimental investigations on the heat transfer performance of supercritical water flowing in the subchannel of supercritical water-cooled reactor (SCWR) simulated by a triangular channel were conducted at pressures of 23–28 MPa, mass flow rates of 700–1300 kg·m⁻²·s⁻¹, and inner wall surface heat fluxes of 200–600 kW·m⁻². An 8 mm diameter fuel rod with a 1.4 pitch to diameter ratio was used. The effects of pressure, mass flow rate, and heat flux on the heat transfer performance under the resistance of a standard grid spacer were analyzed. Experimental results showed the significant positive influence of the grid spacer on the supercritical water in the subchannel. Moreover, in the presence of the grid spacer, the parameters influenced the heat transfer with different degrees of strengthening reaction. In view of the phenomenon in the tests, the rule of the supercritical heat transfer was further revealed by the comparison between empirical formulas and experimental data. This paper mainly studied the positioning grid function and the fluid flow characteristics downstream of the subchannel under the influence of the standard grid spacer and the impact mechanism of each parameter on the whole heat transfer process coefficient. Full article

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

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27 pages, 10182 KiB

Open AccessArticle

Optimization and Extended Applicability of Simplified Slug Flow Model for Liquid-Gas Flow in Horizontal and Near Horizontal Pipes

by Tea-Woo Kim, Nam-Sub Woo, Sang-Mok Han and Young-Ju Kim

Energies 2020, 13(4), 842; https://doi.org/10.3390/en13040842 - 14 Feb 2020

Cited by 4 | Viewed by 2660

Abstract

The accurate prediction of pressure loss for two-phase slug flow in pipes with a simple and powerful methodology has been desired. The calculation of pressure loss has generally been performed by complicated mechanistic models, most of which require the iteration of many variables. [...] Read more.

The accurate prediction of pressure loss for two-phase slug flow in pipes with a simple and powerful methodology has been desired. The calculation of pressure loss has generally been performed by complicated mechanistic models, most of which require the iteration of many variables. The objective of this study is to optimize the previously proposed simplified slug flow model for horizontal pipes, extending the applicability to turbulent flow conditions, i.e., high mixture Reynolds number and near horizontal pipes. The velocity field previously measured by particle image velocimetry further supports the suggested slug flow model which neglects the pressure loss in the liquid film region. A suitable prediction of slug characteristics such as slug liquid holdup and translational velocity (or flow coefficient) is required to advance the accuracy of calculated pressure loss. Therefore, the proper correlations of slug liquid holdup, flow coefficient, and friction factor are identified and utilized to calculate the pressure gradient for horizontal and near horizontal pipes. The optimized model presents a fair agreement with 2191 existing experimental data (0.001 ≤ μ_L ≤ 0.995 Pa∙s, 7 ≤ Re_M ≤ 227,007 and −9 ≤ θ ≤ 9), showing −3% and 0.991 as values of the average relative error and the coefficient of determination, respectively. Full article

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

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19 pages, 10978 KiB

Open AccessArticle

Experimental Study of Sand Particle Deposition on a Film-Cooled Turbine Blade at Different Gas Temperatures and Angles of Attack

by Fei Zhang, Zhenxia Liu, Zhengang Liu and Weinan Diao

Energies 2020, 13(4), 811; https://doi.org/10.3390/en13040811 - 13 Feb 2020

Cited by 16 | Viewed by 3700

Abstract

Particle deposition tests were conducted in a turbine deposition facility with an internally staged single-tube combustor to investigate the individual effect of the gas temperature and angle of attack. Sand particles were seeded to the combustor and deposited on a turbine blade with [...] Read more.

Particle deposition tests were conducted in a turbine deposition facility with an internally staged single-tube combustor to investigate the individual effect of the gas temperature and angle of attack. Sand particles were seeded to the combustor and deposited on a turbine blade with film-cooling holes at temperatures representative of modern engines. Fuel-air ratios were varied from 0.022 to 0.037 to achieve a gas temperature between 1272 and 1668 K. Results show that capture efficiency increased with increasing gas temperature. A dramatic increase in capture efficiency was noted when gas temperature exceeded the threshold. The deposition formed mostly downstream of the film-cooling holes on the pressure surface, while it concentrated on the suction surface at the trailing edge. Deposition tests at angles of attack between 10° and 40° presented changes in both deposition mass and distribution. The capture efficiency increased with the increase in the angle of attack, and simultaneously the growth rate slowed down. On the blade pressure surface, sand deposition was distributed mainly downstream of the film-cooling holes near the trailing edge in the case of the small angle of attack, while it concentrated on the region around the film-cooling holes near the leading edge, resulting in the partial blockage of holes, in the case of the large angle of attack. Full article

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

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15 pages, 5209 KiB

Open AccessArticle

CFD Analysis of Falling Film Hydrodynamics for a Lithium Bromide (LiBr) Solution over a Horizontal Tube

by Furqan Tahir, Abdelnasser Mabrouk and Muammer Koç

Energies 2020, 13(2), 307; https://doi.org/10.3390/en13020307 - 8 Jan 2020

Cited by 18 | Viewed by 3710

Abstract

Falling film evaporators are used in applications where high heat transfer coefficients are required for low liquid load and temperature difference. One such application is the lithium bromide (LiBr)-based absorber and generator. The concentration of the aqueous LiBr solution changes within the absorber [...] Read more.

Falling film evaporators are used in applications where high heat transfer coefficients are required for low liquid load and temperature difference. One such application is the lithium bromide (LiBr)-based absorber and generator. The concentration of the aqueous LiBr solution changes within the absorber and generator because of evaporation and vapor absorption. This causes the thermophysical properties to differ and affects the film distribution, heat, and mass transfer mechanisms. For thermal performance improvement of LiBr-based falling film evaporators, in-depth analysis at the micro level is required for film distribution and hydrodynamics. In this work, a 2D numerical model was constructed using the commercial CFD software Ansys Fluent v18.0. The influence of the liquid load corresponding to droplet and jet mode, and the concentration, on film hydrodynamics was examined. It was found that the jet mode was more stable at a higher concentration of 0.65 with ±0.5% variation compared to lower concentrations. The recirculation was stronger at a low concentration of 0.45 and existed until the angular position (θ) = 10°, whereas at 0.65 concentration it diminished after θ = 5°. The improved heat transfer is expected at lower concentrations due to lower film thickness and thermal resistance, more recirculation, and a higher velocity field. Full article

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

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17 pages, 3563 KiB

Open AccessArticle

Heat and Mass Transfer in Hydromagnetic Second-Grade Fluid Past a Porous Inclined Cylinder under the Effects of Thermal Dissipation, Diffusion and Radiative Heat Flux

by Sardar Bilal, Afraz Hussain Majeed, Rashid Mahmood, Ilyas Khan, Asiful H. Seikh and El-Sayed M. Sherif

Energies 2020, 13(1), 278; https://doi.org/10.3390/en13010278 - 6 Jan 2020

Cited by 20 | Viewed by 3181

Abstract

Current disquisition is presented to excogitate heat and mass transfer features of second grade fluid flow generated by an inclined cylinder under the appliance of diffusion, radiative heat flux, convective and Joule heating effects. Mathematical modelling containing constitutive expressions by obliging fundamental conservation [...] Read more.

Current disquisition is presented to excogitate heat and mass transfer features of second grade fluid flow generated by an inclined cylinder under the appliance of diffusion, radiative heat flux, convective and Joule heating effects. Mathematical modelling containing constitutive expressions by obliging fundamental conservation laws are constructed in the form of partial differential equations. Afterwards, transformations are implemented to convert the attained partial differential system into ordinary differential equations. An implicit finite difference method known as the Keller Box was chosen to extract the solution. The impact of the flow-controlling variables on velocity, temperature and concentration profiles are evaluated through graphical visualizations. Variations in skin friction, heat transfer and mass flux coefficients against primitive variables are manipulated through numerical data. It is inferred from the analysis that velocity of fluid increases for incrementing magnitude of viscoelastic parameter and curvature parameter whereas it reduces for Darcy parameter whereas skin friction coefficient decreases against curvature parameter. Assurance of present work is manifested by constructing comparison with previous published literature. Full article

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

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17 pages, 5521 KiB

Open AccessArticle

Effect of Viscous Dissipation in Heat Transfer of MHD Flow of Micropolar Fluid Partial Slip Conditions: Dual Solutions and Stability Analysis

by Liaquat Ali Lund, Zurni Omar, Ilyas Khan, Seifedine Kadry, Seungmin Rho, Irshad Ali Mari and Kottakkaran Sooppy Nisar

Energies 2019, 12(24), 4617; https://doi.org/10.3390/en12244617 - 5 Dec 2019

Cited by 31 | Viewed by 3735

Abstract

In this study, first-order slip effect with viscous dissipation and thermal radiation in micropolar fluid on a linear shrinking sheet is considered. Mathematical formulations of the governing equations of the problem have been derived by employing the fundamental laws of conservations which then [...] Read more.

In this study, first-order slip effect with viscous dissipation and thermal radiation in micropolar fluid on a linear shrinking sheet is considered. Mathematical formulations of the governing equations of the problem have been derived by employing the fundamental laws of conservations which then converted into highly non-linear coupled partial differential equations (PDEs) of boundary layers. Linear transformations are employed to change PDEs into non-dimensional ordinary differential equations (ODEs). The solutions of the resultant ODEs have been obtained by using of numerical method which is presented in the form of shootlib package in MAPLE 2018. The results reveal that there is more than one solution depending upon the values of suction and material parameters. The ranges of dual solutions are

S \geq S_{c i}

,

i = 0, 1, 2

and no solution is

S < S_{c i}

where

S_{c i}

is the critical values of

S

. Critical values have been obtained in the presence of dual solutions and the stability analysis is carried out to identify more stable solutions. Variations of numerous parameters have been also examined by giving tables and graphs. The numerical values have been obtained for the skin friction and local Nusselt number and presented graphically. Further, it is observed that the temperature and thickness of the thermal boundary layer increase when thermal radiation parameter is increased in both solutions. In addition, it is also noticed that the fluid velocity increases in the case of strong magnetic field effect in the second solution. Full article

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

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13 pages, 8606 KiB

Open AccessArticle

Experimental Study on Flat-Glass Heating and Edge-Sealing Using Multiple Microwave Sources

by Jae Kyung Kim, Young Shin Kim and Euy Sik Jeon

Energies 2019, 12(22), 4359; https://doi.org/10.3390/en12224359 - 15 Nov 2019

Cited by 1 | Viewed by 2789

Abstract

There has been a recent surge of interest in vacuum insulating glass (VIG) due to its excellent thermal insulation performance. Vacuum glazing is necessary for high-performance sealing solders and various applications in sealing technology. This paper describes experimental studies into heating and edge-sealing [...] Read more.

There has been a recent surge of interest in vacuum insulating glass (VIG) due to its excellent thermal insulation performance. Vacuum glazing is necessary for high-performance sealing solders and various applications in sealing technology. This paper describes experimental studies into heating and edge-sealing of flat glass using microwaves. Electric–thermal coupled analysis using ANSYS was employed and heating and edge-sealing experiments were conducted on flat glass. In order to ensure a uniform electric field distribution in the microwave chamber, the electric field and temperature distributions were analyzed according to waveguide patterns. In addition, the electric field and temperature distribution were analyzed with the inclusion of carbon susceptor plates. Based on the electric simulation results by waveguide pattern, a microwave heating chamber was fabricated, and a basic experiment was conducted on both heating and edge-sealing of the glass. The cross-section of the sealed glass confirmed that it was sealed without cracks or breakage. Full article

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

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22 pages, 5857 KiB

Open AccessArticle

Brownian Motion and Thermophoretic Diffusion Effects on Micropolar Type Nanofluid Flow with Soret and Dufour Impacts over an Inclined Sheet: Keller-Box Simulations

by Khuram Rafique, Muhammad Imran Anwar, Masnita Misiran, Ilyas Khan, Asiful H. Seikh, El-Sayed M. Sherif and Kottakkaran Sooppy Nisar

Energies 2019, 12(21), 4191; https://doi.org/10.3390/en12214191 - 2 Nov 2019

Cited by 28 | Viewed by 3175

Abstract

The principal objective of the current study is to analyze the Brownian motion and thermophoretic impacts on micropolar nanofluid flow over a nonlinear inclined stretching sheet taking into account the Soret and Dufour effects. The compatible similarity transformations are applied to obtain the [...] Read more.

The principal objective of the current study is to analyze the Brownian motion and thermophoretic impacts on micropolar nanofluid flow over a nonlinear inclined stretching sheet taking into account the Soret and Dufour effects. The compatible similarity transformations are applied to obtain the nonlinear ordinary differential equations from the partial differential equations. The numerical solution of the present study obtained via the Keller-Box technique. The physical quantities of interest are skin friction, Sherwood number, and heat exchange, along with several influences of material parameters on the momentum, temperature, and concentration are elucidated and clarified with diagrams. A decent settlement can be established in the current results with previously published work in the deficiency of incorporating effects. It is found that the growth of the inclination and nonlinear stretching factor decreases the velocity profile. Moreover, the growth of the Soret effect reduces the heat flux rate and wall shear stress. Full article

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

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Review

Jump to: Research

26 pages, 3893 KiB

Open AccessReview

Efficient Stabilization of Mono and Hybrid Nanofluids

by Sylwia Wciślik

Energies 2020, 13(15), 3793; https://doi.org/10.3390/en13153793 - 23 Jul 2020

Cited by 27 | Viewed by 2866

Abstract

Currently; the transfer of new technologies makes it necessary to also control heat transfer in different industrial processes—both in practical and research—applications. Not so long ago water and ethylene glycol were the most frequently used media in heat transfer. However, due to their [...] Read more.

Currently; the transfer of new technologies makes it necessary to also control heat transfer in different industrial processes—both in practical and research—applications. Not so long ago water and ethylene glycol were the most frequently used media in heat transfer. However, due to their relatively low thermal conductivity, they cannot provide the fast and effective heat transfer necessary in modern equipment. To improve the heat transfer rate different additives to the base liquid are sought, e.g., nanoadditives that create mono and hybrid nanofluids with very high thermal conductivity. The number of scientific studies and publications concerning hybrid nanofluids is growing, although they still represent a small percentage of all papers on nanofluids (in 2013 it was only 0.6%, and in 2017—ca. 3%). The most important point of this paper is to discuss different ways of stabilizing nanofluids, which seems to be one of the most challenging tasks in nanofluid treatment. Other future challenges concerning mono and hybrid nanofluids are also thoroughly discussed. Moreover, a quality assessment of nanofluid preparation is also presented. Thermal conductivity models are specified as well and new representative mono and hybrid nanofluids are proposed. Full article

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

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