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Zhang, Li y Xiaodong Chen. "“Gigantische” Energiegewinnung mittels Nanofluidik". Angewandte Chemie 125, n.º 30 (17 de junio de 2013): 7792–94. http://dx.doi.org/10.1002/ange.201302707.
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Han, W. S. y S. H. Rhi. "Thermal characteristics of grooved heat pipe with hybrid nanofluids". Thermal Science 15, n.º 1 (2011): 195–206. http://dx.doi.org/10.2298/tsci100209056h.
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In the present study, the specially designed grooved heat pipe charged with nanofluids was investigated in terms of various parameters such as heat transfer rate(50-300 W with 50 W interval), volume concentration(0.005%, 0.05%, 0.1%, and hybrid combinations), inclination(5?, 45?, 90?), cooling water temperature (1?C, 10?C, and 20?C), surface state, transient state and so on. Hybrid nanofluids with different volume concentration ratios with Ag-H2O and Al2O3-H2O were used as working fluids on a grooved heat pipe(GHP). Comparing with the pure water system, nanofluidic and hybrid nanofluidic system shows greater overall thermal resistance with increasing nano-particle concentration. Also hybrid nanofluids make the system deteriorate in terms of thermal resistance. The post nanofluid experimental data regarding GHP show that the heat transfer performance is similar to the results of nanofluid system. The thermal performance of a grooved heat pipe with nanofluids and hybrid nanofluids were varied with driving parameters but they led to worse system performance.
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Mohd Mokhtar, Nurul Afiqah, Hoe Guan Beh y Kean Chuan Lee. "The Potential Application of MnZn Ferrite Nanofluids for Wettability Alteration and Oil-Water Interfacial Tension Reduction". Crystals 9, n.º 12 (27 de noviembre de 2019): 626. http://dx.doi.org/10.3390/cryst9120626.
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Recently, a non-invasive method of injecting magnetic/dielectric nanofluids into the oil reservoir was used for oil recovery application. The use of magnetic nanofluids in Enhanced Oil Recovery (EOR) has been reported to improve oil recovery. It is believed that the magnetic properties of nanoparticles (NPs) have a direct influence on the viscosity and wettability of nanofluid, and on oil-water interfacial tension (IFT). Thus, Mn0.5Zn0.5Fe2O4 (MnZn) ferrites may be a good candidate to be used in nanofluids for wettability alteration and oil-water IFT reduction due to their excellent magnetic properties, such as a high initial permeability and low magnetic losses. Therefore, this work investigated the potential of MnZn ferrite NPs to alter viscosity, wettability, and oil-water IFT. MnZn Ferrite NPs have been synthesized by a sol-gel auto-combustion process. The effects of calcination temperature varying from 300 °C to 700 °C on the phase formation, microstructures such as surface morphology, and magnetic characterizations were studied. MnZn ferrite nanofluids were prepared using synthesized MnZn NPs that dispersed into brine along with sodium dodecylbenzenesulfonate (SDBS) as a dispersant, and their effects on the wettability and oil-water IFT were studied. X-ray diffraction (XRD) measurements revealed that MnZn ferrite calcined at 300 °C and 400 °C were single phase. The average crystallite size calculated through Scherrer’s equation differed from 32.0 to 87.96 nm. The results showed that the nanofluid with MnZn particles calcined at 300 °C is the best nanofluid in terms of IFT reduction and base nanofluid’s wettability alteration. Moreover, the overall results proved that nanofluid with MnZn ferrite NPs can alter the wettability of base nanofluid, oil-nanofluid IFT, and nanofluid viscosity. This study provides insights towards a better understanding of the potential application of MnZn Ferrite nanofluids to Wettability Alteration and IFT Reduction in Enhanced Oil Recovery.
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Shajahan, Mohamed Iqbal, Chockalingam Sundar Raj, Sambandan Arul y Palanisamy Rathnakumar. "Heat transfer intensification of Zirconia/water nanofluid". JOURNAL OF ADVANCES IN CHEMISTRY 13 (9 de enero de 2017): 01–08. http://dx.doi.org/10.24297/jac.v13i1.4530.
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This paper investigated convective heat transfer and friction factor of ZrO2/H2O nanofluid through a circular pipe under laminar flow condition with constant heat flux. Nanofluid is prepared for 0.5, 0.75 and 1% volume concentrations with yttrium oxide surfactant. Nanofluid’s thermal conductivity and viscosity is measured by KD2 Pro thermal analyser and Brookfield viscometer respectively. Results showed that the thermal conductivity and viscosity increased with increase in particle volume concentration. These nanofluids are experimented in a forced convection system, first heat transfer characteristics of DI (Deionised) water under laminar flow in a copper tube measured, then three nanofluids are carried out the tests, results revealed that the enhanced Nusselt numbers of 21.09,28.05 and 35.73% at the 0.5, 0.75 and 1% volume concentrations, There is no excess penalty in pumping power and results showed less variations in friction factor for nanofluids comparatively with the base fluid DIWater.
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Bobbo, Sergio, Bernardo Buonomo, Oronzio Manca, Silvio Vigna y Laura Fedele. "Analysis of the Parameters Required to Properly Define Nanofluids for Heat Transfer Applications". Fluids 6, n.º 2 (2 de febrero de 2021): 65. http://dx.doi.org/10.3390/fluids6020065.
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Nanofluids are obtained by dispersing nanoparticles and dispersant, when present, in a base fluid. Their properties, in particular their stability, however, are strictly related to several other parameters, knowledge of which is important to reproduce the nanofluids and correctly interpret their behavior. Due to this complexity, the results appear to be frequently unreliable, contradictory, not comparable and/or not repeatable, in particular for the scarcity of information on their preparation. Thus, it is essential to define what is the minimum amount of information necessary to fully describe the nanofluid, so as to ensure the possibility of reproduction of both their formulation and the measurements of their properties. In this paper, a literature analysis is performed to highlight what are the most important parameters necessary to describe the configuration of each nanofluid and their influence on the nanofluid’s properties. A case study is discussed, analyzing the information reported and the results obtained for the thermophysical properties of nanofluids formed by water and TiO2 nanoparticles. The aim is to highlight the differences in the amount of information given by the different authors and exemplify how results can be contradictory. A final discussion gives some suggestions on the minimum amount of information that should be given on a nanofluid to have the possibility to compare results obtained for similar nanofluids and to reproduce the same nanofluid in other laboratories.
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Suhaimi, Sabrina N., Abdul R. A. Rahman, Muhamad F. Md Din, Muhammad Zahir Hassan, Mohd Taufiq Ishak y Mohd Taufik bin Jusoh. "A Review on Oil-Based Nanofluid as Next-Generation Insulation for Transformer Application". Journal of Nanomaterials 2020 (29 de febrero de 2020): 1–17. http://dx.doi.org/10.1155/2020/2061343.
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Due to the increasing demand on developing good insulation, several researchers have performed experimental studies to prove the effectiveness and capabilities of transformer oil. This is done by suspending nanosized solid particles in the oil (nanofluid) for transformer applications. In brief, this paper presents a compilation of research studies which is divided into three parts. Part I discuss the preparation of the nanofluid which involves different types of nanomaterials, the optimal amount of concentrations, and applicable synthesisation methods for producing stably suspended nanofluids. In Part II, the nanofluid’s performances including the electrical breakdown voltages, impulse tests, and thermal and dielectric behaviour are reviewed in depth and compared. Part III emphasizes the limitation of nanofluids. Most researchers have agreed that appropriate concentrations of nanomaterials and the preparation method for nanofluids mainly affect the performance of nanofluids especially in terms of electrical properties. Meanwhile, types of nanomaterials and base oil also play a vital role in producing nanofluids as a better alternative transformer oil. However, among a few researchers, there are concerns regarding the issue of agglomeration and inconsistencies of findings that need to be resolved. Therefore, a few aspects must be taken into consideration to produce the next generation of high heat dissipation insulation.
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Sharifi, Amir Hossein, Iman Zahmatkesh, Fatemeh F. Bamoharram, Amir Hossein Shokouhi Tabrizi, Safieh Fazel Razavi y Sara Saneinezhad. "Experimental Measurement of Thermophysical Properties of Alumina- MWCNTs/Salt–Water Hybrid Nanofluids". Current Nanoscience 16, n.º 5 (5 de octubre de 2020): 734–47. http://dx.doi.org/10.2174/1573413716666191218122600.
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Background: Hybrid nanofluids are considered as an extension of conventional nanofluids which are prepared through suspending two or more nanoparticles in the base fluids. Previous studies on hybrid nanofluids have measured their thermal conductivity overlooking other thermophysical properties such as viscosity and electrical conductivity. Objective: An experimental investigation is undertaken to measure thermal conductivity, viscosity, and electrical conductivity of a hybrid nanofluid prepared through dispersing alumina nanoparticles and multiwall carbon nanotubes in saltwater. These properties are the main important factors that must be assessed before performance analysis for industrial applications. Methods: The experimental data were collected for different values of the nanoparticle volume fraction, temperature, salt concentration, and pH value. Attention was paid to explore the consequences of these parameters on the nanofluid’s properties and to find optimal conditions to achieve the highest value of the thermal conductivity and the lowest values of the electrical conductivity and the viscosity. Results: The results demonstrate that although the impacts of the pH value and the nanoparticle volume fraction on the nanofluid’s thermophysical properties are not monotonic, optimal conditions for each of the properties are reachable. It is found that the inclusion of the salt in the base fluid may not change the thermal conductivity noticeably. However, a considerable reduction in the viscosity and substantial elevation in the electrical conductivity occur with an increase in the salt concentration. Conclusion: With the addition of salt to a base fluid, the thermophysical properties of a nanofluid can be controlled.
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Abdulwahid, Ammar Fakhir. "Experimental Investigation on the Multi-metallic Cu-Zn NanofluidsHeat Transfer Enhancement and Pressure Losses". Journal of University of Babylon for Engineering Sciences 26, n.º 2 (1 de enero de 2018): 49–61. http://dx.doi.org/10.29196/jub.v26i2.381.
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Metallic nanofluidsare suspensions of metallic particles of nanometre size in base fluids. The combination of two kinds of metallic particles mixed at the same volume ratio is known as multi-metallic nanoparticles. These multiple metallic particles of nanometre size were suspended in deionized H2Ovia the use of ultrasonic vibratorsat varying volume fractions as well as variations in the ratios of metallic/metallic particles of nanometre size. In our study the dynamic viscosity, the nanofluid’s heat conductivities were determined for varying temperatures and volume fractions. The coefficient of thermal transmissionof the flowing nanofluid in the constant wall heat flux tube were determined experimentally in laminar condition. The results revealedhuge thermal transmission enhancement comparison to the base fluids. The pressure loses were illustrated for all nanofluids. The comparisons of the different metallic and multi-metallic types of the nanofluids were showed that Cu nanofluids have a greater coefficient ofthermal transmission compared with the Cu-Zn, Zn atequal volume fractions.
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Bakthavatchalam, Balaji, Khairul Habib, R. Saidur, Nagoor Basha Shaik y Turnad Lenggo Ginta. "Analysis of Multiwalled Carbon Nanotubes Porosimetry And Their Thermal Conductivity with Ionic Liquid-Based Solvents". Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 77, n.º 2 (14 de noviembre de 2020): 63–75. http://dx.doi.org/10.37934/arfmts.77.2.6375.
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The suspension of nanoparticles with common heat transfer fluids like Ethylene glycol and water yields nanofluid exhibits superior thermal properties than their host fluids. Ionic liquids have the potential to demonstrate remarkable thermophysical properties (especially thermal conductivity) that ordinary nanofluids cannot achieve. On the other hand, the quantity and structure of nanoparticles porosity affects the nanofluid’s thermal conductivity considerably. Various investigations have revealed the improved thermophysical characteristicts of Multiwalled Carbon nanotubes (MWCNTs) nanofluids containing common solvents or base fluids. However, only limited studies are available on the impact of thermal conductivity in Ionic liquid-based nanofluids (Ionanofluids) owing to their high cost and viscosity. Ultrasonication technique is employed in preparing the three different Ionanofluids containing 0.5 Wt.% via the two-step method to achieve a greater stability and thermal conductivity without utilizing surfactants. Experimental investigations are performed to boost the thermal conductivity of MWCNT/Propylene glycol nanofluid using 1,3-dimethyl imidazolium dimethyl phosphate [Mmim][DMP], 1-ethyl-3-methyl imidazolium octyl sulfate [Emim][OSO4] and 1-ethyl-3-methyl imidazolium diethyl phosphate [Emim][DEP] at a temperature ranging from 295 K to 355 K. The acquired results illustrated that the thermal conductivity of MWCNT Ionanofluids incorporated with [Mmim][DMP], [Emim][OSO4] and [Emim][DEP] increased by 37.5%, 5% and 2% respectively. This unique class of Ionanofluids shows incredible capacity for use in high temperature applications as conventional heat transfer fluids.
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Lei, Lei. "Testing algorithm for heat transfer performance of nanofluid-filled heat pipe based on neural network". Open Physics 18, n.º 1 (13 de noviembre de 2020): 751–60. http://dx.doi.org/10.1515/phys-2020-0170.
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AbstractTraditional testing algorithm based on pattern matching is impossible to effectively analyze the heat transfer performance of heat pipes filled with different concentrations of nanofluids, so the testing algorithm for heat transfer performance of a nanofluidic heat pipe based on neural network is proposed. Nanofluids are obtained by weighing, preparing, stirring, standing and shaking using dichotomy. Based on this, the heat transfer performance analysis model of the nanofluidic heat pipe based on artificial neural network is constructed, which is applied to the analysis of heat transfer performance of nanofluidic heat pipes to achieve accurate analysis. The experimental results show that the proposed algorithm can effectively analyze the heat transfer performance of heat pipes under different concentrations of nanofluids, and the heat transfer performance of heat pipes is best when the volume fraction of nanofluids is 0.15%.
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Safiei, W., M. M. Rahman, A. R. Yusoff y M. R. Radin. "Preparation, stability and wettability of nanofluid: A review". Journal of Mechanical Engineering and Sciences 14, n.º 3 (30 de septiembre de 2020): 7244–57. http://dx.doi.org/10.15282/jmes.14.3.2020.24.0569.
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Nanofluids possess many advantages over conventional working fluid especially in physical, thermal and rheology properties. Nowadays, nanofluids have been applied extensively in many engineering applications in enhancing the overall performance. Preparation and characterization of nanofluids are vital as the nanomaterials have significant effects on the dispersion and stability of nanofluids. On the other hand, there is a trend to employ more than a single nanoparticle for preparing nanofluid. The hybrid nanofluid receives wide attention due to its capability in improving the thermal-physical properties of single phase nanofluids. In this paper, the flow of formulating nanofluid from preparation method, characterization, wettability analysis and stability techniques are discussed comprehensively. Furthermore, the challenges for obtaining stable suspension and wettability behaviour of nanofluids are discussed as well. The main objective when preparing the nanofluids is to obtain a well-dispersed nanoparticle into the base fluid. Based on the literature review, the impact of surfactant on the stability and the correlation between nanofluids wettability and thermal-physical properties of nanofluids have great potential to discover. There are some aspects that can be considered to expand the knowledge of nanofluids such as the composition ratio of hybrid nanofluid with regards to achieving the best stability and wettability study of hybrid nanofluid with and without surfactant in the suspension. Therefore, a lot of research should be conducted in order to explore the behaviour of nanofluid and the effect of various surfactants in terms of stability as well as its thermal and viscosity effect on the engineering applications.
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Lee, Youngho, Hyomin Jeong y Yonmo Sung. "Thermal Absorption Performance Evaluation of Water-Based Nanofluids (CNTs, Cu, and Al2O3) for Solar Thermal Harvesting". Energies 14, n.º 16 (10 de agosto de 2021): 4875. http://dx.doi.org/10.3390/en14164875.
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For solar thermal harvesting, an experimental study was performed on the thermal absorption performance of water-based carbon nanotubes (CNTs), Cu, and Al2O3 nanofluids using a halogen lamp-based thermal radiation system. The effect of nanoparticle concentrations (0.01 wt.%, 0.1 wt.%, and 1 wt.%) on the nanofluid dispersion, stability, and thermal absorption characteristics was investigated, and a comparative analysis was performed for each type of nanofluid. All types of nanofluids increased the absorbance and electrical conductivity with increasing nanoparticle concentration, which contributed to improving the thermal absorption performance of nanofluids. The results showed that the thermal absorption performance was high in the order of carbon-based nanofluids (CNTs), metal-based nanofluids (Cu), and oxide-based nanofluids (Al2O3). In CNTs nanofluids, the thermal absorption performance expressed the time reduction rate, which was 12.8%, 16.3%, and 16.4% at 0.01 wt.%, 0.1 wt.%, and 1 wt.% test cases, respectively. Therefore, the 0.1 wt.%-CNTs nanofluid is more economical and appropriate. However, in Al2O3 nanofluids, the time reduction rate of the 1 wt.% nanofluid was significantly higher than that of the 0.01 wt.% and 0.1 wt.% nanofluids. In Cu nanofluids, unlike CNTs and Al2O3 nanofluids, the time reduction rate constantly increased as the nanoparticle concentration increased.
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Ahmed, Asmaa, Hasan Baig, Senthilarasu Sundaram y Tapas K. Mallick. "Use of Nanofluids in Solar PV/Thermal Systems". International Journal of Photoenergy 2019 (16 de junio de 2019): 1–17. http://dx.doi.org/10.1155/2019/8039129.
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The continuous growth in the energy demand across the globe due to the booming population, in addition to the harmful effects of the fossil fuels on the environment, has made it essential to harness renewable energy via different technologies and convert it to electricity. The potential of solar energy still remains untapped although it has several advantages particularly that it is a clean source to generate both electricity and heat. Concentrating sunlight is an effective way to generate higher throughput per unit area of the absorber material used. The heat extraction mechanisms and the fluids used in solar thermal systems are key towards unlocking higher efficiencies of solar thermal systems. Nanofluids can play a crucial role in the development of these technologies. This review is aimed at presenting the recent studies dealing with cooling the photovoltaic thermal (PVT), concentrated photovoltaic thermal (CPVT), and other solar systems using nanofluids. In addition, the article considers the definition of nanofluids, nanoparticle types, nanofluid preparation methods, and thermophysical properties of the most common nanoparticles and base fluids. Moreover, the major factors which affect the nanofluid’s thermal conductivity according to the literature will be reviewed.
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Subramaniyan, A. L., S. Lakshmi Priya, M. Kottaisamy y R. Ilangovan. "Analysis of UV Spectrum of TiO2 and Carbon Doped TiO2 Nanofluids". Journal of Advanced Physics 6, n.º 1 (1 de marzo de 2017): 26–29. http://dx.doi.org/10.1166/jap.2017.1285.
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Nanofluids are tailored or engineered suspensions of nanoparticles in a suitable base fluid. Nanofluids gained importance as next generation heat transfer fluids due to high thermal conductivity. The nanofluids are also proved as a potential candidate for direct absorption solar collectors (DASC). The present work investigates the optical absorption of TiO2 and carbon doped TiO2 (C-TiO2) nanofluids which is necessary for DASC and tunable optical filters. TiO2 and C-TiO2 are prepared by sol gel and characterized by XRD. Nanoparticles of TiO2 and C-TiO2 with weight fractions of 0.04 are dispersed in water and ethylene glycol to obtain TiO2 and C-TiO2 nanofluids. The nanofluids are investigated for their sedimentation time by gravity sedimentation method. Stability of TiO2 nanofluid is nine times more than C-TiO2 nanofluid with water as base fluid but C-TiO2 nanofluid are found to be efficient absorbers than TiO2 nanofluid in certain wavelength regime as shown by the UV results. We suggest that implementing a low volume fraction of C-TiO2 nanofluid can give high stability and good absorption which is a prerequest for DASC and tunable optical filters.
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Lin, Jianzhong, Mingzhou Yu, Martin Seipenbusch, Xiaoke Ku y Yu Feng. "Nanofluidics and Nanofluids". Journal of Nanotechnology 2019 (2 de mayo de 2019): 1–2. http://dx.doi.org/10.1155/2019/8767624.
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Zhao, Mingwei, Wenjiao Lv, Yuyang Li, Caili Dai, Hongda Zhou, Xuguang Song y Yining Wu. "A Study on Preparation and Stabilizing Mechanism of Hydrophobic Silica Nanofluids". Materials 11, n.º 8 (8 de agosto de 2018): 1385. http://dx.doi.org/10.3390/ma11081385.
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Nanofluids have increasingly drawn interest in recent years with their various applications in a number of fields. The method for the preparation of stable nanofluids is a key concern for extending the application of nanofluids. This study focuses on the effect of pH, dosage of surfactant (TX-100), and nanofluid concentration on the stability of a silica nanofluid. Particle size and zeta potential are two important factors to consider in evaluating the stability of the silica nanofluid. Results indicate that the stability of the silica nanofluid highly depends on pH, dosage of surfactant (TX-100), and nanofluid concentration. On the basis of these experiments, the best conditions for the preparation of a silica nanofluid are 0.1 wt. % for the concentration of silica nanoparticles and TX-100 and 10 for pH. A transparent and stable silica nanofluid can thus be obtained.
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Apmann, Kevin, Ryan Fulmer, Alberto Soto y Saeid Vafaei. "Thermal Conductivity and Viscosity: Review and Optimization of Effects of Nanoparticles". Materials 14, n.º 5 (8 de marzo de 2021): 1291. http://dx.doi.org/10.3390/ma14051291.
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This review was focused on expressing the effects of base liquid, temperature, possible surfactant, concentration and characteristics of nanoparticles including size, shape and material on thermal conductivity and viscosity of nanofluids. An increase in nanoparticle concentration can lead to an increase in thermal conductivity and viscosity and an increase in nanoparticle size, can increase or decrease thermal conductivity, while an increase in nanoparticle size decreases the viscosity of the nanofluid. The addition of surfactants at low concentrations can increase thermal conductivity, but at high concentrations, surfactants help to reduce thermal conductivity of the nanofluid. The addition of surfactants can decrease the nanofluid viscosity. Increasing the temperature, increased the thermal conductivity of a nanofluid, while decreasing its viscosity. Additionally, the effects of material of nanoparticles on the thermal conductivity and viscosity of a nanofluid need further investigations. In the case of hybrid nanofluids, it was observed that nanofluids with two different particles have the same trend of behavior as nanofluids with single particles in the regard to changes in temperature and concentration. Additionally, the level of accuracy of existing theoretical models for thermal conductivity and viscosity of nanofluids was examined.
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Jin, Xin, Guiping Lin y Haichuan Jin. "Experimental Investigations on Steam Generation in Nanofluids under Concentrated Solar Radiation". Energies 14, n.º 13 (2 de julio de 2021): 3985. http://dx.doi.org/10.3390/en14133985.
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Developing renewable energy, especially solar energy related, is of great importance for securing our future energy society. Steam generation in nanofluids based on solar radiation has been increasingly studied. It has been determined that the efficiency of steam generation is significantly enhanced when nanoparticles are seeded into the fluid owing to their unique radiative heat transfer performance. The nanoparticles trap solar energy inside the fluid and convert it into thermal form, which dramatically accelerates the steam generation process. In this study, we experimentally investigated different nanofluids that directly absorb solar energy to generate steam. Ag nanofluid, Au nanofluid and MWCNT nanofluid with different concentration have been carefully investigated. We analyzed the temperature increase and steam generation combined with the calculation of the efficiency factor from radiative heat transfer. The heating power and steam generation power of different nanofluids and the same nanofluid with different concentrations were compared. For Au nanofluid with concentration of 0.5 wt‰, the absorbed solar energy for heating the volume and generating steam is 6 and 40 times higher than those of pure water, respectively. We concluded that localized boiling generates steam rapidly in nanofluids based on the observation of three types of nanofluids. Furthermore, the heating power and steam generation power of different nanofluids increase with concentration. Moreover, the difference between the efficiency factors results in varied volume heating and steam generation efficiencies for different nanofluids despite identical concentrations.
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Chehrazi, Mohammad y Bahareh Moghadas. "Experimental study of single walled carbon nanotube/water nanofluid effect on a two-phase closed thermosyphon performance". Journal of the Serbian Chemical Society, n.º 00 (2020): 70. http://dx.doi.org/10.2298/jsc200628070c.
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Thermosyphons are one of the most efficient heat exchanger apparatus that are used extensively in different industries. One of the most common uses of this device is energy recovery, which is essential due to the energy crisis. Several parameters, such as geometric dimensions, type of working fluid, type of thermosyphon's body, affect a thermosyphon efficiency. In this experiment, the effect of type and concentration of single-walled carbon nanotube nanofluid (SWCNT / Water) on heat transfer efficiency in a two-phase closed thermosyphon (TPCT) has been investigated. For this purpose, a system with a two-phase closed thermosyphon was initially constructed. Then SWCNT/water nanofluids at 0.2, 0.5 and 1 % weight concentration were used as a working fluid in the thermosyphon system. The results of current experiments showed that the addition of nanofluid with any weight concentration and the increase of input power increases the performance of the system. Also, the heat resistance of TPCT reduced when the level of SWCNT and input power increased. So, for prepared nanofluid's samples, minimum thermal resistance obtained at 1 wt.% SWCNT and 120 W. Also, the Nusselt number increased with raising the input power and decreased with increasing the concentration. In all experiments, all prepared nanofluid samples have significantly better thermal performance in comparison with pure water.
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Le, Thu, Hisashi Shimizu y Kyojiro Morikawa. "Advances in Label-Free Detections for Nanofluidic Analytical Devices". Micromachines 11, n.º 10 (23 de septiembre de 2020): 885. http://dx.doi.org/10.3390/mi11100885.
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Nanofluidics, a discipline of science and engineering of fluids confined to structures at the 1–1000 nm scale, has experienced significant growth over the past decade. Nanofluidics have offered fascinating platforms for chemical and biological analyses by exploiting the unique characteristics of liquids and molecules confined in nanospaces; however, the difficulty to detect molecules in extremely small spaces hampers the practical applications of nanofluidic devices. Laser-induced fluorescence microscopy with single-molecule sensitivity has been so far a major detection method in nanofluidics, but issues arising from labeling and photobleaching limit its application. Recently, numerous label-free detection methods have been developed to identify and determine the number of molecules, as well as provide chemical, conformational, and kinetic information of molecules. This review focuses on label-free detection techniques designed for nanofluidics; these techniques are divided into two groups: optical and electrical/electrochemical detection methods. In this review, we discuss on the developed nanofluidic device architectures, elucidate the mechanisms by which the utilization of nanofluidics in manipulating molecules and controlling light–matter interactions enhances the capabilities of biological and chemical analyses, and highlight new research directions in the field of detections in nanofluidics.
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Das, Anshuman, Saroj Kumar Patel y Sudhansu Ranjan Das. "Performance comparison of vegetable oil based nanofluids towards machinability improvement in hard turning of HSLA steel using minimum quantity lubrication". Mechanics & Industry 20, n.º 5 (2019): 506. http://dx.doi.org/10.1051/meca/2019036.
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The search of finding best vegetable oil based nanofluid from a set of three nanoparticle enriched cutting fluids for machining is core objective of the work. Extensive research has been done to replace conventional cutting fluids by nanofluids, but abundant analysis for vegetable oil based nanofluids is accomplished in this work which was not seen earlier. Also, the study investigated the cutting performance and comparative assessment towards machinability improvement during hard turning of high-strength-low-alloy (HSLA) AISI 4340 steel using four different compositions of nanofluids by minimum quantity lubrication (MQL) technique. Cutting are investigated and analyzed through this article during hard turning using minimum quantity lubrication (MQL). Cutting force, tool wear (flank and crater), surface integrity (surface roughness, residual stress, microhardness, and surface morphology), and chip morphology are considered as technological performance characteristics to evaluate the machinability of hardened AISI 4340 steel. Additionally, the effect of various fluid properties like thermal conductivity, viscosity, surface tension and contact angle were examined for all nanofluids. Three set of nanofluid samples were prepared using Al2O3, CuO and Fe2O3 with rice bran oil and their various properties are analysed at 0.1% concentration. On comparison among these three nanofluids used, CuO nanofluid exhibited superior behavior followed by Fe2O3 nanofluids while Al2O3 nanofluid was last in the row.
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Esfe, Mohammad Hemmat, Somchai Wongwises, Saeed Esfandeh y Ali Alirezaie. "Development of a New Correlation and Post Processing of Heat Transfer Coefficient and Pressure Drop of Functionalized COOH MWCNT Nanofluid by Artificial Neural Network". Current Nanoscience 14, n.º 2 (1 de febrero de 2018): 104–12. http://dx.doi.org/10.2174/1573413713666170913122649.
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Background: Because of nanofluids applications in improvement of heat transfer rate in heating and cooling systems, many researchers have conducted various experiments to investigate nanofluid's characteristics more accurate. Thermal conductivity, electrical conductivity, and heat transfer are examples of these characteristics. Method: This paper presents a modeling and validation method of heat transfer coefficient and pressure drop of functionalized aqueous COOH MWCNT nanofluids by artificial neural network and proposing a new correlation. In the current experiment, the ANN input data has included the volume fraction and the Reynolds number and heat transfer coefficient and pressure drop considered as ANN outputs. Results: Comparing modeling results with proposed correlation proves that the empirical correlation is not able to accurately predict the experimental output results, and this is performed with a lot more accuracy by the neural network. The regression coefficient of neural network outputs was equal to 99.94% and 99.84%, respectively, for the data of relative heat transfer coefficient and relative pressure drop. The regression coefficient for the provided equation was also equal to 97.02% and 77.90%, respectively, for these two parameters, which indicates this equation operates much less precisely than the neural network. Conclusion: So, relative heat transfer coefficient and pressure drop of nanofluids can also be modeled and estimated by the neural network, in addition to the modeling of nanofluid’s thermal conductivity and viscosity executed by different scholars via neural networks.
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Zakaria, Irnie Azlin, Zeno Michael, Suhadiyana Hanapi y Wan Ahmad Najmi Wan Mohamed. "Thermal and Electrical Experimental Characterization of Ethylene Glycol and Water Mixture Coolants for a 400 W Proton Exchange Membrane Fuel". Applied Mechanics and Materials 660 (octubre de 2014): 391–96. http://dx.doi.org/10.4028/www.scientific.net/amm.660.391.
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Nanofluid is an emerging technology in heat transfer study. The effect of nanofluids as a cooling medium in Proton Exchange Membrane Fuel Cell (PEMFC) is studied. Nanofluids with 0.1% and 0.5% of Al2O3 dispersed in base fluid of 50:50 mixture of Ethylene Glycol and water were analyzed experimentally. A 400 W liquid cooled PEMFC was used to verify the findings. The result showed that insignificant improvement in performance of PEMFC with nanofluids, perhaps due to the lower wattage of PEMFC used. However, the thermal performance is improved through the heat transfer rate increment of 68.5 % and 46 % for both 0.5 % of Al2O3 nanofluid and 0.1 % of Al2O3 nanofluid respectively.
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Nazar, Reinaldy. "KARAKTERISTIK PERPINDAHAN PANAS KONVEKSI ALAMIAH ALIRAN NANOFLUIDA AL2O3-AIR DI DALAM PIPA ANULUS VERTIKAL". JURNAL TEKNOLOGI REAKTOR NUKLIR TRI DASA MEGA 18, n.º 1 (11 de marzo de 2016): 21. http://dx.doi.org/10.17146/tdm.2016.18.1.2328.
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ABSTRAK KARAKTERISTIK PERPINDAHAN PANAS KONVEKSI ALAMIAH ALIRAN NANOFLUIDA AL2O3-AIR DI DALAM PIPA ANULUS VERTIKAL. Hasil beberapa penelitian menunjukan bahwa nanofluida memiliki karakteristik termal yang lebih baik dibandingkan dengan fluida konvensional (air). Berkaitan dengan hal tersebut, saat ini sedang berkembang pemikiran untuk menggunakan nanofluida sebagai fluida perpindahan panas alternatif pada sistem pedingin reaktor. Sementara itu, konveksi alamiah di dalam pipa anulus vertikal merupakan salah satu mekanisme perpindahan panas yang penting dan banyak ditemukan pada reaktor riset TRIGA, reaktor daya generasi baru dan alat konversi energi lainnya. Namun disisi lain karakteristik perpindahan panas nanofluida di dalam pipa anulus vertikal belum banyak diketahui. Oleh karena itu penting dilakukan secara berkesinambungan penelitian-penelitian untuk menganalisis perpindahan panas nanofluida di dalam pipa anulus vertikal. Pada penelitian telah dilakukan analisis numerik menggunakan program computer CFD (computational of fluids dynamic) terhadap karakteristik perpindahan panas konveksi alamiah aliran nanofluida Al2O3-air konsentrasi 2% volume di dalam pipa anulus vertikal. Hasil kajian ini menunjukkan terjadi peningkatan kinerja perpindahan panas (bilangan Nuselt- NU) sebesar 20,5% - 35%. Pada moda konveksi alamiah dengan bilangan 2,4708e+09 £ Ra £ 1,9554e+13 diperoleh korelasi empirik untuk air adalah dan korelasi empirik untuk nanofluida Al2O3-air adalah Kata kunci: Nanofluida Al2O3-air, konveksi alamiah, pipa anulus vertikal ABSTRACT THE CHARACTERISTICS OF NATURAL CONVECTIVE HEAT TRANSFER OF AL2O3–WATER NANOFLUIDS FLOW IN A VERTICAL ANNULUS PIPE. Results of several research have shown that nanofluids have better thermal characteristics compared to conventional fluid (water). In this regard, currently developing ideas for using nanofluids as an alternative heat transfer fluid in the reactor coolant system. Meanwhile the natural convection in a vertical annulus pipe is one of the important mechanisms of heat transfer and is found at the TRIGA research reactor, the new generation nuclear power plants and other energy conversion devices. On the other hand the heat transfer characteristics of nanofluids in a vertical annulus pipe has not been known. Therefore, it is important to do research continuously to analyze the heat transfer nanofluids in a vertical annulus pipe. In the research has been carried out numerical analysis by using computer code of CFD (computational of fluids dynamic) on natural convection heat transfer characteristics of nanofluids flow of Al2O3-water 2% volume in the vertical annulus pipe. The results showed an increase in heat transfer performance (Nusselt numbers - NU) by 20.5% - 35%. In natural convection mode with Rayleigh numbers 2.4708e+09 £ Ra £ 1.9554e+13 obtained empirical correlations for water is and empirical correlations for Al2O3-water nanofluids is . Keywords: Al2O3-water nanofluids, the natural convection, the vertical annulus pipe
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Subramaniyan, A. L., Sukumaran Lakshmi Priya, M. Kottaisamy y R. Ilangovan. "Investigations on the absorption spectrum of TiO2 nanofluid". Journal of Energy in Southern Africa 25, n.º 4 (19 de diciembre de 2014): 123–27. http://dx.doi.org/10.17159/2413-3051/2014/v25i4a2245.
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Nanofluids are tailored nano- colloidal suspensions of nanoparticles in a suitable base fluid. This present work investigates the absorption spectrum in TiO2-water nanofluids to identify the potential application of nanofluids in Direct Absorption Solar Collectors (DASC). Nanoparticles of Titanium dioxide (TiO2) are prepared by sol gel and characterized by X Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). TiO2-water nanofluids with weight fraction of 0.1% are prepared by a two-step process with sonication. The prepared nanofluids are investigated for their stability by a gravity sedimentation method and for their optical property by UV-Vis spectroscopy. Stability of nanofluid is essential for the applications of nanofluid in DASC. TiO2 nanoparticles with a crystallite size of 43nm are obtained .The SEM image reveals the agglomerated state of TiO2 nanoparticles and the stability of TiO2 nanofluid is reported as 9-10days. UV results indicate the decrease in absorption from 440-500nm, complete absorption from 500-700nm and increase in absorption from 700-900nm.TiO2 nanofluids are recommended as potential candidates for DASC in UV and IR regions.
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Abdul, Kaggwa, James K. Carson, Martin Atkin y Michael Walmsley. "Physical Properties and Rheological Characteristics of Activated Carbon Nanofluids with Varying Filler Fractions and Surfactants". Applied Mechanics and Materials 884 (agosto de 2018): 58–65. http://dx.doi.org/10.4028/www.scientific.net/amm.884.58.
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For the past fifteen years, there has been considerable interest in the use of nanofluids in various fields mainly in heat transfer applications. This paper investigated thermophysical properties of activated carbon nanofluids using hexane, water and ethylene glycol (EG) as base fluids. Experimental and qualitative observational tests were conducted to study the viscosity, specific heat capacity and stability of the nanofluids using arabinogalactan (ARB), sodium lauryl sulphate (SDS) and TritonX-114 as stabilising agents. The results revealed that the addition of ARB to activated carbon-water (C/H2O) nanofluids yielded nanofluid stability for up to 39 days. However, ARB decreased the heat capacity of C/H2O nanofluid. C/H2O nanofluid viscosity decreased with an increase in shear rate. On the other hand, results revealed that C/C6H14 viscosity increased with the increase in shear rate specifically for high shear rate values. C/H2O heat capacity was enhanced by 6.1% compared to C/EG that decreased by 6.3%. Keywords: Nanofluids; Viscosity; Specific heat capacity; Surfactant; Stability.
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Abbasi, Fahad Munir, Tasawar Hayat y Bashir Ahmad. "Impact of Magnetic Field on Mixed Convective Peristaltic Flow of Water Based Nanofluids with Joule Heating". Zeitschrift für Naturforschung A 70, n.º 2 (1 de febrero de 2015): 125–32. http://dx.doi.org/10.1515/zna-2014-0213.
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AbstractPeristaltic transport of water-based nanofluids in the presence of applied magnetic field is studied. Two different types of nanofluids (silver-water and copper-water nanofluids) are used in the analysis. Effects of mixed convection, viscous dissipation, Joule heating, and heat generation/absorption are considered. Long wavelength and low Reynolds number approximations are used in the mathematical modelling. Numerical solutions are obtained for the velocity, pressure gradient, pressure rise per wavelength, temperature, and heat transfer rate at the wall. Physical quantities of interest are studied through graphs and tables. Comparison of water, silver-water, and copper-water nanofluid is presented. Results show that velocity and temperature of ordinary water are larger than those of nanofluids. Maximum velocity, temperature, and heat transfer rate at the wall of silver-water nanofluid is relatively higher than the copper-water nanofluid.
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Fang, F., J. Futter, E. Hutchinson, J. Leveneur y J. Kennedy. "Enhanced thermal conductivity of nanofluids made of metal oxide nanostructures synthesized by arc discharge method". International Journal of Modern Physics B 34, n.º 01n03 (26 de noviembre de 2019): 2040001. http://dx.doi.org/10.1142/s0217979220400019.
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We have modified the mineral oil used in transformers by dispersing 1-wt.% metal oxide nanostructures (commercially available [Formula: see text], ZnO and [Formula: see text] spherical structures and ZnO rod-shaped structures synthesized by arc discharge) into the oil through ball milling without surfactant. A good dispersion that lasted for at least 24 h was obtained for all nanofluids, however sedimentation was discovered by 72 h after ball milling. All nanofluids with different nanostructures exhibited enhanced thermal conductivity compared with the raw transformer oil. The nanofluid with ZnO nanoparticles showed better thermal conductivity than the nanofluids with [Formula: see text] and [Formula: see text] nanoparticles. The nanofluid with elongated ZnO nanoparticles (nanorods) synthesized by arc discharge showed the best thermal conduction among all the nanofluids studied in this work over the whole measurement period. The enhanced thermal conductivity of the nanofluid with elongated nanostructure is considered to be due to the rod-shaped nanostructure creating heat flow paths with lower thermal resistance. The arc discharge provides a cost-effective and scalable method to fabricate metal oxide nanostructures for potential nanofluid applications.
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Bhattad, Atul, Jahar Sarkar y Pradyumna Ghosh. "Energy-Economic Analysis of Plate Evaporator using Brine-based Hybrid Nanofluids as Secondary Refrigerant". International Journal of Air-Conditioning and Refrigeration 26, n.º 01 (marzo de 2018): 1850003. http://dx.doi.org/10.1142/s2010132518500037.
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Energy and economic analyses of corrugated plate evaporator have been performed in this study by using brine-based hybrid nanofluids as secondary refrigerant for low temperature applications (milk chilling, ice making and fish freezing). Various hybrid nanofluids containing alumina with different nanoparticles (copper, silver and multi walled carbon nanotube) dispersed in ethylene glycol/water, propylene glycol/water, calcium chloride/water and potassium acetate/water brines have been considered. A comparison has been made based on overall heat transfer coefficient, evaporator size (heat transfer area), pump work, COP, annual cost and payback period. The maximum reduction in heat transfer area has been observed for PG brine-based alumina–silver hybrid nanofluid. Whereas, the maximum reduction in pump work and augmentation in COP have been obtained for PG brine-based alumina–MWCNT hybrid nanofluid. EG brine-based Alumina–Cu hybrid nanofluid yields minimum annual cost. Most of the nanofluids (except PG brine-based Al2O3–Ag nanofluid) seem to be not beneficial for practical use due to comparatively long payback period; however, that can be significantly reduced in future by decreasing nanoparticle cost and increasing nanofluid stability. The present study reveals that the brine-based hybrid nanofluids may be the potential option as next generation secondary refrigerants for low temperature applications.
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Martínez-Merino, Paloma, Rodrigo Alcántara, Teresa Aguilar, Juan Jesús Gallardo, Iván Carrillo-Berdugo, Roberto Gómez-Villarejo, Mabel Rodríguez-Fernández y Javier Navas. "Stability and Thermal Properties Study of Metal Chalcogenide-Based Nanofluids for Concentrating Solar Power". Energies 12, n.º 24 (6 de diciembre de 2019): 4632. http://dx.doi.org/10.3390/en12244632.
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Nanofluids are colloidal suspensions of nanomaterials in a fluid which exhibit enhanced thermophysical properties compared to conventional fluids. The addition of nanomaterials to a fluid can increase the thermal conductivity, isobaric-specific heat, diffusivity, and the convective heat transfer coefficient of the original fluid. For this reason, nanofluids have been studied over the last decades in many fields such as biomedicine, industrial cooling, nuclear reactors, and also in solar thermal applications. In this paper, we report the preparation and characterization of nanofluids based on one-dimensional MoS2 and WS2 nanosheets to improve the thermal properties of the heat transfer fluid currently used in concentrating solar plants (CSP). A comparative study of both types of nanofluids was performed for explaining the influence of nanostructure morphologies on nanofluid stability and thermal properties. The nanofluids prepared in this work present a high stability over time and thermal conductivity enhancements of up to 46% for MoS2-based nanofluid and up to 35% for WS2-based nanofluid. These results led to an increase in the efficiency of the solar collectors of 21.3% and 16.8% when the nanofluids based on MoS2 nanowires or WS2 nanosheets were used instead of the typical thermal oil.
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Giwa, Solomon O., Mohsen Sharifpur, Mohammad H. Ahmadi, S. M. Sohel Murshed y Josua P. Meyer. "Experimental Investigation on Stability, Viscosity, and Electrical Conductivity of Water-Based Hybrid Nanofluid of MWCNT-Fe2O3". Nanomaterials 11, n.º 1 (8 de enero de 2021): 136. http://dx.doi.org/10.3390/nano11010136.
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The superiority of nanofluid over conventional working fluid has been well researched and proven. Newest on the horizon is the hybrid nanofluid currently being examined due to its improved thermal properties. This paper examined the viscosity and electrical conductivity of deionized water (DIW)-based multiwalled carbon nanotube (MWCNT)-Fe2O3 (20:80) nanofluids at temperatures and volume concentrations ranging from 15 °C to 55 °C and 0.1–1.5%, respectively. The morphology of the suspended hybrid nanofluids was characterized using a transmission electron microscope, and the stability was monitored using visual inspection, UV–visible, and viscosity-checking techniques. With the aid of a viscometer and electrical conductivity meter, the viscosity and electrical conductivity of the hybrid nanofluids were determined, respectively. The MWCNT-Fe2O3/DIW nanofluids were found to be stable and well suspended. Both the electrical conductivity and viscosity of the hybrid nanofluids were augmented with respect to increasing volume concentration. In contrast, the temperature rise was noticed to diminish the viscosity of the nanofluids, but it enhanced electrical conductivity. Maximum increments of 35.7% and 1676.4% were obtained for the viscosity and electrical conductivity of the hybrid nanofluids, respectively, when compared with the base fluid. The obtained results were observed to agree with previous studies in the literature. After fitting the obtained experimental data, high accuracy was achieved with the formulated correlations for estimating the electrical conductivity and viscosity. The examined hybrid nanofluid was noticed to possess a lesser viscosity in comparison with the mono-particle nanofluid of Fe2O3/water, which was good for engineering applications as the pumping power would be reduced.
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Giwa, Solomon O., Mohsen Sharifpur, Mohammad H. Ahmadi, S. M. Sohel Murshed y Josua P. Meyer. "Experimental Investigation on Stability, Viscosity, and Electrical Conductivity of Water-Based Hybrid Nanofluid of MWCNT-Fe2O3". Nanomaterials 11, n.º 1 (8 de enero de 2021): 136. http://dx.doi.org/10.3390/nano11010136.
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The superiority of nanofluid over conventional working fluid has been well researched and proven. Newest on the horizon is the hybrid nanofluid currently being examined due to its improved thermal properties. This paper examined the viscosity and electrical conductivity of deionized water (DIW)-based multiwalled carbon nanotube (MWCNT)-Fe2O3 (20:80) nanofluids at temperatures and volume concentrations ranging from 15 °C to 55 °C and 0.1–1.5%, respectively. The morphology of the suspended hybrid nanofluids was characterized using a transmission electron microscope, and the stability was monitored using visual inspection, UV–visible, and viscosity-checking techniques. With the aid of a viscometer and electrical conductivity meter, the viscosity and electrical conductivity of the hybrid nanofluids were determined, respectively. The MWCNT-Fe2O3/DIW nanofluids were found to be stable and well suspended. Both the electrical conductivity and viscosity of the hybrid nanofluids were augmented with respect to increasing volume concentration. In contrast, the temperature rise was noticed to diminish the viscosity of the nanofluids, but it enhanced electrical conductivity. Maximum increments of 35.7% and 1676.4% were obtained for the viscosity and electrical conductivity of the hybrid nanofluids, respectively, when compared with the base fluid. The obtained results were observed to agree with previous studies in the literature. After fitting the obtained experimental data, high accuracy was achieved with the formulated correlations for estimating the electrical conductivity and viscosity. The examined hybrid nanofluid was noticed to possess a lesser viscosity in comparison with the mono-particle nanofluid of Fe2O3/water, which was good for engineering applications as the pumping power would be reduced.
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Nah, Kim Soon y Yew Mun Hung. "Characterization of Thermal Conductivity and Viscosity of Nanofluids with Aqueous Base Fluids". Advanced Materials Research 1101 (abril de 2015): 344–47. http://dx.doi.org/10.4028/www.scientific.net/amr.1101.344.
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Two different nanofluids (SiO2 – EG/DW and SiO2 – DW) with various volume fractions are prepared by dispersing SiO2 nanoparticles (< 20 nm) into two different types of base fluid: distilled water and ethylene glycol/distilled water mixture. The effective thermal conductivity and viscosity of nanofluids are characterized and compared over a temperature range of 25oC - 50oC. It is found that the effective thermal conductivity and viscosity of nanofluid are influenced by the nanoparticle volume fraction and the operating temperature. The thermal conductivity of the SiO2 nanofluids with different volume concentrations increases as temperature increases while the viscosity decreases with the increasing temperature. The base fluid alters the characteristics of both the thermal conductivity and viscosity of nanofluid. Over the same range of operating temperature, the effective thermal conductivity and viscosity of SiO2 – EG/DW nanofluid manifest stronger dependency on the nanoparticle concentration compared to those of water-base-fluid nanofluid.
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Kravets, V. Yu y D. I. Hurov. "Heat transfer characteristics of miniature two-phase thermosyphons with nanofluids". Технология и конструирование в электронной аппаратуре, n.º 3-4 (2020): 42–46. http://dx.doi.org/10.15222/tkea2020.3-4.42.
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This paper presents and analyzes experimental data on the total thermal resistances of two-phase miniature thermosyphons with nanofluids; the geometric parameters of the thermosyphons for all experimental samples are identical: total length 700 mm, internal diameter 5 mm. The following nanofluids used as heat carriers are: aqueous nanofluid based on carbon nanotubes, aqueous nanofluid based on synthetic diamond, and aqueous nanofluid based on amorphous carbon. Much attention is also paid to the influence of the filling ratio on the heat transfer characteristics of the thermosyphons. The influence of filling ratio and types of nanofluid on the performance of miniature closed two-phase thermosyphons is demonstrated.
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Harun, Muhammad Arif, Nor Azwadi Che Sidik y Mohamed Adham Mohamad Rohaizan. "A Review on Stability and Heat Transfer Performance of Nanofluid Using Surfactants". Journal of Advanced Research in Materials Science 75, n.º 1 (24 de diciembre de 2020): 1–9. http://dx.doi.org/10.37934/arms.75.1.19.
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Nanofluid had been widely used in heat transfer applications due to its better thermophysical properties. However, nanofluid had a problem in the stability of nanoparticles suspended in the based fluid. Several ways had been done to increase the stability of nanofluids including using surfactants. The purpose of this review is to uncover the stability and heat transfer performance of nanofluid using surfactants. A systematic review was used to collect the related articles for this review. This review shows the mechanism of two types of surfactants that had been used which are ionic and non-ionic. Furthermore, the stability of nanofluid is very important to enhance the thermal performance of nanofluid. The recommendations are highlighted to study the optimum amount of surfactant for respective nanofluids.
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Subramaniyan, A. L., M. Kotaisamy y R. Ilangovan. "Optical Sensing of TiO2 Nanofluid for Self Stability". Materials Science Forum 807 (noviembre de 2014): 143–49. http://dx.doi.org/10.4028/www.scientific.net/msf.807.143.
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Nanofluids are colloidal suspensions of nanoparticles in a base fluid which are mainly used as modern heat transfer fluids. The applications of nanofluids include electronic cooling systems, direct absorption solar collectors, magnetic smart fluids and in biomedical treatments. The success of these applications depends on stability of nanofluid. In the present work TiO2nanofluids have been synthesized by two step technique .The nanoparticle of TiO2are prepared by sol gel and characterized by XRD, SEM and UV. The sedimentation of prepared nanofluid is observed by the gravity sedimentation method and transmitted intensity is recorded by a photo detector. A profile between the transmitted intensity and distance of nanofluid from laser source is obtained which shows the potential application of nanofluid as optical sensors for detecting stability of nanofluid.
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Kishore, N., H. N. Vidyasagar y D. K. Ramesha. "Preparation and Characterization of Transformer Oil Based Nano Fluids". Applied Mechanics and Materials 895 (noviembre de 2019): 218–23. http://dx.doi.org/10.4028/www.scientific.net/amm.895.218.
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This paper is concerned with the preparation and characterization of transformer oil based nanofluids with the suspensions of Al2O3 and CuO nanoparticles . As a part of experimental study the transformer oil based nanofluids for heat exchangers in transformer cooling application, preparation and characterization has been performed. The preparation of nanofluids is the first key step in experimental studies with nanofluids. One step technique and two step technique are generally used for preparing the nanofluids. This work deals with the preparation methods of (Al2O3-Transformer oil ,CuO-Transformer oil) and characterizing the transformer oil based nanofluids of different volume concentrations (0.05%, 0.1%, 0. 5%, 1.0% and 1.5%).From the results it is revealed that increasing the volume concentration resulted in increase in thermal conductivity, viscosity of the nanofluid and decrease in density and specific heat of nanofluid.
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Sharif, Shabir, Sadia Sagar Iqbal, Farzana Siddique, Alvina Rafiq Butt, Tasawer Shahzad Ahmad y Arshad Bashir. "Synthesis, Spectral and Thermal Characteristics of Silica/PVP Nanofluids". Key Engineering Materials 875 (febrero de 2021): 168–76. http://dx.doi.org/10.4028/www.scientific.net/kem.875.168.
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Nanofluid is well known as smart fluid which has high ability to recover oil. Therefore, it gains more significant effect in oil and gas industry. With the low concentration of nanofiller in nanofluid is used to enhance the numerous characteristics for oil recovery applications. Then, the main feature is the size of reinforcing agent and properties along matrix medium. Nano dimensional particles suspension in polymeric matrix have major advantages are stable sedimentation, optical, mechanical, electrical, and rheological properties that can be affected during the synthesis of nanofluids. Therefore nanoparticles/polymeric nanofluid have exceptional characteristics over the conventional fluid. Mixed nanoparticles/polymeric nanofluid in the presence of surfactant have effective interfacial tension and wettability which is evident for the development of nanofluids for oil recovery. In this context, the designed experimental study of silica/PVP nanofluids is synthesized via two step methods and characterized by SEM, TG/DTA, contact angle measurement, centrifugal effect and sedimentation test intended for Enhanced Oil Recovery (EOR) system.
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Ali, Abdallah Yousef Mohammed, Ahmed Hassan El-Shazly, Marwa Farouk El-Kady, Hesham Ibrahim Elqady, Kholoud Madih y Essam Hares. "Experimental and Theoretical Studies of Thermophysical Properties of MgO-Water Nanofluid". Materials Science Forum 1008 (agosto de 2020): 47–52. http://dx.doi.org/10.4028/www.scientific.net/msf.1008.47.
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Magnesium oxide (MgO) nanoparticles were synthesized using the sol-gel technique then characterized. Cetyl Trimethyl Ammonium Bromide (CTAB) surfactant was added to reduce Van der Waal forces among MgO nanoparticles and distilled water forming a stable nanofluid using two-step method with aid of ultrasound sonication. Pure distilled water and nanofluids with different volume fractions of 0.25, 0.5, 0.75, and 1% are used as working fluids. Thermophysical properties of prepared nanofluids were measured experimentally and determined theoretically. Effect of solid volume fraction on the thermophysical properties; including thermal conductivity, heat capacity, viscosity, and density of MgO-water nanofluids are discussed. Moreover, experimental results have been compared with the suitable correlations for MgO-water nanofluid. The findings show that thermal conductivity, viscosity, and density of nanofluid increases with increasing solid volume fraction.
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Gugulothu, Srinu y Vamsi Krishna Pasam. "Performance Evaluation of CNT/MoS2 Hybrid Nanofluid in Machining for Surface Roughness". International Journal of Automotive and Mechanical Engineering 16, n.º 4 (30 de diciembre de 2019): 7413–29. http://dx.doi.org/10.15282/ijame.16.4.2019.15.0549.
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Present work is motivated by the high thermal conductivity of MWCNT and low coefficient of friction due to MoS2 nanoparticles which can significantly improve the heat transfer and lubrication performance of hybrid nanofluids than nanofluids. Hybrid nanofluids are prepared with CNT/MoS2 nanoparticles of 1wt% in sesame oil, neem oil and mahua oil by varying hybrid ratio (i.e. 1: 1; 1:2 and 2:1) and surfactant. The hybrid nanofluid composition is evaluated based on stability analysis from sedimentation and zeta potential studies. The concentration of nanoparticles is varied by preparing CNT/MoS2 hybrid nanofluid using obtained composition for stability and selected the optimal concentration for the lowest coefficient of friction obtained in friction test. The property of thermal conductivity is also evaluated for varying concentration of hybrid nanofluid at room temperature. The contact angle for CNT/MoS2 hybrid nanofluids is evaluated with a contact angle meter to understand the lubrication effect. Experimental findings for stable hybrid nanofluid are found to be sesame oil, SDS with 15% content of nanoparticle weight and 1:2 hybrid ratio. From friction test, it is observed that 2 wt%concentration is optimal for least coefficient of friction (0.038). Minimum surface roughness (Ra) is observed with 2 wt% of hybrid nanofluid compared to dry machining and conventional cutting fluid. Optimum conditions for minimum surface roughness are evaluated in turning of AISI1040 steel with the use of 2wt% of CNT/MoS2 hybrid nanofluid in RSM. Ra value is observed to decrease with an increase in cutting speed and increased with an increase in feed and depth of cut.
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Zhou, XiaoRong, Yi Wang, Kai Zheng y Haozhong Huang. "Comparison of heat transfer performance of ZnO-PG, α-Al2O3-PG, and γ-Al2O3-PG nanofluids in car radiator". Nanomaterials and Nanotechnology 9 (1 de enero de 2019): 184798041987646. http://dx.doi.org/10.1177/1847980419876465.
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In this study, the cooling performance of nanofluids in car radiators was investigated. A car radiator, temperature measuring instrument, and other components were used to set up the experimental device, and the temperature of nanofluids passing through the radiator was measured by this device. Three kinds of nanoparticles, γ-Al2O3, α-Al2O3, and ZnO, were added to propylene glycol to prepared nanofluids, and the effects of nanoparticle size and type, volume concentration, initial temperature, and flow rate were tested. The results indicated that the heat transfer coefficients of all nanofluids first increased and then decreased with an increase in volume concentration. The ZnO-propylene glycol nanofluid reached a maximum heat transfer coefficient at 0.3 vol%, and the coefficient decreased by 25.6% with an increase in volume concentration from 0.3 vol% to 0.5 vol%. Smaller particles provided a better cooling performance, and the 0.1 vol% γ-Al2O3-propylene glycol nanofluid had a 19.9% increase in heat transfer coefficient compared with that of α-Al2O3-propylene glycol. An increase in flow rate resulted in a 10.5% increase in the heat transfer coefficient of the 0.5 vol% α-Al2O3-propylene glycol nanofluid. In addition, the experimental temperature range of 40–60°C improved the heat transfer coefficient of the 0.2 vol% ZnO-propylene glycol nanofluid by 46.4%.
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Alomair, Osamah A., Khaled M. Matar y Yousef H. Alsaeed. "Experimental Study of Enhanced-Heavy-Oil Recovery in Berea Sandstone Cores by Use of Nanofluids Applications". SPE Reservoir Evaluation & Engineering 18, n.º 03 (14 de julio de 2015): 387–99. http://dx.doi.org/10.2118/171539-pa.
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Summary The application of nanotechnology in the oil industry has become a useful approach in oil production. The main objective of this study is to investigate the effect of nanofluids on the recovery of heavy crude oil compared with waterflooding. The nanofluids are prepared by the addition of pure and mixed nanoparticles—silicon oxide, aluminum oxide, nickel oxide, and titanium oxide—at different concentrations to the formation water. The prepared nanofluids were screened to determine the suitable type for the heavy oil and rock samples subjected to the study. The effect of nanofluids on the interfacial tension and viscosity of emulsion were also investigated. Nanofluid-flooding tests were performed on a heavy-oil sample of 17.45 °API by use of Berea sandstone core samples with average air permeability of 184 md, liquid permeability of 60 md, and porosity of 20%. After selection of the optimum type of nanofluid, additional tests were performed including effect on asphaltene precipitation by use of a flow-assurance system. Results from the experiments show that the aluminum oxide nanofluid at concentration of 0.05 wt% reduced the emulsion viscosity by 25%. The mixed nanofluid of silicon and aluminum oxides at 0.05 wt% has shown the highest incremental oil recovery among the other nanofluids. It is expected to be the best type of chemical flooding because of its performance in reservoir condition (high pressure, temperature, and water salinity) and its capability to oppose asphaltene precipitation.
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Sohel, M. R., Saidur Rahman, Mohd Faizul Mohd Sabri, M. M. Elias y S. S. Khaleduzzaman. "Investigation of Heat Transfer Performances of Nanofluids Flow through a Circular Minichannel Heat Sink for Cooling of Electronics". Advanced Materials Research 832 (noviembre de 2013): 166–71. http://dx.doi.org/10.4028/www.scientific.net/amr.832.166.
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Nanofluid is the suspension of nanoparticle in a base fluid. In this paper, the heat transfer performances of the nanofluids flow through a circular shaped copper minichannel heat sink are discussed analytically. Al2O3-water, CuO-water, Cu-water and Ag-water nanofluids were used in this analysis to make comparative study of their thermal performances. The hydraulic diameter of the minichannel is 500 μm and total block dimension is 50mm× 50mm× 4mm. The analysis is done at different volume fractions of the nanoparticle ranging from 0.5 vol.% to 4 vol.%. The results showed that the heat transfer performance increases significantly by the increasing of volume fraction of nanoparticle. Ag-water nanofluid shows the highest performance compared to the other nanofluids. So, this nanofluid can be recommended as a coolant flow through a circular minichannel for cooling of electronic heat sink.
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Zheng, Dan, Jin Wang, Yu Pang, Zhanxiu Chen y Bengt Sunden. "Heat transfer performance and friction factor of various nanofluids in a double-tube counter flow heat exchanger". Thermal Science 24, n.º 6 Part A (2020): 3601–12. http://dx.doi.org/10.2298/tsci200323280z.
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Experimental research was conducted to reveal the effects of nanofluids on heat transfer performance in a double-tube heat exchanger. With nanoparticle weight fraction of 0.5-2.0% and Reynolds number of 4500-14500, the flow resistance and heat transfer were analyzed by using six nanofluids, i.e., CuO-water, Al2O3-water, Fe3O4-water, ZnO-water, SiC-water, SiO2-water nanofluids. Results show that SiC-water nanofluid with a weight concentration of 1.5% provides the best improvement of heat transfer performance. 1.0% CuO-water and 0.5% SiO2-water nanofluids have lower friction factors in the range of Reynolds number from 4500-14500 compared to the other nanofluids. Based on test results of heat transfer performance and flow resistance, the 1.0% CuO-water nanofluid shows a great advantage due to a relatively high heat transfer performance and a low friction factor. Finally, empirical formulae of Nusselt numbers for various nanofluids were established based on experimental data tested in the double-tube heat exchanger.
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Chen, Pengfei, Zhuangzhuang Jia, Zhumei Luo, Shan Qing y Xiaoyan Huang. "Research on heat transfer characteristics of flow in tube of water-based nanofluids". Thermal Science, n.º 00 (2020): 301. http://dx.doi.org/10.2298/tsci200621301c.
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In this paper, the characteristics of forced convection heat transfer in water-based nanofluids are studied by means of experimental and theoretical analysis. Nusselt number of nanofluids were calculated by changing the volume fraction and the type of nanoparticles in the tube. The effects of Reynolds number and the volume fraction of nanoparticles on the forced convection heat transfer were studied. An exergy analytical model was established for the laminar heat transfer of nanofluid under the condition of constant heat flow. At the same Reynolds condition, the friction entropy production of the flow and heat transfer process in the tube increases with the addition of nanoparticles, and the heat transfer entropy production decreases at the same time. However, the magnitude of friction entropy production is only 10-6, which is negligible compared with the heat transfer entropy production. Therefore, in general, the loss of nanofluids is lower than that of pure water; for nanofluids, the exergy loss of hybrid nanofluid is lower than that of single nanofluid at the same volume fraction.
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Chen, Xueye. "Molecular dynamics simulation of nanofluidics". Reviews in Chemical Engineering 34, n.º 6 (27 de noviembre de 2018): 875–85. http://dx.doi.org/10.1515/revce-2016-0060.
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Abstract This review reports the progress on the recent development of molecular dynamics simulation of nanofluidics. Molecular dynamics simulations of nanofluidics in nanochannel structure, surface roughness of nanochannel, carbon nanotubes, electrically charged, thermal transport in nanochannels and gases in nanochannels are illustrated and discussed. This paper will provide an expedient and valuable reference to designers who intend to research molecular dynamics simulation of nanofluidic devices.
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Syarief, Dani Gustaman. "Characteristics of Water-ZrO2 Nanofluids with Different pH Utilizing Local ZrO2 Nanoparticle Prepared by Precipitation Method". Advanced Materials Research 896 (febrero de 2014): 163–67. http://dx.doi.org/10.4028/www.scientific.net/amr.896.163.
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Changing water as the conventional nuclear reactor coolant with nanofluid in order to increase the efficiency of heat transfer in the nuclear reactors becomes a strong need. In this work, a study of synthesis and characterization of ZrO2 nanoparticle and water-ZrO2 nanofluid was done. The ZrO2 nanopowder was synthesized using a precipitation method from ZrOCl2.8H2O (ZOC) that was prepared from local zircon (ZrSiO4) using caustic fusion method with calcination temperature of 800°C. The ZrO2 nanoparticle contained two phases namely cubic and monoclinic with crystallite size of 12 nm measured using Debye Scherrer method. Stability of nanofluids that prepared by mixing the ZrO2 nanoparticle with water depended on pH. The nanofluids with pH less than 5 and larger than 8 were stable. Sedimentation test showed that the Water-ZrO2 nanofluid produced in this study was very stable until at least 9 days. A typical basic nanofluid has zeta potential of about-41 mV and a typical acidic one has zeta potential of +45 mV. Thermal conductivity of the nanofluids was 4-9 % larger than that of water.
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Ali, Abdallah Yousef Mohammed, Ahmed H. El-Shazly, M. F. El-Kady, Hesham Ibrahim Fathi y Mohamed R. El-Marghany. "Effect of Using MgO-Oil Nanofluid on the Performance of a Counter-Flow Double Pipe Heat Exchanger". Key Engineering Materials 801 (mayo de 2019): 193–98. http://dx.doi.org/10.4028/www.scientific.net/kem.801.193.
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In the present study, heat transfer characteristics of MgO-oil based nanofluid in a miniature counter-flow double-pipe heat exchanger are investigated experimentally and numerically. The nanofluid is a mixture of corn oil as a base fluid and MgO particles in nanorange. The heat exchanger is fabricated from 316 stainless steel with length 500 mm. Cold water flows in the annulus side, and the nanofluid is utilized as the hot medium in the inner tube. ANSYS FLUENT 17,0 commercial software was employed for numerical investigation. The results obtained from using nanofluids are compared with the pure oil base fluid as a hot medium. Effects of inlet flow rate of hot nanofluids and concentration of nanoparticles are considered. It is observed that the average heat transfer rates for nanofluids are higher than those for pure corn oil. The improvement of both MgO concentration and inlet flow rates of nanofluid has a positive impact on the overall heat transfer coefficient and heat transfer rate. In contrast, the pumping power augments as well as the pressure drop increases.
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Xie, Siyu, Yi Zhang, Yanfang Song, Fang Ge, Xin Huang, Honghua Ge y Yuzeng Zhao. "Comparison of the Corrosion Behavior of Brass in TiO2 and Al2O3 Nanofluids". Nanomaterials 10, n.º 6 (29 de mayo de 2020): 1046. http://dx.doi.org/10.3390/nano10061046.
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The corrosion behavior of brass in TiO2 and Al2O3 nanofluids using a simulated cooling water (SCW) as the base solution and sodium dodecyl benzene sulfonate (SDBS) as the dispersant was studied by electrochemical measurements and surface analysis in this paper. It was found that SDBS could be adsorbed on the brass surface to form a protective film and have a corrosion inhibition effect on brass in SCW. In the SCW-SDBS-TiO2 nanofluid, some negatively charged TiO2 nanoparticles were attached to the brass surface and no obvious SDBS adsorption film was found, and the SDBS in this nanofluid had almost no corrosion inhibition on brass. In the SCW-SDBS-Al2O3 nanofluid, the brass surface was covered by a uniformly distributed SDBS film containing some Al2O3 nanoparticles which were positively charged, and the corrosion inhibition of brass was significantly improved in this nanofluid. It is concluded that the adsorption of SDBS on the brass surface in nanofluids is related to the charge status of the nanoparticles, which makes brass have different corrosion resistance in various nanofluids.
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Lee, Areum, Chinnasamy Veerakumar y Honghyun Cho. "Effect of Magnetic Field on the Forced Convective Heat Transfer of Water–Ethylene Glycol-Based Fe3O4 and Fe3O4–MWCNT Nanofluids". Applied Sciences 11, n.º 10 (20 de mayo de 2021): 4683. http://dx.doi.org/10.3390/app11104683.
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This paper discusses the forced convective heat transfer characteristics of water–ethylene glycol (EG)-based Fe3O4 nanofluid and Fe3O4–MWCNT hybrid nanofluid under the effect of a magnetic field. The results indicated that the convective heat transfer coefficient of magnetic nanofluids increased with an increase in the strength of the magnetic field. When the magnetic field strength was varied from 0 to 750 G, the maximum convective heat transfer coefficients were observed for the 0.2 wt% Fe3O4 and 0.1 wt% Fe3O4–MWNCT nanofluids, and the improvements were approximately 2.78% and 3.23%, respectively. The average pressure drops for 0.2 wt% Fe3O4 and 0.2 wt% Fe3O4–MWNCT nanofluids increased by about 4.73% and 5.23%, respectively. Owing to the extensive aggregation of nanoparticles by the external magnetic field, the heat transfer coefficient of the 0.1 wt% Fe3O4–MWNCT hybrid nanofluid was 5% higher than that of the 0.2 wt% Fe3O4 nanofluid. Therefore, the convective heat transfer can be enhanced by the dispersion stability of the nanoparticles and optimization of the magnetic field strength.