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Artykuły w czasopismach na temat "HYBRID NANO FLUIDS"
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Arifuddin, A., A. A. M. Redhwan, A. M. Syafiq, S. Zainal Ariffin, A. R. M. Aminullah i W. H. Azmi. "Stability analysis of hybrid Al2O3-TiO2 nano-cutting fluids". Archives of Materials Science and Engineering 117, nr 1 (1.09.2022): 5–12. http://dx.doi.org/10.5604/01.3001.0016.1392.
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This paper is to study the stability of the current combination of hybrid nano-cutting fluids due to the recent progress in the analysis of nano-cutting fluids, such as the assessment methods for the stability of nano-cutting fluids, have revealed that instability is a common problem associated with nano cutting fluids. Five samples of 0.001 vol% that are suitable to be tested at UV-Vis machine, Al2O3–TiO2 hybrid nano-cutting fluid was prepared using a one-step process with the help of a magnetic stirrer to stir for 30 minutes with different sonication time to determine the best or optimum sonication time for this hybrid nano-cutting fluid. Stability of nano-cutting fluids was analyses using UV–Vis spectrophotometer (0.001%, 0.0001%, 0.00001%), visual sedimentation (1%, 2%, 3%, 4%), TEM photograph capturing techniques (2%) and zeta potential analysis (0.001%, 0.00001%), that used different volume concentration that is suitable for each type of stability analysis. The stability analysis reveals that the best sonication time is 90 minutes, and the UV-vis spectrophotometer shows the stability of all samples is above 80% during a month compared to the initial value. Further, visual sedimentation shows good stability with minimum sedimentation and colour separation only. The zeta potential value also shows great stability with a value of 37.6 mV. It is found that the hybrid nano-cutting fluid is stable for more than a month when the nano is suspended in the base fluid of conventional coolant. The result in this paper is based on the experimental study of Al2O3-TiO2/CNC coolant base hybrid nano-cutting fluid for a month. However, to further validate the results presented in this paper, it is recommended to prolong the stability assessment time for six months for longer shelf life. The finding of this experimental study can be useful for high-precision product machining using similar CNC coolants, especially for aircraft and airspace applications for machining parts. No thorough stability assessment using all four types of stability analysis is done on Al2O3-TiO2/CNC Coolant base hybrid nano cutting fluid.
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Arifuddin, Ariffin, Abd Aziz Mohammad Redhwan, Wan Hamzah Azmi i Nurul Nadia Mohd Zawawi. "Performance of Al2O3/TiO2 Hybrid Nano-Cutting Fluid in MQL Turning Operation via RSM Approach". Lubricants 10, nr 12 (16.12.2022): 366. http://dx.doi.org/10.3390/lubricants10120366.
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Cutting fluids can be used to cool workpieces at high cutting speeds and remove chips from cutting zones. The effectiveness of cutting fluids may be improved with the addition of hybrid nanoparticle dispersion. This study evaluates the effectiveness of an Al2O3-TiO2 hybrid as a cutting fluid in turning operations. The Al2O3-TiO2 hybrid nano-cutting fluid was prepared using a one-step method in computer numerical control (CNC) coolant with concentrations of up to 4%. Utilizing air-assisted nano-cutting fluids injected through a minimum quantity lubrication (MQL) setup, the effectiveness of turning cutting performance, cutting temperature (°C), average surface roughness (Ra), and tool wear (%) were evaluated. Then, the response surface method (RSM) was utilized as the design of experiment (DOE) to optimize the turning cutting performance parameters. The combination of 4% hybrid nano-cutting fluid concentration, 0.1 mm/rev feed rate, and 0.55 mm depth of cut yielded the lowest cutting temperature, surface roughness, and tool wear values of 25.3 °C, 0.480 µm, and 0.0104%, respectively. The 4% concentration of Al2O3/TiO2 hybrid nano-cutting fluid inclusion achieved the highest surface roughness reduction that led to better surface finish and the lowest tool-wear reduction led to longer tool life. Therefore, Al2O3/TiO2 hybrid nano-cutting fluids were strongly recommended in turning operations for CNC lathes.
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Arifuddin, A., A. A. M. Redhwan, A. M. Syafiq, S. Zainal Ariffin, A. R. M. Aminullah i W. H. Azmi. "Effectiveness of hybrid Al2O3-TiO2 nano cutting fluids application in CNC turning process". Archives of Materials Science and Engineering 117, nr 2 (1.10.2022): 70–78. http://dx.doi.org/10.5604/01.3001.0016.1777.
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The purpose of this study is to evaluate the effectiveness of hybrid Al2O3-TiO2 nano-cutting fluid in the turning process application under the selected significant machining parameters consisting of nano concentration, depth of cut and feed rate. The preparation of aqueous hybrid Al2O3-TiO2 water-based nano-cutting fluids and their application as the cutting fluid in turning operations are undertaken. The Al2O3-TiO2 hybrid nano-cutting fluids were prepared through a one-step method; by dispersing nanoparticles of Al2O3 (average diameter 30 nm) and TiO2 (average diameter 30-50 nm) in CNC coolant based at four different volume concentrations (1%, 2%, 3%, 4%). The effectiveness of turning cutting performance, namely cutting temperature (°C), average surface roughness (Ra), and tool wear (%), were assessed via air-assisted nano cutting fluids impinged through MQL setup in turning of Aluminium Alloy AA7075. The response surface method (RSM) was employed in the design of the experiment (DOE). The lowest cutting temperature, surface roughness, and tool wear of 25.8°C, 0.494 µm, and 0.0107%, are obtained, respectively, when the combinations of hybrid nano cutting fluid concentration of 4%, feed rate value of 0.1 mm/rev, and 0.3 mm depth of cut is used. The result in this paper is based on the experimental study of Al2O3-TiO2 hybrid nano-cutting fluid using CNC turning operation. The process focuses on the finishing process by using a finishing insert. Further work using roughing process may be suggested to observe the better performance of this cutting process using nano-cutting fluid towards reducing the wear rate. The use of Al2O3-TiO2 hybrid nano-cutting fluid coupled with MQL in the CNC turning process is considered a new method. Machining soft and delicate materials such as Aluminium should consider using this combination technique since it lowers the cutting temperature and removes the chips, reducing the adhesive wear. The hybrid nano-cutting fluid can replace the conventional cutting fluid and will perform better if combined with the MQL cooling technique; this new method should be considered by major industry players that require a high-precision finished product such as the product that involves aircraft and aerospace applications.
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Khan, Yasir, Sohaib Abdal, Sajjad Hussain i Imran Siddique. "Numerical simulation for thermal enhancement of $ H_2O $ + Ethyl Glycol base hybrid nanofluid comprising $ GO + (Ag, AA7072, MoS_2) $ nano entities due to a stretched sheet". AIMS Mathematics 8, nr 5 (2023): 11221–37. http://dx.doi.org/10.3934/math.2023568.
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<abstract><p>The evaluation of compact heat density gadgets requires effective measures for heat transportation. Enhancement in thermal transportation of hybrid nanofluids comprising of water plus ethyl glycol with the dispersion of three different nano-entities is considered. The fluids are transported through a porous medium over a permeable elongating sheet. Water and ethyl glycol are $ (50 \% -50 \%) $. The three cases for hybrid species consist of (a) Graphene oxide (Go) + AA7072, (b) Go + Molybdenum sulfide, (c) Go + silver. The volume fraction of nano-entities is greater than 0.3%. It is presumed that the fluid flow is non-Newtonian. Two on-Newtonian fluids models namely Maxwell fluid and Casson fluid are taken into consideration to present comparative behavior in the existence of the nano-particle mixture. The leading equations are altered into ordinary differential form. A robust numerical procedure embraced with Runge-Kutta methodology and shooting strategy is employed to attain results for the dependent physical quantities. It is noticed that the velocity is diminished against the magnetic field parameter and porosity parameter. The temperature for case (a) Go + AA7072 is the highest and it is lowest for case (c) Go + silver. The temperature and velocity functions of both the fluids (Casson and Maxwell fluids) are incremented with larger inputs of hybrid nano-species. The results can find applications for the better performance of electronic equipment, and heat exchangers.</p></abstract>
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Sridhar Yesaswi, Ch, K. Ajay Krishna, A. Pavan Gopal Varma, K. Girish i K. Jagadeesh Varma. "Characterization of AL2O3 Nano Particles in Engine Oil for Enhancing the Heat transfer rate". International Journal of Engineering & Technology 7, nr 2.32 (31.05.2018): 237. http://dx.doi.org/10.14419/ijet.v7i2.32.15575.
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Selection of suitable engine oils becoming more challenging for automobile engineers. Life of the engine majorly depends upon engine oil, type of fuel being used and various other thermal and structural characteristics of the engine. Dissipation of heat is one of the major consideration in the design of automobile engines. Generally engine oils are used for the lubrication between piston and cylinder but to enhance the cooling effectiveness Nano-particles are added in the lubricant, so that internal heat generation in the engines can be minimized. Nano-fluids are playing a vital role in heat transfer applications because of its enhanced thermal conductivity nature and generally these fluids are colloidal mixture of Nano particles and base fluids. Intense research studies over Nano fluids are very high because of their sublime behavior.Recently. Advanced research over Nano technology has gone to a situation where two or more Nano particles are made to mix in a base fluids and generally we call this as hybrid Nano fluids. In this work, preparation of Al2O3 nanoparticles and mixing them with 10W30 engine oil were carried out. By various techniques thermal characteristics of fluid are identified with different parameters.
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S, Vignesh, Mohammed Iqbal U i Jaharah A. Ghani. "A Study on the Effects of Hybridized Metal Oxide and Carbonaceous Nano-Cutting Fluids in the End Milling of AA6082 Aluminum Alloy". Lubricants 11, nr 2 (17.02.2023): 87. http://dx.doi.org/10.3390/lubricants11020087.
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Finding an alternate solution for supplanting the existing conventional lubricant in machining is a challenge. This work narrows the search down to the use of nano-cutting fluids, as they exhibit excellent properties such as high thermal conductivity and good lubricity. A technical analysis of the performance of hybrid nano-cutting fluids in the end milling of AA6082 aluminium alloy in a constrained end milling condition is presented. Alumina and carbon nanotubes were chosen in this study for their better physical characteristics and compatibility during machining. Coconut oil was chosen as the base fluid (dispersal medium) as it provides good lubricity and better dispersion of nanoparticles due to its excellent rheological behaviour. The hybrid nanofluid was prepared by mixing alumina-based nanofluid with carbon nanotube nanoparticles in different volumetric concentrations. The thermo-physical properties of the prepared hybrid nanofluid were tested. Furthermore, they were tested for their spread-ability and other mechanical properties. Later, their performances as cutting fluid were studied with the minimum quantity lubrication (MQL) technique, wherein nanoparticle mist was formed and evaluated in the end milling of AA6082 aluminium to reduce the quantity of nanofluids’ usage during end milling. The controllable parameters of speed, feed rate, and type of cutting fluid were chosen, with the levels of cutting speeds and feed rate at 75–125 m/min, and 0.005–0.015 mm/tooth, respectively, and the response parameters studied were surface roughness and tool wear. The results show that better performance is achieved in hybridized nano-cutting fluid, with a sharp improvement of 20%, and 25% in tool wear and surface roughness when compared to the base fluid. This study has explored the concept of hybridization and the capability of nanofluids as cutting fluids that can be used as eco-friendly cutting fluids in manufacturing industries.
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Bhattad, Atul, Vinay Atgur, Boggarapu Nageswar Rao, N. R. Banapurmath, T. M. Yunus Khan, Chandramouli Vadlamudi, Sanjay Krishnappa, A. M. Sajjan, R. Prasanna Shankara i N. H. Ayachit. "Review on Mono and Hybrid Nanofluids: Preparation, Properties, Investigation, and Applications in IC Engines and Heat Transfer". Energies 16, nr 7 (31.03.2023): 3189. http://dx.doi.org/10.3390/en16073189.
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Nano fluids are widely used today for various energy-related applications such as coolants, refrigerants, and fuel additives. New coolants and design modifications are being explored due to renewed interest in improving the working fluid properties of heat exchangers. Several studies have investigated nanofluids to enhance radiator and heat exchanger performance. A new class of coolants includes single, binary, and tertiary nanoparticle-based hybrid nano-coolants using ethylene glycol/deionized water combinations as base fluids infused with different nanoparticles. This review article focuses on the hydrothermal behavior of heat exchangers (radiators for engine applications) with mono/hybrid nanofluids. The first part of the review focuses on the preparation of hybrid nanofluids, highlighting the working fluid properties such as density, viscosity, specific heat, and thermal conductivity. The second part discusses innovative methodologies adopted for accomplishing higher heat transfer rates with relatively low-pressure drop and pump work. The third part discusses the applications of mono and hybrid nanofluids in engine radiators and fuel additives in diesel and biodiesel blends. The last part is devoted to a summary of the research and future directions using mono and hybrid nanofluids for various cooling applications.
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Aboob, Eman A. A. "Experimental study of nonlinear characterization of hybrid SWCNTs/Ag-NPs fluids, using nonlinear diffraction technique". Iraqi Journal of Physics (IJP) 16, nr 36 (1.10.2018): 199–205. http://dx.doi.org/10.30723/ijp.v16i36.44.
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Based on nonlinear self- diffraction technique, the nonlinear optical properties of thin slice of matter can be obtained. Here, nonlinear characterization of nano-fluids consist of hybrid Single Wall Carbon Nanotubes and Silver Nanoparticles (SWCNTs/Ag-NPs) dispersed in acetone at volume fraction of 6x10-6, 9x10-6, 18x10-6 have been investigated experimentally. Therefore, CW DPSS laser at 473 nm focused into a quartz cuvette contains the previous nano-fluid was utilized. The number of diffraction ring patterns (N) has been counted using Charge - Coupled- Device (CCD) camera and Pc with a certain software, in order to find the maximum change of refractive index ( of fluids. Our result show that the fraction volume of 18x10-6 is more nonlinearity than others.
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Ashraf, Asifa, Zhiyue Zhang, Tareq Saeed, Hussan Zeb i Taj Munir. "Convective Heat Transfer Analysis for Aluminum Oxide (Al2O3)- and Ferro (Fe3O4)-Based Nano-Fluid over a Curved Stretching Sheet". Nanomaterials 12, nr 7 (30.03.2022): 1152. http://dx.doi.org/10.3390/nano12071152.
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In this work, the combined effects of velocity slip and convective heat boundary conditions on a hybrid nano-fluid over a nonlinear curved stretching surface were considered. Two kinds of fluids, namely, hybrid nano-fluid and aluminum oxide (Al2O3)- and iron oxide (Fe3O4)-based nano-fluid, were also taken into account. We transformed the governing model into a nonlinear system of ordinary differential equations (ODEs). For this we used the similarity transformation method. The solution of the transformed ODE system was computed via a higher-order numerical approximation scheme known as the shooting method with the Runge–Kutta method of order four (RK-4). It is noticed that the fluid velocity was reduced for the magnetic parameter, curvature parameter, and slip parameters, while the temperature declined with higher values of the magnetic parameter, Prandtl number, and convective heat transfer. Furthermore, the physical quantities of engineering interest, i.e., the behavior of the skin fraction and the Nusselt number, are presented. These behaviors are also illustrated graphically along with the numerical values in a comparison with previous work in numerical tabular form.
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Yasmin, Humaira, Solomon O. Giwa, Saima Noor i Mohsen Sharifpur. "Experimental Exploration of Hybrid Nanofluids as Energy-Efficient Fluids in Solar and Thermal Energy Storage Applications". Nanomaterials 13, nr 2 (9.01.2023): 278. http://dx.doi.org/10.3390/nano13020278.
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In response to the issues of environment, climate, and human health coupled with the growing demand for energy due to increasing population and technological advancement, the concept of sustainable and renewable energy is presently receiving unprecedented attention. To achieve these feats, energy savings and efficiency are crucial in terms of the development of energy-efficient devices and thermal fluids. Limitations associated with the use of conventional thermal fluids led to the discovery of energy-efficient fluids called “nanofluids, which are established to be better than conventional thermal fluids. The current research progress on nanofluids has led to the development of the advanced nanofluids coined “hybrid nanofluids” (HNFs) found to possess superior thermal-optical properties than conventional thermal fluids and nanofluids. This paper experimentally explored the published works on the application of HNFs as thermal transport media in solar energy collectors and thermal energy storage. The performance of hybrid nano-coolants and nano-thermal energy storage materials has been critically reviewed based on the stability, types of hybrid nanoparticles (HNPs) and mixing ratios, types of base fluids, nano-size of HNPs, thermal and optical properties, flow, photothermal property, functionalization of HNPs, magnetic field intensity, and orientation, and φ, subject to solar and thermal energy storage applications. Various HNFs engaged in different applications were observed to save energy and increase efficiency. The HNF-based media performed better than the mono nanofluid counterparts with complementary performance when the mixing ratios were optimized. In line with these applications, further experimental studies coupled with the influence of magnetic and electric fields on their performances were research gaps to be filled in the future. Green HNPs and base fluids are future biomaterials for HNF formulation to provide sustainable, low-cost, and efficient thermal transport and energy storage media.
Rozprawy doktorskie na temat "HYBRID NANO FLUIDS"
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Vu, Van Huyen. "Modélisation hybride et multi-échelle pour la simulation des écoulements et des transferts thermiques dans les micro-canaux". Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC1163/document.
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L'objectif de cette thèse est de mettre en œuvre une description multi-échelle adaptée aux écoulements de fluides dans des micro-/nano-conduites. Cette approche doit permettre de décrire, aussi bien les petites échelles relatives aux interactions du fluide avec les atomes du mur, que les grandes échelles de l’écoulement engendrées par les conditions aux limites d'entrée/sortie du canal. Pour cela, nous avons développé une méthode qui couple une modélisation continue des écoulements et des transferts de chaleur dans le cœur du canal avec une modélisation discrète proche des parois, basée sur une représentation atomistique du fluide et du mur.Les équations de Navier-Stokes et de l’énergie, couplées à une équation d’état, sont approximées par une méthode de volumes finis dans le cœur de l’écoulement alors que des simulations de dynamique moléculaire sont utilisées pour représenter finement les interactions entre le fluide et la paroi. Cette approche hybride nécessite la transmission d’informations entre les modélisations : les grandeurs moyennées moléculaires sont imposées comme conditions aux limites pour le modèle continu, et la dynamique sous contrainte, couplée à un thermostat de Langevin, est utilisée pour piloter l’échelle moléculaire. Une représentation par des plots moléculaires locaux de petite taille, intelligemment répartis le long de l’interface entre le fluide et le mur, permet de traiter des écoulements et des transferts dans des canaux de très grands allongements, pour des coûts de calcul raisonnables.Après une partie de validation, des simulations hybrides multi-échelles d’écoulements dans des canaux constitués de parois en platine ont été menées pour de l’argon en phase liquide (incompressible) ou gazeuse (compressible), en tenant compte éventuellement du changement de phase au voisinage de la paroiThe main objective of this thesis is to model the multi-scale heat and fluid flows in micro-/nano channels. This method must be able of capturing at the same time the fluid/solid interaction at the small scale but also the flows induced by the inlet/outlet boundary conditions at the large scale. To this aim, we have adopted an approach coupling the continuum model in the bulks of the channel and the discrete model at the vicinity of the wall, based on an atomistic representation of the fluid and the solid.The Navier-Stokes and energy equations, coupled with an equation of state, are approximated by a finite volume method and the molecular dynamics simulations are used to finely represent the interaction between the fluid and the solid. This hybrid method requires information transmission between the former two regions: averaged quantity in molecular dynamics simulations are imposed as boundary conditions for the continuous model and constrained dynamics, coupled with a thermostat Langevin, is used to control in the molecular level. A set of small molecular dynamics blocks, smartly distributed all along the wall/fluid interface, allows to treat flow and heat transfers in a long micro/nano-channel with a reasonable computational cost.After a validation step, the hybrid multi-scale simulations of complex fluid flows in the channel composed of the platinum wall have been conducted for argon in incompressible liquid or compressible gaseous phase with and without phase change in the vicinity of the wall
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KUMAR, RAUNAK. "EXERGETIC ANALYSIS OF PARABOLIC TROUGH COLLECTORS USING VARIOUS MONO & HYBRID NANO FLUIDS". Thesis, 2021. http://dspace.dtu.ac.in:8080/jspui/handle/repository/18969.
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Solar boasts itself to be most sustainable, employable and ecologically acceded
renewable sources of energy due to its simplicity of usage and low environmental
effect. Solar energy may be utilized for a variety of applications, including solar water
heaters. Solar collectors are used for cooling and dehumidification in addition to room
and water heating. Heat losses and fluid absorption characteristics, on the other hand,
restrict the collector's efficiency. Alternative fluids, which are essentially the same as
conventional fluids but include a specific quantity of suspension of metal or nonmetal
particles, have been utilised to great success in solar collectors during the past several
decades. Nanofluids are fluids that have microscopic particles suspended in them, thus
the name. It has been established through numerous experiments and investigation that
floating these nanoparticles enriches base fluid thermal properties, yielding better
thermal conductivities than conventional fluids. As a consequence, nanofluids are more
suited than traditional fluids for heat transfer enhancement applications.
It has been proved to be one among the most popular and promising ways for improving
and enhancing the concentrating power collector performance . This work intents to
investigate various thermal and energetic based efficiency optimization of parabolic
through collector using various mono and hybrid Nano fluids. The goal of this study
was to improve the LS-2 parabolic trough model and examine the enhancing effects of
mono and hybrid Nano fluids. The methodology of heat transfer analysis is used in this
study to construct a software using the Engineering Equation Solver for the numeric
simulation of the parabolic trough collector. Solar irradiation, inlet fluid temperature,
and volumetric flow rate of heat transfer fluid are the primary inputs to the proposed
model, while the thermal and exergetic efficiency is the main output. The final result
and findings clearly shows the optimized condition for exergetic efficiency in addition
to the optimized conditions for thermal efficiency.
Części książek na temat "HYBRID NANO FLUIDS"
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Kant, Vashisht, Khirod Kumar Mahapatro i P. Vamsi Krishna. "Influence of vegetable oil based hybrid nano cutting fluids in titanium alloy machining". W Recent Advances in Material, Manufacturing, and Machine Learning, 433–39. London: CRC Press, 2023. http://dx.doi.org/10.1201/9781003358596-47.
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Dhanola, Anil, i Amit Raturi. "Current Research Trends on the Utilization of Mono and Hybrid Nano-Fluids for Solar Energy Applications". W Biofuel Technologies for a Sustainable Future: India and Beyond, 119–45. New York: River Publishers, 2023. http://dx.doi.org/10.1201/9781003338321-6.
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Sonawane, Shriram S., Manjakuppam Malika, Parag P. Thakur i Shirish Hari Sonawane. "Carbon nano tubes (CNT) based hybrid nano fluids for the wastewater treatment plants in the industry". W Novel Approaches Towards Wastewater Treatment and Resource Recovery Technologies, 313–24. Elsevier, 2022. http://dx.doi.org/10.1016/b978-0-323-90627-2.00021-6.
Pełny tekst źródłaStreszczenia konferencji na temat "HYBRID NANO FLUIDS"
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Hegde, Shreyas S., Narendran Ganesan i N. Gnanasekaran. "Conjugate Heat Transfer in a Hexagonal Micro Channel Using Hybrid Nano Fluids". W ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels collocated with the ASME 2016 Heat Transfer Summer Conference and the ASME 2016 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icnmm2016-7961.
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Research is being focused on the use of micro channels with nano fluids as the heat sinks. This requires fundamental understanding of the heat transfer phenomenon in micro channels. The objective of this paper is to present results from a numerical study on laminar forced convection in a Hexagonal Micro Channel (HMC) heat sink. In particular, the numerical study is carried out using a single phase model. The fluid considered is Alumina-Copper hybrid Nano fluid. The performance of Al2O3+Cu+water is compared with Al2O3+water nano fluid and pure water with different volume fractions. The solid region of the channel is assumed as aluminum with a hydraulic diameter of 175μm. The solid and fluid regions of the micro channel are discretized using finite volume method by combining Navier Stokes equation and energy equation for conjugate heat transfer. The thermo physical properties for alumina nanoparticles are calculated by considering it as a spherical particle of 45nm diameter. The effect of surface roughness on convective heat transfer coefficient and pressure drop for the case of nano fluids is also considered. The analysis is further extended by adding pulsating input and by varying the velocity sinusoidally. The Brownian motion of nano particles is increased to study the efficiency of the heat sink. This ensures all the nano particles are in suspension and the randomness increases the micro convection in the fluid. Incorporating the pulsating flow increases the dispersion of the heat in the nano fluid at a faster rate and also decreases particle settlement in laminar flow. The combined effect of surface roughness and pulsating flow accounts for the change in the velocity profile and thermal boundary layer of the channel. Also the effect of surface roughness ranging from 0.2–0.6 is attempted and the variations in pressure drop, Nusselt number, and heat transfer coefficient are studied. The influence of hexagonal geometry and its interaction with alumina nano fluids is intensively studied by evaluating a three dimensional conjugate heat transfer model. The effect of side wall angle of 45°, 50° and 55° are computed to relate the velocity function with pressure drop, surface roughness and local heat transfer coefficient. The variation of Nusselt number with very low volume fraction of nano particles with a minimal amount of pressure drop is also presented.
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Rohini, B., i V. Revathi. "Investigation of dielectric study of CuO/DEA–isopropanol hybrid nano fluids". W NATIONAL CONFERENCE ON PHYSICS AND CHEMISTRY OF MATERIALS: NCPCM2020. AIP Publishing, 2021. http://dx.doi.org/10.1063/5.0060870.
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Yang, Xiaofan, i Zhongquan C. Zheng. "Effects of Channel Scale on Slip Length of Flow in Micro/Nano-Channels". W ASME 2009 Fluids Engineering Division Summer Meeting. ASMEDC, 2009. http://dx.doi.org/10.1115/fedsm2009-78378.
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The concept of slip length, related to surface velocity and shear rate, is often used to analyze the slip surface property for flow in micro or nanochannels. In this study, a hybrid scheme that couples Molecular dynamics simulation (used near the solid boundary to include the surface effect) and a continuum solution (to study the fluid mechanics) is validated and used for the study of slip length behavior in the Couette flow problem. By varying the height of the channel across multiple length scales, we investigate the effect of channel scale on surface slip length. In addition, by changing the velocity of the moving-solid wall, the influence of shear rate on the slip length in a certain range of the channel height is studied. The results show that within a certain range of the channel heights, the slip length is size-dependant. This upper bound of the channel height can vary with the shear rate.
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Stephenson, Dave, Duncan A. Lockerby, Matthew K. Borg i Jason M. Reese. "Multiscale Simulation of Nano-Fluidic Networks". W ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels collocated with the ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icnmm2014-21149.
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We present a hybrid molecular-continuum method for the simulation of general nano-fluidic networks, which consist of a multiscale system of channels with high aspect ratios. This develops on the hybrid molecular-continuum internal multiscale method recently devised by Borg et al. [1, 2] with three main additions: a) method generalisation to accurately model any nano-fluidic network, rather than just serial channel systems; b) density correction, enabling the modelling of compressible fluids; and c) utilisation as a design tool, rather than just a simulation tool, by replacing pressure boundary conditions for the network with mass flow rate boundary conditions (inlet/outlet pressures are the output of the simulation). We compare our multiscale method with a full molecular dynamics (MD) simulation for a bifurcating channel network, and show that it converges quickly, within 3 iterations, and with good agreement. The multiscale method produces errors of < 2%, while providing a computational speed up of 2.1. The speed up demonstrated is far more modest than it would be for larger networks, but our validation case is restricted by the need to perform a full MD simulation.
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Sabouri, Moslem, Masoud Darbandi i Gerry E. Schneider. "Extending a Hybrid Continuum-Molecular Simulation Method to Solve the Micro/Nanoscale Gas Mixing Problems". W ASME 2018 5th Joint US-European Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/fedsm2018-83454.
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Despite vast efforts in developing hybrid continuum-molecular methods, there has been no specific work focused on the gas mixture flow simulations including the mixing and/or separation of species. In present study, we extend a hybrid method to analyze such phenomena suitably and study the gas mixing problems in micro/nano length scales reliably. The results of current hybrid simulations are compared against the results of full-molecular simulations to evaluate the physical accuracy of developed hybrid method. The effect of continuum breakdown criterion is investigated to find out the achieved accuracy of developed hybrid simulation method from different perspectives. The current results indicate that using a reasonable breakdown parameter can result in very good physical accuracy. The results also indicate that using the hybrid simulation can be quite effective to avoid the statistical fluctuations, which are inherent to the molecular simulation methods.
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Kharazmi, Ali, i Reza Kamali. "A Continuum - Molecular Dynamics Hybrid Method for Micro- and Nano-Fluid Flow". W ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels collocated with 3rd Joint US-European Fluids Engineering Summer Meeting. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30447.
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A computer program based on a Molecular Dynamics-Continuum hybrid numerical method has been developed in which the Navier-Stokes equations are solved in the continuum region and the atomistic molecular dynamics in molecular region. The prepared algorithm and the computer code are capable of computing flows in micro and nano-scale geometries. The coupling between the continuum equations and the molecular dynamics is constructed through constrained dynamics within an overlap region where both molecular and continuum equations are solved simultaneously. An Overlap region is introduced in two directions to improve the choice of using molecular region in smaller areas. The proposed method is used to simulate steady and start-up Couette flow showing quantitative agreement with results from analytical solutions and full molecular dynamics simulations.
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Mayakrishnan, Jaikumar, Ramanathan Velmurugan, Induja SARAVANAN, Sasikumar Nandagopal, Sangeethkumar Elumalai, Selvakumar Raja i Karma Bhutia. "Effect of Hybrid Nano additives on Performance and Emission Characteristics of a Diesel Engine Fueled with Waste Cooking Oil Biodiesel". W International Conference on Advances in Design, Materials, Manufacturing and Surface Engineering for Mobility. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2020. http://dx.doi.org/10.4271/2020-28-0521.
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<div class="section abstract"><div class="htmlview paragraph">The search for a new renewable biofuel and aiming to make the environment clean is always a challenge for a researcher in developing a sustainable fuel for future mobility. In this context, vegetable oils were found as good alternative biofuels for diesel engines as they are biodegradable and renewable in nature. Most of the physio-chemical properties of vegetable oils are very closer to diesel. However, pure vegetable oils are expensive and using them to operate the diesel engine may affect the food supply chain. In view of this limitation, Waste Cooking Oil Biodiesel (WCOB) derived from waste cooking oil (WCO) was found to be very attractive solution for the above said constraints as they are easily available, renewable, economically and environmentally viable. This research aims at studying the effect of hybrid nano additives (i.e. Copper Oxide with Zinc Oxide) on performance and emission characteristics of a diesel engine fueled with Waste Cooking Oil Biodiesel. The Copper oxide with Zinc oxide hybrid nano fluids were prepared by a novel wet chemical method. These nano fluids were prepared in two mass fractions (i.e. 50ppm and 100ppm) and blended with WCOB and considered as test fuels such as WCOBCZ50 and WCOBCZ100. The stability of hybrid nano fluids prepared by wet chemical method and blended with WCOB was found good. The fuels diesel, WCOB, WCOBCZ50 and WCOBCZ100 were tested in the test engine at different loading conditions to evaluate the engine performance and emission parameters. The experimental results revealed that the addition of hybrid nano additives in WCOB improved the fuel properties which were reflected in terms of increased brake thermal efficiency and reduced brake specific fuel consumption compared to neat WCOB. It was also observed that HC, CO, NOx and smoke emissions were reduced with the addition of hybrid nano additives as compared to neat WCOB. Thus, it can be concluded that inclusion of hybrid nano additives pave way for effective utilization of WCOB in an unmodified diesel engine over a period of time.</div></div>
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Vu, Van Huyen, Benoît Trouette, Quy-Dong To i Eric Chenier. "Multi-Scale Modeling and Hybrid Atomistic-Continuum Simulation for Condensation of Gas Flow in a Micro-Channel". W ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels collocated with the ASME 2016 Heat Transfer Summer Conference and the ASME 2016 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icnmm2016-7971.
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In this paper, we present a hybrid Molecular Dynamics/Finite Volume method to study flows in micro-channel involving phase changes. For the simulation of long micro/nano-channels, we adopt multiple molecular blocks along the flow direction, what enables the accurate capture of the velocity and temperature variations from the inlet to the outlet. The validity of the hybrid method is shown by comparisons with both analytical solutions and Finite Volume simulations. This method is then applied successfully to the study the hydrodynamic and thermal development of a fluid flow in a long micro/nano-channel with condensation.
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Yang, Xiaofan, i Z. Charlie Zheng. "Continuum/Nano-Scale Simulation of Surface Diffusion Process in Flow". W ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-62960.
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Fluid transport with diffusion through micro-/nano-channels is found in many natural phenomena and industrial processes, including fluid transport or diffusion through nano-materials, molecular/atomistic transfer across nuclear pores or in the MEMS devices among other applications. Those nano-pores can be treated as nano-channels in the thin layers of the membranes. The transport phenomena of fluid in such small confined channels, usually in the size of ten molecular diameters or less, differs significantly from its bulk behaviors and cannot be described with continuum theory. In this case, molecular dynamics (MD) simulation, rather than continuum methods, is better suited to study the phenomena. The surface diffusion, related to both the fluid and solid material properties and the flow rate, can be used as a parameter for estimating the adsorbing capacity of a porous nano-material. The transport of fluids through porous materials occurs mainly by diffusion. In this study, a molecular-continuum hybrid scheme is used for the study of the diffusion in a representative Couette flow problem. By varying the velocity of the moving-solid wall, we investigated the effect of the shearing condition on the mass flux going through the pores. The relationship of the physical mechanisms and the transport phenomena (e.g. Fick’s law) were then linked among the different length scales. Activated carbon with its high surface area has been emerging as a promising candidate for an adsorbent due to not only its stable thermodynamic and mechanical properties but also its homogenous and isotropic porous distribution and relatively even pore size. In this study, we focus on the characteristics of the permeation and the adsorption process between different gases and the carbon substrate under various shearing conditions. The investigation of the diffusion process of fluids through the pores of the nano-materials has become an interesting topic in recent decades. This investigation has been divided into two major areas: 1) the diffusivity estimation and 2) the transient diffusion rate. We apply a continuum/MD hybrid scheme to a model problem of various gases transport through a carbon substrate with several pores in a channel flow under different shear rates. Instead of inserting and deleting particles from the control volumes used in the DCV-GCMD method, we keep the number of particles in the simulation system constant. The interactions between fluid/fluid, fluid/solid and solid/solid are all assumed to be under Lennard-Jones potentials. In the modeled Couette flow, the two solid walls are constructed with nano-pores that allow fluids to go through the substrate to study the transient diffusion rate (flux). Before simulating the fluid transport through the nano-pores, we need to validate the natural diffusion properties of the bulk fluid. To do this, a system (as a cube) consisting of pure liquid argon molecules is used to perform the pure MD simulation. The radial distribution function (RDF) is used as the parameter to verify the natural diffusion of the liquid argon fluid in the bulk flow, which is a structural correlation. It describes the spherically averaged local organization around any given molecule. Figure 1 shows a good comparison of the radial distribution functions between the MD prediction and the experimental measurement of Eisenstein and Gingrich (1942). By comparing our calculation to Wu et al. (2008) under similar circumstances, we found that the average (from 8 pores) and corrected mass flux J · (RTh) is linearly proportional to the average pressure gradient along the pore. And the slope of this relationship is the transport diffusivity, which is 4.6 × 10−7m2/s under 273K and 4.9 × 10−7m2/s under 300K. This indicates that the current simulation follows the Fick’s law exactly. Similarly, for other gases, the same linear relationships can also be obtained. These calculations are listed in Table 1 that shows the transport diffusivity increases with temperature. The mass fluxes of three gases at various pore widths are calculated as shown in Fig. 2. Generally, with larger pores, the mass fluxes increase. However, among three gases, the increase of H2 is much faster than the other two gases because of hydrogen’s smaller molecular size. In another word, smaller molecules as H2 have faster diffusion rates during the adsorption process.
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Sunakoda, Katsuaki, Shin Morishita, Seiichi Takahashi i Toshiyuki Hakata. "Development and Testing of Hybrid Magnetic Responsive Fluid for Vibration Damper". W ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77651.
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A new intelligent fluid is studied and developed. Rheological characteristics of the developed fluid change rapidly and can be controlled in the presence of an applied magnetic field. The developed fluid is a hybrid type fluid, and it consists consisting of carbonyl irons and super fine magnetite. Average diameters of carbonyl iron and super fine magnetite are a size in the order of a few microns and about 10 nano-meters respectively. Special treatment is made by coating the surface of carbonyl iron with super fine magnetite. Physical properties such as dispersion stability and thixotropical characteristics are examined. Shearing stress and pressure drops of the new fluid flow are examined and evaluated by changing the strength of magnetic fields. A small capacity damper is made, and damping tests are performed using the new fluids and also commercial MR fluid. Dynamic properties of the damper are evaluated. As a result of a series of studies, the developed hybrid magnetic responsive fluid is expected to be used as an intelligent fluid.