Application Of Nanofluids Research Articles

Elastic deformation of thermal radiative and convective hybrid SWCNT-Ag and MWCNT-MoS4 magneto-nanofluids flow in a cylinder

An increasing interest in heat transfer of industrial working fluids and thermal applications of nanofluids propels the advancement of nanotechnology. Recently, focuses have been shifted to hybridization of nanofluids with the aim of enhancing heat propagation rate of conventional fluids. Hence, in this study, the elastic deformation of thermal radiation and convection for hybridized SWCNT-Ag and MWCNT-MoS4 magneto-nanomaterials in engine oil is examined. The thermal transfer of the hybrid nanofluids occurs in a vertical cylinder with thermofluidic features being considered in the model formulation. With appropriate variables, an invariant transformation of the model is obtained, which is then solved using Chebyshev Collocation Scheme (CCS). The data outcomes revealed that heat distribution is reduced with rising Prandtl number, elastic deformation and the viscoelastic term for both SWCNT-Ag and MWCNT-MoS4 hybrid nanofluids.

Improving the efficiency of the concentrating solar power plants using heat transfer nanofluids with gold nanoplates: An analysis from laboratory to industrial scale

We report about the remarkable changes in the thermophysical properties of the heat transfer fluid used in concentrating solar power plants with parabolic-trough collectors (Dowtherm A, a mixture of diphenyl oxide and biphenyl) by addition of Au nanoplates in mass fractions around 10−2 wt%. The resulting nanofluids are stable for weeks, and their enhanced physical properties make them good candidates for the application. Particularly, with 4.8·10−2 wt% of Au nanoplates, specific heat increases by 12.0 ± 1.2 % at 523 K and thermal conductivity increases by 24.9 ± 6.1 % at 373 K, with no measurable changes in density or dynamic viscosity. This set of physical properties allows to make a realistic estimation of the performance of a prototypical concentrating solar power plant using these nanofluids for solar-to-thermal energy conversion. We determine, using computational cost-free numerical models available in literature, that the performance of a concentrating solar power plant could increase up to 35.1 %, compared to the predicted 24.7 % with the conventional heat transfer fluid, with neither rheological penalties nor economically prohibitive structural changes. The findings here reported may contribute to encourage the application of heat transfer nanofluids in order to improve the efficiency of concentrating solar power plants, and to consolidate a working scheme that positively promotes the transition from laboratory scale to industrial scale.

Particle-resolved simulations for nanofluid thermal enhancement in channel flows

Nanofluids have been studied extensively for improved heat transfer performances in various thermal systems. In this article, we adopt the particle-resolved method to study the thermal enhancement of nanofluids in channel flows under constant wall temperature (CWT) and constant heat flux (CHF) conditions. The smoothed profile method is employed to describe the nanoparticles suspending in the base fluid and the lattice Boltzmann method is utilized to solve the flow and temperature fields. Unlike the continuum representation of nanofluids, this particle-resolved approach can incorporate the thermophysical properties of the base fluid and nanoparticles directly in simulation, and flow and temperature distributions around nanoparticles are available. Our simulations reveal detailed information on the nanoparticle influence on the wall thermal distributions, and illustrate the enhancement mechanism for heat transfer between the boundary wall and fluid flow: The nanoparticles near the wall increase the local heat flux under CWT and decreases the local wall temperature under CHF condition. The heat transfer coefficient is utilized to characterize the thermal performance for nanofluids, and it increases 6–16% for the nanofluid systems considered in our simulations. The effects of key system parameters, such as the nanoparticle volume fraction, thermal conductivity, and Reynolds number, are also investigated. Our results show that, for both CWT and CHF systems, the particle volume fraction and thermal conductivity can both increase the heat transfer coefficient; however, the particle conductivity effect becomes less significant or even negligible when it is greatly larger than the base fluid conductivity. For the limited range and relatively low values of Reynolds numbers considered in this work, it appears that the Reynolds number has no obvious influence on the system thermal performance. These finding could be beneficial for a better understanding of the complexity of nanofluid systems and for future nanofluid development and applications.

Modified Buongiorno's model for the analysis of chemically reacting jet flow of ternary hybrid nanofluid under the influence of activation energy and bio‐active mixers

AbstractIn the modern era, the heat transfer is the basic need in every field of sciences and engineering. To augment the energy transfer, the ternary hybrid nanofluid (Thnf) has been used. After the successful nanofluid working performance, the researchers used this idea in many physical situations. Later on, the researchers tried to further improve the performance of nanofluid with high stability. Motivated from the unique practical applications of hybrid nanofluid, in the present analysis, we have considered ternary nanoliquid, which is obtained by the suspension of three nano particulates in base fluids. The aim of the present research is to highlight the thermal applications of ternary nanofluid in the vertical stretching wall jet flow. The suspension of three different nano solid particles is considered in a base liquid water a jet flow over a vertical extending sheet is addressed. In addition to this, the presence of chemical reaction in the concentration, thermophoresis effect in the energy equation and heat source is also addressed. To model the present phenomena of flow using the modified Buongiorno's model, that highlights the impact of Brownian motion and thermophoresis effect. The present flow problem is modelled in terms of PDE's. To transform the obtained model, we use appropriate similarity variables. The transform model is then solved numerically, using the fast convergence numerical PCM approach (parametric continuation method). The solution obtained is shown through graphical representation by indicating the impact of pertinent flow parameters. Finally, from the present results, we obtained that the performance of Thnf is effective in water as compared to hybrid nanoliquid and mono nanofluid. Furthermore, the motile gyrotactic microbes profile gets lower with the varying values of bioconvection Lewis number and Peclet number.

Effects of Key Parameters on Nanofluid Thermal Performance in Heat Exchangers

AbstractNanofluids are utilized in cooling equipment such as heat exchangers and renewable energies such as solar cells as heat transfer fluid. The techniques for nanofluid stability enhancement and stability evaluations, such as zeta potential, electron microscopy, and photographic techniques for sedimentation, are reviewed as well as some recent achievements in nanofluid stabilization and research on the parameters affecting the thermal properties of nanofluids. Finally, the applications of nanofluids in cooling devices are described. Increased heat transfer, reduced heat transfer time and size of heat exchangers, and finally higher energy and heat efficiency could be the most significant achievements. The parameters affecting the thermal conductivity of nanofluids include concentration, temperature, particle fluid, type of base fluid, and nanoparticles.

Stability issues and operating limitations of nanofluid filled heat pipe: A critical review

It has been proved by researchers that nanofluids are good alternatives to conventional fluids in heat pipes. Typically, application of nanofluids in heat pipes results in improved thermal performance but some contradictions were also reported by the researchers. Although nanofluids are widely used in heat pipes some issues are yet to be resolved like the stability of nanofluids and operational limitations. The stability problem is a big issue for researchers either before or after the operational cycle. Therefore, it is important to enhance the nanofluid stability for the commercialization of the heat pipe. In this regard, this paper aims to study and summarise the outcomes of applications of nanofluids in different heat pipes. The authors emphasized on stability problems of nanofluids in heat pipes. Moreover, the impacts of operating limitations are also reviewed in this article.

An overview of recent advancements and applications of hybrid nanofluids

As a result of the continuing rise in global temperature, catastrophic climatic conditions are being brought on by a growth in energy demand. Creating long-lasting, highly effective thermal solutions is essential to solving this problem. Research on diverse nanofluids for enhancing performance in thermal applications has recently attracted much attention due to their exceptional properties. This review provides a summary of the various approaches used to synthesize nanofluids. Hybrid nanoparticles are a good candidate for improving the efficiency of thermal systems due to their distinctive morphology, stability, optical characteristics, high surface area, low toxicity, and improved thermo-physical properties. Therefore, hybrid nanofluids, consisting of diverse nano-sized particles that may be binary or ternary, have improved thermo-physical properties. In addition to methods for assessing and enhancing thermophysical properties, this review also highlights several factors that affect nanofluids' stability. In addition, potential applications for nanofluids are also discussed.

Review of the impact of nanomaterial on the thermal efficiency of an evacuated tube solar air heater

The purpose of this review article is to analyse the use of nanomaterials to augment the thermal efficiency of an evacuated tube solar air heater (ETSAH). As a consequence of this, different varieties of nanomaterial are developed and utilized in the evacuated tube solar air heater. A comprehensive investigation is being carried out into both the incorporation of nanomaterials into the evacuated tube collector and the improvement in performance. During the course of this in-depth research, a number of issues have been investigated. One of these is how the enhancement of heat transfer is affected by the use of distinct nanofluid types, sizes, volume fractions, and applications in a variety of evacuated tube collector types. For the purpose of justifying and, ultimately, explaining the behaviors of nanomaterials for the purpose of thermal augmentation of evacuated tube collector, analyses have been performed and are being addressed here. Incorporating nanoparticles, as shown by an analysis of the relevant literatures, results in a substantial improvement in the thermal efficiency. From the literature survey, the heat pipe evacuated solar air heater tube using SWCNTs nanofluids was found to have a maximum enhanced efficiency of 93.43%.

A Review Paper on Thermal Comfort and Ventilation Systems in Educational Buildings: Nano-Mechanical and Mathematical Aspects

Thermal comfort has always been an essential factor that affects students’ productivity and success. Students spend considerable time at their schools or universities more than any other building type except their homes. Thus, indicating the importance of providing thermal comfort in educational buildings. Many studies worldwide are conducted to assess and optimize thermal comfort inside classrooms. However, the results have not been accurate even for similar study conditions due to the differences in the studies’ conditions. This paper focuses on thermal comfort studies in educational buildings (classrooms). The studies are divided into two sections, the first covering field studies methodologies, objective, and subjective questionnaires, and the second reviewing thermal comfort results based on the climatic zone, educational level, and analysis approach. It is recommended that thermal comfort studies be carried out using rational and adaptive models as they provide more accurate, reliable results. Also, it is found that thermal comfort standards are generally inadequate to assess thermal comfort in classrooms. Thus, other international standards should be created and considered for classroom assessment. Over the past few years, the combination between nanotechnology and architecture engineering has been widely used in several disciplines because of its crucial significance in finding new nanodevices to contribute in reducing of energy consumption, particularly on construction materials. Filling functionalized tools with nanoparticles plays a critical role in improving the thermal and optical properties, particularly with respect to nanofluids applications, i.e., buildings applications of thermal comfort. The experimental results of long-term studies show that the calculation values of optimization have a consistent agreement with the experimental transmission of nanofluids models.

Simultaneous features of nonuniform heat sink/source and activation energy in entropy optimized flow of Sutterby fluid subject to thermal radiation

The applications of nanofluids (NFs) have been comprehensively explored in current years, as they have abundant potential for technical progress and more prominently offer assistances that can be associated with the applications of NFs for several determinations. Nanotechnology can be applied in various technological fields such as medicine, information technologies, food safety and novel materials. Here, novel properties of entropy generation in a mixed convective magneto flow of a Sutterby nanomaterial to an extended surface is scrutinized. Nanofluid model comprises Brownian motion and thermophoresis aspects. The expression of energy depends upon the phenomenon of viscous dissipation and thermal radiation. We formulated the Bejan number and entropy generation. To reduce PDEs into nonlinear ODEs, we use transformation of variables and then the resultant system is solved by bvp4c technique. The influence of the parameters involved, such as thermal radiation, chemical reaction parameter, diffusive variable, magnetic parameter, thermophoresis parameter and Schmidt number for temperature, concentration as well as Bejan number, entropy generation are inspected through tables and graphs.

Heat transfer performance of nanofluids in heat exchanger: a review

Energy is a key aspect of any country’s economic development. Improving heat transfer performance leads to saving energy. Nanotechnology has a key role to play in optimizing heat exchangers. Fluids containing nanosized particles are called nanofluids. Nanofluids have higher thermal conductivity than typical liquids. This paper outlines current research on convective heat transfer performance, thermophysical properties, particle size, and volume concentration effects in nanofluid studies. M easurement m ethods f ort h ermal conductivity and correlations used by earlier researchers to determine thermal conductivity are also encompassed. The main applications of nanofluids as liibricants a nd radiator systems to improve the efficiency of he at removal fr om ve hicle en gines ha ve al so be en emphasized. Results suggest that by using a larger size of particle some drawbacks include particle sedimentation, clogging, erosion, stability, and increasing pressure drop. Enhancing thermal conductivity with optimum volume concentration. Improving the efficiency of heat exchange systems is one of the possible ways to reduce energy consumption. The need for optimum concentration of nanofluids is required. The Problem of stability, corrosion, and erosion arrived by increasing the volume concentration of nanoparticles in a nanofluid.

Significance of nanoparticle radius and inter-particle spacing toward the radiative water-based alumina nanofluid flow over a rotating disk

Abstract The study of nanofluid flow over a rotating disk has significant importance because of its enormous range of implementations, including cancer treatments, chemotherapy, nanomedicines, fermentation sciences, selective drug delivery, food sciences, biosensors, biomedicines, and electronics. Due to these applications of nanofluid, the present problem investigates the magnetohydrodynamic flow of nanofluid with nonlinear thermal radiation and viscous dissipation. In this analysis, the aluminum oxide nanoparticles are mixed with water. Furthermore, the mechanism for inter-particle spacing and radius of aluminum oxide nanoparticles on the dynamics of the two-dimensional flow of nanofluid are investigated. The present problem is modeled in the form of partial differential equations (PDEs), and these PDEs are converted into ordinary differential equations with the help of suitable similarity transformations. The analytical solution to the current modeled problem has been obtained by using the homotopy analysis technique. The main purpose of the present research work is to analyze the behavior of the velocity and temperature of the nanofluid for small and large radius of the aluminum oxide nanoparticles and inter-particle spacing. Also, the role of heat transport is computed for linear and nonlinear thermal radiation cases. The major findings and principal results of this investigation are concluded that the primary velocity of nanoliquid is augmented due to the intensification in suction parameter for both the small and larger radius of aluminum oxide nanoparticles. Furthermore, it is perceived that the heat rate transfer is larger when the Eckert number and nanoparticle volume fraction are higher for both nonlinear and linear thermal radiation cases.

Synthesis, characterization and application of SiO2 and CuO nanofluid in spray cooling of hot steel plate

Synthesis, characterization and application of SiO2 and CuO nanofluid in spray cooling of hot steel plate

Performance analysis of a concentrated direct absorption solar collector (DASC) with nanofluids using computational fluid dynamics and discrete ordinates radiation modelling (CFD-DORM)

This study utilises computational modelling to investigate the application of thermal nanofluids in direct absorption solar collectors (DASC), including the effect of optical and thermal properties on the prediction of thermal energy production. A single-phase, computational fluid dynamics (CFD) model has been used to understand the hydrothermal behaviour of nanofluids operated at high temperature. A non-gray discrete ordinate radiation model (DORM) was coupled to the CFD to capture the dependence of optical parameters on the bulk temperature variation. In order to increase the robustness of the numerical modelling approach, the extinction coefficient of the solar participating media, including the reflective and transmissive behaviour of the semitransparent wall, were taken into consideration. Results show that the exergy efficiency is lower when using fully diffusive conditions at the semitransparent wall as opposed to fully specular conditions. Overall, exergy efficiency decreases with the Nusselt number, Nu, (until Nu=10∼12), although it increases with non-dimensional irradiation. When modelling with temperature-dependent as opposed to temperature-independent properties of the working fluid, the Carnot efficiency was found to vary by 0.67% to 3.30%. Additionally, a correlation between the hydraulic entrance length and Reynolds number, Re, (in the range Re<1,000) has been established and this can be applied for the further hydrothermal analysis. This study serves as a basis for future numerical modelling of any volumetric solar receiver that takes into account the various key system performance indicators of the solar participating media.

Influence of Preparation Characteristics on Stability, Properties, and Performance of Mono- and Hybrid Nanofluids: Current and Future Perspective

Nanofluids (NFs) synthesized via the suspension of diverse nanoparticles into conventional thermal fluids are known to exhibit better thermal, optical, tribological, and convective properties, photothermal conversion, and heat transfer performance in comparison with traditional thermal fluids. Stability is pivotal to NF preparation, properties, performance, and application. NF preparation is not as easy as it appears, but complex in that obtaining a stable NF comes with the harnessing of different preparation parameters. These parameters include stirring duration and speed, volume, density, base fluid type, weight/volume concentration, density, nano-size, type of mono or hybrid nanoparticles used, type and quantity of surfactant used, and sonication time, temperature, mode, frequency, and amplitude. The effect of these preparation parameters on the stability of mono and hybrid NFs consequently affects the thermal, optical, rheological, and convective properties, and photothermal conversion and heat transfer performances of NFs in various applications. A comprehensive overview of the influence of these preparation characteristics on the thermal, optical, rheological, and properties, photothermal conversion, and heat transfer performance is presented in this paper. This is imperative due to the extensive study on mono and hybrid NFs and their acceptance as advanced thermal fluids along with the critical importance of stability to their properties and performance. The various preparation, characterization, and stability methods deployed in NF studies have been compiled and discussed herein. In addition, the effect of the various preparation characteristics on the properties (thermal, optical, rheological, and convective), photothermal conversion, and heat transfer performances of mono and hybrid NFs have been reviewed. The need to achieve optimum stability of NFs by optimizing the preparation characteristics is observed to be critical to the obtained results for the properties, photothermal conversion, and heat transfer performance studies. As noticed that the preparation characteristics data are not detailed in most of the published works and thus making it mostly impossible to reproduce NF experimental studies, stability, and results; future research is expected to address this gap. In addition, the research community should be concerned about the aging and reusability of NFs (mono and hybrid) in the nearest future.

Nanofluids application in machining: a comprehensive review

Nanofluids application in machining: a comprehensive review

Nanofluids, micro-lubrications and machining process optimisations − a review

The lubrication is a prime requirement of metal cutting industries to assure high quality performance. The conventional technique of coolant flow is less economical and eco-friendly. Recently, nano fluids found better cutting fluid in machining due to potential thermal and heat transfer properties. The role of micro-lubrication techniques and process optimization are equally important for improving process performance. The literature review presents the findings of different researchers in the field of nano fluids and micro-lubrication techniques. The experimental studies were focused on better process performance using micro-lubrication techniques, especially nanofluid MQL with optimized process parameters. The thermal conductivity of water based TiO2 nano fluid shows improvement by 22% in base fluids. The case study discussed which is focused on preparation and characterization of nano fluid, experimental setup and optimization of process parameters by Jaya algorithm. Finally, application of nano fluid, and challenges during nano fluid preparation is identified. The scope of research work is recommended for further study to obtain an economical, eco-friendly manufacturing process.

Recent advances in thermal conductivity and thermal applications of graphene and its derivatives nanofluids

• Seven factors should be considered in the study of graphene thermal conductivity. • Significant research gap exists in factors of graphene thermal conductivity. • Positive and negative effects both exist when graphene nanofluids are applied. • Economics and environment must be considered in application of graphene nanofluids. • More thermal studies on the graphene nanofluids are warranted. With the rapid development of industrial technology, more and more high-power-consumption devices are utilized, resulting in significant challenges to the durability, reliability, and efficiency of devices, facilities, and systems. Developing efficient thermal management systems for high power consumption application scenarios has evolved as a prominent research topic. Graphene nanomaterials are suitable candidates for nanofluids because of their excellent physical properties and high thermal conductivity. Although there are many studies on graphene nanofluids, there is no comprehensive review article about the influencing factors of thermal conductivity and the applications of graphene nanofluids, especially in economic and environmental analysis. This paper reviews the influencing factors of the graphene nanofluid thermal conductivity, including temperature, nanoparticle size and shape, base fluid, concentration, pH, surface modification, and ultrasonication. Moreover, the applications of graphene nanofluids in heat pipes, heat exchangers, solar collectors, and pool boiling devices are presented. Their applications are also discussed in terms of economics and the environment. In addition, the findings of thermal research on graphene nanofluids are summarized, and available opportunities and challenges are demonstrated. It is concluded that graphene nanomaterials significantly improve the thermal conductivity of the base fluid by 1.2% to 83.4%. Graphene nanofluids significantly improved the performance of thermal management devices. This comprehensive review is necessary to promote the research and effective application of graphene nanofluids in the context of sustainable development and carbon neutrality.

Enhancing Heat Transfer Performance: Nanofluids Application in Helical Microfin Tube Concentric Heat Exchangers

This manuscript explores the application of nanofluids in helical microfin tube concentric heat exchangers and investigates the potential for improved heat transfer performance. Helical microfin tubes offer enhanced heat transfer characteristics due to increased surface area and improved fluid mixing. When combined with nanofluids, which are base fluids with suspended nanoparticles, the thermal conductivity and convective heat transfer properties can be further enhanced. The objective of this present work is to investigate experimentally on heat transfer enhancement Al2O3/distilled water (0.05 vol.%) flowing through a helical microfin concentric heat exchanger in both parallel and counter flow in the vertical direction. The result is revealed that Al2O3/water nanofluids has enhanced thermal evaluation performance to water as base fluid. Counter flow might exhibit a more balanced performance, with a moderate enhancement in heat transfer while considering the pressure drop compared to parallel flow.

Structure and self-diffusivity of alkali-halide electrolytes in neutral and charged graphene nanochannels.

Understanding the microscopic behaviour of aqueous electrolyte solutions in graphene-based ultrathin nanochannels is important in nanofluidic applications such as water purification, fuel cells, and molecular sensing. Under extreme confinement (<2 nm), the properties of water and ions differ drastically from those in the bulk phase. We studied the structural and diffusion behaviour of prototypical aqueous solutions of electrolytes (LiCl, NaCl, and KCl) confined in both neutral and positively-, and negatively-charged graphene nanochannels. We performed molecular dynamics simulations of the solutions in the nanochannels with either one, two- or three-layer water structures using the effectively polarisable force field for graphene. We analysed the structure and intermolecular bond network of the confined solutions along with their relation to the self-diffusivity of water and ions. The simulations show that Na and K cations can more easily rearrange their solvation shells under the graphene nanoconfinement and adsorb on the graphene surfaces or dissolve in the confinement-induced layered water than the Li cation. The negative surface charge together with the presence of ions orient water molecules with hydrogens towards the graphene surfaces, which in turn weakens the intermolecular bond network. The one-layer nanochannels have the biggest effect on the water structure and intermolecular bonding as well as on the adsorption of ions with only co-ions entering these nanochannels. The self-diffusivity of confined water is strongly reduced with respect to the bulk water and decreases with diminishing nanochannel heights except for the negatively-charged one-layer nanochannel. The self-diffusivity of ions also decreases with the reducing the nanochannel heights except for the self-diffusivity of cations in the negatively-charged one-layer nanochannel, evidencing cooperative diffusion of confined water and ions. Due to the significant break-up of the intermolecular bond network in the negatively-charged one-layer nanochannel, self-diffusion coefficients of water and cations exceed those for the two- and three-layer nanochannels and become comparable to the bulk values.