Utilization Of Nanofluids Research Articles

Natural convection magneto hydrodynamic filled with TiO2 nanofluid with a right-angled triangle obstacle within square cavity

The goal of this study is to examine the result of natural convection, magnetohydrodynamics, and nanofluids within a square cavity with an obstacle of a right-angle triangle within it. Among the various nanoparticles, TiO2 nanoparticles blended with water have shown promise in improving heat transfer. The Finite Element Method is used for the simulation. By utilizing the commercial software 'COMSOL Multiphysics 6.1' graphical illustrations, the influence of prominent parameters on streamline, isotherm contours and the local Nusselt number is effectively portrayed. The key factors that play a dominant role include the Prandtl number (Pr = 6.2) and Rayleigh number (104 <= Ra <= 106), Hartmann number (Ha = 0, 30, 50), and the heat source/sink (Q = -6, 0, 6) employed. The result confirms that the decline in fluid velocity and convective heat transfer is due to the enhancement of the Lorentz force. This outcome of the study affirms that the appropriate amalgamation of nanoparticles significantly improves the transmission of heat properties of fundamental fluids. The discoveries of this investigation could aid in comprehending the hydrothermal aspects of thermal systems, including electronic cooling, solar power and the utilization of nanofluid to regulate liquid movement and thermal exchange attributes within the annular space.

Study of impact of nano fluids on performance of microchannel heat exchangers using CFD

Addressing the critical issue of heat generation in electronic devices due to miniaturization and higher power density is essential. As electronic components become more compact, they generate more heat flux, necessitating efficient thermal management solutions. Traditional methods and fluids, such as water, struggle to meet the demand for efficient heat dissipation. To address this challenge, the utilization of nanofluids presents a promising solution. The objective of this study is to use CFD methods to examine how a nanofluid can improve heat transmission and lower the maximum temperature in a microchannel heatsink. This article presents the study of microchannel heatsinks with two distinct channel counts (five and eight). A constant flow, incompressible, laminar model was used to verify the findings. The working fluids used in the study were water in various concentrations, water-based nanofluids of Fe3O4-water and MWCNTs. CFD simulations revealed that a MWCNT-water nanofluid at 0.2 % concentration significantly improved cooling performance compared to water, demonstrating the potential of nanofluids for efficient thermal management in electronic devices.

Enhancing heat exchanger performance with perforated/non‐perforated flow modulators generating continuous/discontinuous swirl flow: A comprehensive review

AbstractHeat exchangers are crucial in transferring heat and finding applications across various industries. Numerous strategies have been devised to improve and optimize the heat transfer process within these systems. Among these, passive methods have garnered significant attention for their ability to operate without external power consumption. This article examines the recent experimental and computational studies conducted by researchers since 2018 on passive enhancement techniques, especially twisted tape, wire coil, swirl flow generator, and others, to boost the thermal efficiency of heat exchangers and aid designers in adopting passive augmentation methods for compact heat exchangers. Recently, researchers' new class of flow maldistribution devices, referred to as swirl flow devices, has gained attention; which enhances convective heat transfer by introducing swirl into the main flow and disrupting the boundary layer at the tube surface through alterations in surface geometry. Twisted tape inserts are devices that demonstrate better performance in laminar flow compared to turbulent flow. Conversely, other passive techniques like ribs, conical nozzles, and conical rings are generally more effective in turbulent flow than laminar flow. A recent research trend is the utilization of nanofluids in combination with other passive heat transfer enhancement techniques like turbulators, ribs, and twisted tape inserts in heat exchangers, which can reduce exergy losses and improve overall convective heat transfer coefficient and effectiveness of heat exchanger.

A Comprehensive Evaluation of Recent Studies Investigating Nanofluids Utilization in Heat Exchangers

This comprehensive review critically examines recent research concerning the application of nanofluids in heat exchangers. The utilization of nanofluids, which are colloidal suspensions of nanoparticles in a base fluid, has garnered significant attention in enhancing heat transfer performance. Various studies have explored the potential benefits and challenges associated with incorporating nanofluids into heat exchanger systems. Through a systematic analysis of recent literature, this review assesses the effectiveness of nanofluids in improving heat transfer efficiency and overall performance of heat exchangers. Key parameters such as nanoparticle concentration, size, and type are thoroughly evaluated to understand their influence on heat transfer characteristics. Additionally, factors such as stability, flow behavior, and thermal conductivity enhancement are scrutinized to provide a comprehensive understanding of nanofluid behavior in heat exchangers. The review also addresses potential limitations and areas requiring further investigation to optimize the utilization of nanofluids in heat exchanger applications. By synthesizing recent findings, this review aims to contribute to the advancement of knowledge in the field of heat exchanger technology and nanofluid applications. Ultimately, the insights provided in this review offer valuable guidance for researchers and engineers seeking to enhance heat transfer processes through the implementation of nanofluid-based heat exchangers. Nanofluids offer advantages like enhanced thermal conductivity and tailored properties, promising optimized heat exchanger designs, leading to energy efficiency and reduced costs. However, challenges remain, such as nanoparticle dispersion and cost-effectiveness, necessitating further research for refinement. Interdisciplinary collaboration is crucial for advancing nanofluid applications, fostering innovation to meet demands for sustainable heat transfer solutions.

Innovative insights into nanofluid-enhanced gear lubrication: Computational and experimental analysis of churn mechanisms

This study offers unique insights into the churn lubrication mechanism in gear transmission systems through the utilization of nanofluids for the first time. Various performance parameters of the prepared nanofluid lubrication oil are measured, along with the discussion of suspension stability. Based on the overset mesh method and VOF multiphase flow model, a rotating fluid domain calculation model considering the nanofluid-air two-phase is proposed. The high-speed nanofluid lubrication experiment platform is established to track churn phenomena and identify the oil volume fraction on the gear surface. Comparing simulation results with experimental data confirms the calculation accuracy in depicting oil flow and churn lubrication. Result shows that the interaction between droplets and the gear surface involves splash, rebound, adhesion, and diffusion. The nanofluid exhibits improved adsorption, resulting in a higher oil volume fraction. When the rotation speed is increased, intensified oil spatter and atomization are observed. The ranking of nanofluid lubrication performance is Al2O3, SiO2, Fe3O4, CuO, and TiO2 particles, which are approximately aligned with contact angle magnitudes. For 3 % nanoparticles concentration, less oil is swung off, more is drawn into the gear meshing zone, and subsequently squeezed out. Image recognition results align with numerical simulation, indicating that the oil distribution of nanofluid is better than that of base fluid lubrication. This work serves as a foundational exploration for future nanofluid lubrication and heat dissipation, offering insights into preventing oil film rupture, tooth surface wear, gluing and other failure mechanisms.

A Novel Cooling System by Surface Corrugation and Nanofluid Utilization for the Performance Improvement of Photovoltaic Module Coupled with Thermoelectric Generator and Efficient Computations by Using Artificial Neural Network-Based Hybrid Scheme

For a photovoltaic module coupled with thermoelectric generator, a unique wavy cooling channel is proposed, and its performance is numerically assessed by using three-dimensional computations. The cooling channel uses nanofluid of alumina–water with various shaped nanoparticles (spherical, cylindrical and brick). Numerical simulations are performed for a range of parameters for the corrugation amplitude (0≤Amp≤0.1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$0 \\le \ ext {Amp} \\le 0.1$$\\end{document}), wave frequency (2≤Nf≤16\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$2 \\le \ ext {Nf} \\le 16$$\\end{document}), nanoparticle loading quantity (0≤SVF≤0.03\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$0 \\le \ ext {SVF} \\le 0.03$$\\end{document}), and nanoparticle shape (spherical, brick, and cylindrical). We analyze the photovoltaic module’s average temperature and temperature uniformity for a variety of parameter variations. When nanofluid and greater channel corrugation amplitudes are utilized, the average panel surface temperature is decreased more. A wavy shape of the cooling channel at the maximum corrugation amplitude yields a cell temperature reduction of 1.88 o\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\ ext {o}$$\\end{document}C, while frequency has little impact on average cell temperature and its uniformity. The best-performing particles are those with cylindrical shapes, and the drop-in average photovoltaic temperature with solid volume fraction is essentially linear. As utilizing cylindrical-shaped particles, the average temperature of corrugated cooling channels decreases by around 1.9 o\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\ ext {o}$$\\end{document}C as compared to flat cooling channels with base fluid at the greatest solid volume fraction. As compared to un-cooled photovoltaic, cell temperature drops by around 43.2 o\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\ ext {o}$$\\end{document}C when employing thermoelectric generator. However, temperature drop value of 59.8 o\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\ ext {o}$$\\end{document}C can be obtained by using thermoelectric generator and nano-enhanced wavy cooling channel utilizing cylindrical-shaped nanoparticles. An hybrid computational strategy for the fully coupled system of photovoltaic with cooling system is provided, which reduces the computational time by a factor of 75.

Computational analysis of transient thermal diffusion and propagation of chemically reactive magneto-nanofluid, Brinkman-type flow past an oscillating absorbent plate

The current work concentrates on increasing the thermal and solutal performance in exponentially accelerating vertical surfaces via the utilization of nanofluids containing the mixtures of base water fluid and Aluminum oxide (Al2O3), Copper (Cu), Titanium dioxide (TiO2) and Silver (Ag) nanoparticles. During the fully utilize the capabilities of nanoparticles in a variety of applications and to evaluate the effects that they will have on the environment and biological systems, it is crucial to comprehend and manage heat transmission. This motivation allows us to investigate the nanofluid boundary layer flows under cross-diffusion effects, as this model study earlier was not conducted, thus the results of this work are new, which describe the novelty of the current problem. The partial differential equations for the developed model are altered into dimensionless statements first via non-dimensionalization. The numerical simulations implementing a finite difference scheme are applied for the solution description. The physical description of the variation of momentum, temperature, and mass fields for different factors is computed and presented graphically for ramped temperature and isothermal heat cases. Convergence and validation of the problem are checked with the help of tables. We found that enhancement in the Reynolds number, Brinkman parameter and magnetic field mark a downward trend in the fluid velocity, but it strengthens with the porosity parameter and time factor. The temperature distribution expands for advancing diffusion-thermal and radiation effects, whereas a contrary pattern was noted with the Prandtl number and heat consumption parameter. The thermo-diffusion effect enlarges the concentration distribution but decays with chemical reaction and Schmidt number.

Numerical modeling and analysis of nanofluids subcooled boiling in a horizontal circular tube

Subcooled flow boiling, characterized by large heat transfer coefficient (HTC), is widely encountered and of great significance in energy industry. To enhance its thermal efficiency for compact applications, nanofluids are employed by improving the thermophysical properties. This article numerically investigates nanofluids subcooled boiling in a horizontal tube under wide-range, multi-factor impacts, including Reynolds number of 40,000–50,000, nanoparticle type, that is, Al2O3, TiO2, Cu, and volume fraction of 1%–5%. The thermal equilibrium assumption and Eulerian multiphase model are utilized after numerical validations. Results indicate that the vapor volume fraction augments along the tube while nanoparticles reduce the vapor production during boiling. As for thermal and flow performance, nanofluids can enhance the HTC at the expense of a rising pressure drop. In the case of Al2O3/Water nanofluid, the maximum of HTC increases by 10.56%. In contrast, the pressure drop increases by 2.1 times when the Al2O3 concentration changes from 1% to 5%. The performance evaluation criterion (PEC) in this article always exceeds 1 for nanofluids, demonstrating that the heat transfer enhancement outweighs the pressure drop penalty, and the Al2O3/Water nanofluid show superior performance with PEC achieving 1.1. This work can provide support for a profound understanding and utilization of nanofluids subcooled boiling.

Vehicle Engine Cooling System: Review Research

This study reveals that nano-refrigerants can improve the overall performance of these systems, particularly when used as nanoparticles in conjunction with a base refrigerant. The results show that nano refrigerants outperform base liquids in warm conductivity, and the size of the nanoparticles affects this conductivity. The thickness of nano-refrigerants shows a vertical pattern as the volume of particles increases, while it decreases with temperature increases. Traditional models, such as the Hamilton-Crosser and Einstein models, fail to accurately predict the warm conductivity and consistency of nanoliquids when temperature is considered. Even a small amount of nanoparticles can significantly improve the base liquid’s conductivity. The use of nano-fluids results in an improved convective intensity transfer coefficient for all volume concentrations of nanoparticles compared to water under different working conditions. This study delves into the characterization of nanofluids for vehicle engine cooling systems, focusing on their thermal properties and heat transfer capabilities. Through an analysis of thermal conductivity, heat transfer coefficients, viscosity, and nanoparticle size, the research aims to optimize the design and implementation of nanofluid-based cooling systems to enhance engine performance and fuel efficiency. By investigating the impact of different nanoparticles and concentrations on these properties, the study provides insights into the potential of nanofluids to improve cooling efficiency in automotive applications. The findings highlight the importance of understanding the relationship between nanoparticle characteristics and thermal properties for the effective utilization of nanofluids in vehicle cooling systems. By synthesizing findings from previous studies, this review aims to provide insights into the potential benefits of utilizing nanofluids in enhancing cooling efficiency and overall engine performance in automotive systems. The analysis underscores the importance of considering nanoparticle characteristics in optimizing nanofluid formulations for effective heat transfer in vehicle cooling systems.

A Review: Nanofluids in Machining for Performance and Sustainability

This study examines the use of hybrid and normal nano cutting fluids in drilling, a process commonly used by sectors of the economy that normally depend on gulf cut or dry cut oil. These lubricants work well for drilling, but they don’t improve surface smoothness enough and might shorten the tools lifespan. In order to mitigate these problems, scientists are investigating nanofluids as an alternative to conventional lubricants. They are experimenting with different mixtures of nanofluids as a foundation in drilling operations. Multiple investigations demonstrate that the utilization of nanofluid as cutting fluid can improve lubrication as well as cooling in comparison to conventional cutting fluids. Various drilling techniques, such as dry machining, minimum quantity of lubrication, and solid lubricant, are employed however literature suggests that MQL is the most environmentally friendly option. Given that drilling involves working on tough surfaces, it is imperative to have a high-quality coolant lubricant. While there are several choices available for base lubricants, none of them can achieve the required level of surface finish during drilling. As a possible lubricant option in the future, the research suggests using a hybrid nanofluid in combination with multiple base lubricants.

Assessment of thermohydraulic performance and entropy generation in an evacuated tube solar collector employing pure water and nanofluids as working fluids

This study conducts a numerical comparison of the thermal performance of three distinct working fluids (pure water, TiO2, and SiO2 water-based nanofluids) within an evacuated tube solar collector using Computational Fluid Dynamics. The study evaluates thermohydraulic performance alongside global and local entropy generation rates, while considering variations in solar radiation values and inlet mass flow rates. Results indicate that nanofluids demonstrate superior performance under low solar radiation, exhibiting higher outlet temperatures, velocities, thermal efficiency, and exergy efficiency compared to pure water. However, at the higher solar radiation level, the efficiency of SiO2 water-based nanofluid diminishes due to its impact on specific heat. Furthermore, the entropy generation analysis reveals significant reductions with TiO2 water-based nanofluid in all the phenomena considered (up to 79 %). The SiO2 nanofluid performance aligns closely with pure water under high radiation value. This investigation offers valuable insights into the utilization of nanofluids in solar collectors across diverse operating conditions, emphasizing their pivotal role in enhancing overall performance.

Thermophoretic particle deposition in a nanofluid flow across a disc with non-fourier heat flux: An investigation using tangent hyperbolic model

Non-Newtonian nanofluids are attracting the attention of researchers and academics due to the high heat transmission rates that they possess. To improve thermal devices and exchangers, the researchers come up with innovative and expense-effective methods. One of the advanced technological approaches that can be utilized to enhance the thermal performance of devices is the utilization of nanofluids. This non- Newtonian nanofluid possesses the advanced properties of increasing heat transfer and destroying harmful bacteria. For this purpose, the present theoretical work is to explore the heat and thermophoretic particle deposition analysis on the tangent hyperbolic nanofluid flow over the rotating porous disk with presence of non-Fourier heat flux model and nanoparticle aggregation effect. Darcy-Forchheimer fluid model is adopted to develop the fluid flow system. Furthermore, the nanofluid’s viscosity and thermal conductivity are expressed through advanced modeling, employing the modified Krieger-Dougherty model for viscosity and the Maxwell-Bruggeman model for thermal conductivity. The nanoparticles and base fluid involved in this context are Molybdenum disulfide ( Mo S 2 ) and Water/carboxyl-methyl cellulose (CMC) respectively. The mathematical representation of the fluid flow and energy propagation involves a system of coupled partial differential equations (PDEs). The system of partial differential equations (PDEs) is transformed into non-dimensional ordinary differential equations (ODEs), which are then solved both analytically and numerically using the Homotopy Analysis Method(HAM) and Runge-Kutta-Fehlberg (RKF) method along with shooting technique. Exploring the graphical representation reveals a comprehensive analysis of key factors influencing velocity, temperature, and concentration. Through innovative visualization, these parameters take center stage, providing insights into their intricate interplay and dynamic relationships. The heat transfer rate is enhanced 0.24% and 1.4% by rising the values of thermal relaxation parameter and Weissenberg number. Also, the mass transfer rate is accelerated 0.8% and 0.14% due to enhancing the values of thermophoretic coefficient and thermophoresis parameter.

An Experimental and Numerical Study of the Effect of Microchannels Geometry on Heat Transfer of Nanofluids

The use of micro-channel heat exchangers is widespread across a variety of different industrial sectors. This study presents both an experimental and a numerical analysis to compare the performance of four different designs of microchannel heat sinks. The study dealt with using pure water and nanofluid (Al2O3, CuO, and TiO2–H2O) with volumetric concentrations of (0.01- 0.03) as coolants. The software Comsol Multiphysics was employed for conducting numerical analysis in order to simulate and resolve the issue pertaining to fluid and heat flow in a three-dimensional domain. A constant heat flux of 170 kW/m2 is applied to the lower wall of the four microchannels. The simulations were exclusively conducted within the laminar regime, covering a range of Reynolds numbers spanning from 50 to 150. The impact on the temperature of the microchannel's wall, thermal resistance, pressure drop, and friction factor is demonstrated. Based on the results obtained, it is evident that the utilization of nanofluid in the cooling process of a wavy and zigzag microchannel heat sink yields superior performance in terms of both heat transfer and dissipation, as compared to the implementation of pure water as the cooling medium for the heat sink.

Numerical Study of Nonlinear Convective Heat Transfer Flow of Metal Oxide Nanoparticle TiO<sub>2</sub>-Enhanced Fluid between Two Concentric Cylinders with Aggregation of Nanoparticles

The utilization of nanofluid is one of the most used techniques for improving heat transfer in applications like heat exchangers, heat storage systems, mining and nuclear power plants. Because of high thermal conditions, the density relation of the working fluids may not be linear, therefore, an analysis is conducted on the quadratic convection of nanofluid flow in a porous annulus region considering an inclination. The phenomenon of temperature-dependent viscosity on the flow, kinematics of nanoparticle aggregation, and heat transport phenomenon with Exponential Space-Related Heat Source (ESHS) and a Temperature-Related Heat Source (THS) are considered. The governing equations are solved numerically. The influence of key parameters is analyzed using 2D and 3D graphs.

Numerical examination of exergy performance of a hybrid solar system equipped with a sheet-and-sinusoidal tube collector: Developing a predictive function using artificial neural network

Integrating cooling systems with photovoltaic-thermal (PVT) collectors has the potential to mitigate the exergy consumption in the building sector due to their capability for simultaneous power and thermal energy generation. The simultaneous utilization of nanofluid and geometry modification resulted in a synergetic enhancement in the performance of PVTs and thereby reducing their sizes and costs. In addition, there is still a lack of high accurate predictive model for the estimation of the performance of PVTs at a given Re number and nanofluid concentration ratio to be used in engineering design for the further product commercialization. To this end, the current numerical study investigates the exergy electricity, thermal, and overall exergies of a building-integrated photovoltaic thermal (BIPVT) solar collector with Al2O3/water coolant. The increase in nanoparticle concentration (ω) from 0 % to 1 % increased the useful thermal exergy and overall exergy efficiency (Exu,t/ Υov) by 0.3999 %/0.0497 %, 1.3959 %/0.2598 %, and 0.7489 %/0.1771 % at Re numbers of 500, 1000, and 1500, respectively, while Exu,t/ Υov exhibited a reducing trend at Re = 2000; 0.3928 %/0.1056 % decrease. In addition, the increase in ω from 0 % to 1 % caused the useful electricity and electrical exergy (Exu,e/ Υe) to be diminished by 0.0060 %/0.0025 % at Res 500 and 1000, and to be escalated by 0.0113 %/0.0055 % at Res of 1500 and 2000. Meanwhile, the Re augmentation, from 500 to 2000, improved the Exu,t, Exe, Υe, and Υov by 60 %, 1.26 %, 1.26 %, and 17.50 %, respectively, at different ω s. In addition, two functions were developed and proposed by applying a group method of data handling-type neural network (GMDH-ANN) to forecast the value of Υov based on two input values (Re and ω). The results showed high accuracy of the proposed model with MSE, EMSE, and R2 of 0.0138, 0.1143, and 0.99785, respectively.

Numerical investigation on pillow plate heat exchangers: Effects of nanofluid and geometry

The current research involves a comprehensive numerical simulation of nanofluid flow within a pillow-plate heat exchanger. Al2O3-water nanofluid and water are used as the working fluids, simulated using a two-phase mixture model. The study explores the influence of geometric properties on the heat exchanger’s hydrodynamic and thermal performance. It also delves into the utilization of nanofluids as the working medium and its impact on dimensionless pressure drop, Nusselt numbers, and dimensionless temperature. An innovative aspect of this research lies in the integration of artificial intelligence (AI) techniques for heat exchanger design optimization. Specifically, a Random Forest Regressor (RFR) AI model is employed to predict crucial parameters, including heat transfer coefficient (HTC) and pressure drop, based on input design variables. Key findings reveal that non-linear hole layouts in heat exchangers significantly improve Nusselt numbers by up to 25 percent. Conversely, larger holes result in higher pressure drops. The use of nanofluids enhances thermal efficiency by up to 10% while increasing pressure drop by around 7%.

Revolutionizing Automotive Cooling: A Comprehensive Review on Enhancing Radiator Performance through Nanofluid-Based Heat Transfer Augmentation and Pipeline Integration of Phase Change Materials

Abstract: This review explores cutting-edge advancements in automotive cooling systems, specifically focusing on enhancing radiator performance through a dual approach: the utilization of nanofluids for improved heat transfer and the incorporation of phase change materials (PCMs) within radiator pipelines. Nanofluids, engineered colloidal suspensions of nanoparticles in traditional coolants, exhibit enhanced thermal conductivity, leading to improved heat dissipation. The paper provides an overview of various nanofluid synthesis methods and reviews experimental studies showcasing their efficacy in augmenting thermal performance within automotive radiators. In parallel, the integration of PCMs into radiator pipelines introduces a novel dimension to heat management. Phase change materials, with their ability to store and release latent heat during phase transitions, contribute to temperature regulation and energy efficiency. The review explores different types of PCMs, their selection criteria, and summarizes experimental findings related to their incorporation in automotive cooling systems. A significant portion of the paper delves into the synergies and challenges associated with combining nanofluid-based heat transfer enhancement and PCM integration. The discussion underscores the potential for a holistic approach to radiator design, leveraging the complementary benefits of both nanofluids and PCMs. The findings presented in this review offer insights into the evol

Hydroxyl functionalized MWCNT nanofluids with excellent photothermal conversion performance in direct absorption solar collectors

Developing novel nanofluids with good stability, excellent photothermal conversion performance, and appropriate thermophysical properties is of great importance in promoting the practical utilization of nanofluids in solar collectors. In this work, hydroxyl multi-walled carbon nanotube (MWCNT-OH) nanofluids are proposed, which can achieve a high photothermal conversion of 88.2 % at a concentration of 20 ppm under 1-sun irradiation. Both the sedimentation experiment and spectrophotometer analysis prove that the prepared MWCNT-OH nanofluids have excellent stability. The influence of hydroxyl functionalization, MWCNT-OH concentrations, and temperature on the thermophysical and optical properties is analyzed. Moreover, the comparison between MWCNT-based nanofluids with different functionalization reported in the literature and our work is carried out, the results show that MWCNT-OH nanofluids in our work outperform MWCNT-based nanofluids with other types of functionalization reported in the literature. This work may promote the use of MWCNT-OH nanofluids as working fluids in solar collectors.

A comparative experimental investigation of dynamic viscosity of ZrO2/DW and SiC/DW nanofluids: Characterization, rheological behavior, and development of new correlation

In general, A nanofluid is a substance in which solids and fluids are mixed. The nano-powder of zirconium oxide (ZrO2) and silicon carbide (SiC) was dispersed into the distilled water (DW) using the widely adopted two-step technique. A Brookfield viscometer was used to measure the viscosity of the nanoparticles of ZrO2/DW and SiC/DW, where the temperature ranged between 20 and 60 °C and different solid volume fractions of 0.025, 0.05, 0.075, and 0.1 % were used. An examination of the mono nanofluids of ZrO2/DW and SiC/DW was conducted to assess their rheological behaviour. The findings of the experiments revealed that the Newtonian behaviour did not change when the nano-powder was added. Increasing the solid volume fraction of the nanoparticles and lowering the temperature resulted in the sample's dynamic viscosity being augmented. Hence, as the temperature rose, nanoparticles had a more observable impact on the viscosity. Furthermore, the findings showed that the increase in the ZrO2/DW nanofluid's viscosity peaked at 226.3 %, whereas for the SiC/DW nanofluid, it was 110.5 %. Additionally, according to the results of the experiments, new correlations capable of predicting the investigated nanofluids' viscosity in relation to solid concentration and temperature has been suggested. The study's results could motivate expanded utilization of nanofluids by researchers working on energy applications.

Recent advances in solar thermal system involving nanofluid utilization: A mini review

Nanofluids are fluids that contain nanoparticles that improve thermal characteristics. The thermal efficiency of systems that use nanofluids is higher than that of systems that use water as the working fluid. Solar thermal energy and systems, nanofluids and their structures, nanofluid integration into solar thermal systems, and the positive and negative consequences of nanofluid usage in these systems were all addressed in this study, emphasizing the importance of their integration. This study describes a study on using nanofluids in solar thermal systems. This research aims to examine the potential benefits of employing nanofluids, such as increased efficiency and lower prices. Furthermore, the study demonstrates that using nanofluids can reduce the size of the solar collector required to achieve the same performance level, which can lead to a decrease in the overall cost of the solar thermal system. This study's results indicate that using nanofluids in solar thermal systems can significantly enhance efficiency and reduce costs. However, further research is needed to fully explore the benefits and limitations of using nanofluids in solar thermal systems.