Volume Concentration Of Nanofluid Research Articles

Experimentally exploring the synergy of rotating twisted tape turbulators and hybrid nanofluids for enhanced photovoltaic thermal system performance

In the present study, it is experimentally investigated how the functionality of a photovoltaic thermal unit is affected by utilizing a rotating turbulator and a hybrid nanofluid at the same time. Twisted tape is used as turbulator and water-TiO2/Co3O4 is considered as nanofluid. Two perspectives of energy and exergy are used to analyze the functionality of the unit. The impacts of mixing ratio of TiO2:Co3O4 nanoparticles (1:0, 0.9:0.1, 0.7:0.3, 0.5:0.5, 0.3:0.7, 0.1:0.9, and 0:1), volume concentration of nanofluid (0 %, 0.1 %, 0.5 %, and 1 %), mass flow rate of nanofluid (20, 40, 60, and 80 kg/h), twist pitch of turbulator (10, 30, and 66 mm), and turbulator rotating speed (0, 100, 200, 300, 400, and 500 rpm) on the system functionality are examined. The highest overall energy efficiency of 73.28 % was achieved at a nanofluid concentration of 1 %, twist pitch of 10 mm, rotational speed of 500 rpm, and mass flow rate of 80 kg/h. Moreover, the highest overall exergy efficiency of 13.83 % was achieved at a nanofluid concentration of 1 %, twist pitch of 10 mm, rotational speed of 400 rpm, and mass flow rate of 20 kg/h.

Numerical Study on Heat Transfer Characteristics of Jet Impingement by using MgO Nanofluid

Liquid impingement jet can provide high local heat transfer coefficients between the impinged liquid and the targeted surface. Jet impingement is utilized in the applications which is related to rapid cooling and better control of high temperature in many applications. The studies are carried out numerically by using ANSYS Workbench 18.2. Hexagonal meshing and Shear-Stress Transport (SST) turbulence model is used in the numerical simulation. By using SST turbulence model, the effect of jet Reynolds number, nanofluid volume concentration on the average heat transfer coefficient of the target plate is analysed and discussed. For the effect of varying the Reynolds number, it is observed that the surface average heat transfer coefficient increases at least 76.18% as the Reynolds number increases from 5000 to 10000. Moreover, the heat transfer coefficient increases as the volume concentration increases from 0% to 5%. It is also observed that when the nanofluid with higher thermal conductivity will results in higher heat transfer coefficient where the MgO nanofluid showed the highest heat transfer coefficient. As a conclusion, by increasing Reynolds number, volume concentration and thermal conductivity of nanofluid, the heat transfer coefficient can be enhanced.

Parabolic trough solar collector technology using TiO2 nanofluids with dimpled tubes

Nanoparticle concentrations have recently attracted attention as a means to increase the effectiveness of parabolic trough solar collectors (PTSC). Computational fluid dynamics (CFD) study has recently gained popularity for evaluating the performance of PTSC with Dimpled Tubes using a nanofluid made of TiO2 nanoparticles distributed in deionized water (DI-H2O). The effect of using Dimpled Tubes with varied turbulent flow rates, from 0.5 kg/minto 2.5 kg/min, is studied via a battery of tests and computational fluid dynamics simulations. TiO2nanofluid performance is compared to water, the “base fluid,” in this study.This study investigates the utilization of TiO2 nanofluids in enhancing the heat transfer performance of parabolic trough solar collector (PTSC) technology, particularly when integrated with dimpled tubes.The importance of this research lies in the quest for improving the efficiency of solar thermal systems, which is crucial for sustainable energy production.Variables such as solar collector efficiency, Reynolds number, and Nusselt number are tracked as the inquiry progresses. When TiO2 nanofluids are added to the base fluid within the dimpled tube, the convective heat transfer coefficient increases by an astonishing 34.25 percent.This improvement is most pronounced at a mass flow rate of 2.5 kg/min and a volume concentration of TiO2 nanofluid of 0.3 %. Parabolic trough solar collectors have recently been the focus of attempts to improve efficiency via nanoparticle concentrations. The paper uses Computational Fluid Dynamics analysis to investigate how well Dimpled Tubes work with TiO2/DI-H2O nanofluid. The significant increase in the convective heat transfer coefficient was clarified by experimental and CFD calculations that considered fluctuations in turbulent flow rates. The improvement is particularly striking at a mass flow rate and a volume concentration of TiO2 nanofluid.Findingsindicate a significant improvement in heat transfer rates when TiO2 nanofluids are used, particularly in conjunction with dimpled tubes. The combined effect leads to a notable thermal efficiency enhancement, representing the potential of nanofluid-based improvements in optimizing PTSC performance.

Influence of the twisting and nano fluids on performance of a triangular double tube heat exchanger

Abstract The hydraulic and thermals performance of flow in a double-tube heat exchanger with an inner twisted triangle tube of length L = 1 m has been studied numerically. Equations for energy, turbulence, and Navier–Stokes were used to model the fluid flow and heat transfer in a double-tube heat exchanger with an inner twisted triangle tube. The Reynolds number range was 5000–30,000 for nanofluid (water-Al2O3) as a working fluid under a turbulent flow regime. The considered configuration was examined by varying the volume concentration of nanofluid while keeping the twist ratio constant (Tr = 5). Different cases of volume concentration of nanofluid are triggered (0.05 %, 1 %, 2.5 %, and 4 %, respectively). The numerical outcomes of a double-twisted tube heat exchanger with an inner triangle-twisted tube are validated with the obtainable numerical data. The governing equations were solved with ANSYS Fluent 18.2. The findings reveal that the larger volume concentration of nanofluid (4 %) gives a greater Nusselt number and vice versa due to the increased thermal conductivity of the nanofluid in the double twist tube heat exchanger compared with a plain tube. However, the nanofluid Nusselt number grows with the rise of both the Reynolds number and volume concentration (Ø), and the best value of the Nusselt number is 210 when Reynolds number = 30,000 and Ø = 4 %. The effectiveness of the heat exchanger grows with an increase in the concentration of the nanofluid and a reduction in the torsion ratio compared to the normal tube. The effectiveness of the double-tube heat exchanger with an inner twist triangle tube increases to the highest value of 0.38 at Reynolds 30,000 and Ø = 4 %.

The integration of double-layer triangular micro-channel in three-dimensional integrated circuits for enhancing heat transfer performance

This paper proposed a new heat dissipation structure called double-layer triangular micro-channel (DLTMC) to solve the increasingly serious thermal problem of three-dimensional integrated circuits (3D-ICs). The matrix equation of heat transmission is established to derive steady-state temperature of 3D-ICs with embedded DLTMC, which is based on equivalent thermal resistance network. According to proposed computation thermal model, the heat transfer performances of 3D-ICs with embedded DLTMC concerning different cooling liquids are investigated, where the impacts of different bottom angle of DLTMC, volume concentration of nanofluid and flow velocity of cooling liquid are considered. The results show that the proposed DLTMC structure can significantly reduce steady-state temperature compared with conventional structure of single layer rectangular micro-channel (SLRMC), the corresponding steady-state temperature for them can be reduced over 32.098 %. Besides, it is demonstrated that the steady-state temperature for MWCNT-water and SWCNT-water nanofluids as cooling liquids can be reduced by 22.490 % and 19.801 % than conventional water case, respectively. Moreover, it is manifested that the increase of bottom angle of DLTMC, volume concentration of nanofluid and flow velocity of cooling liquid can evidently improve heat transfer performance of 3D-ICs. Therefore, the presented results in this paper are beneficial for solving complex thermal problems of 3D-ICs.

A TOPSIS-based thermal performance optimization of DHCTHX using MWCNT nanofluids

Double-helically coiled tube heat exchangers are employed in many different heat transfer applications because of their better heat transfer capabilities and compact construction. The double helically coiled tube heat exchanger (DHCTHX) improves turbulence and maximizes heat transfer rate compared to straight tubes. A full factorial, orthogonal array of trials is used in this study (L27) to test various volume concentrations of nanofluids. The pressure drop, de, LMTD0C, re, and F have all been attempted to be optimized using the order preference similarity to the ideal solution technique. In this case, the mass flow rate and volume concentration are the variables for the input process, while the outputs are the heat transfer rate, pressure drop, de, LMTD0C, and F. The experimental results show that a nanofluids volume concentration is 0.6% and its mass flow is 120 with a range of 1460 Dean Numbers, which is the optimal configuration for maximizing the overall heat transmission and minimizing the pressure drop. The multiple-criteria decision-making technique was used in this study to identify the ideal cooling fluids in a DHCTHX with a significant pressure drop. The multi-walled carbon nanotube nanofluids may be used instead of conventional coolants in conjunction with the DHCTHX. According to this strategy, A3B1 is the ideal value, which aligns with the experiments’ findings.

Twisted helical Tape's impact on heat transfer and friction in zinc oxide (ZnO) nanofluids for solar water heaters: Biomedical insight

This study explores the influence of Zinc Oxide (ZnO) nanofluids on solar water heaters with Dimple Tubes and Helical Twisted Tape (DTHTT) surfaces. The helical twisted tape design enhances turbulence, improving nanofluid mixing and thermal exchange. Computational fluid dynamics (CFD) validates the efficiency of the parabolic trough solar water heater (PTSWH) with emphasis on solar light concentration and feed water flow velocity. Optimal conditions include a 0.3% ZnO nanofluid volume concentration, mass flow rates between 1.0 kg/min and 5.0 kg/min, and copper-type twisted helical tapes. Experimental results reveal Nusselt number enhancements of 15.1% and 20.96% at H/D = 10, and 16.72% and 32.12% at H/D = 3, for 0.3% ZnO nanofluid, at Reynolds numbers from 3000 to 8000. The twisted tape arrangement at H/D = 3 exhibits increased fluid mixing, leading to higher convective heat transfer. Friction factor enhancements at Reynolds numbers 3000 and 8000 are 0.26% and 0.38%, respectively, compared to the base fluid. At a 3.0 kg/min mass flow rate, thermal efficiency increases to 39.25%, a 13.25% gain over plain tapes. The model shows a ±3.24% deviation from the expected friction factor, with a total ±1.2% discrepancy between experimental and simulated findings, remaining within an acceptable range.

Water:Ethylene Glycol Properties Alteration Upon Dispersion Of Al2O3 and SiO2 Nanoparticles

Proton exchange membrane fuel cell (PEMFC) seems to be a popular option as a green energy carrier due to its high efficiency and pollutant-free operation. However, the slight temperature difference between the working temperature and surroundings requires innovation in cooling strategy. Active thermal management strategy is limited due to the larger space requirement. Alternatively, utilizing nanofluids as coolant as the passive cooling strategy tends to be a viable quick fix. In this research, thermophysical properties of Al₂O₃:SiO₂ hybrid nanofluids in the base fluid of water: Ethylene Glycol (EG) were discussed comprehensively concerning alterations made in thermal conductivity, dynamic viscosity, and electrical conductivity properties. There were four mixture ratios of 0.5% volume concentration of hybrid nanofluids considered ranging from 10:90, 30:70, 50:50, and 70:30 Al₂O₃:SiO₂. Upon completion of the study, there is an improvement of 9.8% shown in 10:90 Al₂O₃:SiO₂ hybrid nanofluids for thermal conductivity measured at 60C in comparison to the base fluid. Meanwhile, 10:90 Al₂O₃:SiO₂ hybrid nanofluids are also favorable with the lowest values of viscosity as compared to other mixture ratios resulting in lower parasitic loss. Electrical conductivity on the other hand also showed an increment in 10:90 Al₂O₃:SiO₂ hybrid nanofluids as compared to base fluid and other mixture ratios.

The TLBO algorithm-based optimal heat transfer parameters prediction of Al2O3 water nanofluids in variable pitch corrugated tube heat exchanger

This study investigated an Al2O3 nanofluid water-based tube heat exchanger fitted with a corrugated copper tube under laminar flow conditions. This study is carried out to observe the heat transfer rate within the heat exchanger. The effect of nanoparticle concentrations, the flow rate of the working fluid, and the corrugated tube pitch on the heat exchanger efficiency were analysed. The results show that when Al2O3 water nanofluids are sandwiched between corrugated copper tubes, the heat transfer rate is significantly enhanced compared to the smooth tubes. Nanofluids of Al2O3 were prepared with concentrations of 0.25%, 0.5%, and 1% in deionised water. Corrugated tubes with 25 mm, 20 mm, and 18 mm pitches were fabricated for this investigation. The deionised water and Al2O3 nanofluid-flow rates were maintained at 0.1 m3 per hours, 0.15 m3 per hours, and 0.2 m3 per hours, respectively. Results showed that Al2O3 nanofluids improved the heat transfer rate related to water-based fluids. The highest heat transfer occurred in the 18 mm pitch corrugated copper tube in which 1% nanofluid volume concentration was used as the heat transfer medium. It is observed that the heat exchanger containing corrugated copper tubes with pitch 17.88 mm having 0.98 vol.% of Al2O3 nanofluids, flowing at 0.198 m3 per hour, enhances the heat transfer rate between the working fluids.

Mathematical model for a thermal cooling system with variable viscosity and thermal conductivity over a rotating disk

Mathematical models involving rotation of the disks and the flow of fluid over these serve as a prototypical representation of electronic devices including rotational components. The rotation results in substantial heat generation and the excessive heat buildup can affect performance and reliability, and can cause failure. Therefore efficient cooling mechanisms are essential to dissipate the generated heat and maintain the devices’ temperature within safe operating limits. In this research paper, the focus is on investigating the magnetohydrodynamic (MHD) slip flow and heat transfer of power-law nanofluid over an infinite rotating disk. The study incorporates numerical methods to analyze the system, considering the variable thermal conductivity and viscosity as a function of velocity gradients, and employing velocity slip conditions at the boundary. To facilitate the analysis, the similarity transformation technique is applied, which effectively reduces the governing boundary value problem to a set of nonlinear ordinary differential equations (ODEs). The research explores the dependence of the velocity and temperature profiles on various parameters, including the nanofluid volume concentration parameter, power-law index, magnetic parameter, and velocity slip parameters. Through the numerical results, the influence of these parameters on the flow and heat transfer characteristics is presented and thoroughly discussed. The outcomes of the study are presented in the form of graphs and tables, providing valuable insights into the behavior of the power-law nanofluid flow and heat transfer over the rotating disk.

Heat Transfer and Fluid Flow Behavior of a Carbon-Based Hybrid Nanofluid in a Microchannel Heat Sink

In this article, detailed work on the heat transfer and fluid flow behavior of carbon-based hybrid nanofluid (multi-walled carbon nanotubes + graphene nanoplatelets/H2O) was studied numerically. The carbon-based hybrid nanofluids have been prepared experimentally and their measured properties were used for this study. The numerical study was carried out by passing the nanofluids under laminar flow through the tube side of the microchannel heat sink (MCHS). A constant heat flux on the heat sink base was applied and a single-phase model approach was used for analyzing the heat transfer. The nanofluid volume concentration varied from 0.01% to 0.2%. The improvement in the heat transfer coefficient is observed to be a maximum of 73%, with a maximum of 18% pressure drop variation across the MCHS for 0.2 vol%. The pressure drop variation across the MCHS is minimal for all the considered volume fractions of the nanomaterials. The results confirmed that the hybrid nanofluid possesses a remarkable heat transfer characteristic for transporting heat effectively.

Improving the performance of room temperature magnetic regenerators using Al2O3-water nanofluid

The present study examines the use of Al2O3-water nanofluid as the heat transfer fluid in a magnetic regenerator and evaluates the improved cooling capabilities of the device. Room-temperature magnetic refrigeration exploits a special property of some materials, the “magnetocaloric effect”, that is the ability of the material to change its temperature when exposed to rapid changes in an external magnetic field. As adiabatic magnetic field variations of 1 to 1.5 T produce a small temperature change of a few degrees, active magnetic regeneration is often employed to achieve larger temperature spans for practical cooling applications. The effectiveness of this process greatly depends on the properties of the heat transfer fluid, which is usually a water-based mixture. High values of the fluid thermal conductivity enhance heat transfer allowing for higher cooling capacity. This work presents the outcome of a comprehensive simulation study evaluating the improved performance of a gadolinium-based regenerator using a water-based mixture with added Al2O3 nanoparticles as the heat transfer fluid. In this analysis, both the volume concentration of nanofluid and the particle size were varied. The combined effect of heat transfer enhancement and pressure drop increase was also investigated through the second law efficiency. On average, a more than 15 % increase in cooling capacity was observed when using Al2O3 (6 % vol, 20 nm particles), and the COP can be preserved or increased with a properly tuned regulation of the cycle time and the utilization factor of the regenerator.

Enhancement of an Air-Cooled Battery Thermal Management System Using Liquid Cooling with CuO and Al2O3 Nanofluids under Steady-State and Transient Conditions

Lithium-ion batteries are a crucial part of transportation electrification. Various battery thermal management systems (BTMS) are employed in electric vehicles for safe and optimum battery operation. With the advancement in power demand and battery technology, there is an increasing interest in enhancing BTMS’ performance. Liquid cooling is gaining a lot of attention recently due to its higher heat capacity compared to air. In this study, an air-cooled BTMS is replaced by a liquid cooled with nanoparticles, and the impacts of different nanoparticles and flow chrematistics are modeled. Furthermore, a unique approach that involves transient analysis is employed. The effects of nanofluid in enhancing the thermal performance of lithium-ion batteries are assessed for two types of nanoparticles (CuO and Al2O3) at four different volume concentrations (0.5%, 2%, 3%, and 5%) and three fluid velocities (0.05, 0.075, and 0.1 m/s). To simulate fluid flow behavior and analyze the temperature distribution within the battery pack, a conventional k-ε turbulence model is used. The results indicate that the cooling efficiency of the system can be enhanced by introducing a 5% volume concentration of nanofluids at a lower fluid velocity as compared to pure liquid. Al2O3 and CuO reduce the temperature by 7.89% and 4.73% for the 5% volume concentration, respectively. From transient analysis, it is also found that for 600 s of operation at the highest power, the cell temperature is within the safe range for the selected vehicle with nanofluid cooling. The findings from this study are expected to contribute to improving BTMS by quantifying the benefits of using nanofluids for battery cooling under both steady-state and transient conditions.

Predicting the thermal performance of screen mesh wick heat pipe with alumina nanofluids using response surface methodology

This study aims to investigate the effect of heat load, tilt angle, and volume concentration of alumina nanofluid on the thermal performance enhancement of cylindrical screen mesh wick heat pipe in terms of thermal resistance(R) and thermal conductivity(k). Response surface methodology based on the Box–Behnken design was implemented to investigate the influence of heat input (100–200 W), tilt angle (0–90°), and volume concentration (0.05–0.25 vol%) of nanofluid as the independent variables. Second-order polynomial equations were established to predict the responses, ‘R’, and ‘k’. The significance of the models was tested by means of analysis of variance (ANOVA). In addition, a correlation between the independent variables was derived in this study. The results revealed that the optimum heat input, inclination angle, and concentration of nanofluid were determined as 200 W, 52.72°, and 0.1773 vol. % respectively for both ‘R’ and ‘k’. SEM analysis was performed to observe the thermal performance phenomena of the heat pipe before and after experimentation.

Numerical Investigation of the Effect of Ethylene Glycol with SnFe2O3 Hybrid Nanofluid on Heat Transfer in Flat, Face Step, and Radial Corrugated Microchannels

Nanofluid technology is one of the latest technics aims to enhance the heat exchangers working systems. The nanofluid is used because it has better thermal performance properties than common fluids like water. Tin Oxide (SnO2) and Ferric Oxide (Fe2O3) has used due to their availability and low cost for manufacturing. Flat, face step and radial corrugated microchannels have been studied at the Reynolds number range (4000-7000 Re). In this study, a hybrid nanofluid combined Ferric Oxide and Tin Oxide SnFe2O3 at (0, 5, 15%) of Tin Oxide concentration. The volume concentration of the nanoparticles was from (1-5)% suspended in ethylene glycol as base fluid due to its high thermal performance compared with water. The performance evaluation criteria (PEC) are studied and the results were validated with experimental and numerical results from previous studies. Performance evaluation criteria (PEC) studied the heat transfer in all study steps and found that the 15Sn85Fe2O3 hybrid nanofluid in ethylene glycol at 5% volume concentration in radial corrugated microchannel increased 104% compared with base fluid ethylene glycol in the flat microchannel. The performance evaluation criteria value has increased by 82% from flat microchannel to radial microchannel at 5% of volume concentration of 15Sn85Fe2O3 hybrid nanofluid

Experimental study on the influence of volume concentration on natural convection heat transfer with Al2O3-MWCNT/water hybrid nanofluids

Recent research has focused on combining multiple types of nanoparticles with a base fluid, a process known as the hybridisation of nanofluids. Studies showed that hybrid nanofluids demonstrated improved rheological and thermal properties compared to mono nanoparticle nanofluids. In this study, alumina–multiwalled carbon nanotube/water hybrid nanofluid was prepared using a two-step procedure at a percentage weight ratio of 10:90 Al2O3: MWNCT at various volume concentrations of 0.00, 0.05, 0.10, 0.15, and 0.20 vol%. The natural convection of the formulated hybrid nanofluid was experimentally studied inside a square cavity with an aspect ratio of 1. An exhaustive investigation on the influence of volume concentration of hybrid nanofluid on natural convection heat transfer was performed. Results showed that an increase in volume concentration improved the heat transfer to an optimum value of 49.27% enhancement, at 0.10% volume concentration in comparison to the base fluid. However, a further increment of volume concentration led to a deterioration of natural convection heat transfer. There is evidence from this study that hybrid nanofluids offer an edge over traditional heat transfer fluids. It is concluded that the application of Al2O3-MWCNT/water hybrid nanofluid in a square cavity demonstrated enhanced natural convection heat transfer.

Numerical Investigation of Heat Transfer Enhancement of Al2O3 Nanofluid in Microchannel Heat Sink

This study focusses on using computational fluid dynamics (CFD) to study the enhancement of heat transfer from the use of AL2O3 nanofluid in a microchannel heat sink (MCHS) to develop a more efficient cooling device for high-power integrated circuits. The objective is to investigate the heat transfer performance, parameters, and enhancement rate using Ansys Fluent software, and to compare the results with experiments to show the effectiveness of this method. This study will also focus on the relationship between the friction fraction and nanoparticles volume fraction to improve the heat transfer enhancement in the MCHS. The temperature, pressure, heat transfer coefficient, Nusselt number, and friction coefficient are analysed in this study. The results showed that an increase in the volume fraction of the nanofluid leads to an increase in the average heat transfer coefficient. The results showed that for 4% nanofluid volume concentration, the Nusselt Number has improved by 10% compared to pure water. However, an increase in volume concentration also resulted in an increase in pressure drop.

Exploration of heat and mass transport in oscillatory hydromagnetic nanofluid flow within two verticals alternatively conducting surfaces

AbstractThe key attention of this paper is to explore the heat and mass transport in oscillatory hydromagnetic Titanium alloy water nanofluid flow within two vertical alternatively non‐conducting and conducting walls enclosing Darcy‐Brinkman porous medium. Motional induction is considered because it is sufficiently strong in comparison to Ohmic dissipation. Hall phenomenon is considered because the electromotive force induced due to revolving of fluid particle about the magnetic field lines is significant. Suitable physical laws (constitutive and field equations) are used to derive the equations leading the flow model. An analytical approach is followed to extract the solutions of the flow model. The quantities of physical interest such as wall shear stress (WSS), rate of heat transport rate (RHT) and rate of mass transport rate (RMT) at the walls are obtained from the extracted solutions. The physical insight into flow manners is discovered from the graphs and tables generated from the numerical computation of the solutions. It is important to note from the study that the volume concentration of nanofluid and magnetic diffusion produce resistivity in the flow and tends to slow down the fluid flow. Magnetic diffusion weakens the strength of the primarily motional induced magnetic field.

Stability and thermophysical properties enhancement of Al2O3-water nanofluid using cationic CTAB surfactant

Excellent thermal characteristics of homogeneous dispersion of nano-sized particles in a carrier fluid (nanofluid) make it appealing for use in a variety of thermal applications. The study aims to prepare stable aqua-Al2O3 nanofluid utilizing a two-step method. To increase nanofluid stability, a cationic surfactant called cetyltrimethylammonium bromide (CTAB) is used. The carrier fluid is heated while magnetic stirring is used to increase nanoparticle distribution. Bath sonication with concurrent heating and probe sonication is used to improve long-term stability. The chemical composition of γ-Al2O3 was confirmed by X-ray diffraction (XRD) results, and Scanning Electron Microscopy (SEM) images revealed the shape and mean size of the particles. The stability of the synthesized sample is evaluated utilizing a variety of stability evaluation techniques, including visual examination, UV-vis spectrometry, and Dynamic Light Scattering (DLS), at various time intervals, including 1, 8, 15, and 30 days. After 15 days of manufacture, the stability of the nanofluid without surfactant was low. Due to improved particle suspension, nanofluid with surfactant has demonstrated greater UV-vis light absorption. After a month of synthesis, it was discovered that the mean particle sizes of suspended nanoparticles in carrier fluid were 80 nm and 536 nm for nanofluid with and without surfactant respectively. KD2Pro thermal analyzer and viscometer were used to measure the thermal conductivity and viscosity of nanofluid. As per the experimental results, a nanofluid's thermophysical characteristics were found to be improved with volume concentration of nanofluid. Maximum augmentation in thermal conductivity and dynamic viscosity is 8.5% and 76.2% respectively at 1% nanofluid volume concentration.

An Approach for the Optimization of Thermal Conductivity and Viscosity of Hybrid (Graphene Nanoplatelets, GNPs: Cellulose Nanocrystal, CNC) Nanofluids Using Response Surface Methodology (RSM).

Response surface methodology (RSM) is used in this study to optimize the thermal characteristics of single graphene nanoplatelets and hybrid nanofluids utilizing the miscellaneous design model. The nanofluids comprise graphene nanoplatelets and graphene nanoplatelets/cellulose nanocrystal nanoparticles in the base fluid of ethylene glycol and water (60:40). Using response surface methodology (RSM) based on central composite design (CCD) and mini tab 20 standard statistical software, the impact of temperature, volume concentration, and type of nanofluid is used to construct an empirical mathematical formula. Analysis of variance (ANOVA) is applied to determine that the developed empirical mathematical analysis is relevant. For the purpose of developing the equations, 32 experiments are conducted for second-order polynomial to the specified outputs such as thermal conductivity and viscosity. Predicted estimates and the experimental data are found to be in reasonable arrangement. In additional words, the models could expect more than 85% of thermal conductivity and viscosity fluctuations of the nanofluid, indicating that the model is accurate. Optimal thermal conductivity and viscosity values are 0.4962 W/m-K and 2.6191 cP, respectively, from the results of the optimization plot. The critical parameters are 50 °C, 0.0254%, and the category factorial is GNP/CNC, and the relevant parameters are volume concentration, temperature, and kind of nanofluid. From the results plot, the composite is 0.8371. The validation results of the model during testing indicate the capability of predicting the optimal experimental conditions.