Copper Oxide Nanofluid Research Articles

Enhancing Radiator Cooling with CuO Nanofluid Microchannels

The study explores in employing copper oxide (CuO) nanofluid as a cooling medium in the vehicle radiators. To simulate the heat transfer process, the microchannel is constructed using elec-tron discharge machining (EDM) and a computational fluid dynamics (CFD) modeling is em-ployed. UV-visible spectroscopy, scanning electron microscopy (SEM), and dynamic light scat-tering (DLS) are used to characterize the CuO nanofluid. CuO nanofluid surpasses water in the heat transfer capabilities, with a 40% improvement in thermal conductivity. The average size of CuO nanoparticles was determined via DLS to be 485.1 nm. The heat transfer coefficient of CuO nanofluid is 5366 W/m2K, which is 116% larger than that of water. The increased heat transfer capabilities of CuO nanofluid microchannel flow indicate to its potential as a viable replacement for conventional radiators in the automotive applications. Lower engine tempera-tures, increased fuel efficiency, and longer engine lifespan may result from improved cooling performance. Due of the small size of microchannels, more efficient and space-saving radiators for automobiles are conceivable. More research is needed to improve the microchannel design as well as to realize the practical benefits of CuO nanofluids in car cooling systems.

Enhancing Closed System Efficiency through CuO Nanofluids: Investigating Thermophysical Properties and Heat Transfer Performance

Working fluids play a crucial role in closed systems to ensure efficient performance, particularly in systems for heating, cooling, or power generation, where the heat transfer coefficient is pivotal. This study delves into the thermodynamic properties and stability of copper oxide (CuO) nanofluids as alternative working fluids in closed systems. Investigating colloidal suspensions of CuO nanoparticles, the research aims to enhance heat transfer efficiency. CuO nanoparticles, sized at 40nm and 80nm, were dispersed in base fluids like water, ethylene glycol, and oil sans surfactants. The study, divided into static and dynamic phases, examines key nanofluid properties including viscosity, thermal conductivity, specific heat, and heat transfer rate. Through methodologies such as KD2 Pro for thermal conductivity, rheometer for viscosity, and small heat exchanger for heat transfer rate analysis, the effects of volume concentration, temperature, and nanoparticle size on nanofluid performance were evaluated. Sedimentation analysis employed both quantitative (standard deviation calculations) and qualitative (sediment capture methods) approaches. The findings highlight the superior heat transfer rate of 40nm CuO nanofluid at 0.467% volume concentration which is 9.08 kJ/s, suggesting its potential to optimize system efficiency, particularly in heating, cooling, and power generation applications.

Experimental investigation of copper oxide nanofluids for enhanced oil recovery in the presence of cationic surfactant using a microfluidic model

Microfluidics is an appealing technique for enhanced oil recovery since it offers numerous advantages over traditional core flooding mechanisms due to their realistic representation of reservoir conditions at the microscale. In this work, we investigated the performance of copper oxide-based nanofluids in the presence of a DCMS-8 cationic surfactant. First, copper oxide nanoparticles of an average particle size of 10 nm were synthesized by the sol–gel method and characterized using various characterization techniques. The results indicated that copper oxide and surfactant-based nanofluids reduced the interfacial tension by 54 %, depending on the concentration of nanoparticles in the suspension. Furthermore, the formation wettability alteration was investigated using contact angle measurements, and the results showed that nanofluid was able to reduce the contact angle from 48o to 20o in 10 min. The shear rheological response indicated that the nanofluids could reduce the viscosity of crude oil from 0.48 (Pa s) to 0.31 (Pa s). Notably, the flooding results showed that copper oxide-based nanofluids were able to recover 61 % of the original oil initially in place, with additional recovery rates of 65 % and 72 % when used with cationic surfactants, polyvinyl alcohol (PVA), and polyvinyl pyrrolidone (PVP), respectively. Finally, the fluorescent images confirmed that surfactant-based nanofluid has a higher sweeping efficiency in porous formation. In this study, the use of copper oxide nanoparticles and cationic surfactant has resulted in the creation of captivating and compelling nanofluids that exhibit reasonable stability of nanoparticles in the base fluid and high recovery rates of residual oil.

Analytical analysis and heat transfer of CuO and MgO engine oil base nanofluid with the influence of dynamic viscosity, magnetic field, and convective boundary conditions

AbstractThis research work investigates the semi‐numerical analysis and heat transfer of MHD 2D, Copper Oxide, and Magnesium oxide engine oil base nanofluid with the consider effect of dynamic viscosity and convective boundary conditions (BCs). The convective BCs and the effect of dynamic viscosity on an extensible surface are considered by the flow system. We converted a set of PDEs into NODEs by applying the appropriate transformations. Using the HAM, we solve this dimensionless coupled equation one for temperature and other for velocity. The impact of various parameters for both temperature and velocity are demonstrated, such as the slip parameter, magnetic parameter (MP), Eckert number (EN), PN, and dynamic viscosity. In response to changes in developing factors, the flow features, such as temperature profiles (TPs) and velocity profiles (VPs), are analyzed and simulated using a physical description. The results of this study add to our knowledge of how engine oil‐based nanofluids promote heat transmission and offer practical advice for thermal management and engineering applications.

Influence of various surfactants on the stability and solidification characteristics of DI water-based CuO NFPCM for cool thermal energy storage system

The current study goals to investigate the stability and solidification characteristics of deionized water (DI water) based copper oxide (CuO) nanofluid phase change materials (NFPCMs) with a nucleating agent, different types of surfactants (SBDS, CTAB, and GA) and different weight concentration of surfactant for cool thermal energy storage systems (CTES). The stability of NFPCMs was assessed through average particle size distribution, zeta potential, and UV–vis absorbance. Among all NFPCMs, 0.1 wt% SDBS - CuO NFPCM showed prolonged stability with −42.7 mV and 212.6 nm of zeta potential and average particle size value. The heat transfer properties of NFPCMs were studied with differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA) and thermal conductivity measurements. The introduction of 0.05 wt% SDBS to NFPCM resulted in a notable 17.84 % and 7.64 % increase in thermal conductivity in solid and liquid states, with a slight decrease in latent heat by 5.2 % and 6.01 % during melting and crystallization as compared to DI water. The solidification experiments of NFPCMs were investigated in a spherical encapsulation at a surrounding bath temperature of −8 °C and − 10 °C. Comparing various surfactants in NFPCMs, the SDBS–CuO NFPCM was the most efficient in reducing the solidification time by 26.3 % and 28.4 % at −8 °C and − 10 °C respectively, compared to the nucleating agent PCM (NAPCM). Further, the different concentrations of SDBS in NFPCM demonstrated that 0.05 wt% SDBS–CuO NFPCM displayed the greatest reduction in solidification time, achieving 29.4 % and 27.7 % at −10 °C and − 8 °C, respectively, compared to the NAPCM.

Numerical Investigation on Thermal Performance of Nanofluid-Assisted Wickless Heat Pipes for Electronic Thermal Management

Abstract Heat pipes are passive heat transfer systems and serve as an effective thermal management solution for electronic devices. The adaptability of heat pipes makes these suited for a wide application range, especially in the field of electronic thermal management. The current study highlights the transient numerical analysis of wickless heat pipes (thermosyphons) for the thermal management of electronic devices. The thermal performance of the thermosyphon is analyzed using both copper oxide (CuO) and aluminum oxide (Al2O3) nanofluids with their concentrations at 1% and 5%. Deionized (DI) water is employed as a reference case for comparison. The study is carried out for variable heat inputs to the thermosyphon ranging 10–50 W for a time interval of 30 s. The idea is to analyze the effect of the evaporator heat input and the nanoparticles concentration on the temperature, heat transfer coefficient, thermal resistance, and effective thermal conductivity of the heat pipe. The results indicate that CuO nanoparticles at a 5% concentration lead to a maximum thermal resistance reduction of 4.31% at 50 W, while alumina nanoparticles at the same concentration lead to a more substantial reduction of 6.66% at the same heat load. The evaporator temperature varies between 377.52 K to 374.99 K using deionized water, and 376.95 K to 374.29 K using CuO nanofluid (at 1% concentration). The heat pipe's evaporator attains its highest convective heat transfer coefficient (437.91 W/m2K) by using alumina nanofluid with 1% nanoparticle concentration at 50 W. Moreover, the effective thermal conductivity of the heat pipe is enhanced by 5% and 7% for copper oxide and aluminum oxide nanofluids (with 5% concentration), respectively, at 50 W. Thus, the nanofluids play a significant role in improving the efficiency and reliability of electronic components. These findings demonstrate the potential of using the nanofluids in thermosyphons to enhance their thermal performance in electronic cooling applications.

Numerical solution of entropy generation in nanofluid flow through a surface with thermal radiation applications

The main purpose of this research is to investigate a mathematical model of nanofluid passing through a stretching sheet having titanium dioxide (TiO2), copper oxide (CuO), and carbon nanotubes (CNTs) as nanoparticles, and sodium alginate is used as a base fluid. The present model can be very useful for numerous fields like Bioengineering, science, and technology. The main reason for using titanium dioxide, copper oxide, and carbon nanotubes nanoparticles as nanomaterials they have many applications in several areas. Moreover, impacts of non-linear thermal radiation and entropy generations are taken into account. By utilizing the similarity transformation technique given system of governing PDEs are transformed into a set of ODE. Then dimensionless equations are numerically tackled via the Keller box method a built-in function in the computer tool MATLAB. To support the present study, physical and numerical interpretations of involved parameters against velocity, temperature, and entropy generation profiles are also presented. From the analysis it is concluded that the combination of a magnetic field and suction reduces the rate of fluid mobility due to the synchronization of the magnetic and electric fields generated by the formation of the Lorentz force. In addition, boosting the thermal radiation parameter raises the present authors' heat transfer rate. The velocity profile drops when the Casson parameter is raised, but the heat and entropy production profiles grow. When the porosity parameter is increased, the velocity profile falls, and the heat and entropy production profiles rise. Additionally the temperature distribution is boosted up with increasing the values of nanoparticles volume fraction. The good agreement between current results and published data is observed. It is necessary to investigate the thermophysical characteristics of the magnetite nanofluid (titanium dioxide, copper oxide, and carbon nanotubes-sodium alginate nanofluid) under various situations. The MHD flow of nanofluid is significant because of its wide range of industrial uses, including flows over the tips of rockets, planes, submarines, and oil tankers. The novelty of this work is to scrutinize the MHD flow and heat transfer analysis of a nanofluid towards a stretched surface. The features of magnetite nanofluid (titanium dioxide, copper oxide, and carbon nanotubes-sodium alginate nanofluid) under entropy generation, thermal radiation and velocity slip are investigated. All of this contributes to the work's uniqueness and novel.

Dual solutions for axisymmetric flow and heat transfer due to a permeable radially shrinking disk in copper oxide (CuO) and silver (Ag) hybrid nanofluids with radiation effect

Purpose This study aims to investigate the dual solutions for axisymmetric flow and heat transfer due to a permeable radially shrinking disk in copper oxide (CuO) and silver (Ag) hybrid nanofluids with radiation effect. Design/methodology/approach The partial differential equations that governed the problem will undergo a transformation into a set of similarity equations. Following this transformation, a numerical solution will be obtained using the boundary value problem solver, bvp4c, built in the MATLAB software. Later, analysis and discussion are conducted to specifically examine how various physical parameters affect both the flow characteristics and the thermal properties of the hybrid nanofluid. Findings Dual solutions are discovered to occur for the case of shrinking disk (λ < 0). Stronger suction triggers the critical values’ expansion and delays the boundary layer separation. Through stability analysis, it is determined that one of the solutions is stable, whereas the other solution exhibits instability, over time. Moreover, volume fraction upsurge enhances skin friction and heat transfer in hybrid nanofluid. The hybrid nanofluid’s heat transfer also heightened with the influence of radiation. Originality/value Flow over a shrinking disk has received limited research focus, in contrast to the extensively studied axisymmetric flow problem over a diverse set of geometries such as flat surfaces, curved surfaces and cylinder. Hence, this study highlights the axisymmetric flow due to a shrinking disk under radiation influence, using hybrid nanofluids containing CuO and Ag. Upon additional analysis, it is evidently shows that only one of the solutions exhibits stability, making it a physically dependable choice in practical applications. The authors are very confident that the findings of this study are novel, with several practical uses of hybrid nanofluids in modern industry.

A Numerical Study on the Performance of Water Based Copper Oxide Nanofluids in Compact Channel

A Numerical Study on the Performance of Water Based Copper Oxide Nanofluids in Compact Channel

Semi-analytical solution of nanofluid flow with convective and radiative heat transfer

The application of nanofluids has exploded in recent decades to improve the local number, mean Nusselt number, and rate of heat transfer. However, boundary layer equations of nanofluid across a flat plate with radiation have not been studied, and therefore this paper studies them mathematically for the first time. For water-based copper and aluminum oxide nanofluids, a similarity solution is presented in this study, and the subsequent system of the ordinary differential equation (ODE) is numerically solved by the Runge–Kutta method in MATLAB. Two different hydraulic boundary conditions are used in the simulations. In the first, the flow across a moving plate and the direction of the flow are analyzed, while in the second, the flow over a nonlinearly moving plate in a still fluid is investigated. The nanoparticle’s boundary layer thickness is found less than the thermal and hydraulics boundary layers. The local Nusselt number and friction factor of both the nanofluids are calculated and compared with the base fluid. The results demonstrate that the friction coefficient is high and the Nusselt number is low for nanoparticles with a high volume fraction. It also revealed that the friction factor for water–aluminum oxide is 16% greater than that for the water–CuO whereas the local Nusselt number for water–aluminum oxide is only 5% more than that for the water–CuO.

Numerical simulation and intelligent prediction of thermal transport of a water-based copper oxide nanofluid in a lid-driven trapezoidal cavity

This article investigates the fluid dynamics and heat transfer properties in a trapezoidal enclosure containing a heated cylindrical object. It involves the interaction of multiple physical processes such as the magnetic field, thermal radiation, porous materials, and aqueous copper oxide nanoparticles. The governing partial differential equations are analyzed numerically through the continuous Galerkin finite element algorithm. The analysis takes into account various physical parameter factors, including the Richardson number (0–5), the Hartmann number (5−40), the Darcy number (0.001−0.1), thermal radiation parameter (0.5−2), and nanoparticle volume concentration (0.01−0.1). The physical mechanism of thermal and mass transfer in the enclosure caused by various factors is fully explored. In addition, the multiple expression programming (MEP) technique is implemented to report a comparative analysis of flow profiles and thermal distribution. The findings demonstrated that at low Ri, the primary flow within the cavity is driven by the shear friction generated by the moving walls. The growing importance of radiative heat transfer reduces the effectiveness of convective heat transfer, resulting in a decline in the average Nusselt number with R. The heat transfer rate rises up to 27.7% as ϕ augments; however, its value declines by 9.37% against Ha. The expected results obtained by the MEP approach are very consistent with the numerical ones. There is no doubt that the new MEP concept provides a valuable tool for researchers to predict the heat transfer behavior of any data set in cavities of different shapes. It is expected to provide new idea for the development of efficient cooling systems and the improvement of energy efficiency in various engineering applications.

Optimization of heat pipe charged with CuO nanofluid using Taguchi technique

Aim of this study is to investigate the influence of various working parameters on the performance of thermosyphon heat pipe, charged with aqueous copper oxide nanofluid. This heat pipe was used as an absorber in twin glass evacuated tube solar collector for heating edible oil stored in an insulated tank. Design of experiments was formulated using minitab™ 19 considering prominent heat pipe working parameters like CuO nanoparticle concentration, CuO nanoparticle size, copper heat pipe diameter, filling ratio, stirring speed and surfactant concentration and their levels through research gaps. Experiments were performed on clear sunny days and impact of parameters on heat pipe solar collector performance was examined using Main effect plot, signal to noise (S/N) ratio and ANOVA. From response table of signal to noise ratio and the ANOVA results, it is concluded that the nanoparticle concentration, nanoparticle size, filling ratio and stirring speed plays important role in heat pipe performance improvement while other parameters like heat pipe diameter and surfactant concentration are less significant. Thus Optimum levels of parameters for best heat pipe solar collector performance were obtained as, nanofluid concentration of 0.3 (% weight), nanoparticle size of 30–50 nm, 8 mm of heat pipe diameter, 45 % of filling ratio, stirring speed of 1200 rotations per minute while preparing nanofluid and surfactant mixing in nanofluid as 0.3 (% volume).

Single and multi-objective optimization of PVT performance using response surface methodology with CuO nanofluid application

The nanofluid application in photovoltaic thermal (PVT) systems is widely known as an effective solution for improving output performance. However, studies exploring the optimum operation point of PVT systems with nanofluid application are scant in the current literature. The novelty of the study lies in exploring the optimum operating conditions of each PVT output using single-objective optimization and the overall performance optimization using multi-objective study. The conditions were explored with the application of copper oxide nanofluid as a coolant in PVT systems. The investigation was conducted using a numerical equation-based model developed in TRNSYS simulation environment. An experimental test was conducted to validate the outputs of numerical model. After validating the numerical model, TRNSYS model was investigated for 0.10%-0.50% volume concentration and 60–120 kg/h mass flow. The output data was then imported into Design-Expert software for performance optimization. Central composite design was selected as it is the most suitable fractional factorial design option in response surface methodology. In single-objective investigation, the optimization conditions for PVT outputs are identified as follows, the optimum electrical efficiency output was 14.64% at 90 kg/h fluid flow and 0.10% concentration, the thermal efficiency output was 34.94% at 120 kg/h fluid flow and 0.50% concentration, the overall energy efficiency output was 49.28% at 88 kg/h fluid flow and 0.10% concentration, the overall exergy efficiency output was 16.45% at 60 kg/h fluid flow and 0.50% concentration. The multi-objective study indicated that the collective performance of PVT outputs is optimum at 91 kg/h fluid flow and 0.10% concentration.

Heat transfer analysis of nanofluids for fixed volume fraction of pipe in pipe heat exchanger using CFD

A heat exchanger device having the capability to transfer heat from one source to another. Double pipe heat exchanger (DPHE) has been selected for current study. In this, A metallic solid wall acts as a medium which can separate the two fluids and can transfer the heat though this wall. Nanofluids have higher thermo-physical properties and having high thermal conductivity to enhance the heat transfer. Copper oxide (cuo), silicon oxide (SiO2) and titanium oxide (TiO2) nanofluids are considered to this work. A simulation work is conducted to double pipe heat exchanger to study the heat transfer characteristics. The heat transfer is enhanced 30–40% when temperature maintained at 800C for all mass flow rates. 4–7% and 6–14% high heat transfer coefficient for Cuo nanofluid than TiO2 and SiO2 nanofluids. The global results in this study stating that Cuo nanofluid performed better than TiO2 and SiO2 nanofluids.

Performance assessment of a parabolic trough solar collector using nanofluid and water based on direct absorption

In this investigation, a parabolic trough solar concentrating collector with an evacuated tube was fabricated with an aperture area, collector length, breadth, and rim angle, inner and outer diameter of absorber as 2.45 m2, 2.1 m, 1.2 m, 90 deg, 0.0286 m, and 0.03058 m, respectively. A copper oxide (CuO) and water-based nanofluid was employed as the working fluid. Different mass fractions (0.05%, 0.075%, and 0.1%) and volume flow rates (70 lit/hr and 140 lit/hr) of nanofluid were taken, and performance of an evacuated tube parabolic trough collector was analysed. When CuO–H2O nanofluid of varying concentrations (0.05%, 0.075%, and 0.1%) is used in place of H2O (DI), it has been observed that the solar collector's efficiency increases. The efficiency of the collector increases in direct proportion to the working fluid's volume flow rate increment. The maximum heat transfer coefficients for CuO–H2O based nanofluid were 280.68 W/m2-K and 466.8 W/m2-K while the maximum convective heat transfer coefficients for water as working fluid were 268.11 W/m2-K and 488.7 W/m2-K at 70 lit/h and 140 lit/h, respectively. An efficiency increase of 45.15%, 51.19% and 53.26% for 70 lit/h and 59.61%, 63.56% and 69.07% for 140 lit/h mass flow rate has been observed for different nanoparticle's concentrations, respectively. Economic studies showed that the cost of the experiment (for 0.05% CuO dispersion) has increased by 1.08% for 70 lit/h mass flow rate when compared to the water based direct cooling method.

Application of Copper Oxide Nanofluid and Phase Change Material on the Performance of Hybrid Photovoltaic–Thermal (PVT) System

The objective of the study is to investigate the thermal, electrical, and exergetic performance of a hybrid photovoltaic–thermal (PVT) system under the influence of copper oxide (CuO) nanofluid and phase change material (Vaseline (petroleum jelly)) as a heat storage medium. A mathematical model was developed with the help of various energy-balance equations over the layers of the hybrid system. The performance evaluation of the PVT system was performed using pure water, CuO-water nanofluid (0.2 and 0.4% weight fractions), and CuO-water nanofluid 0.4% weight fraction with Vaseline as a phase change material. The results of the overall analysis show that the performance of the PVT system is better using CuO-water nanofluid (0.4% wt. fraction) with PCM as compared to the water-cooled PVT system and CuO-water nanofluid. The results obtained from the study show indicate that the cell temperature of PVT was reduced by 4.45% using nanofluid cooling with PCM compared to a water-cooled PVT system. Moreover, the thermal, electrical, and overall efficiencies improved by 6.9%, 4.85%, and 7.24%, respectively, using 0.4% wt. fraction of CuO-water nanofluid with PCM as compared to PVT water-cooled systems. The performance of the PVT system was also investigated by changing the mass flow rate (MFR). The increase in mass flow rate (MFR) from 0.05 kg/s to 0.2 kg/s tends to enhance the electrical and overall efficiencies from 12.89% to 16.32% and 67.67% to 76.34%, respectively, using 0.4% wt. fraction of CuO-PCM as fluid.

Heat transport phenomenon of the MHD water-based hybrid nanofluid flow over a rotating disk with velocity slips

The present investigation computes the heat transport phenomenon of the magnetohydrodynamic (MHD) flow of CuO-Ag/H2O hybrid nanofluid over a spinning disc. The authors are confident that there is very less analysis covering the fluid flow containing silver and copper oxide nanoparticles over a rotating disk. Therefore, the authors are interested to consider the water-based nanoliquid flow over a spinning disk. Furthermore, the velocity slip and thermal convective conditions are taken into consideration. The formulation of the problem is made in the form of PDEs and is then converted into the nonlinear ODEs by employing suitable similarity transformations. The homotopic analysis approach is applied for the semi-analytical solution of these resulting equations. The convergence of homotopic approach has also revealed with the help of figure. The performance of the hybrid nanofluid flow velocities and temperature has been shown in a graphical form against distinct flow parameters. Also, the numerical results of skin friction coefficient and Nusselt number have been calculated in a tabular form. The outcomes of the current problem show that the increase in the skin friction of the water-based copper oxide nanofluid is greater than the water-based silver nanofluid at 4% of the nanoparticle volume fraction. Also, the skin friction of the hybrid nanofluid is increased by 8% compared to the silver nanofluid at 4% of the nanoparticle volume fraction. Furthermore, the heat transfer rate of the water-based copper oxide nanofluid is greater than the water-based silver nanofluid at 4% of the nanoparticle volume fraction. Also, the heat transfer rate of the hybrid nanofluid is 52% greater than that of silver nanofluid at 4% of the nanoparticle volume fraction. It is found that the Nusselt number of the hybrid nanofluid is highly affected by the embedded parameters as compared to nanofluids.

Synthesis of Novel CuO–Gelatin Nanofluids Using Ultrasonic Technique

AbstractNanofluid molecular properties, such as acoustical properties, vary widely in system parameters and are influenced by liquid cohesive characteristics. Gelatin is a natural polymer made from the partial hydrolysis of collagen, which allows the triple helix to unfold and split, resulting in a polydisperse mixture of proteins in solution. The use of ultrasonic technology to create nanoparticles from biopolymer base fluids is a novel method of nanofluid synthesis. The focus of this research is to measure the ultrasonic velocity and density of synthesized nanoparticles using gelatin as the base fluid at various weight percentages. The study have synthesized the Copper oxide (CuO) nanofluid by transforming an unstable Cu(OH)2 to CuO as a precursor in aqueous gelatin by ultrasonication process. To characterize the prepared nanoparticles, the XRD and FESEM methods are used. The results of ultrasonic velocity, density, and viscosity measurements are discussed after ultrasonication. Experimental data and a theoretical approach to nanofluids are used to study the stability of nanofluids. The outcomes of ultrasonic spectroscopy and other investigations are very similar.

Optimisation of flow and fluid properties of nanofluids to enhance the performance of solar flat plate collector using MCDM technique

In this research work, aluminium oxide (Al2O3), copper oxide (CuO) and gold (Au) nanofluids are prepared with the volume concentrations of 0.1%, 0.2%, 0.3% and 0.4% nanoparticles and tested in solar flat plate collector to estimate the heat transfer characteristics and collector efficiency. The influence of the input variable such as material (type of nanofluid), nanoparticle concentration and the mass flow rate (such as 0.016 kg/s, 0.033 kg/s and 0.05 kg/s) are studied experimentally. With the aim of determining the best possible heat transfer and the collector efficiency with minimum pressure drop, the parameters were optimised using multi-criterion decision-making (MCDM) optimisation techniques. Considering the rate of heat transfer, collector efficiency and drop in pressure are the objective functions, the prime ranks of the optimised variables were obtained using TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) and MOORA (Multi-Objective Optimization on the basis of Ratio Analysis) techniques. Finally, the prediction accuracy of the models and the confidence levels were evaluated and analysed through ELECTRE (ELimination Et Choix Traduisant la REalite) method to create the hypothesis of the experiment. Al2O3 nanofluid with 0.1% and 0.2% volume concentrations of nanoparticle at 0.05kg/s mass flow rate was obtained as best alternatives from others and it shows good agreement between experimental analysis and optimisation techniques. While using, when compared to water, Al2O3 nanofluid with 0.05kg/s containing 0.1% and 0.2% nanoparticle concentrations, the enhancements were found to be 11.25% and 14.45%, respectively, for heat transfer rate; 11.16% and 14.34%, respectively, for collector efficiency; and 22.7% and 37.7%, respectively, for pressure drop across the collector.

Viscosity Analysis of Water-based Copper Oxide Nanofluids

In this paper, the effects of weight concentration of nanoparticles and temperature on the viscosity of water-based copper oxide nanofluids have been studied experimentally using analysis of variance (ANOVA)-based two-factor three-level (23) factorial design. The results show that a maximum increase of 23.12% in viscosity is observed at 30°C temperature as the weight concentration of nanoparticles increases from 0.03 to 0.3wt.%. Whereas the temperature increases from 30 to 60°C, the viscosity decreases up to 46.19% in the case of 0.3wt.% nanofluid. Temperature is found to be more dominant than the concentration of nanoparticles. The optimum value of viscosity (0.513 mPa.s) is found at concentrations of 0.1wt.% and 60°C temperature with an 18.72% enhancement in viscosity as compared to the base fluid. The experimental and model values of viscosity have been compared with the predictions of the proposed equation for viscosity. The experimentally measured results are found near the proposed results whereas the model underestimates the viscosity in the case of all nanofluids. The maximum underestimation of 25.92 % was observed in the case of 0.3wt.% nanofluid at 60°C temperature.