Water-based Nanofluids Research Articles

Experimental and modeling of CO2 absorption in a bubble column using a water-based nanofluid containing co-doped SiO2 nanoparticles

Experimental and modeling of CO2 absorption in a bubble column using a water-based nanofluid containing co-doped SiO2 nanoparticles

Thermal performance investigation of water-based nanofluids in an ice storage system

In this study, the combined effects of heat transfer enhancement and cost increment of water-based nanofluids in an ice storage system are investigated theoretically. First, a model for describing the ice formation process of water around a helical coil is established, and the model is verified by comparing the simulation and experimental results. Second, the heat transfer performance of water-based Al2O3 nanofluids and multi-wall carbon nanotubes (MWCNT) nanofluids with different nanoparticle volume fractions are simulated with the established model. Although 0.05 v.% M/W shows the best heat transfer performance, it has a higher cost. In this study, an economic analysis of these two nanofluids is conducted, and a benchmark based on economic analysis and heat transfer performance analysis is obtained, comparing the ice-making performance of the two nanofluids. Based on the benchmark point E, the ice-making performance of two nanofluids can be separated into three regions: a low-performance region, an economic region, and a heat transfer region. In the low-performance region, the enhancement effect on heat transfer performance is small. In the economic region, A/W is a more ideal ice-making medium. In the heat transfer region, M/W is a more ideal ice-making medium.

The electrically conducting water-based nanofluid flow containing titanium and aluminum alloys over a rotating disk surface with nonlinear thermal radiation: A numerical analysis

Abstract A metallic alloy is a combination of two or more elements, often called a compound or a solution. Steel is largely composed of carbon, a nonmetal, but alloys are often made up of metals. In this article, the authors have explored the electrically conducting water-based viscous nanofluids flow past a rotating disk surface. The nanofluids flow is composed of titanium and aluminum alloys where water is used as a base fluid. Two important cases, namely the stretching case and the shrinking case, were investigated to analyze the flow behaviors due to the different embedding factors. The impacts of viscous Joule heating, thermophoresis, Brownian motion, activation energy, nonlinear thermal radiation, and chemical reaction are investigated here. By employing an appropriate set of variables for shifting the leading equations to dimension-free form. The mathematical model is solved numerically by incorporating the bvp4c MATLAB scheme. Current work is validated with previous studies. The outcomes showed that the radial velocity increases when the disk surface stretches and reduces when the disk surface shrinks. On the other hand, the Azimuthal velocity increases when the disk surface shrinks and reduces when disk surface stretches. Both the radial and Azimuthal velocities are the diminishing functions of the magnetic factor, whereas temperature is the growing function of magnetic factor. In addition, the temperature is more influenced by the magnetic factor in the case of nonlinear radiation. The higher magnetic factor increases skin friction. In addition, the stretching case experiences more surface drag than the shrinking case. It is found that nanofluid flow containing titanium alloy has perceived the greater impacts of the embedded factors compared to the nanofluid flow containing aluminum alloy.

Cu-Graphene water-based hybrid nanofluids: synthesis, stability, thermophysical characterization, and figure of merit analysis

Hybrid nanofluids are emerging as an alternative to conventional heat transfer fluids and nanofluids for improving the thermal efficiency of heat exchanging devices synergistically due to their outstanding thermophysical properties associated because of the dispersion of different types of nanoparticles as compared to mono nanofluids. This will help in optimizing fluid characteristics in different flow regimes for several applications. However, enhancing the thermal energy efficiency of heat exchangers is challenging owing to the deprived stability of hybrid nanofluids at greater volume concentrations. This work concentrated on the synthesizing, thermophysical depiction, and thermal performance estimation of stable water-based Cu-graphene hybrid nanofluids using very low volume concentrations of Cu and graphene hybrid nanostructures. Cu-graphene hybrid nanofluid was successfully synthesized by dispersing the synthesized Cu and graphene nanostructures (keeping the Cu concentration constant at 0.04 vol % and varying the graphene concentration from 0.01 to 0.1 vol %) in water. Hybrid nanofluids display excellent stability against aggregation for up to 7 weeks, as proven by higher zeta potential values. Thermophysical characteristics of the prepared hybrid nanofluids were effectively measured. The thermal conductivity of Cu-graphene hybrid nanofluids shows exceptional enrichment (~ 35%) at minimal concentrations of hybrid nanostructures. Viscosity of the water-based hybrid nanofluids shows remarkable enhancement as compared to water and represents the increasing trend in viscosity of the base fluid with respect to the increase in concentration of hybrid nanostructures. The thermal and rheological properties of hybrid nanofluids are effectively validated with existing theoretical models. In addition, the specific heat and pumping power of Cu-graphene hybrid nanofluids with respect to the volume concentration of hybrid nanostructures are calculated using the existing theoretical equations. A figure of merit (FOM) analysis was conducted for the synthesized hybrid nanofluids to gauge thermal efficiency and evaluate the applicability of these hybrid nanofluids under laminar and turbulent flow conditions.

Energy matrices, enviro-economic and characteristic equation-based performance analyses of photovoltaic thermal compound parabolic concentrator (PVT-CPC) coupled solar still equipped with heat exchanger using SWCNTs and MWCNTs–water nanofluids

In this paper, effect of single wall carbon nanotubes (SWCNTs) and multiwall carbon nanotubes (MWCNTs)- water based nanofluid have been studied to examine the performance, long-term feasibility andenviro-enviro-economic analysis of partially covered series connected N- photovoltaic thermal (PVT)-compound parabolic concentrator (CPC) collectors coupled double slope solar still (DSSS) equipped with helically coiled heat exchanger (HE). Analysis have been carried out by developing thermal modelling of the proposed system. Instantaneous gain and loss efficiencies; annual thermal energy/exergy, and productivity – is investigated for optimized parameters of the proposed system in detail. Gain efficiency of the proposed system is found to be approximately 25-30% higher using CNT-NPs as compared to the system without using NPs. Annual thermal energy and exergy of CNTs, particularly SWCNTs water-based nanofluid (thermal energy- 2491.55 kWh, thermal exergy-894.67 kWh) have been found to be greater in comparison to basefluid (thermal energy -2185.76 kWh, thermal exergy-772.18 kWh). Also, results give higher value of CO2 mitigation using CNT-NPs both on the basis of energy (SWCNT-5.082t, MWCNT-4.787t) and exergy (SWCNT-1.83t, MWCNT-1.76t) respectively. SWCNT-NPs shows better performance due to their better TPPs; also PVT-CPC collector integrated DSSS equipped with HE is more viable practically.

A numerical exploration of the comparative analysis on water and kerosene oil-based Cu–CuO/hybrid nanofluid flows over a convectively heated surface

The fluid flow over an extending sheet has many applications in different fields which include, manufacturing processes, coating, thin film decomposition, heat and mass transfer, biomedical applications, aerospace engineering, environmental science, energy production. Keeping in mind these applications, the non-Newtonian hybrid nanofluid flow comprising of Cu and CuO nanoparticles over an extending sheet is analyzed in this work. Two different base fluids called kerosene oil and water have been incorporated. The sheet is considered to be thermally convective along with zero mass flux condition. The main equations of modeled problem have been transformed to dimensionless form by using similarity variables. The designed problem is evaluated computationally by using bvp4c Matlab function. Validation of the present results is also performed. The impacts of magnetic, Brownian motion, chemical reaction, suction and thermophoresis factors are analyzed and discussed in details. The outcomes of the present investigation declare that the kerosene oil-based hybrid nanofluid flow has greater velocity and concentration profiles than that of the water-based hybrid nanofluid flow. The water-based hybrid nanofluid has greater temperature distribution than that of kerosene oil-based hybrid nanofluid flow. The streamlines of the kerosene oil-based Newtonian and non-Newtonian hybrid nanofluid flows are more stretched than water-based Newtonian and non-Newtonian hybrid nanofluid flows.

Efficiency assessment of thermal radiation utilizing flow of advanced nanocomposites on riga plate

Utilizing nanostructured materials to optimize thermal processes for renewable energy is an important strategy that has been applied in numerous engineering disciplines for diverse interventions such as photovoltaic thermal systems. Ternary nanofluids have demonstrated potential for improving the cooling capabilities of this kind of system. The current research focuses on enhancing the thermal performance of convective flow of a water-based trihybrid nanofluid across a Riga plate incorporating carbon nanotubes in spherical, graphene in cylindrical and Al2O3 in platelet shapes. Several mechanisms like non-linear heat production, thermal radiation, velocity and thermal slip conditions have all been investigated regarding the flow describing equations. Due to the high complexity of the problem modeling and numerical methods, conventional techniques to the parametric work that incorporate various model factors can fail to derive accurate solutions. This study assesses the ability of soft computing techniques to determine the behavior of a problem with various connected parameters to resolve this issue. With help from numerical scheme Lobatto IIIa technique reference data, the artificial neural network is trained. Furthermore, a constructive technique using artificial neural networks (Levenberg–Marquardt) is used to quantitatively determine the rate of heat transmission on the surface of Riga plates. With the use of correlation, fitting analysis, regression, mean squared error, absolute error, and error histogram, the prediction performance of the proposed algorithms is examined. The Cfx and Nux reach convergence with mean squared errors close to 10−8 and 10−10 after 626 and 100 epochs. The investigation illustrates the benefits of using soft computing methods to accurately investigate the behavior of complex flow models. The most important discovery is that, in comparison to mono- and binary-hybrid nanofluids, ternary hybrid nanofluids have a greater thermal responsiveness.

Numerical simulation on thermohydraulic performance of different types of nanofluids in a corrugated-triangular channel

Nanofluids have garnered significant interest as a potential solution to address overheating challenges across diverse industries. Researchers are actively exploring different types of nanofluids to mitigate these issues. In this study, a numerical analysis was conducted using ANSYS software to examine the fluid flow and heat transfer characteristics of nanofluids (ranging from 0 to 4 volume fractions) in a corrugated wavy channel within the turbulent range. Various nanoparticles, including Al2O3, CuO, SiO2, and ZnO, were employed and dispersed in different base fluids such as ethylene glycol, glycerin, and water. The particle size of the nanoparticles ranged from 20 to 70 nm. The results revealed that SiO2/water-based nanofluids provide better heat transfer than all the water-based nanofluids. The maximum average Nusselt number and pressure drop of 200 and 115 Pa, respectively, were observed for SiO2 nanofluid (volume fraction of 0.04) with a particle size of 20 nm. Highlights Al2O3, CuO, SiO2 and ZnO considered in this work. Corrugated plates with three different corrugated angles of 20° to 60° are tested. Eexperiments are performed for different heat flux in turbulent range. Maximum heat transfer obtained for SiO2/water nanofluid.

Effects of water-based SiO2 nanofluids on the wettability of coal dust and particle deposition characteristics

Coal wettability plays a crucial role in the prevention of coal mine dust and associated disasters such as coal and gas outbursts. Water-based SiO2 nanofluids have emerged as promising wetting agents because of their sustainable wetting effects on coal. However, the current research on the wetting characteristics of nanofluids has predominantly focused on small coal fragments, with limited studies on coal dust. This study aims to investigate the influence of water-based SiO2 nanofluids with varying particle concentrations on the wettability of coal dust via physical experiments. The findings revealed that the modification by nanofluids significantly reduced the contact angles of the coal dust particles with the particle size ranges of 60–80, 80–100, and 100–150 mesh, compared to the initial contact angles. Moreover, higher particle concentrations resulted in smaller contact angles. Notably, the wetting effects of the nanofluid modification on coal dust were particularly prominent for larger particles. Furthermore, compared with water immersion, nanofluid modification demonstrated a significantly more positive impact on the wettability of coal dust. Notably, the SiO2 nanoparticles exhibited a wide distribution and substantial adsorption capacity on the coal surface, enabling the formation of a hydrophilic structure coverage. This study contributes to a comprehensive understanding of the wetting behavior of coal dust when exposed to water-based SiO2 nanofluids. These findings underscore the potential of nanofluids to enhance coal dust prevention and control, and provide valuable insights for future research in this field.

Numerical simulation of convective heat transfer behavior of nanofluids in elliptical microchannels

This study employs a numerical simulation approach to investigate the heat transfer performance of elliptical microchannel heat sinks (MCHS) with varying aspect ratios (AR) of the elliptical cross-section. The convective heat transfer behavior of water and water-based nanofluids containing CuO nanoparticles at different volume fractions within the MCHSs is examined. The research results indicate that at Re = 600, as the AR of the elliptical cross-section increases from 1:1 to 1.75:1, the thermal performance of the MCHS improves by 5.33%. Furthermore, with an increase in the volume fraction of nanofluid from 0 to 0.75%, the convective heat transfer coefficient of the nanofluid increases by 11.87%. Compared to the circle MCHS using water as the coolant, the MCHS with an elliptical cross-section with an AR of 1.75:1 and a nanofluid volume fraction of 0.75% can reduce the maximum temperature of the chip by 9.78%.

Improving Thermal Energy Storage in Solar Collectors: A Study of Aluminum Oxide Nanoparticles and Flow Rate Optimization

Solar thermal energy storage improves the practicality and efficiency of solar systems for space heating by addressing the intermittent nature of solar radiation, leading to enhanced energy utilization, cost reduction, and a more sustainable and environmentally friendly approach to meeting heating needs in residential, commercial, and industrial settings. In this study, an indoor experimental setup was employed to investigate the impact of a water-based Al2O3 nanofluid on the storage capacity of a flat plate solar collector under varying flow rates of the heat transfer fluid. The nanofluid, introduced at specific concentrations, was incorporated into a water-contained storage tank through which the hot heat transfer fluid circulated within a heat exchanger. This process resulted in the storage of thermal energy for future applications. The research identified that the optimal flow rate of the heat transfer fluid, corresponding to the maximum storage temperature, was 15 L per hour, and the ideal nanofluid concentration, associated with the maximum specific heat capacity of the storage medium, was 0.6%. Furthermore, the introduction of nanoparticles into the storage tank led to a significant increase in the specific heat of the water, reaching a maximum of 19% from 4.18 to 5.65 kJ/(kg·°C).

Dual solutions of water-based micropolar nanofluid flow over a shrinking sheet with thermal transmission: Stability analysis

Investigation of the nature of dual solutions of the water-based micropolar nanofluid-flow with thermal transmission due to a contracting surface has been done in the work. The flow is characterized by its shrinking velocity and imposed magnetic field. Also, this work is one of the contributions that illustrate the microrotation and microinertia descriptions of nanofluids. The effects of metallic nanoparticles Cu and CuO have been discussed throughout this study. A uniform magnetic field has been applied in the normal direction of the flow. A set of basic equations that supports the present problem are derived from the principle of conservation laws and have been modernized into a set of solvable forms by employing suitable similarity variables. The MATLAB built-in bvp4c solver scheme is engineered to solve this problem. In order to tackle boundary value problems that are highly non-linear, this numerical method largely relies on collocation and finite difference techniques. From this study, we have perceived that the speed of the motion of CuO-water nanofluid in both cases (the first and second solutions) is less than CuO-water nanofluid. The material parameter plays an important role by enhancing the heat transfer rate of the fluid at the surface of the sheet in both time-dependent and time-independent cases. From the stability analysis, the first solution has been found as the stable and physically attainable solution. Additionally, the material parameter aids in reducing the effects of couple stress and shear stress on the fluid in both situations near the surface.

Artificial Neural Network analysis on the effect of mixed convection in triangular-shaped geometry using water-based Al2O3 nanofluid.

The objective of the study is to investigate the fluid flow and heat transfer characteristics applying Artificial Neural Networks (ANN) analysis in triangular-shaped cavities for the analysis of magnetohydrodynamics (MHD) mixed convection with varying fluid velocity of water/Al2O3 nanofluid. No study has yet been conducted on this geometric configuration incorporating ANN analysis. Therefore, this study analyzes and predicts the complex interactions among fluid flow, heat transfer, and various influencing factors using ANN analysis. The process of finite element analysis was conducted, and the obtained results have been verified by previous literature. The Levenberg-Marquardt backpropagation technique was selected for ANN. Various values of the Richardson number (0.01 ≤ Ri ≤ 5), Hartmann number (0 ≤ Ha ≤ 100), Reynolds number (50 ≤ Re ≤ 200), and solid volume fraction of the nanofluid (ϕ = 1%, 3% and 4%) have been selected. The ANN model incorporates the Gauss-Newton method and the method of damped least squares, making it suitable for tackling complex problems with a high degree of non-linearity and uncertainty. The findings have been shown through the use of streamlines, isotherm plots, Nusselt numbers, and the estimated Nusselt number obtained by ANN. Increasing the solid volume fraction improves the rate of heat transmission for all situations with varying values of Ri, Re, and Ha. The Nusselt number is greater with larger values of the Ri and Re parameters, but it lessens for higher value of Ha. Furthermore, ANN demonstrates exceptional precision, as evidenced by the Mean Squared Error and R values of 1.05200e-6 and 0.999988, respectively.

NUMERICAL SIMULATION OF HEAT TRANSFER IN A SQUARE CAVITY FILLED WITH HYBRID NANOFLUID

This study uses numerical simulations to investigate the characteristics of laminar natural convection in a square cavity filled with a mixed nanofluid containing Ag and Ag-TiO<sub>2</sub> solid spherical nanoparticles. The cavity contains one heat source and one heat sink, and the cavity walls are adiabatic. The fluid is a water-based hybrid nanofluid. The temperature in the cavity is randomized using a random function. The main parameters, including volume fraction of nanoparticles, temperature type, and type of hybrid nanofluid, are varied and analyzed using the finite volume method. The numerical results are compared with previous studies, and a good agreement is observed. The obtained results show that the addition of nanoparticles significantly enhanced the heat transfer in the cavity (φ = 0.1%). In addition, the larger the Rayleigh number, the more obvious the influence of temperature type. Also, the average Nusselt number increases as the volume fraction increases, and the best results are obtained from the (Ag-TiO<sub>2</sub>)/water hybrid nanofluid.

Coupling at the molecular scale between the graphene nanosheet and water and its effect on the thermal conductivity of the nanofluid.

Graphene nanofluid is a promising way to improve heat transfer in many situations. As a two-dimensional material, graphene's anisotropic thermal conductivity influences the heat transfer of nanofluids. In the present study, a nonequilibrium molecular dynamics (MD) simulation is adopted to study the interaction between graphene nanosheets (GNSs) and liquid water in water-based graphene nanofluids. Consequently, the coupling interaction between the orientation and length of GNSs and the thermal conductivity of nanofluids is then investigated. We discover that the molecular thermal coupling between GNSs and water can effectively influence the orientation angle of the GNSs. A preferential orientation angle of the GNSs inside the nanofluid is then observed during heat transfer. The preferential orientation angle decreases with the GNS length and has no apparent relation with the size of heat flux in this study. The overall thermal conductivity of the nanofluid decreases as the orientation angle of the GNS rises. Increasing the GNS length not only reduces the preferential orientation angle but also improves the thermal conductivity along the graphene length direction. The thermal conductivity of the nanofluid along the graphene length direction increases from 0.414 to 4.085 W m K-1 as the length increases from 103 to 3274 A. Our results provide the fundamental knowledge of the heat transfer performance of graphene nanofluids.

Numerical study of flow behavior and heat transfer of ternary waterbased nanofluids in the presence of suction/injection, stretching/ shrinking sheet

Numerical study of flow behavior and heat transfer of ternary waterbased nanofluids in the presence of suction/injection, stretching/ shrinking sheet

Electrical conductivity of nanofluids based on water and Cu-C nanoparticles synthesized by the electric arc method

In this work, electric arc synthesis was carried out by sputtering a graphite electrode with copper powder in a helium environment at a pressure of 12 Torr, resulting in the production of copper nanoparticles coated with carbon, with an average size of 6 nm. The synthesized material was characterized by transmission electron microscopy, Raman spectroscopy, and X-ray phase analysis. The effect of nanoparticle concentration on the electrical conductivity of water-based nanofluids was studied. It was found that when nanoparticles are added to water, the electrical conductivity of nanofluids increases, however at concentrations above 0.01 wt%, the electrical conductivity begins to decrease.

EFFECT OF AN INWARD-FACING BAFFLE ON LAMINAR FORCED CONVECTION HEATING ALONG A CYLINDRICAL HORIZONTAL PIPE FOR DIFFERENT NANOFLUIDS

Improving heat exchange intensity is a major goal in the heat exchanger industry. The use of baffles is one of the techniques employed to achieve this goal. In this numerical work, the effect of an inward-facing baffle placed on the wall of a cylindrical horizontal pipe is treated for the case of nanofluid. A sequential analysis is offered to better understand the different effects and their consequences, particularly on the average exchange rate, in addition to somewhat filling the gap identified in the literature for the case of nanofluid with various shapes of the baffle. The study, divided into three parts, begins for 10 ≤ Re ≤ 250 with the case of pipe without baffle, where the water-based nanofluid effect is treated. Three types of nanoparticles (Cu, Al<sub>2</sub>O<sub>3</sub>, and TiO<sub>3</sub>) at volume concentration 0 ≤ φ ≤ 10% are considered. An insulated primary pipe is placed to ensure dynamic establishment at the entrance to the heating pipe assumed to be under imposed temperature. The results showed the clear effects of modifying the kinematic viscosity and thermal diffusivity on the dynamic and thermal lengths, respectively, with the addition of nanoparticles compared to the base fluid. Correlations are proposed for their determination. A heat exchange rate that improves as the volume concentration increases is recorded, particularly for nanoparticles with high thermal conductivity. In the second part, a rectangular baffle is assumed in the heated pipe, where the effects of its position, length and width are analyzed respectively. The results showed a greater interest in placing the baffle close to the entrance, especially if it is longer. In the last part of the work, three other shapes of the baffle are proposed (trapezoidal, triangular, and elliptical). The results confirm that the non-smooth shape of the baffle creates more disturbances in the dynamic and thermal fields, and therefore a greater improvement in the heat exchange rate. For the last two parts, the nanofluid effect remains similar to that recorded for pipe without baffle.

Time-independent three-dimensional flow of a water-based hybrid nanofluid past a Riga plate with slips and convective conditions: A homotopic solution

Abstract In the present analysis, we have analyzed the three-dimensional flow of an electromagnetohydrodynamic copper–aluminum/water hybrid nanofluid flow on a Riga plate. The heat and mass flux model proposed by Cattaneo-Christov is deliberated here. Thermal radiation, thermophoretic diffusion, Brownian motion, and chemical reaction phenomena are considered in analyzing the flow problem. Thermal convective, mass convective, and velocity slip conditions are adapted in this analysis. Suitable resemblance variables are implemented for the conversion of the model equations to dimension-free form. The homotopy analysis method is adopted to solve the modeled equations. The obtained results show that the velocity profiles are reduced with an increasing estimation of the slip factors. Additionally, the nanoparticles’ concentration and the temperature of the hybrid nanofluid increase with higher values of thermal and solutal Biot numbers. The Nusselt number is increased with an increase in the radiation factor and thermal Biot number.

Measurement of the dynamic viscosity of water-based nanofluids containing Al2O3, TiO2, and ZnO using the Artificial Neural Network method

Measurement of the dynamic viscosity of water-based nanofluids containing Al2O3, TiO2, and ZnO using the Artificial Neural Network method