Types Of Nanofluids Research Articles

Optimization of Heat Transfer in Parabolic Trough Collectors Using Advanced Turbulator Designs and Nanofluids

Parabolic trough collectors (PTCs) are essential for solar thermal energy systems, and their thermal efficiency can be significantly enhanced using turbulators and nanofluids. This numerical study introduces three novel fin-spiral turbulator configurations (4, 7, and 10 blades) to enhance heat transfer within the absorber tube. Additionally, three nanofluid types including water-based single-walled carbon nanotubes (SWCNT), cupric oxide (CuO), and a hybrid SWCNT-CuO, at concentrations of 1%, 3%, and 5% were evaluated. The simulations, conducted in ANSYS-FLUENT under steady-state turbulent flow conditions, revealed that the 10-blade turbulator improved the heat transfer coefficient by 12.25% compared to a plain tube, while the hybrid SWCNT-CuO/water nanofluid exhibited a 24.8% increase in thermal conductivity compared to the base fluid. Furthermore, a maximum pressure drop increase of 44% was observed for the hybrid nanofluid at 5% volume concentration and a Reynolds number of 12,500. The study also demonstrated that the Performance Evaluation Criterion (PEC) improved by 15.6% for the hybrid nanofluid compared to CuO/water nanofluid. These findings highlight the effectiveness of combining fin-spiral turbulators and hybrid nanofluids to optimize the thermal and hydraulic performance of PTC systems.

ENHANCING HEAT TRANSFER WITH NEW HYBRID NANOFLUIDS TYPE CORE@SHELL NANOPARTICLES

This numerical study aims to enhance heat transfer in non-uniformly heated systems using a novel hybrid of core@shell nanoparticles with a ZnO@Ag structure. The primary objective is to evaluate the effectiveness of these nanoparticles in improving thermal performance. The analysis spans a range of Rayleigh numbers while maintaining a constant nanoparticle density of 0.1%. The finite volume method is employed to solve the governing equations, using the second-order upwind method for convection contributions and the SIMPLE approach for coupling velocity and pressure fields. Pressure discretization is performed using the PRESTO method, and convergence is ensured with an under-relaxation scheme, achieving an absolute residual below 10<sup>-6</sup>. The results demonstrate a significant improvement in Nusselt numbers, with ZnO@Ag nanoparticles achieving a 20.15% enhancement. This improvement is attributed to the even coating of Ag, which possesses superior thermal properties onto ZnO, leading to increased overall thermal conductivity. These findings underscore the promising potential of core@shell nanoparticles for enhancing heat transfer in engineering applications. This study motivates further research and optimization efforts to harness the full potential of these advanced materials in thermal management systems.

Irreversible effects for SWCNT‐MWCNT/water based flow with Coriolis force over rotating frame: A numerical study

AbstractIn this study, two different types of nanofluids are used: One is the simple nanofluid consist of single‐wall carbon nanotubes (SWCNT), and the other is the hybrid nanofluid composed of single and multi‐wall carbon nanotubes (SWCNT‐MWCNT). The famous Xue model is incorporated for the thermal energy analysis. An important property related to the nanoparticles is the Brownian motion and thermal‐migration, which is described by using Buongiorno's model. The appropriate similarity transformations are used to convert the governing nonlinear partial differential equations into the nonlinear coupled ordinary differential equations for the both velocity and temperature profiles. The numerical solution is obtained for the present problem by using bvp4c Matlab routine. This code is based on the finite difference method that implements the three‐stage Lobatto IIIa formula. The comparative analysis for the entropy generation in rotating frame due to heat transfer, viscous heating, and mass diffusion is the main focus in this study. The impact of different parameters such as, rotational motion , thermomigration and Brownian motion , volume fractions of SWCNT & SWCNT‐MWCNT ,, Eckert number , Lewis number , chemical reaction parameter , Brinkman number the temperature ratio parameter and concentration difference parameter on axial and transverse velocity, temperature profile, entropy generation, and Bejan number are obtained. The obtained results for these different variables are presented through graphs and tabular form. When the solid volume fraction is enhanced, the flow and heat distribution are observed to increase. The Nusselt and Sherwood numbers for both nanofluids are investigated. The decay in Nusselt number is observed as the values of the heat source/sink parameter, thermophoresis, Brownian motion, and Eckert number are increased. However, in the case of Sherwood enhancement an increment in the value of the chemical reaction parameter, thermophoresis, Brownian motion, and Lewis number is observed. The entropy generation is enhanced as a result of increment in Brinkman number and temperature ratio. However, in the case of Bejan number, opposite trend was seen in the entropy generation. For the hybrid nanofluid, the enhancement in both heat transmission and irreversibility effect is observed as compared to simple nanofluid.

Computational Investigation on Helical Coil Heat Exchanger with Nanofluids

Heat exchangers are critical components in various industrial processes, and their efficiency directly impacts system performance and energy utilization. In the helical coil heat exchanger, three different types of nanofluids are used (CuO/water, Al2O3 /water and ZnO/water). The heat transfer coefficient rate of the helical coil heat exchanger was analytically investigated considering the nanofluid volume fraction in the range of 1-4% and volume flow rates in the range of 3-6L/min respectively. In their study to 3D model of the helical coil heat exchanger is done in SOLID WORKS parametric programming. After modelling, computational fluid dynamics analysis is used to study the heat transfer characteristics of a helical coil heat exchanger using nanofluids under turbulent flow conditions. CuO/Water, TiO2/water and ZnO/Water with volume concentration of (5-7%) are used as the working nanofluid. The heat transfer rate and heat transfer coefficient results of CuO/Water, TiO2/water and ZnO/water are compared with varying volume concentrations. Finally, we conclude the nanofluid and volume concentration that gives better performance.

Evaluation of photovoltaic thermal system performance with different nanoparticle sizes via energy, exergy, and irreversibility analysis

The PVT system efficiency generally depends on diverse factors, such as design parameters, solar radiation intensity, and the concentration and type of nanofluid, among other major factors. The present work focuses on the effect of nanoparticle size on a nanofluid-based PVT collector system with a spiral-flow absorber. Besides nanoparticle size, the system is experimentally investigated at various flow rates, nanoparticle concentrations, and different working conditions. Moreover, PV efficiency is also calculated and compared with thermal efficiency by employing both energy and exergy analyses. The rate of exergy loss in PVT is calculated in order to provide a appropriate understanding of the key factors that affect the overall performance of such systems. The most important factor significantly affecting the PVT net efficiencies is the absorber outlet temperature, which illustrates the trade-off between the temperature increase and the increase of the potential concentration factor.The nanoparticles are milled several times to produce four groups based on particle size, such as A (2-5 nm), B (22-29 nm), C (34-50 nm), and D (75-92 nm). The nanofluid thermal conductivity of groups A, B, C, and D compared to water increased by approximately 50.0%, 45.7%, 34.7%, and 21.4%, respectively. The viscosity of these aggregates increased compared to water by approximately 12.9%, 6.4%, 4.3%, and 3.2%, respectively. There were no observed changes in density with changing groups. The stability of the prepared aggregates was close to the superiority of group A with the smallest nanoparticles. Group A, due to its higher thermal conductivity compared to the rest of the fluids tested, provided the best electrical and thermal energy, but it consumed more pumping energy due to its high viscosity. Therefore, the results show that the electrical and thermal exergy of group A, as well as the entropy generation and irreversibility, were higher than the rest groups, which indicates higher losses. The data calculated hereby should be useful in determining the optimal operating condition of the nanofluid PVT based on nanoparticle size.

Stability scrutinization of a non‐Newtonian (Williamson) ternary hybrid nanofluid past a stretching/shrinking sheet

AbstractThe thermal superiority of ternary hybrid nanofluids (THNFs) over conventional heat transfer fluid has led to growing interest in their applications. This new type of nanofluid can be customized for cooling systems, heat exchangers, and electronic cooling by carefully selecting nanoparticle types and their volume fraction. Hence, this study seeks to investigate the Heimenz flow in a Williamson THNF over a sheet that stretches or shrinks. The fundamental objective is to assess the effect of the stretching/shrinking parameter, the Weissenberg number, and the nanoparticle volume fraction on the physical quantities and flow profiles. Besides, attention is also given to the occurrences of multiple solutions in this fluid flow situation. By employing a similarity transformation, the governing equations are modified as a simpler form of ordinary differential equations (ODEs). Next, the numerical method is put to use to solve the resulting ODEs system, specifically the bvp4c solver in MATLAB. Significant changes in heat transmission occur due to variations in the Weissenberg number and volume fractions of nanoparticles, particularly when the sheet starts to shrink. The escalating Weissenberg number correlates with growing critical values of the stretching/shrinking parameter, suggesting that both parameters help to hold off the detachment of the boundary layer. These findings emphasize the capacity of THNFs to improve heat transfer performance in numerous applications. This study also reveals that while stretching sheets often have unique solutions, a shrinking sheet has multiple solutions when the shrinking parameter falls within a certain range. By scrutinizing the robustness of these solutions, it was concluded that only one of them maintains stability over an extended period. It is essential to highlight that these present discoveries apply exclusively to the mixture of copper, alumina, and titania. Various mixtures of nanoparticles can demonstrate distinct characteristics of THNFs concerning both flow dynamics and thermal transfer.

Multi-objective optimization of nanofluid thermal performance in battery cold plates using computational fluid dynamics

Inspired by the tree root structure, this paper uses commercial CFD software to simulate and analyze the cold plate of three-dimensional battery, and focuses on the heat transfer problem of tree root sine pipe to improve the heat dissipation performance of LiFePO4 battery. Utilizing nanofluids as working fluids, the research explores the impact of channel geometry, discharge power, nanofluid type, volume fraction, initial temperature, and velocity on heat transfer characteristics. The results show that the heat transfer effect of sinusoidal pipeline is obviously improved compared with traditional pipeline. Among the tested nanofluids, a 5 % Cu-water mixture exhibited the highest heat transfer efficiency. Furthermore, higher initial nanofluid velocity and lower initial temperature led to reduced average cold plate temperatures. Response surface methodology and genetic algorithm were utilized to optimize the thermophysical properties and initial operating conditions of the nanofluid. The influencing factors, including initial temperature (288 K-298 K), initial velocity (0.05 m/s-0.25 m/s), and volume fraction (1 %-5 %), were analyzed with the objective of establishing a relationship between the average battery temperature and pressure drop. And the optimized solution identified an ideal combination of inlet velocity, temperature, and nanofluid volume fraction of 0.14 m/s, 288.00 K, and 4.41 %, respectively, maximizing heat dissipation while minimizing pressure loss.

Soret and Dufour effects for unsteady flow with shapes and (Cu+Fe3O4)/(ethelene–glycol+methanol) between two stretchable rotating disks

The ongoing study looks at the multiple shapes of nanoparticles in an unsteady flow between two stretchable rotating disks. Unsteady flow of hybrid nanofluid takes place between the stretchable disks, using (ethelene–glycol+methanol) as the base fluid and (Cu+Fe3O4) as the hybrid nanofluid. This study uses three distinct forms of (Cu+Fe3O4) hybrid nanofluids: brick, blade, and cylinder. Using chosen similarity transmutations, corresponding mathematical expressions (partial differential equations) are transformed into nonlinear ordinary differential equations. The whole set of equations takes the shape of an ordinary differential equation depending on the boundary conditions, and the solution is numerically computed using the bvp4c MATLAB solver. The influence of multiple factors across the velocity field is illustrated graphically. To acquire tiny quantities of the unsteady factors S, the momentum boundary layer for all types of nanofluids becomes less and more conspicuous. We compared our findings to previous findings and discovered an intriguing pattern. The main discovery of this work is Dufour and Soret effect on the heat and concentration profile. The rise in the rotation and the unsteady parameter ends up with an increase in the tangential velocity. The temperature rises as the Brinkman number and heat source factors rise, and falls as the unsteady parameter S rises. The concentration falls as the Schmidt number and unsteady factor increase, but it increases as the activation energy increases.

Evaluating the Thermal and Hydraulic Performance of Various Nanofluids for Cooling Efficiency in Diverse Heat-Sink Configuration

Using nanofluids in thermal applications is widely believed to enhance efficiency compared to conventional fluids, presenting the significant role of nanofluids as a crucial step in implementing energy-saving measures across various commercial applications. However, the selection of nanofluid concentration often lacks a systematic approach, with decisions made independently of specific application requirements, type of nanofluid, cost considerations, and economic factors such as energy cost and system lifetime. This study examines the thermal and hydraulic performance of four nanofluids (Al2O3, TiO2, CuO, and SiO2) in heat-sink configurations designed for cooling data center servers. The research quantifies the effects of these nanofluids across three heat-sink cross-sectional shapes—circular, square, and rectangular—by analyzing metrics such as maximum chip surface temperature and cross-sectional pressure drop over a range of Reynolds numbers and flow rates. Key findings reveal that the square cross-sectional shape achieves a balanced performance, optimizing thermal transfer with a moderate pressure drop, making it a promising option for data center applications. The rectangular configuration offers superior heat transfer but incurs higher pressure drops, suited for cases prioritizing cooling efficiency over energy cost. Al2O3 nanofluid demonstrated the highest thermal conductivity but also resulted in the greatest increase in pressure drop, especially at higher nanoparticle concentrations. These results offer critical quantitative insights into selecting appropriate nanofluids and geometric configurations for enhanced cooling performance in data centers, highlighting the trade-offs between cooling efficiency and hydraulic energy demands.

Computational Analysis of Convective Heat Transfer in Ternary Nanofluid (Al2O3 + CuO + TiO2/H2O) Flowing Past a Porous Stretching Sheet with Temperature Dependent Viscosity and Viscous Dissipation

The main objective of this study is to develop a two-dimensional mathematical model to understand the heat transfer phenomenon across a stretched surface in a ternary hybrid nanofluid. A ternary hybrid nanofluid, also known as a tri-hybrid nanofluid, consists of three different types of nanoparticles dispersed within a base fluid, resulting in a complex and advanced type of nanofluid. Al2O3–CuO–TiO2–H2O combination is formed in this study by dispersing the nanoparticles of Al2O3, CuO and TiO2 into water. This mixture helps to cool other appliances, break down hazardous contaminants, and purify the surroundings. The impact of temperature-dependent viscosity as well as viscous dissipation are discussed. Nonlinear ordinary differential equations are created from governing PDE utilizing similarity transformations. In MATLAB software, bvp4c method can then be used to solve these transformed equations. In this study, incorporated viscous dissipation terms into the energy equations, and the effects of radiation were accurately addressed using the Rosseland approximation. The study also takes into account the impact of nanoparticles, specifically Al2O3, CuO and TiO2. Key parameters have been extensively illustrated in graphical form for clarity and better understanding. A detailed analysis and discussion are provided of the effects of distinct parameters on the temperature as well as velocity profiles. This work is novel in that it modifies the momentum equation by including variable viscosity in conjunction with natural convection and viscous dissipation in the energy equation.

Thermal analysis of hybrid nano-fluids: Modeling and non-similar solutions

The thermal analysis of hybrid nano-fluids is a significant research area with diverse applications in industries such as paint, electronics, and mechanical engineering. Existing literature provides limited solutions to the governing equations for the flow of these fluids. Modeling and deriving non-similar solutions for these equations pose interesting and challenging mathematical problems. This study focuses on investigating heat transfer in the flow of two types of nano-fluids, specifically Al2O3/H2O micropolar nano-fluid and Al2O3 + Ag/H2O hybrid nano-fluid, near an isothermal sphere. Conservation laws are employed to formulate the mathematical problem, and by normalizing the variables, the governing equations are converted into a set of dimensionless partial differential equations. Non-similar solutions are then obtained using numerical methods. A comparative analysis is carried out to assess the influence of various parameters on different profiles and engineering quantities for both types of nano-fluids. Both linear and rotational velocities fall down near the surface of sphere with rising microstructure in hybrid nanofluid. The micro-rotation parameter rises the temperature profile while reduces the Nusselt number of both traditional Al2O3/water based nanofluid as well as hybrid nanofluid.

Influence of Nanofluid Types on the Enhancements of Solar Collector Performance

Nowadays, solar energy is attracting a great deal of research interest. Optimizing solar collectors by incorporating nanoparticles into the base fluid is one area of current research focus. This study investigates how the types of nanoparticles affect the performance of solar collector. We investigated the effects of various nanoparticles types on performance of solar collector. Nanofluid 1 (alumina nanoparticles; Al2O3) and nanofluid 2 (silicon dioxide nanoparticles; SiO2) were combined with water. Nanofluids are made with a constant nanoparticle concentration of 0.5 vol. %. Data collection was conducted under Iraqi environments during the three-month study period (January, February, and March) from 9 a.m. to 3 p.m. In particular, the data for every two-hour period is displayed. The results demonstrated the collector’s efficiency significantly influenced by nanoparticles’ type. At 1 p.m. in February, nanofluid 1 was 4.8% in front of nanofluid 2. The significance of nanoparticle materials in enhancing solar collector efficiency is highlighted by this outcome. When water-based fluid in the solar collector was compared to nanofluids 2 and 1, the latter demonstrated a typically better efficiency. Nanoparticle owns higher thermal conductivity which is one of the reasons behind the increments of the nanofluid's overall conductivity.

A computational analysis of the impact of nanofluids (Al2O3)on the PCM melting process in a rectangular container

The effect of nanofluids on the melting process of PCMs (RT58 paraffin wax) in a rectangle container is a topic of interest for many researchers. The use of nanofluids in PCMs can lead to faster and more efficient melting, resulting in improved energy storage and cooling performance. This paper has studied four cases with varying percentages of nanofluids. The percentage of nanofluid in PCM can affect the material's thermal conductivity and heat transfer performance. By varying the percentage of nanofluids, researchers aim to optimize the use of these in PCMs to achieve the best melting performance. Findings have shown that increasing the percentage of nanofluids in PCM can lead to improved thermal conductivity and heat transfer performance. However, at high concentrations (30% percent), the viscosity of the nanofluid can increase, leading to a decrease in heat transfer performance. Results show that at 30 min, PCM with 30% nanofluid melts 13.79% more than PCM without. Using 20% nanofluid in the PCM results in a melting percentage of 7.41%, decreasing to 3.85% at 10%.The specific application and the type of nanofluid used determine the optimal concentration of nanofluid in PCMs. This study is important for the use of phase-change materials in the cooling of large electronic devices.

Experimental Investigation of Thermo-Hydraulic Characteristics and Sustainability Measure of a Novel Multi-Fluid Heat Exchanger for Turbulent Water-Based Nanofluid Flow through the Inserted Brazed Helix Tube

Abstract A Novel Multi-Fluid Heat Exchanger (NMFHE) deployed for simultaneous heating of water and space is experimentally investigated to predict its thermo-hydraulic, exergetic, and sustainability performance for distinct Al2O3, TiO2, and CuO nanofluid flow of 50ppm concentration of each through the inserted Brazed Helix Tube (BHT). The input parameters such as flow rates, helix tube diameters, and nanofluid types are varied throughout the experiments to evaluate their effect on output performance parameters i.e., Nusselt number (Nu), Friction factor (f), entropy generation number (Ns), JF factor (JF), exergy efficiency (εE), and sustainability index (SI). The nanofluid (NF) flowing through the BHT is the heating fluid that simultaneously heated the cold water (CW), and air (CA) flowing through the outer shell and inner conduit of the BHT respectively. A distinct Nusselt number correlation for turbulent nanofluid flow inside BHT was developed, compared, and validated reasonably with the current result. For Al2O3 NF at a Reynolds number of 5698 with a 1/2-inch diameter helix tube, the best results for JF, εE, and SI are found to be 0.009, 0.72, and 3.53, respectively. Furthermore, for Al2O3 and TiO2 NF at a Reynolds number of 14250 and a helix tube diameter of 1/4 and 1/2-inch, f, and Ns are found to be 0.0032 and 0.043, respectively are optimum. It is observed that the use of Al2O3 NF, higher helix tube diameters, and lower flow rates all make the proposed heating application more sustainable.

A second law analysis on flow of a PCM based nanofluid in a shell-and-tube heat exchanger: An experimental study for sustainable energy

In the foreseeable future, heat exchangers will continue to play an important role in environmental management and have numerous applications, their geometry has been the subject of interest for many researchers. The main goal of this research is to improve the heat exchangers' thermal performance and exergetic efficiency using new type of nanofluid. In this concept, the effect of nanoencapsulated phase change material (NEPCM) addition to water and producing NEPCM nanofluid for heat transfer augmentation in shell and tube heat exchanger (STHE) was investigated, experimentally. Nanocapsules were synthesized by miniemulsion polymerization containing phase change material (PCM) as core and chitosan (GO/CS) as shell material. After synthesis of nanocapsules, nanofluids with different concentration of NEPCM have been prepared and the stability and thermophysical properties of the nanofluids were characterized. In the subsequent stage, thermal and exergy efficiencies test was conducted on STHE using response surface method. The experiments were performed at different conditions; NPCM concentration (φ), inlet temperature (Tin) and Re number to optimse exergy efficiency. The optimum level of the φ, Tin and Re inlet for maximum ɛ (73 %) were found to be 10.55 %, 78.35 °C and 10365, respectively. The experimental results demonstrated that proposed nanofluid could enhance exergy efficiency for thermal system. It appears that a combination of NEPCM nanofluids gives a better cooling rate in the heat exchangers and could be a promising alternative along with other cooling techniques.

Experimental investigation on stability and thermal conductivity of SiO2 nanoparticles as green nanofluids for application thermal system

In the last few years, much research has focused on the stability and improvement of the thermo-physical properties of single-component nanofluids. Some studies have not made many improvements to the stability and thermophysical properties of various types of green nanofluids from several variations of nanoparticles. Green nanofluids must be developed to improve heat transfer performance from their stability and thermal conductivity factors. Stability and thermal conductivity of Nano-silicate suspended in a base mixture of water /ethylene glycol with the ratio of 60:40, different volume concentrations were investigated. The experiments carried out were the stability of the green nanofluids investigated for volume concentrations of 0.1~0.3% and temperature conditions from 30 to 70°C for thermal conductivity measurement using TEMPOS Thermal Properties Analyzer. The experimental results showed that the stability analysis of the green nanofluids prepared by the UV-Vis method was stable up to 30 days after preparation with a sonication time of 1 hour with a ratio of 70-80%. The evaluation of the zeta potential for green nanofluids obtained a value of 33.57 mV with a moderate stability classification. The highest thermal conductivity for the green nanofluids was obtained at 0.3%, and the maximum increase was 17% higher than that of the base liquid (W/EG). Green nanofluids with a concentration of 0.1% gave the lowest effective thermal conductivity of 1.09 time at 70°C.

Hydrothermal analysis of hybrid nanofluid flow inside a shell and double coil heat exchanger; Numerical examination

In a shell-and-coil heat exchanger, employing a double coil instead of a simple coil causes more heat transfer compared to a simple coil because the double coil improves heat exchange through enhanced fluid flow and turbulence, enabling a longer tube length in constrained locations.. In addition to reducing fouling and the requirement for maintenance, the helical shape may also provide the benefit of a self-cleaning action. Ensuring a more even flow distribution also maximizes the heat exchanger's surface area use and reduces low flow zones. Applications needing compact solutions without compromising performance especially benefit from this design's versatility, allowing customization to meet unique operational demands. In numerous industrial applications, helical coils offer substantial benefits in terms of effectiveness, upkeep, and design freedom.In the present work, heat transfer and fluid flow in a shell-and-coil tube heat exchanger equipped with a double helical coil are evaluated numerically. The employed heat transfer fluids are water-based hybrid nanofluids, including TiO2-Mgi/water and AG-HEG/Water. The obtained outcomes are compared with the results of pure water. The range of considered Reynolds numbers is 500 – 2000. This work consists of two sections. In the first part, the impact of the type of hybrid nanofluid on the hydrothermal behaviour of the proposed heat exchanger is analysed. The volume concentration of the nanoparticles here is ϕ1 = ϕ2 = 0.3. In the second section, the best hybrid nanofluid is selected according to the results of the first section; then, the impact of the nanoparticles' volume concentration on the thermal performance of the proposed heat exchanger is evaluated. Three various nanoparticle volume concentrations, including ϕ1 = ϕ2 = 0.1, ϕ1 = ϕ2 = 0.3, and ϕ1 = ϕ2 = 0.5, are considered, and the results are compared with those of the pure water case (ϕ1 = ϕ2 = 0).The obtained results show that amongst the different heat transfer fluids considered, the Water/MgO-TiO2 model shows the most outstanding value of thermal performance in all the studied Reynolds numbers. Also, the obtained numerical results show that the use of the proposed double coil tube leads to an increase in the heat transfer rate.

Heat transfer in shear flow over a still nanofluid: A direct integration approach

Heat transfer in a two-layer fluid system, including shear-driven viscous fluid in the upper layer and still nanofluid in the lower layer, is investigated in this work. Following single phase model for nanofluid, three different types of nanofluids are considered. Different from existing literatures on two-layer fluid flow problem, this work introduces the heat transfer of shear-driven viscous fluid over a still nanofluid which makes this investigation new. The main equations which are partial in nature are reduced to a set of coupled nonlinear ordinary differential equation (ODE) by employing suitable similarity transformations. These ODEs together with the coupled interfacial boundary conditions are supplied to MATLAB software to get the solution numerically. Comparing the results obtained in this study with the previous authoritative research results, the accuracy and correctness of the present research methodology are ensured. The results show that the temperature of the upper fluid and the lower fluid are controlled by the thermophysical properties of different types of nanofluids. Also, opposite behavior of temperature distribution for the upper and the lower fluid are observed.

Mo-MOF-based ionanofluids for highly efficient extraction coupled catalytic oxidative desulfurization

Ionanofluids as newly introduced types of nanofluids with promising potential for diverse applications are created through dispersing nanoparticles into ionic liquids. Ionanofluids capitalize on both the catalytic ability of nanoparticles and the rapid mass transfer along with the extraction performance of ionic liquids. Herein, a novel kind of ionanofluids (denoted Mo-INFs) was constructed by employing a Mo-MOF as the nanoparticle and an imidazole-based ionic liquid ([BDIM][NTF2]) as the base fluid. As the efficiency of Mo-INFs (97.9 %) surpassed the summarized efficiency of Mo-MOF and [BDIM][NTF2], a synergistic effect between the Mo-MOF moiety and the [BDIM][NTF2] moiety in Mo-INFs did exist. Under optimum reaction conditions, the Mo-INFs exhibited remarkable selectivity and recyclability in desulfurization. A possible desulfurization mechanism was proposed that aromatic sulfur compounds in the model oil phase were initially extracted into ionanofluids phase via C-H···π and π···π interactions and subsequently oxidized by peroxo species that formed in the presence of H2O2 and Mo-MOF.

Impact of variable electrical conductivity, viscosity on convective heat and mass transfer flow of CuO- and Al2O3-water nanofluids in cylindrical annulus

In the food industry, electrical conductivity is essential for heating processes. The dependence on temperature conductivity of electricity on the outermost layers flow of the nanofluid is the main topic of this paper. Variable electrical conductivity, viscosity, thermo diffusion, thermal radiation and radiation absorption on convective heat and mass transfer flow Cuo and Al2O3-water nano-fluids confined in cylindrical annulus. The non-linear governing equations have been solved by finite element technique with quadratic approximation functions. For various parametric adjustments, the temperature, speed, and nanoconcentration have all been examined. Similar to the cylindrical wall, quantitative evaluations have been made of the surface resistance, temperature rate and mass transport. It is discovered that for both types of nanofluids, a higher thermo-diffusion effect leads to a lower concentration and Sherwood digits on the cylinders. An augment in Q1 enriches the rapidity in CuO-water nanofluidic system as well as decreases in Al2O3-water nanofluidic. Increased Q1 lowers the real temperature and nanoconcentration in both types of nanofluids.