Nanofluid Concentration Research Articles

MHD double diffusive convective squeezing ternary nanofluid flow between parallel plates with activation energy and viscous dissipation

Purpose This study aims to present the consequences of activation energy and the chemical reactions on the unsteady MHD squeezing flow of an incompressible ternary hybrid nanofluid (THN) comprising magnetite (FE3O4), multiwalled carbon nano-tubes (MWCNT) and copper (Cu) along with water (H2O) as the base fluid. This investigation is performed within the framework of two moving parallel plates under the influence of magnetic field and viscous dissipation. Design/methodology/approach Due to the complementary benefits of nanoparticles, THN is used to augment the heat transmit fluid’s efficacy. The flow situation is expressed as a system of dimensionless, nonlinear partial differential equations, which are reduced to a set of nonlinear ordinary differential equations (ODEs) by suitable similarity substitutions. These transformed ODEs are then solved through a semianalytical technique called differential transform method (DTM). The effects of several changing physical parameters on the flow, temperature, concentration and the substantial measures of interest have been deliberated through graphs. This study verifies the reliability of the results by performing a comparison analysis with prior researches. Findings The enhanced activation energy results in improved concentration distribution and declined Sherwood number. Enhancement in chemical reaction parameter causes disparities in concentration of the ternary nanofluid. When the Hartmann number is zero, value of skin friction is high, but Nusselt and Sherwood numbers values are small. Rising nanoparticles concentrations correspond to a boost in overall thermal conductivity, causing reduced temperature profile. Research limitations/implications Due to its firm and simple nature, its implications are in various fields like chemical industry and medical industry for designing practical problems into mathematical models and experimental analysis. Practical implications Deployment of the squeezed flow of ternary nanofluid with activation energy has significant consideration in nuclear reactors, vehicles, manufacturing facilities and engineering environments. Social implications This study would be contributing significantly in the field of medical technology for treating cancer through hyperthermia treatment, and in industrial processes like water desalination and purification. Originality/value In this problem, a semianalytical approach called DTM is adopted to explore the consequences of activation energy and chemical reactions on the squeezing flow of ternary nanofluid.

Experimental and machine learning study on the influence of nanoparticle size and pulsating flow on heat transfer performance in nanofluid-jet impingement cooling

Maximizing heat transfer efficiency is crucial for enhancing performance and durability in diverse engineering applications, including fuel cells, EV batteries, and solar PV/T systems, thereby advancing sustainable energy innovation. This study investigates thermal dissipation from a simulated heat sink aligned with a PV cell’s back plate via jet impingement cooling. Specifically, it examines the impacts of pulsatile cooling and nanoparticle size in hybrid nanofluids, comprising combinations of Al2O3 and MWCNT in water, with varied nanofluid volume fraction (0.05 vol% ≤ ɸ ≤ 0.3 vol%) and flow Reynolds number (15000 < Re < 40000). Key findings reveal significant influences of nanoparticle size, nanofluid concentration, and pulsating flow on heat transfer performance. Notably, sample D demonstrated the highest heat transfer enhancement, achieving approximately 52.94 % and 79.06 % improvement in continuous and pulsating jet cooling compared to de-ionized water under continuous jet cooling. Machine learning classifiers were employed to identify critical thermal performance parameters, with Reynolds number identified as the most significant factor influencing heat transfer. Random Forest and Gradient Boosting classifiers showed notable accuracy in predicting Nu, emphasizing the role of machine learning techniques in optimizing thermal management strategies for improved heat dissipation from solar PV cell backplates.

Effect of the use of metal–oxide and boron-based nanoparticles on the performance in a photovoltaic thermal module (PV/T): Experimental study

Renewable energy sources are constantly on the agenda because the fossil fuels used are limited and the need for energy is constantly increasing. Among these resources, solar energy stands out because it is clean and endless energy. Nowadays, heat energy and electrical energy production from solar energy are quite common. Photovoltaic (PV) solar panels can convert a limited portion of the solar energy falling on them into electrical energy. In PV panels, heat energy that cannot be converted into electricity is discharged back to the external environment. Photovoltaic thermal (PV/T) panels are used to remove this heat from the system and convert it into useful energy. Many cooling techniques are applied to reduce the surface temperature of PV/T panels and increase their electrical efficiency. One of these techniques is liquid-cooled PV/T panels. In some of the studies, forced circulation (using a pump) and in others natural circulation (thermosiphon effect) were applied. In this study, a natural circulation indirect heated PV/T system was designed. Al2O3, ZnO, and BN nanoparticle concentrations were added to the cooling water to increase heat transfer within the PV/T panel. According to the experimental results, using nanofluid in the PV/T panel increased the thermal and total efficiency. Total efficiencies of ZnO, BN, and Al2O3 were obtained as 52.8 %, 47.86 %, and 43.49 %, respectively, at 0.03 concentration. The highest exergy efficiency and sustainability index were determined as 17.155 % and 1.207, respectively, at 0.03 concentration of ZnO nanofluid.

Implementation of stacking regressor model on the flow induced by TiO2‐H2O and Ti6Al4V‐H2O nanofluid with waste discharge concentration

AbstractThe present investigation examines the circulation of and based nanofluids while considering the concentration of waste discharge. An innovative stacking regressor model is used to increase prediction accuracy. Using Shooting and Runge Kutta Fehlberg's fourth and fifth‐order schemes, the governing equations are converted into ordinary differential equations using similarity transformation and then numerically solved. The findings are represented graphically, and the model's correctness is assessed using Gaussian Process Regression, Categorical Boost, Extreme Gradient Boosting, and Random Forest, with linear regression acting as a meta‐model. The closely related testing and training data show the model's consistency and stability. Magnetic field and inclination angle will decline the velocity, space, and temperature‐dependent internal heat generation factors will enhance the temperature. Raising the pollutant external source parameter raises concentration. In all the cases, shows better performance than based nanofluid. The work's application ranges from fluid dynamics to waste management. By offering precise forecasts of nanofluid concentration, the proposed prediction model may aid in designing and optimizing waste discharge systems.

Performance assessment of graphene oxide based nano-cutting fluids during sustainable hard turning through synthesis, characterization and machinability investigation

Achieving sustainability in manufacturing necessitates the implementation of eco-friendly solutions by adopting environmentally friendly coolants with cost-effective, energy-efficient and cleaner production processes without posing any risk to the operator's health. In this current work, mineral oil-based graphene oxide (GO) nano-cutting fluids of different concentration (0.05, 0.1, 0.2, 0.3, 0.4, 0.5 % wt.) are synthesized and their characteristics such as rheological, thermo-physical and tribological properties along with their stability and toxicology impact are thoroughly investigated. Further, the influence of nano-cutting fluid concentration on machinability and sustainability aspects during hard turning such as flank wear, surface integrity, power consumption, cutting temperature, carbon and noise emissions are investigated. According to the result an enhancement of 28.83 % and 29.54 % in viscosity and thermal conductivity have been recorded when concentration of nanofluid increases from 0.05 % to 0.5 %. GO nano-cutting fluids shows anti wear and friction reduction properties by providing excellent lubricious properties, as a result coefficient of friction has been reduced up to 28.36 % at 0.5 % wt. GO compared to plane mineral oil. A notable reduction in flank wear, cutting temperature, surface roughness, cutting temperature, power consumption, carbon emission and noise emission were noticed to be 25.96 %, 27.82 %, 23.86 %, 25.22 %, 11.66 % and 2.72 % respectively when the concentration of GO nanoparticles increases from 0.05 % to 0.5 % wt. Smoother surface with minimal defect has been noticed from the SEM and AFM image of machined workpiece at highest concentration (0.5 % wt.) of GO due to the synergetic effect of GO nano-cutting fluid and dual nozzle MQL system.

Effects of a device containing heat pipe sticks on thermal performance of a heat exchanging tube: An experimental study

Applying heat pipes (HP) on heat-exchanging tubes is the main idea of this experimental work. One, two, or three mini copper heat pipes are soldered around a cooper ring to form a new device to passively enhance the performance of a heat-exchanging test tube. The test tube, containing a hot turbulent flow of water-EG solution, is inserted into a cold-water tank. The hot-flow regime is turbulent with Reynolds numbers of 5600 to 10,700. The results for fully developed turbulent flow were compared with existing correlations to validate the experimental setup. The validation showed less than a 10 % difference in both Nusselt number and friction factor. The base fluid in the heat pipes are distilled water and dilute Cu-water nanofluids. The nanofluids with different concentrations (50, 100, 150, and 200 ppm) are applied in HP-sticks. The role of the Cu-nanoparticle's concentration on the performance of the presented device is discussed. The results reveal the notable performance of the device in the target goal. It is reported that the presented device containing HP-sticks filled with water enhances convection rate of the test tube up to 35 %. It is also ascertained that applying the Cu-water nanofluid in the HP-sticks lead to about 14 % better thermal performance, compared to water. The outcomes also reveal that dilute Cu-water nanofluids (φ≤100 ppm) notably improve the device's performance. Conversely, more concentrated nanofluids possibly decrease the device's performance.

Heat transfer performance of MHD [Ag+Gr+GO/H2O]t ternary nanofluid squeezing flow between two parallel plates in a porous medium with variable viscosity and brownian motion

A novel notion in the realm of research is that ternary nanofluid presents itself as a cutting-edge concept showcasing enhanced heat transfer capabilities when pitted against hybrid nanofluids as well as traditional nanofluids. These ternary nanofluids are employed for boosting thermal conductivity in cooling systems, thereby enhancing energy efficiency in electronics and industrial operations. This research aims to investigate the dynamic viscosity variations within a three-component nanofluid comprising Ag, Gr, and GO nanoparticles suspended in water enclosed between dual parallel plates with entropy generation. The examination encompasses the impact of viscous dissipation, thermophoresis, and Brownian motion occurrences within the energy equation, along with considering chemical reactions in the concentration equation. Techniques of similarity are utilized to transform the complex nonlinear partial differential equations into a collection of ordinary differential equations. The necessary equations that arise are attempted through the utilization of the Runge–Kutta-Fehlberg technique in combination with a shooting method. The research examines graphs and tables to study the effects of new factors on velocity, temperature, concentration, and engineering measures. The outcome of the finding shows that the magnetic field and suction cause a greater decrease in [Ag/H2O]n nanofluid velocity, while an increased squeezing limit elevates [Ag+Gr+GO/H2O]t ternary nanofluid velocity. Increasing thermophoresis and Brownian motion enhance temperature in ternary nanofluid, but [Ag/H2O]n nanofluid concentration diminishes with chemical reaction. Entropy production intensifies in ternary nanofluids due to higher radiation and Brinkman numbers. The magnetic field increases the skin friction of ternary nanofluids by 3.4% at both plates but it decreases by 4.12 more in nanofluids because of alterations in the viscosity factor. Heat transfer decreases by 3.05% at the lower plate but increases by 6.01% at the upper plate in ternary nanofluids due to heat production and thermophoresis. An increase of 3.95% in mass transfer rate is observed in the ternary nanofluid at the lower plate but a decrease of 2.06% is noted at the upper plate due to thermophoresis and Brownian motion. The discoveries illuminate the possibilities of ternary nanofluids to boost thermal conductivity and maximize energy efficiency across a range of industrial applications.

Effect of hBN/MoS2 hybrid nanofluid minimum quantity lubrication on the cutting performance of self-lubricating ceramic tools when machining AISI 4340

Difficult-to-machine materials have consistently limited the improvement of machining efficiency. To address this challenge, this study proposes a strategy of combining Al2O3/SiC/G self-lubricating ceramic tools with hBN/MoS2 hybrid nanofluids. The experiment evaluates the ratio and concentration of the hBN/MoS2 hybrid nanofluid based on cutting forces, friction coefficients, cutting temperatures, surface roughness, and tool wear. Results show that better lubrication is achieved by hBN/MoS2 hybrid nanofluids compared to single nanofluids. The optimal hBN/MoS2 mixing ratio and nanofluid concentration are 2:1 and 1.5 wt%, respectively. Finally, the cutting lubrication mechanism and the synergistic mechanism of self-lubricating ceramic tools with hybrid nanofluids were proposed.

Nonlinear Mixed Convective Analysis of Thomson and Troian Slip Flow Conditions for Ag–Cu–TiO2/H2O Hybrid Nanofluid Over a Riga Plate

The use of nanofluids to improve thermal performance is a significant area of research. In this study, a ternary nanofluid (composed of water suspending silver, copper, and titanium dioxide nanoparticles) was used to investigate flow characteristics over a Riga plate. The analysis included Thomson and Troian slip conditions, variable viscosity, and nonlinear mixed convection. After establishing the dynamics of the flow accurately, the partial differential equations representing these formulations were transformed into dimensionless nonlinear coupled ordinary differential equations. A solution methodology using the Chebyshev collocation method was developed to assess the impact of key physical parameters. The results obtain demonstrated consistency with existing literature under limiting flow conditions. The Hartmann number ( Υ ∈ [ 0.0 , 1.5 ] ) was found to increase the velocity of the ternary nanofluid by approximately 3.24 % , while slightly reducing both temperature by about 0.58 % and nanoparticle concentration by about 1.38 % in the flow distribution. In contrast, varying the mass Grashof parameter ( Λ 3 ∈ [ 0.0 , 0.3 ] ) decreased fluid velocity but promoted higher temperature and concentration distributions. The decrease in nanoparticle concentration of the ternary nanofluid due to increasing ϕ 3 * ∈ [ 0.01 , 0.09 ] led to sedimentation of ϕ 1 * and ϕ 2 * .

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.

Systematic design of tree-like branching network microchannel heat sinks for enhanced heat transfer with nanofluids

Branched or tree-shaped networks of microchannels are often preferred heatsink designs for microelectronic cooling due to their ability to offer a substantially large surface area-to-volume ratio. Designing an optimized tree-shaped heatsink in terms of hydrothermal performance poses challenges due to the intricate geometry and small-scale fluid–structure interactions involved, making prototyping challenging. We propose a systematically designed microchannel network heat exchanger inspired by tree branching patterns, aiming for ease in rapid prototyping and improved flow distributions offering enhanced thermal performance. Starting from a simpler geometrical consideration, we systematically improve the design by introducing a pin fin at the junction for improved flow distribution and then by imparting a converging angle in the channel for enhanced thermal performance. Additionally, we conduct an entropy generation analysis to examine the thermal performance of various nanofluid concentrations within the proposed device and witness significant thermal performance improvement that can benefit the thermal management of microelectronic components and other cooling applications.

Heat transfer enhancement and pressure drop performance of Al2O3 nanofluid in a laminar flow tube with deep dimples under constant heat flux: An experimental approach

This study examines the heat transfer enhancement and pressure drop of Al2O3 nanofluid in deep dimpled tubes in both longitudinal and circumferential directions. It explores mechanisms that improve the thermal performance of this novel tube geometry. Experiments were conducted using plain and deep dimpled tubes under laminar flow with Reynolds numbers from 500 to 2250, a constant heat flux of 10,000 W/m2, and nanofluid concentrations from 0.1 wt% to 1 wt%. The findings indicate that local velocity enhancement, vortex generation, and flow rotation and mixing are the three main mechanisms that improve the thermal performance of deep dimpled tubes. The results demonstrate that a deep dimpled tube with 1 wt% nanofluid can increase the convective heat transfer coefficient by up to 3.42 times compared to a smooth tube at Re = 2250. At this Reynolds number, the Nusselt number reaches a maximum of 41.80, and the friction factor ratio increases by only 1.82. Additionally, circumferential analysis reveals how dimple-induced vortices enhance heat transfer. The results also indicate that the tube geometry modification changes the flow regime zones, allowing turbulent flow at lower Reynolds numbers near Re = 2000, as identified by Nusselt number and friction factor plots. The deep dimpled tube has a low improvement penalty, with the highest friction factor of 0.38 at Re = 500 and high thermal enhancement, resulting in a performance evaluation criterion (PEC) of up to 2.80 in the studied region. However, the deep dimpled tube is unsuitable for Reynolds numbers below 1000. For higher velocities, replacing simple tubes with deep dimpled tubes in traditional heat exchangers is highly recommended.

Indoor dynamic light/thermal environment of smart windows using ATO nanofluids in summer: An experimental study

Windows are crucial in regulating indoor daylighting, cooling, and heating to ensure suitable living conditions. However, conventional windows lack the capability for spectrum splitting and exhibit unpredictable light and heat management. This study introduces a smart window to propose a reversible function by utilizing Antimony Tin Oxide (ATO) nanofluids with near-infrared (NIR) selective absorption. An experimental study was conducted in a controlled chamber to evaluate these smart windows' dynamic light and thermal environment. The study examined the effects of ATO nanofluid concentrations at 10 ppm, 100 ppm, and 500 ppm. Results showed that the maximum indoor air temperature decreased by 4.35 °C, 2.78 °C, and 4.29 °C, respectively. Additionally, the maximum temperature differences on the outer surfaces of the exterior glass (EG) and the control glass (CG) were 4.27 °C, 3.78 °C, and 4.43 °C, respectively. When the smart window was oriented to the east, west, or north, the maximum indoor temperature differences between EG and CG were 1.37 °C, 2.9 °C, and 2.43 °C, respectively. This study demonstrates the potential of ATO nanofluid-based smart windows to enhance indoor environmental control through effective light and heat management.

Streamlines and neural intelligent scheme for thermal transport to infinite shear rate for ternary hybrid nanofluid subject to homogeneous-heterogeneous reactions

SignificanceThe CuO, Al2O3, and TiO2 nanoparticles find extensive applications in advanced chemical reaction-based thermal transport and quadratic convective nanofluids due to their exceptional thermal properties and chemical stability. Increased thermal conductivity of these nanoparticles used to enhance heat transfer in various chemical reactors, resistance to chemical degradation and photocatalytic reactors and solar energy applications. MotiveThis study brings the investigation about quadratic convection-based thermal transport to infinite shear rate for magnetized ternary radiative cross nanofluid with homogeneous-heterogeneous chemical reactions. Water is taken as base fluid and three nanoparticles are Copper oxide (CuO), aluminium oxide (Al2O3), and titanium dioxide (TiO2). Heat transport analysis is made through quadratic convection, magnetic field and thermal radiation. Concentration of nanofluid is scrutinized though homogeneous-heterogeneous chemical reactions. Methodology: Physical problem with assumptions generates the system of partial differential equations (PDEs) and these PDEs are transformed into ordinary differential equations (ODEs) through similarity variables. Furthermore, a unique combination of Bvp4c and Levenberg Marquardt neural network (LM-NN) schemes is utilized to fetch the numerical solutions. Bvp4c is utilized to solve the governing equations, while LM-NN serves to enhance predictive capabilities and capture intricate nonlinear relationships. FindingsMagnetic environment, chemical process, radiations effects and volumetric fraction of nanoparticles make better heat transfer efficiency and control.

Photo-thermal decoupling CdTe PV windows with selectively near-infrared absorbing ATO nanofluids

Solar energy conversion and utilization are crucial for buildings. Photovoltaic windows are a promising path to improving building energy efficiency. This study proposes a novel photo-thermal decoupling cadmium telluride (CdTe) PV windows with selectively near-infrared absorbing antimony-doped tin oxide (ATO) nanofluids. The PV-ATO window features four concentrations (200/400/800/1000 ppm). Hot box experiment results show that PV-ATO windows can reduce the peak indoor air temperature by up to 2.56, 2.06, 2.86, and 2.72 °C respectively, while the corresponding peak illuminance is cut by 13.01 %, 12.37 %, 17.40 %, and 56.28 %. Measured transmitted spectra's correlated color temperature (CCT) of the PV-Water and PV-ATO windows are in the range of 4811.0～5271.0 K; color render index (Ra) is between 95.7～98.8; color fidelity index (Rf) is between 96.9～99.1; color gamut index (Rg) is between 97.6～99.3. Regarding color rendering performance, the PV-ATO windows can outperform conventional windows. Energy simulation results show that the comprehensive energy-saving ratios of different PV-ATO windows in Guangzhou, Changsha, Chongqing, and Wuhan can achieve −11.27 %, −20.38 %, −0.08 %, and −5.17 %. The study points to low concentrations of ATO nanofluids (200 ppm) as the recommended value.

Extraction evolutionary features of continuous light-induced plasmonic nanobubbles by a dynamic spectral regression model

A comprehensive understanding of the nature of light-induced plasmonic nanobubbles (PNBs) generated around noble metal nanoparticles is essential for optimizing PNB-based applications, such as light-driven microfluidic control. To investigate the overall evolution pattern of plasmonic nanobubbles (PNBs) under continuous light illumination, a computational model based on the least-squares method is established. Meanwhile, the variations in nanofluid transmittance and vaporization mass under continuous light illumination are measured by an immersion fiber and an electronic balance, respectively. The effects of nanoparticle concentration on the nanofluid transmittance and vaporization mass are analyzed. Considering the variations in nanofluid concentration, the overall evolution pattern of PNBs is preliminarily analyzed by monitoring the real-time dynamic change in nanofluid transmittance. The experimental results indicate that the nanoparticle concentration has an important effect on the nanofluid vaporization process. During the illumination stage, an increased nanofluid concentration intensifies the synergistic effect of water vaporization and PNB growth on transmittance reduction. The change in nanofluid transmittance caused by PNB scattering greatly exceeds that caused by increasing nanoparticle concentration. The nanofluid concentration gradually increases and peaks at the end of the cooling stage, and the rate of change of the nanofluid concentration is proportional to the nanofluid concentration. The numerical calculations show that the average size and the range of the PNB size distribution continuously increase with increasing irradiation time, and decrease during the cooling stage. A higher nanofluid concentration corresponds to a wider range of PNB size distribution.

Parabolic trough solar collector technology using TiO2 nanofluids with dimpled tubes

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

Electro osmotic flow of nanofluids within a porous symmetric tapered ciliated channel

AbstractIn this investigation, a comprehensive study has been made to reveal electro osmosis flow through a tapered ciliated symmetric porous channel. The flow is initiated due to metachronal dynamics of cilia. Axial electric field is deployed and thermal radiation phenomenon is scrutinised by applying convective conditions. The equations tackling the flow are non dimensionalized and simplified by capitalizing the low Reynolds number and long wave length approximations. Analytical solution is presented for well reputed Poissson equation and the axial velocity. Whereas, traverse velocity, temperature and nanofluids concentration profiles are examined numerically in MATHEMATICA. Variation of emerging crucial parameters on the velocity profile, temperature and concentration profiles, pressure gradient, pressure rise per wavelength, and on the velocity distribution inside the micro ciliated are exhibited with the aid of graphical deliberations. It worth to mention in this work that in case of tapered channel transverse velocity also has significant contribution in the flow, which is observed trivial in symmetric and non‐symmetric channel flows. Temperature of the nanofluid in the ciliated tapered channel is raised with permeability and thermal radiations phenomena and can be controlled with Helmholtz Smoluchowski velocity, and electroosmotic parameter. Pumping phenomena is affected with increase in Helmholtz Smoluchowski velocity and permeability. Reported investigation cover a informative insight about biological fluid system, may be beneficial for the understanding the flow through ductus efferentes of human reproductive tract since it assumed that cilia are responsible for the transport of sperm from rete testis to the epididymis, also have worth in cilia designed bio‐sensors and in certain drug delivery systems.

Double diffusive thermogravitational convection in a convex U-shaped porous chamber filled with radiative ternary hybrid nanoliquid

This research deals with the intricate dynamics of double diffusive thermogravitational convection within a convex U-shaped porous chamber and sheds light on the use of a radiative ternary hybrid nanoliquid. In this configuration, the lower flat boundary is assumed to be thermally hot and densely concentrated while the curved lateral boundaries remain cold and dilute. The other boundaries of the enclosure are kept under adiabatic conditions. The governing Navier–Stokes equations along with thermal and species equations are effectively solved by employing a higher order compact technique. The developed in-house program has been rigorously verified against experimental and computational benchmark results. The research meticulously examines the impact of several pivotal parameters, including the Lewis number (1≤Le≤20), buoyancy ratio (0≤N≤10), Darcy number (10−4≤Da≤10−2), Rayleigh number (104≤Ra≤106), volumetric heat source/sink coefficient (−10≤q≤10), radiation parameter (1≤Rd≤5), aspect parameter of the U-shaped chamber (0.2≤AR≤0.6), and solid particles concentration (0.0≤ϕthnp≤0.04) of the ternary hybrid nanofluid. The findings are eloquently portrayed through graphical representations by showcasing streamlines, iso-solutals, isotherms, and the dimensionless Nusselt (Nuavg) and Sherwood (Shavg) parameters. Our investigation demonstrates that the ternary hybrid nanofluid outperforms both hybrid and mono nanofluids in facilitating double diffusion processes. Moreover, optimal heat transfer efficiency is achieved under conditions characterized by an aspect ratio of AR = 0.2, Rayleigh number Ra=106, Darcy number Da=10−2, buoyancy ratio N = 10, Lewis number Le = 1, and solid volume fraction ϕthnp=0.04.

Dielectric relaxation spectroscopy of hybrid insulating nanofluids in time, distribution, and frequency domain

Improving the dielectric properties of insulating liquids belongs to the modern motivation to optimize the operation of high-voltage devices. Hybrid nanofluids can provide the mentioned improvement, and thus, it is necessary to reveal their hidden potential. This study investigates hybrid nanofluids with different concentrations of magnetite and fullerene nanoparticles, a separate fullerene and magnetic nanofluid, and a base carrier fluid based on gas-to-liquid technology. The investigated samples are subjected to dielectric relaxation spectroscopy analysis at three applied electric field intensities in the time, distribution, and frequency domain. The lack of information about the studied parameters of the mentioned nanofluids is another reason for our experimental measurements. A significant dispersion of the charging current characteristics of nanofluids with magnetic nanoparticles is observed. At lower electric field intensities, the increasing fullerene concentration of the hybrid nanofluids reduces the charging currents up to a charging time of 200 s. Magnetic nanofluid shows the highest values of conductivity currents. Experiments show that the suspension of fullerene in the base oil causes a higher charging current and a more pronounced relaxation response than pure base oil. Significant relaxation information in the low-frequency band is detected from the distribution spectra. At higher electric field intensities in the low-frequency spectrum, the relaxation peaks decrease when the concentration of fullerene in hybrid nanofluids increases. The distribution area shows the effect of higher polarizability of magnetite nanoparticles. Compared to lower electric field intensities, at the value of 333.3 kV/m, several polarization processes are captured in the entire frequency spectrum. The frequency-dependent complex permittivity confirms the findings from the time and distribution domains. Comparing the distribution domain with the frequency domain shows higher sensitivity and accuracy in capturing relaxation processes in the distribution domain.