Flow Characteristics Of Nanofluids Research Articles

Unsteady slip flow of special second-grade fluid induced by Fe3O4 particles past a movable sheet with magnetic and nonlinear heat source/sink

Purpose Ferrofluids are aqueous or non-aqueous solutions with colloidal particles of iron oxide nanoparticles with high magnetic characteristics. Their magnetic characteristics enable them to be controlled and manipulated when ferrofluids are exposed to magnetic fields. This study aims to inspect the features of unsteady stagnation point flow (SPF) and heat flux from the surface by incorporating ferromagnetic particles through a special kind of second-grade fluid (SGF) across a movable sheet with a nonlinear heat source/sink and magnetic field effect. The mass suction/injection and stretching/shrinking boundary conditions are also inspected to calculate the fine points of the features of multiple solutions. Design/methodology/approach The leading equations that govern the ferrofluid flow are reduced to a group of ordinary differential equations by applying similarity variables. The converted equations are numerically solved through the bvp4c solver. Afterward, study and discussion are carried out to examine the different physical parameters of the characteristics of nanofluid flow and thermal properties. Findings Multiple solutions are revealed to happen for situations of unsteadiness, shrinking as well as stretching sheets. Greater suction slows the separation of the boundary layers and causes the critical values to expand. The region where the multiple solutions appear is observed to expand with increasing values of the magnetic, non-Newtonian and suction parameters. Moreover, the fluid velocity significantly uplifts while the temperature declines due to the suction parameter. Originality/value The novelty of the work is to deliberate the impact of mass suction/injection on the unsteady SPF through the special second-grade ferrofluids across a movable sheet with an erratic heat source/sink. The confirmed results provide a very good consistency with the accepted papers. Previous studies have not yet fully explored the entire analysis of the proposed model.

Comparative study of thermo-structural analysis of nano-fluid flow in a baffle-corrugation rectangular channel for adoptable sustainable multifunctional application

Recent years have seen a rise in interest in and usage of thermo-hydraulic research of nano-fluid flow phenomena in a variety of engineering applications. Under uniform heat flux, thermo-physical characteristics of nano-fluid flow in baffle-corrugation rectangular channels have been observed from a numerical standpoint for various Reynolds numbers and different values of the aspect ratio of baffles. Employing the finite volume method, the governing equations have been solved and to visualize the simulation results, fluent software has been employed. Four various types of baffle-corrugation shapes (plane, trapezoidal, isosceles, and triangular) with their interchanged positions have been examined in the present analysis. Different types of base fluids viz., water, glycerin, and ethylene glycol, four distinct forms of nanoparticles, Al2O3, CuO, SiO2, and ZnO are assumed to be transmitted for varying values of volume fractions (D%) and diameter of nanoparticles. From the present study, it is found that in the presence of plane baffle-isosceles corrugation provides the highest average Nusselt number ([Formula: see text]) than the rest of the baffles. It is revealed that SiO2 nano-fluid provides the highest [Formula: see text] in comparison to other nano-fluids. Further, it is concluded that [Formula: see text] enhances with the enhancement of D%, Reynolds number (Re), height, and pitch of the baffles and is found to decrease as the diameter of nanoparticles increases. This study also indicates that glycerin-SiO2 provides the highest [Formula: see text] than the rest of the base fluids.

Understanding the impact of magnetic dipole and variable viscosity on nanofluid flow characteristics over a stretching surface

The purpose of this research article is to investigate the impact of magnetic dipole on the flow of nano-fluids over the stretching surface with variable viscosity and thermal conductivity. Fluid fills the porous space. Heat transfer analysis is carried out in the presence of Newtonian heating. Water and ethylene glycol are used as base fluid while gamma alumina acts as a nanoparticle. System of ordinary differential equations is obtained by appropriate transformations. Numerical solutions are computed for the resulting nonlinear differential system by applying shooting method with RK-4 scheme. Impact of different parameters on the velocity and temperature profiles is examined. Computations for surface drag force and heat transfer rates are presented and examined for the influences of pertinent parameters. It is observed that fluid velocity reduces for larger viscosity parameter while opposite behavior is observed for temperature. Increasing values of ferro hydrodynamic interaction parameter and Curie temperature correspond to the enhancement in temperature. Surface drag force increases for larger values of nanoparticles volume fraction. Gamma alumina-ethylene glycol nano-fluid produce less surface drag force than gamma alumina-water nano-fluid. Heat transfer rate is increasing function of Prandtl number.

Numerical Analysis of MHD Nanofluid Flow Characteristics with Heat and Mass Transfer over a Vertical Cone Subjected to Thermal Radiations and Chemical Reaction

Nanoparticles have the ability to increase the impact of convective heat transfer in the boundary layer region. An investigation is made to analysis of magnetohdrodynamic nanofluid flow with heat and mass transfer over a vertical cone in porous media under the impact of thermal radiations and chemical reaction. In addition, thermal radiations, Hall current, and viscous and Joule dissipations and chemical reaction effects are considered. Considered three different nanoparticles types namely copper, silver, and titanium dioxide with water as base fluid. The governing equations are transformed by similarity transformations into a set of non-linear ordinary differential equations involving variable coefficients. Two numerically approaches are used to solve the transformed boundary layer system Finite Difference Method (FDM) and Chebyshev-Galerkin Method (CGM). As stated in the present analysis, it is appropriate to address a number of physical mechanisms, including velocity, temperature and concentration, as well as closed-form skin friction/mass transfer/heat transfer coefficients. Different comparisons are done with previously published data in order to validate the current study under specific special circumstances, and it is determined that there is a very high degree of agreement. The main results indicated that as the Prandtl number increases, the temperature profile decreases, but it grows for higher values of the thermophoresis parameter, Brownian motion, and Eckert number. Moreover, higher Brownian motion values lead to a less prominent concentration profile. Consequently, this speeds up the cooling process and enhances the surface’s durability and strength.

Effect of Al2O3, SiO2, and ZnO Nanoparticle Concentrations Mixed with EG–Water on the Heat Transfer Characteristics through a Microchannel

Nanofluids have gained attention for their potential to solve overheating problems in various industries. They are a mixture of a base fluid and nanoparticles dispersed on the nanoscale. The nanoparticles can be metallic, ceramic, or carbon based, depending on the desired properties. While nanofluids offer advantages, challenges such as nanoparticle agglomeration, stability, and cost effectiveness remain. Nonetheless, ongoing research aims to fully harness the potential of nanofluids in addressing overheating issues and improving thermal management in different applications. The current study is concerned with the fluid flow and heat transfer characteristics of different nanofluids using different types of nanoparticles such as Al2O3, SiO2, and ZnO mixed with different base fluids. Pure water and ethylene glycol–water (EG–H2O) mixtures at different EG–H2O ratios (ψ = 0%, 10%, 30%, 40%) are used as the base fluid. Furthermore, a rectangular microchannel heat sink is used. Mesh independent study and validation are performed to investigate the current model, and a good agreement is achieved. The numerical analysis evaluates the influence on the heat transfer coefficient and flow characteristics of nanofluids for Reynolds numbers 500 to 1200 at a 288 K inlet flow temperature. The results show that ZnO nanofluid and 40% EG–H2O increase the heat transfer coefficient by 63% compared to ZnO–H2O nanofluid obtained at Re = 1200 and φ = 5%. Conversely, the pressure drop by ZnO is nearly double that obtained by Al2O3 and SiO2.

Numerical analysis on the heat and mass transfer MHD flow characteristics of nanofluid on an inclined spinning disk with heat absorption and chemical reaction

AbstractThis work examines the heat transfer properties of magnetohydrodynamic nanofluid flow. Through a similarity conversion, the leading structure of partial differential equations is changed to that of ordinary differential equations. A rigorous mathematical bvp4c methodology is used to generate numerical results. The purpose of this study is to characterize the different temperature, concentration, and velocity limitations on a nanofluid with a magnetic effect that is spinning. The findings for rotating nanofluid flow and heat transfer characteristics of nanoparticles are shown using graphs and tables. The influence of physical factors such as heat transfer rates and skin friction coefficients is studied. When the magnetic parameter M is raised, the velocity of the nanoliquid decreases. A rise in thermal radiation (Rd) causes the temperature graphs to grow substantially, although the concentration profiles exhibit the opposite tendency. The effect of the convective heat transfer factor Bi on temperature is shown to increase as Bi increases, but the concentration distribution decreases as Biot increases.

Numerical assessment of the impacts of non-Newtonian nanofluid and hydrophobic surfaces on conjugate heat transfer and irreversibility in a silicon microchannel heat-sink

BackgroundThe current investigation aims to examine the thermal and hydraulic performances and irreversibility of a non-Newtonian nanofluid including water-Carboxymethyl cellulose (CMC)/CuO in a silicon microchannel heat sink. MethodsThe finite volume method with SIMPLE algorithm and second-order upwind approach for discretizing the equations and power-law model for simulation of the viscosity of nanofluid were used in this numerical assessment. Hydrophobic and fully-hydrophobic surfaces are applied in this study by surface modification. Reynolds numbers in the range of 10 to 250, the volume fraction of nanoparticles between 0 and 1.5%, and slip coefficient of 0, 0.02, and 0.1 for ordinary, hydrophobic, and fully-hydrophobic surfaces, respectively, are employed in this numerical investigation to examine their effects on heat transfer and irreversibility under a constant heat flux of 50 W/cm2. The obtained results show that implementing the fully-hydrophobic surface, higher Reynolds number and nano-additives rate lead to considerable improvement in thermal characteristics of nanofluid flow, especially near the corner region of the rectangular microchannel. However, increasing the Reynolds number significantly boosts the pressure drop. Significant FindingsAnalyzing the related data to the second law of thermodynamics shows the least amount of total entropy generation belongs to the fully-hydrophobic surface, φ =1.5% and Re= 250.

Study on the cooling and lubrication mechanism of magnetic field-assisted Fe3O4@CNTs nanofluid in micro-textured tool cutting

To address the challenge of insufficient lubricity and thermal conductivity of conventional lubricating fluids and single type of nanofluids during cutting, a new nanofluid (Fe3O4@CNTs nanofluid) was prepared in this paper, and the coupling effect of Fe3O4@CNTs nanofluid and micro-texture on the cutting performance of TiC ceramic tools under the action of magnetic field was revealed for the first time. The micro-texture (TTC) was prepared on the rake face of the tool by laser processing technique, and the non-textured tool (TC) was used as a control group. The conventional Fe3O4 nanofluid (F-0.5) and Fe3O4@CNTs composite nanofluid (FC-0.5) and with a volume fraction of 0.5 vol% were prepared by co-precipitation method. For facilitating the penetration of the nanofluid into the tool/chip contact area, an external magnetic field was applied during machining operations. The cutting test of titanium alloy was performed, and the influence of various magnetic field strengths on the friction properties of micro-textured tool/chip interface under the lubrication condition of Fe3O4@CNTs nanofluid was studied. Simulation analysis of the flow characteristics of nanofluid in micro-texture under the action of magnetic field was performed to provide theoretical support for the subsequent results. The results of the cutting tests showed that the cutting forces and tool wear of TTC + FC-0.5 were alleviated in the presence of magnetic field, and the cutting performance was further improved with the increasing of magnetic field from 300 Gs to 1200 Gs. Under the highest magnetic field strength (1200 Gs), TTC + FC-0.5 has 36.9 % lower cutting force and 28.15 % lower surface roughness than TC + F-0.5. Additionally, the penetration and lubrication mechanisms of Fe3O4@CNTs nanofluid on micro-textured tool/chip contact interface under the influence of applied magnetic field was exposed.

Experimental Investigation of Nanofluid Turbulent Flow Over Microscale Backward-Facing Step

Experimental research was presented in this paper to illustrate the heat transmission and flow characteristics of nanofluid on a microscale backward-facing step channel. Except for the downstream wall, which was applied with uniform heat flow, the channel side walls were deemed adiabatic. Water was used as the base fluid and mixed with 30 nm diameter CuO nanoparticles with a volume fraction in the range of 0-0.04. The experiment was conducted at a Reynolds number range of 5,000–10,000. The results showed that the Nusselt number increases as the volume fraction increases. However, the increase in the nanoparticle volume fraction leads to an increment in the friction factor. Furthermore, the results indicated that increasing the Reynolds number lead to the volume fraction decreasing. It was found that there is an improvement of heat transfer by applying the CuO/water nanofluid with a 0.03 volume fraction of CuO nanoparticles with a significant performance evaluation criterion (PEC>1).

Natural convective nanofluid flow characteristics with Brownian motion effect in an annular space between confocal elliptic cylinders

The principal aim of this work is to study numerically the natural convection in an annular space between confocal elliptic cylinders. The Brownian motion was added based on the thermal conductivity model and the simulation was carried out using finite volume control method. Various nanofluids with different volume concentrations were undertaken ranging from 2% to 6% and various Rayleigh numbers were tested for different particles. The isotherms and stream function are presented and it was clearly seen that by increasing the Rayleigh number, the heat transfer rate increases on the domain. On the other hand it was noticed that the heat transfer enhancement is less sensitive to the nanoparticles when the Brownian motion was considered

Thermal performance of Fe3O4/water nanofluid flow in a newly designed dimpled tube under the influence of non-uniform magnetic field

The effects of alternating and constant magnetic fields on heat transfer characteristics of nanofluid flow in a dimpled tube have not been investigated either numerically or experimentally. In this context, the hydrothermal performance of Fe3O4/water (1.0 vol%) ferronanofluid flow in the dimpled tube (P/d = 3.75 and 11.25) has been examined under laminar flow regime (1131 ≤ Re≤2102) in this experimental study. While the magnitudes of magnetic fields are 0.16 T, the alternating magnetic field is utilized with square wave type at frequencies of 1, 2, 5 Hz. It is concluded that the dimpled tube causes up to 78.4% increase in Nusselt number compared to the smooth tube, while up to 118.9% increase in Darcy friction factor. The constant magnetic field enhances the Nusselt number up to 4.04% compared to the absence of a magnetic field using ferronanofluid as a working fluid. Higher frequencies of the alternating magnetic field results in higher thermal performance. Alternating magnetic field effect with f = 5 Hz offers 37.3% Nusselt number enhancement compared to the constant magnetic field effect in all tube geometries. It was also seen that P/d = 11.25 gives the highest Performance Evaluation Criteria while the magnetic field effect decreases it in all tube geometries.

Rheological Modeling of Metallic Oxide Nanoparticles Containing Non-Newtonian Nanofluids and Potential Investigation of Heat and Mass Flow Characteristics.

Nanofluids have great potential due to their improved properties that make them useful for addressing various industrial and engineering problems. In order to use nanofluids on an industrial scale, it is first important to discuss their rheological behavior in relation to heat transfer aspects. In the current study, the flow characteristics of nanofluids are discussed using a mathematical model that is developed by fundamental laws and experimental data. The data are collected in the form of viscosity versus shear rate for different homogeneous ethylene glycol- (EG) based nanofluids, which are synthesized by dispersing 5–20% nanoparticle concentrations of SiO2, MgO, and TiO2 with diameters of (20–30 nm, 60–70 nm), (20 nm, 40 nm), and (30 nm, 50 nm), respectively. The data are fitted into a rheological power-law model and further used to govern equations of a physical problem. The problem is simplified into ordinary differential equations by using a boundary layer and similarity transformations and then solved through the numerical Runge–Kutta (RK) method. The obtained results in the form of velocity and temperature profiles at different nanoparticle concentrations and diameters are displayed graphically for discussion. Furthermore, displacement and momentum thicknesses are computed numerically to explain boundary-layer growth. The results show that the velocity profile is reduced and the temperature profile is raised by increasing the nanoparticle concentration. Conversely, the velocity profile is increased and the temperature profile is decreased by increasing the nanoparticle diameter. The results of the present investigation regarding heat and mass flow behavior will help engineers design equipment and improve the efficacy and economy of the overall process in the industry.

Heat Transfer Characteristics of Conventional Fluids and Nanofluids in Micro-Channels with Vortex Generators: A Review

An effective way to enhance the heat transfer in mini and micro electronic devices is to use different shapes of micro-channels containing vortex generators (VGs). This attracts researchers due to the reduced volume of the electronic micro-chips and increase in the heat generated from the devices. Another way to enhance the heat transfer is using nanofluids, which are considered to have great potential for heat transfer enhancement and are highly suited to application in practical heat transfer processes. Recently, several important studies have been carried out to understand and explain the causes of the enhancement or control of heat transfer using nanofluids. The main aim upon which the present work is based is to give a comprehensive review on the research progress on the heat transfer and fluid flow characteristics of nanofluids for both single- and two- phase models in different types of micro-channels. Both experimental and numerical studies have been reviewed for traditional and nanofluids in different types and shapes of micro-channels with vortex generators. It was found that the optimization of heat transfer enhancement should consider the pumping power reduction when evaluating the improvement of heat transfer.

Comprehensive analysis of thermally radiative transport of Sisko fluid over a porous stretchable curved surface with gold nanoparticles

Nanofluid and magnetic field impacts are significant in bioengineering and medical treatment. The effectiveness of gold particles in blood flow (Sisko fluid flow) with nonlinear thermal radiation and heat source over a curved surface is investigated in this work. The partial slip influence is utilized to explore the characteristics of nanofluid flow in depth. The Sisko model’s first-order partial differential equations (PDEs) are simplified to ordinary differential equations (ODEs) by employing suitable variables. The findings are displayed by using the bvp4c (shooting approach) in MATLAB. When compared to earlier reports, the accuracy is found to be satisfactory. In addition to the influence of a magnetic field and radiation, although both are useful in therapeutic hyperthermia, the magnetic field reduces the velocity distribution. The velocity profile is boomed for the estimations of slip parameter while declined for the suction parameter. The thermal profile is boosted up for the higher magnitude of temperature ratio parameter and Biot number. The thermal profile is decreased for the greater values of the suction parameter while increases for the heat source parameter.

Modelling and Comparison of the Thermohydraulic Performance with an Economical Evaluation for a Parabolic Trough Solar Collector Using Different Nanofluids

This study examines the three-dimensional heat transfer and flow characteristics of nanofluids in a parabolic trough solar collector under turbulent flow conditions, whereas a non-uniform focused heat flux was applied to the absorption pipe. CuO/water, Al2O3/water, TiO2/water, and SiO2/water are studied numerically. The dynamic and thermal fields are determined by the Reynolds number varying between 50000 ≤ Re ≤ 250000, while the volume concentration of nanofluids is the following: 3% CuO, 6% Al2O3, 4.82% SiO2 and 3.15% TiO2, the nanoparticle size of 30 nm by means of Finite Element Method (FEM). Effects of various parameters such as volume fraction of nanoparticles (φ), various Reynolds numbers and type of nanoparticle on thermo-hydraulic performance of the parabolic solar collector are studied. The average Nusselt number, heat transfer coefficient, average friction factor, pressure drop, temperature and velocity distribution are illustrated using four different types of nanofluids and four different volume fractions of nanoparticles with various Reynolds numbers. According to the final results, both TiO2 and CuO nanofluids have better performance in terms of thermal and hydraulic efficiency and evaluation economic performance compared with other nanofluids studied.

The Influence of Elasticity on Peristaltic Flow of Nanofluid in a Tube

In this paper, a mathematical model is proposed to study the influence of elasticity on peristaltic flow of nanofluid in a vertical tube with temperature dependent viscosity. The expressions for axial velocity, temperature, flux and pressure gradient are derived. The different nanofluids suspensions are consider to analyze the influence of elasticity on flux variation. Application of blood flow through veins is studied by expressing relationship between pressure gradient and volume flow rate in an elastic tube. The effect of different pertinent parameters on the flow characteristics of nano fluid in an elastic tube with peristalsis is analyzed through graphs. The variation in flux for different nanofluids like pure water H2O, Copper-water nanofluid CuO + H2O, Silver-water Ag + H2O and Titanium oxide-water nanofluid TiO2 + H2O are illustrated through graphs. The variation in flux for various physical parameters such as amplitude ratio, heat source parameter, Grashof number, viscosity parameter and elastic parameters are discussed. The flux takes higher values for nano particles case when compared to pure water. The flux enhances with amplitude ratio, Grashof number, heat source/sink factor and viscosity factor. The flux is more for the Titanium oxide-water nanofluid TiO2 + H2O when compared to remaining cases. The important observation is that pressure rise along mean flow rate is increase due to raise in temperature of source or sink in puming region and decreases in co pumping region. In the absence of elastic parameter (α″ = 0), the results observed in the present study are similar to that of results observed by O. A. Beg et al., Results in Physics 7, 413 (2017).

Performance Evaluation of Shell and Tube Heat Exchanger by Using Fe3O4/water Nanofluidid

This paper studies the forced convection heat transfer and flow characteristics of nanofluids composed of water and different volume concentrations of Fe3O4/water nanofluids (0.35%, 0.2%) under laminar flow conditions that move in counter current in a vertical shell-and-tube heat exchanger. Fe3O4 nanoparticles having a diameter of about 30 nm were used in this work. Various of Reynolds number were used during practical experiments on the device is (200,600,1000,1400). The results show that for the same mass flow and inlet temperature, the convective heat transfer coefficient of the nanofluid is slightly larger than that of the base fluid where the improvement ratio is up to 14%, 22% for 0.2%, 0.35%, respectively. Where it was concluded through the results that the total coefficient of heat transfer of the nanofluid has increased compared to the basic fluid, the maximum improvement at (0.2%, 0.35%) was about 34% and 61%, respectively. When the concentration of nanofluids increases sharply, the Nusselt number also increases sharply compared with the base fluid up to 10%, 19%. As the results showed that the friction factor increases when the concentration of nanofluid increase because the density and viscosity is higher than of base fluid, while decrease when the Reynolds number increase, where the ratios reached 25%, 47%. It was found that the effectiveness of nanofluids is higher than that of base fluids is up to 56%, 62%.

Hydrodynamic and thermal analysis of CNT-based nanofluids over rotating and vertically moving disk

The primary objective of this study is to assess the thermal and solute CNT-based MHD characteristics of nanofluid flow over a vertically moving and rotating disk under the impact of various physical effects such as viscous dissipation, source, sink and thermal radiation. Both the Buongiorno and Xue models are used to study the heat transfer features of nanofluids. Engine oil is considered as the base fluid and nanoparticles of carbon nanotubes are added to the liquid. Moreover, the Brownian motion and thermophoresis mechanisms of nanoparticles are discussed with the help of the Buongiorno model. Similarity transformations are employed to reduce the PDEs into non-linear ODEs. Numerical solutions are acquired for flow and energy transfer by using a MATLAB scheme, namely bvp4c, and the outcomes are examined in graphical and tabular form. The higher value of the magnetic parameter reduces the radial and azimuthal velocity but enhances the temperature field. Moreover, the temperature fields decline by increasing both the Prandtl number and the radiation parameter. By enhancing Brownian motion, the concentration distribution decreases while it is enhanced by increasing the thermophoresis parameter.

Numerical study on heat transfer and flow characteristics of nanofluids in a circular tube with trapezoid ribs

Abstract This study aims to investigate heat transfer and flow characteristics of ethylene glycol/water (EGW) and CuO–EGW nanofluids in circular tubes with and without trapezoid ribs. Nusselt number and friction factor in tubes with trapezoid ribs are analysed under a constant heat flux by changing rib bottom angles. This study compares the convective heat transfer coefficients of 6 vol.% CuO–EGW nanofluid and base fluid. It is found that under a constant Reynolds number, the Nusselt number and friction factor for CuO–EGW nanofluid and base fluid increase with an increase in the inclination angle. The Nusselt number for the CuO–EGW nanofluid in the tube with 75° rib bottom angle averagely increases by 135.8% compared to that in the smooth tube, and the performance evaluation criterion is 1.64.

Magnetic Field Effect on Sisko Fluid Flow Containing Gold Nanoparticles through a Porous Curved Surface in the Presence of Radiation and Partial Slip

The radiation and magnetic field effects of nanofluids play a significant role in biomedical engineering and medical treatment. This study investigated the performance of gold particles in blood flow (Sisko fluid flow) over a porous, slippery, curved surface. The partial slip effect was considered to examine the characteristics of nanofluid flow in depth. The foremost partial differential equations of the Sisko model were reduced to ordinary differential equations by using suitable variables, and the boundary value problem of the fourth-order (bvp4c) procedure was applied to plot the results. In addition, the effects of the parameters involved on temperature and velocity were presented in light of the parametric investigation. A comparison with published results showed excellent agreement. The velocity distribution was enhanced due to the magnetic field, while the temperature increased due to the effects of a magnetic field and radiation, which are effective in therapeutic hyperthermia. In addition, the nanoparticle suspension showed increased temperature and decelerated velocity.