Volumetric Concentration Of Nanoparticles Research Articles

Bioconvective reversible (an esterification process) Casson nanofluid flow over a radiative spinning disc with microorganism

This study describes the Casson (a non-Newtonian fluid) nanofluid bioconvection flow across a spinning disc in the presence of gyrotactic microorganisms, many slips and thermal radiation. Also, the flow is considered as a reversible flow. The esterification process is taken into account. Using the proper variables, a system of extremely nonlinear PDEs is converted into a system of ODEs. To arrive to the solution of such equations, a numerical approach is used. Using the bvp4c approach, nonlinear flow equations can be numerically solved. Investigated are the effects of different numbers on the thermal field, volumetric concentration of nanoparticles and microbiological field. The key characteristics of the parameters in relation to the profiles of the velocity, temperature, concentration and microorganisms are graphically assessed with appropriate physical effects. A graphical explanation is provided for the wall shear stress, local Nusselt number, local Sherwood number and local motile density number. Rate of motile density number shows a prominent difference between reversible and irreversible flows for Brownian motion and Peclet number. The results of the theoretical simulations have dynamic applications in the fields of biotechnology and thermal engineering.

A comprehensive review of the energy efficiency on nano coated fin and tube condenser

AbstractThe condenser is a piece of equipment used to effectively transfer heat from water to the environment. The fin and tube condenser is the most commonly used in commercial applications. The improved performance of heat transfer in the fin and tube condenser is a significant area of study all over the world because optimizing the efficiency of heat transfer in the condenser will contribute to enhancing the effectiveness of system performance. The vapor deposition, plasma spray, and thermal spray techniques are being used, and it is determined that a heat transfer enhancing coating improves condenser performance. This review discusses the nanomaterial coating over the fin and tube condenser in detail. The various nanomaterial coatings with various propositions and coating methods had been discussed with the evidence of previous researchers. At a 50‐degree inclination angle on the condensate plate, the condensate over the coating surface increases by more than 30%. The thermal properties of the working fluid are improved over the condenser, and the overall effectiveness of the condenser is increased by approximately 40% over the non‐coated condenser. A 1% volumetric concentration of Nanoparticles in the coated material achieves a maximum efficiency increase of 78.7%.

Natural convective non-Newtonian nanofluid flow in a wavy-shaped enclosure with a heated elliptic obstacle

A numerical investigation has been carried out in a wavy-shaped enclosure with an elliptical inner cylinder to find out the effect of an inclined magnetic field and a non-Newtonian nanofluid on fluid flow and heat transfer. Here, the dynamic viscosity and thermal conductivity of the nanofluid are also taken into account. These properties change with the temperature and nanoparticle volume fraction. The vertical walls of the enclosure are modeled through complex wavy geometries and are kept at a constant cold temperature. The inner elliptical cylinder is deemed to be heated and the horizontal walls are considered adiabatic. Temperature difference between the wavy walls and the hot cylinder leads to natural convective circulation flow inside the enclosure. The dimensionless set of the governing equations and associated boundary conditions are numerically simulated using the COMSOL Multiphysics software, which is based on finite element methods. Numerical analysis has been scrutinized for varying Rayleigh number (Ra), Hartmann number (Ha), magnetic field inclination angle (γ), rotation angle of the inner cylinder (ω), power-law index (n), and nanoparticle volume fraction (ϕ). The findings demonstrate that the solid volumetric concentration of nanoparticles diminishes the fluid movement at greater values of φ. The heat transfer rate decreases for larger nanoparticle volume fractions. The flow strength increases with an increasing Rayleigh number resulting in a best possible heat transfer. A higher Hartmann number diminishes the fluid flow but converse behavior is exhibited for magnetic field inclination angle (γ). The average Nusselt number (Nuavg) values are maximum for γ = 90°. The power-law index plays a significant role on the heat transfer rate, and results show that the shear-thinning liquid augments the average Nusselt number.

Entropy generation phenomenon for ciliated pumping flow of aluminum oxide and silver nanoparticles with Hall device significances

The study of hybrid nanomaterials subject to the magnetic force and Hall device applications presents many novel applications in the chemical engineering and biomedical domains. This study theoretically investigates the physical features of two-dimensional flow of hybrid fluid via ciliated pumping through a micro-tube. This investigation deals with the performance of aluminum oxide and silver nanoparticles in viscous (water) flow enclosed in a complex ciliated tube. Physical effects of Hartmann number, Hall parameter, volumetric concentration of nanoparticles, ciliated length parameter, Brinkman number, and temperature difference parameter. The impacts of embedded parameters in the velocity profile, pressure gradient, heat transfer, entropy generation, and Bejan number are explored. The larger strength of Hall parameter overcomes the physical impacts of the magnetic device. The absorption of nanoparticles has a remarkable role in the flow features. Additionally, the ciliated length parameter has a significant role in the enhancement of the velocity profile, pressure gradient, and temperature profile. The comprehensive investigation has dynamic applications in the thermos-electric cells, transportation of biological liquids through uniform and non-uniform vessels, nanotechnologies, chemical processes, and mobility of the red blood cells.

Response Surface Methodology (RSM) on the Hybrid Nanofluid Flow Subject to a Vertical and Permeable Wedge.

The mixed convection flow with thermal characteristics of a water-based Cu-Al2O3 hybrid nanofluid towards a vertical and permeable wedge was numerically and statistically analyzed in this study. The governing model was constructed using physical and theoretical assumptions, which were then reduced to a set of ordinary differential equations (ODEs) using similarity transformation. The steady flow solutions were computed using the Matlab software bvp4c. All possible solutions were presented in the graphs of skin friction coefficient and thermal rate. The numerical results show that the flow and thermal progresses are developed by enhancing the controlling parameters (wedge parameter, volumetric concentration of nanoparticles, and suction parameter). Moreover, the response surface methodology (RSM) with analysis of variance (ANOVA) was employed for the statistical evaluation and conducted using the fit general linear model in the Minitab software. From the standpoint of statistical analysis, the wedge parameter and volumetric nanoparticle concentration have a considerable impact on all responses; however, the suction parameter effect is only substantial for a single response.

Performance evaluation of compound parabolic solar collector using different nanofluids: An experimental study

The article reports an experimental study on a non-tracking compound parabolic collector (CPC) with nanofluid and hybrid nanofluids (NFs). An experimental setup was fabricated having a concentration ratio of 4.17, 0.828 m2 collector area, 24° of half acceptance angle, and an evacuated tube receiver having 1.85 m length. Fluids like water and NFs have been investigated in CPC performance improvement, but current research deals with NFs and hybrid NFs in a CPC as rare studies are found on a CPC using NFs. The 0.010 and 0.015 wt% concentration were used of nanofluids (NFs) which were silica/water + ethylene glycol (SiO2)/(H2O + EG), and hybrid nanofluids of magnesium oxide + carbon black/water (MgO + CB/H2O) and carbon black + graphene nanoplatelets/water (CB + GNPs/H2O) at flow rates of 0.020, 0.015, and 0.010 kg/s. The experimentation was performed under real climate conditions of Taxila, Pakistan, and solar irradiance and ambient temperature were measured to determine the performance of the CPC in comparison to a simple base fluid which was water. The experimental results revealed that a maximum temperature difference of 8.5°C with an around thermal efficiency of 38.51% was achieved for hybrid pair of MgO + CB at a flow rate of 0.010 kg/s and volumetric concentration of 0.015 wt%. The efficiency variation using NFs (SiO2/EG + H2O) varies from 12.8% to 59.1% from lowest 0.010 kg/s to highest 0.020 kg/s flow rates, and volumetric concentrations (0.010 and 0.015 wt%) of nanoparticles. For similar experimental conditions, efficiency variation for (CB + GNPs) pair varies from 14.2% to 65.6% for aforementioned conditions. Efficiency variation from 15.3% to 66.3% was attained using MgO + CB in the base fluid of water for said flow rates and volumetric concentrations of nanoparticles. In addition, an efficiency enhancement of 24.3%, 30.8%, and 31.5% was observed for SiO2/EG + H2O, CB + GNPs/H2O, and MgO + CB/H2O, respectively, at maximum flow rates and volumetric concentration of nanoparticles as compared to water. Therefore, the usage of hybrid-based NF in the CPC is beneficial in terms of efficiency enhancement, and it will bring young research workers to get deep into this field to bring revolution in the area of solar energy.

Scrutiny of induced magnetic field and Hall current impacts on transient hydromagnetic nanofluid flow within two vertical alternative magnetized surfaces

The main goal of this presentation is to scrutinize the flow behavior of transient hydromagnetic Ti6Al4V-H2O-based nanofluid flow within a symmetric channel bounding a uniform porous medium with induced magnetic field and Hall current effects. The nanofluid is assumed to be partially ionized and its flow is influenced due to the presence of a strong transverse applied magnetic field domain. Due to this reason, induced magnetic field and Hall current impacts are focused in this study. The right surface of the channel is considered to be magnetized and oscillating vertically while the left surface is non-magnetized and stationary. The flow model is transformed to a similar model by the use of dimensionless transformations and leading resulting equations are solved analytically with the aid of variable separable method. The results are demonstrated with the assistance of Mathematica software and also validated with the existing results in the literature. This study is significant in analyzing the flow nature of highly electrically conducting nanofluids. An important flow characteristic observed from this study is that by increasing the volumetric concentration of nanoparticles in the fluid, the induced magnetic field is increased due to the rise in electrical conductivity of the fluid. Furthermore, the Hall current and magnetic diffusion brings a significant decrement in induced magnetic field along the main flow.

Brownian motion and thermophoretic diffusion impact on Darcy-Forchheimer flow of bioconvective micropolar nanofluid between double disks with Cattaneo-Christov heat flux

The topic of fluid flow through disks is important due to a broad range of its applications in industries, engineering, and scientific fields. The objective of the current article is to analyze the bioconvective micropolar nanofluid flow between the coaxial, parallel, and radially stretching double disks in the occurrence of gyrotactic motile microorganisms with convective thermal boundary conditions. Darcy–Forchheimer medium is considered between the double disks that allow the flow horizontally with additional effects of porosity and friction. The flow is also considered under the impacts of thermal conductivity and thermal radiations. The influence of gyrotactic microorganisms is accommodated through the bioconvection, which increases the strength of thermal transportation. Furthermore, the Cattaneo-Christov heat flux theory is also accounted. The flow model is trans moved into a system of ordinary differential equations (ODEs) utilizing appropriate similarity transformation functions. The bvp4c technique has been used to solve the transformed flow model. The implication of some prominent physical and bioconvection parameters on velocities, microrotation, thermal field, volumetric concentration of nanoparticles, and microorganisms’ fields are presented through graphs and tabular ways. It is observed that the stretching ratio parameter of the disks accelerates the axial and micro rotational velocities of the nanofluid. In contrast, the stretching Reynolds number slows down the radial velocity near the plane’s center. The temperature profile goes high against the Brownian motion, thermal radiation, and thermal conductivity parameters, while an inverse trend has been observed for increasing magnitudes of Prandtl number. The nanoparticles concentration profile is upsurged against the thermophoresis parameter. The density profile of gyrotactic motile microorganisms is de-escalated by the Peclet number and the bioconvection Lewis number. Micropolar parameters cause an increase of couple stresses and a decrement in shear stresses. A comparison with published work is provided under certain limitations to test the validity of numerical scheme accuracy.

Numerical simulation of bioconvection radiative flow of Williamson nanofluid past a vertical stretching cylinder with activation energy and swimming microorganisms

The research focuses on the rheological characteristics of Williamson nanofluid bioconvection flow past a stretching cylinder embedded in Darcy-Forchheimer medium. The thermal radiation properties are used to make changes to the energy equation. The peak topic of Arrhenius activation energy is also included, as are convective boundary conditions. The idea of microorganisms is introduced to stabilize the nanoparticle suspensions. To numerically solve transformed nonlinear equations of momentum, energy, nanoparticle concentration, and motile microbe density, the Runge Kutta Fehlberg technique is utilized. The effects of several important parameters on the velocity profile, thermal profile, volumetric nanoparticle concentration, and microbe distribution are all included and analyzed in depth. Graphs show the numerical results for skin friction coefficient, heat transfer rate, Sherwood number, and microbe density number as a function of various factors. The results show that increasing the Darcy-Forchheimer parameter and the magnetic parameter reduces the fluid velocity and the thickness of the momentum barrier layer. The spread of microorganisms is reduced when the Peclet number is changed. Furthermore, larger bioconvection Lewis numbers were observed to increase the density of motile microorganisms.

On time dependent MHD nanofluid dynamics due to enlarging sheet with bioconvection and two thermal boundary conditions

The current study pertains to heat and mass transportation of magnetic fluid flow having dilute diffusion of nanoparticles and motile microorganisms over a permeable stretched sheet to examine the influence of thermal radiation and activation energy. Similarity functions are utilized to convert the highly mixed non-linear partial differential equations into higher-order non-linear ordinary differential equations. Five coupled equations are derived to be resolved numerically by employing a computing function Bvp4c, built-in Matlab. Two sets of thermal boundaries prescribed surface temperature (PSF) and prescribed heat flux (PHF) are considered. Basic physical quantities, temperature distribution, concentration, velocity field, and motile micro-organism profiles are observed as influenced by emerging parameters. The microorganisms distribution undergoes decreasing behavior against growing values of bio-convection Lewis number and Peclet number. These results are highly useful in the application of heat-transmitting devices and microbial fuel cells. It is seen that decreasing trend is observed in velocity profile when parameters Nr and Nc are uplifted. Also, the motility of the nanofluid decreases when the Lb parameter is raised. On the other hand, an increase in Peclet number Pe showed a rising trend in motility profile. Additionally, the implications of Brownian motion, Rayleigh number, Bioconvection Lewis number thermophoresis parameter, Peclet number, and buoyancy ratio parameter are discussed. Moreover, the obtained outcomes are validated as compared to the existing ones as limiting cases. Representative findings for microorganism concentration, skin friction coefficient, temperature gradient, local Sherwood number and density number of motile microorganisms, velocity field, temperature, the volumetric concentration of nanoparticles, are discussed in tabulated and graphical form.

On the role of bioconvection and activation energy for time dependent nanofluid slip transpiration due to extending domain in the presence of electric and magnetic fields

A mathematical analysis for slip effects on MHD nanofluid in the presence of electromagnetic field and gyrotactic microorganisms is considered. The influence of activation energy and thermal radiation are also discussed. The transportation of nanofluids provides a feasible option for the enhancement of thermal distribution. A rather new aspect of this work is the diffusion and bioconvection of motile microorganisms. It may avoid possible settling of nano-entities. A system of highly non-linear partial differential equations is transformed into Ordinary differential equations by using suitable similarity transformation. The converted ordinary differential equations are then solved numerically by utilizing the shooting technique is built-in function bvp4c solver on the plate form of commercial software Matlab. The results obtained are verified through acceptable agreement with those of the existing one as a special case. The quantities of interest are observed physically. The characteristics of various emerging parameters on the velocity field, temperature distribution and volumetric concentration of nanoparticles, microorganism concentration as well as skin friction coefficient, the gradient of temperature, local Sherwood number, and density number of motile microorganisms are interpreted and reflected in tabulated and graphical form. It is noticed that velocity decreases with the rising values of M . Also, the temperature rises directly with Nb and Nt . With the growing values of Lb , the microorganism profile does down.

Numerical Simulation for Bioconvection of Unsteady Stagnation Point Flow of Oldroyd-B Nanofluid with Activation Energy and Temperature-Based Thermal Conductivity Past a Stretching Disk

A mathematical modeling is explored to scrutinize the unsteady stagnation point flow of Oldroyd-B nanofluid under the thermal conductivity and solutal diffusivity with bioconvection mechanism. Impacts of Joule heating and Arrhenius activation energy including convective boundary conditions are studied, and the specified surface temperature and constant temperature of wall (CTW) are discussed. The consequences of thermal conductivity and diffusivity are also taken into account. The flow is generated through stretchable disk geometry, and the behavior of non-linear thermal radiation is incorporated in energy equation. The partial differential equations governing the fluid flow in the structure is reduced into dimensionless nonlinear ODEs by applying suitable similarity variables. The obtained system of non-dimensional nonlinear ODEs is treated numerically with the help of bvp4c solver in Matlab under shooting algorithm. The impact of various prominent parameters on velocity profile, thermal profile, volumetric nanoparticle concentration and microorganism distribution is depicted in graphical form. The numerical outcomes for skin friction coefficient, heat transfer rate, Sherwood number as well as microorganism density number versus various parameters are listed in the tables. The results show that fluid velocity is reduced by increasing buoyancy ratio parameter, while the fluid flow increases with mixed convective parameter. The temperature profile is enhanced with the amount of nonlinear thermal radiation and temperature dependent thermal conductivity. Furthermore, concentration profiles of nanoparticles have opposite behavior for Brownian motion coefficient and thermophoresis diffusion parameter, and it is noticed that by varying Peclet number the microorganisms profile is declined. The proposed study is useful to control and optimize heat transfer in industrial applications.

Thermo-bioconvection flow of Walter's B nanofluid over a Riga plate involving swimming motile microorganisms

<abstract> <p>The novelty of the current paper is to study the bioconvection effects in Walter's B nanofluid flow due to stretchable surface, which leads to important properties, i.e., thermal radiation, activation energy, motile microorganisms and convective boundary constraints. The considered analysis is explained via partial differential equations (PDEs), which are first embedded into the dimensionless system of nonlinear ODEs through suitable transformations. The governing equations are solved in MATLAB using the bvp4c solver. The impact of interesting parameters on the velocity field, thermal field, concentration of species and concentration of microorganisms is exhibited in graphical and tabular forms. The velocity field increases for higher estimations of the modified Hartmann and mixed convection parameters. The thermal field decays for a higher magnitude of the Prandtl number, while it is enhanced for a larger deviation of the thermal conductivity parameter. The volumetric concentration of nanoparticles enhances the larger activation energy and thermophoresis parameters. The microorganism concentration diminishes for higher Peclet number. The current model is more useful in various fields such as tissue engineering, recombinant proteins, synthetic biology, and biofuel cell and drug delivery devices.</p> </abstract>

Effect of Nano Fluids on the Thermal Performance and Efficiency of Linear Fresnel Collector in Hot Summer Months

One of the best and most important types of concentrating solar power plants is the linear Fresnel collector. The thermal performance and application of absorber in a solar power plant can be enhanced using direct steam generation technology. A particular discrepancy between the present study and others lies in our attempt at applying a new method for calculating critical heat flux based on Look-up Table. In the current study, effects of nanofluid on the length of the critical heat flux and convection heat transfer coefficient were investigated. The nanoparticles considered in this study were aluminum, silver, nickel, and titanium dioxide at concentrations of 0.01, 0.1, 0.3, 0.5, 1 and 2 %. Modeling results revealed that the heat transfer coefficient increased upon enhancing the volumetric concentration of nanoparticles, thereby improving this coefficient at 2 vol. % nickel nanoparticles, which was 10.6 % above the value of pure water. On the other hand, thermal efficiency was enhanced when nickel nanoparticles were dispersed in pure water such that increase rates of thermal efficiency equaled 11.2, 10.8 and 11.3 % in the months of June, July, and August, respectively, when the volume concentration of nanoparticles was 0.5 %.

Maxwell time-dependent nanofluid flow over a wedge covered with gyrotactic microorganism: an activation energy process

With progressively more sophisticated enhancements in nanotechnology and optimisation, the demand is increasing for more effective and robust heat transfer fluids with significantly greater thermal conductivities than those of traditional ones. The current article deals with the flow of Maxwell nanofluid, over a wedge with the impact of activation energy and motile microorganisms. A transformed construction is recognised to avail an ordinary differential system by exploiting appropriate similarity transformations. The controlling equations for governing flow situations are constructed and addressed using the well-known numerical shooting procedure. For numerical results, bvp4c routine built-in MATLAB software is used. The influence of all the parameters is discussed for the velocity profile, temperature, volumetric concentration profile, andconcentration profile of microorganisms. The progressive valuation of magnetic parameter, wedge angle parameter and bioconvection Rayleigh number reduce the velocity of flow. The basic values of these parameters shall be Pr = 1, Bi = EE = γ = 1.0, Nt = Nb = 0.5, Le = Ha = m = Q = 1, β = 0.1, A = 0.5, Nr = 2, λ 1 = 2, n = 1, Ω = 5, and α = π/3. The volumetric concentration of nanoparticles is boosted with higher values of melting parameter and solutal stratification Biot number.

Review on Thermal Analysis of Automobile Radiator

Radiators are used to transfer thermal energy from one medium to another for the purpose of cooling. Low efficiency heat exchangers used in automotive as radiator may cause to serious dangers for the engine. Hence, thermal scientists and engineers always pursuit modern methods to enhance the heat removal of the engine. It seems nanofluids implementation in automotive cooling system promises to achieve high efficiency radiators. This paper reviews almost all performed studies in this area that are available in the literature. Author collects details about nanoparticles materials and size, base fluid, volume, concentration, flow regime and Reynolds number used in studies. Usually, maximum heat transfer enhancement and maximum need of pumping power that occurs at the highest volumetric concentration of nanoparticles, simultaneously. On the other hand, using nanofluids, due to the enhanced heat carrying capacity of the nanofluids; the pumping power required will also be reduced.

Bioconvection flow of Casson nanofluid by rotating disk with motile microorganisms

This paper presents the bioconvection flow of Casson nanofluid by a rotating disk with gyrotactic microorganisms, multiple slips, and thermal radiation. The non-Newtonian fluid (Casson fluid) in the existence of thermophoretic and Brownian diffusion effects is incorporated. The research of rotatable disk has practical applications in numerous processes like rotating machinery, lubrication, computer storage devices, oceanography, crystal growth, etc. Using appropriate variables, a system of strongly non-linear PDEs is translated into a system of ODEs. To construct a numerical solution of nonlinear flow equations, the bvp4c technique is used. The impacts of various numbers on velocities, thermal field, the volumetric concentration of nanoparticles, and microorganism field are investigated. From the results, it can be noticed that radial velocity rises by varying values of mixed convection parameter. An increase in bioconvection Rayleigh number causes decays in velocity fields. A larger Prandtl number declines the temperature distribution. Furthermore, an increment in the estimations of thermophoresis parameter increases the thermal and solutal field of species. Significant heat transfer is acquired with higher radiation effects. Slip parameter for temperature and concentration decreased the thermal and solutal profiles. The microorganisms field is declined with greater microorganisms slip parameter.

Non-Isothermal Hydrodynamic Characteristics of a Nanofluid in a Fin-Attached Rotating Tube Bundle

In the present study, a novel configuration of a rotating tube bundle was simulated under non-isothermal hydrodynamic conditions using a mixture model. Eight fins were considered in this study, which targeted the hydrodynamics of the system. An aqueous copper nanofluid was used as the heat transfer fluid. Various operating factors, such as rotation speed (up to 500 rad/s), Reynolds number (10–80), and concentration of the nanofluid (0.0–4.0%) were applied, and the performance of the microchannel heat exchanger was assessed. It was found that the heat transfer coefficient of the system could be enhanced by increasing the Reynolds number, the concentration of the nanofluid, and the rotation speed. The maximum enhancement in the heat transfer coefficient (HTC) was 258% after adding a 4% volumetric nanoparticle concentration to the base fluid and increasing Re from 10 to 80 and ω from 0 to 500 rad/s. Furthermore, at Re = 80 and ω = 500 rad/s, the HTC values measured for the nanofluid were 42.3% higher than those calculated for water, showing the nanoparticles’ positive impact on the heat transfer paradigm. Moreover, it was identified that copper nanoparticles’ presence had no significant effect on the system’s pressure drop. This was attributed to the interaction of the fluid flow and circulated flow around the tubes. Finally, the heat transfer coefficient and pressure drop had no considerable changes when augmenting the rotation speed at high Reynolds numbers.

Bioconvection applications for double stratification 3-D flow of Burgers nanofluid over a bidirectional stretched surface: Enhancing energy system performance

In recent years, the nanofluids are assumed to be most effective source of energy and reflect many applications in various industrial and engineering processes. With effective thermal properties, the nano-materials convey exclusive beneficial applications in heat exchanges, coolant processes, medical treatment, electronic cooling systems, energy production etc. The prime objective of current analysis is to scrutinize the three-dimensional double stratification flow of Burgers fluid containing microorganisms. The thermal radiation with nonlinear relations and heat absorption and generation applications are also endorsed. The modified forms of heat and mass diffusions are utilized to modify the analysis. The flow expressions for modeled problem are numerically evaluated by employing the shooting scheme. Physical features for various parameters against velocity of fluid, temperature distribution, volumetric concentration of nanoparticles and rescaled density of nanoparticles is deliberated with the help of several graphs. The observations reveal that heat and mass transfer mechanism decline with Deborah number. The concentration field rise up with concentration stratified Biot number while reduces with concentration relaxation constant. The presence of buoyancy parameters enhanced nanofluid temperature, concentration and microorganisms profiles. The obtained theoretical observation reveal applications in industrial, engineering and thermal processes which heat transfer involved. The claimed results are useful to improve the cooling and heating processes, energy generation, thermal devices, solar systems, manufacturing processes etc.

Thermal Transport in Laminar Convective Flow of Ferrofluids in the Presence of External Magnetic Field

Abstract A three-dimensional (3D) numerical investigation is carried out to examine the effect of magnetic field (MF) on laminar forced convection of ferrofluids. Laminar flow (Reynolds number (Re) ≤ 100) of ferrofluid is modeled in a square mini-channel of 2 mm hydraulic diameter in the presence of the MF. A magnetic force is induced in ferrofluids because of the applied MF, which accelerates the upstream flow and decelerates the downstream flow with respect to the magnet's location. The acceleration/deceleration of the flow disrupts the hydrodynamic and thermal boundary layers (BLs), positively affecting the heat transfer. The extent of magnetic influence primarily depends on the Reynolds number and induced magnetic force. At low Re (= 25), where magnetic force dominates over inertial force, the flow of ferrofluid is strongly affected by the MF. This results in a higher augmentation in convective heat transfer. As the Re of the flow is increased to Re = 75, the inertial forces partially overcome the effect of the magnetic force, resulting in a smaller augmentation. The interaction of magnetic and inertia forces is expressed through a dimensionless magnetic Froude number (Frm). The effect of volumetric concentration of nanoparticles, Reynolds number, and the presence of multiple magnets placed along the flow channel on heat transfer is investigated through a parametric study. A correlation has also been proposed to predict the net enhancement in the Nusselt number due to the application of the MF based on the results of the present study.