Influence Of Thermophoresis Research Articles

Computational study of homogeneous–heterogeneous reactions in bioconvective third-grade material flow

The flow of third-grade nanofluid over a stretched surface is analyzed with a particular focus on the transport of heat due to melting by taking into account both homogeneous and heterogeneous reactions. To account for various effects, the energy equation incorporating viscous dissipation, Joule heating and radiation is considered, as well as the influence of thermophoresis and Brownian motion. A similarity transformation is used to simplify the expressions such that the model is analyzable. Utilizing the homotopic technique, series solutions are obtained, and a convergence result is established. Our investigation based on this series solution explores the impact of different factors on the flow model, and demonstrates that increasing the melting parameter leads to a decrease in temperature, entropy rate and concentration, while to an increase in velocity.

Design and Characterization of a Melt Electrostatic Precipitator for Advanced Drug Formulations

Electrostatic precipitators (ESP) are especially known for the efficient separation of micron and submicron particles from aerosols. Wet electrostatic precipitators are particularly suitable for highly resistive materials. Using these, particles can be directly transferred into a liquid for further processing or safer handling, which is advantageous for either hazardous or valuable materials. In this work, a wet ESP, which enables the separation of highly resistive particles into a heated liquid, was designed and investigated. To do this, spray-dried drug particles were embedded in a molten sugar alcohol to enhance the drug dissolution rate. After cooling, the solidified product showed advantageous properties such as a high drug dissolution rate and easy handling for further processing. For the design of the wet ESP, different discharge electrode configurations were tested. A wall film served as the collection electrode, which was generated by a specially designed distributer die. A laminar flow regime was achieved with a homogeneous film serving as the collection electrode, which is particularly important for a high separation efficiency. A prototype was designed and constructed in this respect. The particle separation into hot liquids or onto hot surfaces is challenging due to thermal effects in ESPs. The influence of thermophoresis and drag force on the particle transport was investigated, and optimum operation parameters were found for the present ESP. A broad field of applications can be covered with the presented device, where particles are embedded in even hot liquids to form liquid suspensions or, as it is presented here, solid dispersions. The dissolution of the drug-containing solid dispersion was studied in vitro. A remarkably faster drug dissolution was observed from the solid dispersion, as compared to a powder mixture of the drug and xylitol.

Influence of Thermophoresis and Brownian Motion on MHD Hybrid Nanofluid MgO - Ag/H2O Flow along Moving Slim Needle

The objective of this paper is to analyze the impact of thermophoresis parameter, Brownian motion, velocity ratio parameter, similarity radius of the slim needle, magnetic parameter, Prandtl number and thermal radiation on the steady state, laminar, MHD hybrid nanofluid composed of MgO-Ag/H2O flowing along a horizontal hot thin needle. To achieve this, the BVP-5C shooting technique is employed through MATLAB to solve the transformed nonlinear ODEs governing the fluid flow. This study investigates the impact of non-dimensional parameters on the flow velocity, temperature and concentration profiles within the hybrid nanofluid. The effects of skin friction, local Nusselt number and Sherwood number are demonstrated through the use of tables. The observation reveals that elevating the thermophoresis parameter results in a simultaneous reduction in the temperature and concentration profiles, while an opposite behavior is observed for Brownian motion. The magnetic parameter and thermal radiation values result in a rising temperature profile, while the trend is reversed for the velocity ratio parameter, Prandtl number and Schmidt number. The Nusselt number demonstrates an upward trend with higher values of thermophoresis parameter, velocity ratio parameter and thermal radiation. Further, Sherwood number experiences an increase with greater values of Brownian motion and magnetic parameter but it displays a contrasting pattern for thermophoresis, velocity ratio parameter and thermal radiation parameter. Validation of this model with existing data has been excellent.

Non-similar approach on the MHD Carreau nanofluid flow with quadratic radiation and Soret-Dufour effects

The present study aims to investigate the influence of magnetohydrodynamic (MHD) Carreau nanofluid flow past a stretching cylinder with quadratic Rosseland heat radiation. This paper examines the consequences of the Soret-Dufour effects when considering the influence of thermophoresis and Brownian effects. The convective and diffusive boundary conditions have been implemented. The modeled mathematical system of non-linear partial differential equations (PDEs) is transformed into a dimensionless representation using a non-similar approach. The ensuing set of dimensionless equations are solved numerically with local non-similarity method (LNM) aided by the finite difference algorithm. The findings of the study unveil that the presence of the Dufour and Soret effect declines the heat transfer and mass transfer rates, respectively. It is also noted that flow profiles are more profound in the case of stretching cylinder configuration. Per unit increase in the hydrodynamic slip parameter augments the drag coefficient by 35.87% and 33.40% for cylinder and sheet configurations, respectively. The present study has potential applications in biomedicine, such as targeted drug delivery, hyperthermia, theranostics and cardiovascular treatments.

Analysis of entropy generation and Brownian motion for the pulsatile flow of Herschel–Bulkley fluid in a diseased curved artery

The influence of Thermophoresis and Brownian motion on the pulsing flow of nano-fluid (blood) through a curved artery with stenosis and post-stenotic dilatation in its interior is investigated numerically. The Herschel-Bulkley model of fluid dynamics accurately represents the fluid's rheology. By applying the mild stenosis condition, the highly coupled momentum, energy, and mass concentration equations can be modelled and reduced. Explicit finite differences methods are used to discretize and solve the non-dimensionalized governing equations associated with the boundary condition. Entropy creation in blood flow due to loss and magnetohydrodynamic processes is also investigated. Graphs and discussions of the effects of changing pertinent geometric and rheological factors on key flow characteristics, such as temperature, velocity, and mass concentration, are provided. Because of the small changes in blood temperature and mass concentration caused by the artery's curvature, it is observed that the radius of the curved channel has a significant impact on blood velocity. An increase in Brownian motion also resulted in a drop in the nano-temperature, a fluid's but the thermophoresis parameter exhibited the reverse behavior.

Bioconvective radiative unsteady Casson nanofluid flow across two concentric stretching cylinders with variable viscosity and variable thermal conductivity

The role of variable viscosity and variable thermal conductivity in nanofluid flows is significant, as they can strongly influence the flow behavior and heat transfer performance of nanofluids. Keeping in mind the importance of these effects of variable characteristics, our motivation in this study is to investigate the role of nonlinear radiative heat flux on unsteady Casson nanofluid flow across two concentric stretched cylinders in the presence of temperature-dependent viscosity and thermal conductivity. A convective condition on the inner cylinder wall is also considered. In addition, the nanofluid is immersed with microorganisms that can swim and move independently. The addition of microorganisms has a significant role in the stability of the nanofluid flow. The influence of thermophoresis and Brownian motion on the flow, heat, mass, and microorganisms are scrutinized by employing the Buongiorno model. The governing flow equations are converted into a system of differential equations engaging similarity transformations, and the bvp4c method is employed to solve it numerically. Engineering parameters are computed and tabulated numerically. The findings demonstrate that as the unsteadiness parameter upsurges, the radial profile intensifies while the axial profile diminishes near the outer cylinder surface. It is also comprehended that both Lewis and bioconvective Lewis numbers reduce the motile density profiles. The accuracy of the presented model is also given in a graphical illustration by comparing it with a published result in a limiting case.

Flow of Maxwell Fluid with Heat Transfer through Porous Medium with Thermophoresis Particle Deposition and Soret–Dufour Effects: Numerical Solution

In this paper, we study the magnetohydrodynamics of Darcy flow in a non-Newtonian liquid. The influence of thermophoresis on particle deposition is examined in the Darcy flow of a Maxwell nanofluid. In our model, the temperature distribution is generated by the Fourier law of heat conduction with nonlinear thermal radiation and heat sink/source. We also examine the Soret–Dufour effects in the mass concentration equations. The Brownian and thermophoretic diffusions are assumed to be generated by nanoparticle dispersion in the fluid. The similarity method is used to transform the partial differential equations into nonlinear ordinary differential equations. The transformed flow equations were solved numerically using the BVP Midrich scheme. The results of the computation are displayed graphically and in tabular form. The results obtained show that increasing the Deborah number leads to a decline in radial and angular motion and a decrease in the magnitude of axial flow. As expected, the strength of the heat source and the values of the thermal radiation parameters determine the temperature of the liquid. We also found that as the Soret number rises (or the Dufour number falls), so does the mass transfer rate.

Theoretical analysis of modified non-Newtonian micropolar nanofluid flow over vertical Riga sheet

The main purpose of this work is to study the steady incompressible second-grade micropolar fluid flow over a nonlinear vertical stretching Riga sheet. Velocity slip and zero mass flux are considered at the solid surface of Riga shape such that the friction of nanoparticle maintains itself with strong retardation. The influence of Lorentz forces produced by the Riga plate is an important aspect of the study. The influences of thermophoresis and Brownian motion under the heat generation and e bouncy forces are studied on the nonlinear vertical Riga sheet. The mathematical model is developed under the flow assumptions. The mathematical model in terms of partial differential equations is formed by implementing the boundary layer approximations. The partial differential equations are further reduced to ordinary differential equations by means of suitable transformations. The ordinary differential equations are solved through the numerical procedure. The variations in the horizontal movement of nanofluid, thermal distribution and concentration distribution of the nanoparticle have been noted for different fluid parameters. The values of velocity profile and temperature profile are larger in the case of injection ([Formula: see text] as compared to suction ([Formula: see text]). The values of concentration distribution are smaller in the case of injection ([Formula: see text] as compared to suction ([Formula: see text]. The validation of this analysis with decay literature is provided in the form of tables.

Numerical solution of magnetohydrodynamics radiative flow of Oldroyd‐B nanofluid toward a porous stretched surface containing gyrotactic microorganisms

AbstractIn this article, we explore an incompressible steady flow of Oldroyd‐B nanofluid near a plan porous stretched surface considering the influence of thermophoresis, Brownian motion, and thermal radiation. Moreover, the constant magnetic field of intensity B0 is implemented with a low Reynolds number as well as the induced magnetic effect and the electric fields are ignored. The suitable similarity variables are applied to the governing partial differential equations (PDEs) which yield the dimensionless ordinary differential equations (ODEs). The MATLAB function bvp4c has been used to resolve the resulting ODEs. The attributes of various flow parameters on the transfer rate of mass, heat, density number of motile microorganisms, motile density, temperature, velocity, and nanoparticles concentration have been explored. It is determined that the boosting values of Prandtl number, solutal stratified, and the radiation parameter supports the boosting of heat transfer rate, and their reduction is assisted by the boosting values of thermal stratified and Brownian motion parameter. Moreover, the higher values of Brownian motion parameters and Schmidt number are more effective in the boosting of Sherwood number, although an opposite behavior is spotted for the boosting values of the thermophoresis and solutal stratified parameter. In the same way, the fluid velocity declines with the escalation of Deborah numbers, Hartmann number, and porosity parameter as well as the fluid temperature minimizes for the inclination of Prandtl number and thermal stratified parameter although it is magnified for the inclination of radiation parameter.

Entropy Analysis on Pulsating Flow of Oldroyd-B Nanofluid in a Vertical Channel with Thermophoresis and Brownian Motion

The magnetohydrodynamic pulsatile Oldroyd-B non-Newtonian nanofluid flow via vertical channel with Joule heating, thermal radiation, and viscous dissipation is investigated in the present study. The influence of thermophoresis and Brownian motion are taken into account. In this investigation, the Buongiorno model is used to analyze the entropy generation. The governing coupled partial differential equations are converted into Ordinary differential equations with the help of the perturbation method and numerically solved by using the Runge-Kutta 4th-order scheme along with the shooting method. The impacts of different emerging parameters for temperature, entropy generation, nanoparticles concentration, Bejan number, heat, and mass transfer rate are examined in detail.

Computational analysis of induced magnetohydrodynamic non-Newtonian nanofluid flow over nonlinear stretching sheet

In the current article, induced magnetic field applied on second-grade fluid flow under variable thermal conductivity by an exponentially stretching sheet is taken into account for current analysis. The chemical reaction and viscous dissipation effects under the influence of thermophoresis and Brownian motion are considered on an exponentially stretching sheet. With the above assumptions, a mathematical model was developed in terms of partial differential equations by using the boundary-layer approximations. Similarity transformations in terms of ordinary differential equations considerably simplified this system. The dimensionless system was solved by a numerical procedure, the bvp4c method. The effects of involving physical parameters are presented through graphs and tables. The obtained numerical outcomes of the skin friction coefficient, the Sherwood number, and the Nusselt number are also highlighted in the tabulated form. It is concluded that the velocity and concentration profiles increased due to higher values of material parameter.

Thermal and hydrodynamic analysis of a conducting nanofluid flow through a sinusoidal wavy channel

The main objective of current study is investigation on thermo-hydraulic behavior of nanofluids in a sinusoidal wavy channel as a novel geometry under influences of thermophoresis and Brownian motion. Differential quadrature method and optimal homotopy asymptotic scheme have been employed to solve the momentum, continuity, energy and nanoparticle fraction equations. The validity of the proposed approaches is evaluated by comparing with previously published results. The impacts of some other physical parameters on temperature, nanoparticle concentration and velocity profiles will be analyzed in details. For instance, the results indicate that increment of the thermophoresis leads to enhance in values of temperature distribution. Also, the volume fraction of nanoparticle enhances by decreasing the parameter of thermophoresis.

Mixed convection and melting rheology in dual stratified Eyring-Powell nanofluid flow over surface of variable thickness: Buongiorno model approach

Eyring Powell fluid flow over linear as well as nonlinear stretching surfaces has been discussed in literature by several researchers. However, lesser attention has been paid for such studies with surfaces comprising variable thickness. Present communication inculcates the novel features regarding melting heat transport in Eyring Powell nanofluid over a surface of variable thickness while keeping in view the aspects of radiative heat transfer. Influence of thermophoresis and Brownian motion phenomena is discussed by making use of Buongiorno model approach. Here, the flow characteristics are analyzed in mixed convective and dual stratified porous medium. Appropriate transformations are imposed in order to convert partial differential equations to ordinary differential equations possessing highly nonlinear form. Homotopy analysis method is utilized to achieve desired convergent series solutions. Impact of several emerging variables on velocity temperature and concentration distributions is analyzed graphically. Expressions for drag force and rate of heat transfer are evaluated and demonstrated graphically. Nano particle concentration increases for higher Brownian motion parameter. Enriched thermal field is attained due to rise in thermophoretic parameter. However, recessive behavior of velocity profile results due to higher fluid parameters. Thermal field rises as a result of larger values of mixed convection parameter while it decays gradually for enhanced melting parameter.

Brownian motion and thermophoresis effects on unsteady stagnation point flow of Eyring–Powell nanofluid: a Galerkin approach

This article concerns the analysis of an unsteady stagnation point flow of Eyring–Powell nanofluid over a stretching sheet. The influence of thermophoresis and Brownian motion is also considered in transport equations. The nonlinear ODE set is obtained from the governing nonlinear equations via suitable transformations. The numerical experiments are performed using the Galerkin scheme. A tabular form comparison analysis of outcomes attained via the Galerkin approach and numerical scheme (RK-4) is available to show the credibility of the Galerkin method. The numerical exploration is carried out for various governing parameters, namely, Brownian motion, steadiness, thermophoresis, stretching ratio, velocity slip, concentration slip, thermal slip, and fluid parameters, and Hartmann, Prandtl and Schmidt numbers. The velocity of fluid enhances with an increase in fluid and magnetic parameters for the case of opposing, but the behavior is reversed for assisting cases. The Brownian motion and thermophoresis parameters cause an increase in temperature for both cases (assisting and opposing). The Brownian motion parameter provides a drop-in concentration while an increase is noticed for the thermophoresis parameter. All the outcomes and the behavior of emerging parameters are illustrated graphically. The comparison analysis and graphical plots endorse the appropriateness of the Galerkin method. It is concluded that said method could be extended to other problems of a complex nature.

MHD 3-dimensional nanofluid flow induced by a power-law stretching sheet with thermal radiation, heat and mass fluxes

Abstract In this article, the three-dimensional Magnetohydrodynamics flow of a nanofluid over a horizontal non-linearly stretching sheet in bilateral directions under boundary layer approximation is addressed. A two-phase model has been used for the nanofluid. The influences of thermophoresis, Brownian motion and thermal radiation on heat and mass transfers are considered. Two different cases for the heat and mass transfers are studied. In the first case, uniform wall temperature and zero nanoparticles flux due to thermophoresis are considered. In the second case, prescribed heat and mass fluxes at the boundary are considered. By using the appropriate transformations, a system of non-linear partial differential equations along with the boundary conditions is transformed into coupled non-linear ordinary differential equations. Numerical solutions of the self-similar equations are obtained using a Runge–Kutta method with a shooting technique. Our results for special cases are compared with the available results in the literature, and the results are found to be in good agreement. It is observed that the pertaining parameters have significant effects on the characteristics of flow, heat and mass transfer. The results are presented and discussed in detail through illustrations.

Oldroyd-B fluid flow over a rotating disk subject to Soret–Dufour effects and thermophoresis particle deposition

In this study, an investigation of magnetohydrodynamics flow of Oldroyd-B fluid by a rotating disk with the influence of thermophoresis on the deposition of particles is discussed. Additionally, the Soret–Dufour effects are taken into consideration. The von Karman transformation is used and the numerical results are obtained through BVP Midrich technique in Maple. The results are given through graphical structure and tabular form. The solutions of the governing equations are obtained and presented graphically in the form of velocity fields, temperature and concentration distributions. The results of local Stanton number (or inward axial thermophoretic deposition velocity) are presented through table. Results reveal that axial thermophoretic velocity enhances with the enlargement of relative temperature difference parameter and thermophoretic coefficient.

Unsteady problem of magnetohydrodynamic heat plus mass transfer convective flow over a moveable plate with effects of thermophoresis and thermal radiation

AbstractThis paper investigates the problem of unsteady magnetohydrodynamic heat plus mass transfer convective flow over a moveable vertical plate with the influence of thermophoresis and thermal radiation. The physical problem is governed by a set of partial differential equations. These sets of equations are coupled and are nonlinear. They were transformed into a dimensionless form of equations by introducing appropriate nondimensional quantities. An iterative method called the spectral relaxation method was used to linearize and decouple the set of dimensionless equations. Results were presented both in graphs and tables. It was found out that thermophoresis parameter has a significant effect on velocity and concentration fields. The thermal radiation is seen to have a significant effect on velocity and temperature fields. The skin friction is seen to increase the moment thermal Grashof number is increased. The model of Newtonian fluid flow over a moveable vertical plate is considered. The plate was considered moving toward the ‐direction and the radiative heat flux is only with respect to . This study considered effects of viscous dissipation, thermophoresis, and radiation on heat plus mass transfer. This, to the best of our knowledge, has not been considered in the literature.

Influence of Couple Stresses and Thermophoresis on Free Convective Heat and Mass Transfer of Viscoelastic Fluid.

A theoretical study has been developed to investigate the influence of thermophoresis and couple stresses on the steady flow of non-Newtonian fluid with free convective heat and mass transfer over a channel bounded by two permeable plates. The considered non-Newtonian fluid follows a viscoelastic model. The problem is modulated mathematically by a system of non-linear differential equations pertaining to describe the continuity, momentum, energy, and concentration. These equations involve the effects of viscous dissipation and chemical reaction. The numerical solutions of the dimensionless equations are found as a function of the physical parameters of this problem. The numerical formulas of the velocity (u), temperature Φ and concentration Θ as well as skin friction coefficient T*, Nusselt number(Nu) and Sherwood number(Sh) are computed. The physical parameter's effects of the problem on these formulas are described and illustrated graphically through some figures and tables. It is observed that any increase in the thermophoretic parameter T leads to reduce in velocity profiles as well as concentration layers. In contrast, the velocity increases with increasing the couple stresses inverse parameter.

Effects of thermophoresis, Soret-Dufour on heat and mass transfer flow of magnetohydrodynamics non-Newtonian nanofluid over an inclined plate

Heat together with mass transfer of magnetohydrodynamics (MHD) non-Newtonian nanofluid flow over an inclined plate embedded in a porous medium with influence of thermophoresis and Soret-Dufour is studied. The novelty of this study is the combined effects of Soret, Dufour and thermophoresis with nanofluid flow on heat together with mass transfer. The flow is considered over an inclined plate embedded in a porous medium. Appropriate similarity transformations were used to simplify the governing coupled nonlinear partial differential equations into coupled nonlinear ordinary differential equations. A novel and accurate numerical method called spectral homotopy analysis method (SHAM) was used in solving the modelled equations. SHAM is the numerical version of the well-known homotopy analysis method (HAM). It involves the decomposition of the nonlinear equations into linear and nonlinear equations. The decomposed linear equations were solved using Chebyshev pseudospectral method. The findings revealed that the applied magnetic field gives rise to an opposing force which slows the motion of an electrically conducting fluid. Increase in the non-Newtonian Casson fluid parameter increases the skin friction factor and reduces the rate of heat and mass transfer. The present results are compared with existing work and found to be in good agreement.

Impact of outer velocity MHD slip flow and heat transfer of nanofluid past a stretching cylinder

This manuscript discussed with the analysis of steady MHD slip flow past a stretching cylinder with outer velocity and heat generation. Using similarity conversions, the mathematical equations are moulded into differential equations which are numerically solved by a bvp4c code in MATLAB. The representative model considered the influence of thermophoresis and Brownian motion. The consequences of the various fluid parameters namely Brownian motion, outer velocity, magnetic, heat generation, partial slip, thermophoresis, radiation and outer velocity on the velocity, temperature and concentration are displayed graphically. Validation of this technique is defending by correlated the current results with the extant outcomes in the literature.