Mixed Convection Flow Of Nanofluid Research Articles

Effects of turbulator shape, inclined magnetic field, and mixed convection nanofluid flow on thermal performance of micro-scale inclined forward-facing step

Effects of turbulator shape, inclined magnetic field, and mixed convection nanofluid flow on thermal performance of micro-scale inclined forward-facing step

Unsteady nonlinear mixed convective flow of nanofluid over a wedge: Buongiorno model

The article deals with 2D unsteady nanofluid flow past a vertical wedge along with nonlinear mixed convection. Brownian diffusion and thermophoresis effects are considered to model nanofluid flow. Convenient transformations are assumed to change the coupled nonlinear governing PDEs into ODEs. To analyze the problem, the solutions of transformed equations are numerically achieved via ‘bvp4c’, a MATLAB approach. Graphical presentation is adopted to see the impact of various influential parameters. Results reveal that nonlinear temperature and concentration convection parameters exhibit the same impact for velocity, temperature and concentration profile, though nonlinear convection parameter for temperature is more impactful than concentration. Velocity overshoot is observed for assisting flow situations. In nonlinear mixed convection flow, skin-friction coefficient, heat and mass transfer rates prominently change for favorable and adverse pressure gradient conditions.

Thermal and velocity slip effects in mixed convection flow of magnetized ceramic nanofluids over a thin needle with variable physical properties

The impact of thermal and velocity slips on mixed convection magnetohydrodynamic flow of ceramic nanofluids past a thin needle with variable physical properties has been investigated in the present study. Numeric computation of nonlinear differential expressions has been executed by Runge–Kutta Fehlberg-quadrature method for varying physical parameters. The study is more important in contributing to medicine and engineering. Fluid velocity and temperature exhibit opposite behavior in relation to amplifying Hartmann number. The rise in slip parameters causes the shrinkage of thermal boundary layer which in turn yields significantly greater heat transfer rate. Flow velocity is an increasing function of Richardson number. Higher surface viscous drag is attained for CuO suspension while least of that is obtained for Ti O 2 suspension.

Dual similarity solutions because of mixed convective flow of a double-nanoparticles hybrid nanofluid: critical points and stability analysis

Purpose The purpose of this article is to study the steady laminar magnetohydrodynamics mixed convection stagnation-point flow of an alumina-graphene/water hybrid nanofluid with spherical nanoparticles over a vertical permeable plate with focus on dual similarity solutions. Design/methodology/approach The single-phase hybrid nanofluid modeling is based on nanoparticles and base fluid masses instead of volume fraction of first and second nanoparticles as inputs. After substituting pertinent similarity variables into the basic partial differential equations governing on the problem, the authors obtain a complicated system of nondimensional ordinary differential equations, which has non-unique solution in a certain range of the buoyancy parameter. It is worth mentioning that, the stability analysis of the solutions is also presented and it is shown that always the first solutions are stable and physically realizable. Findings It is proved that the magnetic parameter and the wall permeability parameter widen the range of the buoyancy parameter for which the solution exists; however, the opposite trend is valid for second nanoparticle mass. Besides, mass suction at the surface of the plate as well as magnetic parameter leads to reduce both hydrodynamic and thermal boundary layer thicknesses. Moreover, the assisting flow regime always has higher values of similarity skin friction and Nusselt number relative to opposing flow regime. Originality/value A novel mass-based model of the hybridity in nanofluids has been used to study the foregoing problem with focus on dual similarity solutions. The results of this paper are completely original and, to the best of the authors’ knowledge, the numerical results of the present paper were never published by any researcher.

A study of convective nanofluid flow over a rough slender cylinder under the influence of magnetic field and species diffusion

AbstractThe present work explores the analysis of magnetohydrodynamics nonlinear mixed conv ective nanofluid flow over a vertical slender cylinder in the presence of surface roughness. The application of the present study can be found in the process of coating wires. In fact, during such a process, thin wires in the slender cylinder need to be cooled, and also heat and mass transfer rates need to be controlled through nanofluid and liquid hydrogen to yield better results. By employing nonsimilar transformations, the partial differential equations governing the flow problem are reduced to dimensionless equations. Furthermore, the Quasilinearization technique and implicit finite difference scheme are used to solve the dimensionless governing equations. The novelty of the analysis is the impacts of surface roughness, diffusion of liquid hydrogen, and the presence of nonlinear mixed convective flow over a slender cylinder. The numerical results reveal that the energy transport strength and surface drag coefficient enhance with the roughness parameter values. The nanoparticle volume fraction profile reduces, while nanoparticle Sherwood number enhances with increasing values of velocity ratio parameter. The presence of nanoparticles in the conventional fluid diminishes the energy transfer value significantly for both smooth and rough surfaces. The velocity of the fluid enhances with increasing values of the mixed convection parameter. Due to surface roughness ( ≠ 0), sinusoidal variations of the drag are observed along the length of the cylinder in comparison to smooth surface case ( = 0). The friction between the fluid and the wall rises for a rough surface because pockets of fluid are formed in the cavities due to surface asperities.

Modified Chebyshev wavelets approach for mixed convection flow due to oblique stagnation point along a vertically moving surface with zero mass flux of nanoparticles

In this article mixed convection flow of nanofluid near a vertical wall is studied for cases of active and passive control. Flow is governed by nonlinear Partial Differential Equations (PDEs), which are transformed into nonlinear ODEs by using similarity transformations. Nonlinear system of equations is solved via two different techniques which are: Modified Chebyshev wavelets scheme and Finite different method. The impact of emerging parameters including free parameter "A" on velocity, temperature and concentration profiles is plotted. Some values of the physical parameters against the active and passive controls for streamlines are calculated. Tables for values of A, components of skin friction, heat flux and mass flux against different parameters are also given. Streamlines are also plotted to predict the flow patterns at various locations inside flow. In this study we found that velocity of flow has same behavior in both active and passive controls, however, temperature and concentration profiles are more sensitive to the passive control.

OHAM analysis of Newtonian heating in mixed convective flow of CNTs over a stretched cylinder

This work reports mathematical modeling and analysis of mixed convection flow of nanofluids with stagnation point by a stretching cylinder. Carbon nanotubes are dispersed as nanomaterial in the baseliquid of water. Heat transfer characteristics are explored through Newtonian heating. Transformation method is employed in order to obtain ODEs. Furthermore series solutions are developed. Variations in flow, temperature, skin friction and local Nusselt number under influential variables have been plotted. It is elaborated that fluid velocity intensifies with rise in curvature parameter, conjugate parameter, mixed convection parameter, nanoparticle volume fraction and velocity ratio parameter. Similarly decay in temperature of the fluid is analyzed for higher velocity ratio parameter while it enhances with increment in nanoparticle volume fraction, mixed convection parameter, conjugate parameter and curvature parameter. Skin friction can be minimized via higher estimations of mixed convection parameter, velocity ratio parameter and nanoparticle volume fraction. Heat transfer rate or cooling process (Nusselt number) is regulated through higher conjugate and curvature parameters. During comparative analysis of SWCNTs with MWCNTs, better performance is shown by SWCNTs. Skin friction coefficient in limiting sense is also compared with previously published articles.

Numerical simulation of lid driven flow in a curved corrugated porous cavity filled with CuO-water in the presence of heat generation/absorption

In this article, numerical simulation is performed for mixed convection lid-driven flow of CuO-water nanofluid enclosed in a curved corrugated. Cylindrical obstacles having three different constraints: (adiabatic, cold, and heated) at its surface are considered. Internal heat generation/absorption and uniform heat is provided at the vertical wall of the cavity. The bottom wall is insulated, and the curve surfaces are maintained with cold temperature. Mathematically equations are developed from physical problems and solved through Galerkin weighted residual method of FEM formulation. The effect of various Reynold number (Re), Darcy number (Da), solid volume fraction of nanoparticles (ϕ), heat generation/absorption coefficient (Q) and various cylindrical obstacle on velocity, Nusselt number, molecular movements and the flow structure has been studied. Nusselt number increases for high Darcy number due to the convection in lid cavity. For high Reynold number generally Nusselt numbers decrease or remain the same at the wall with an increase of nanoparticles in porous medium. There significant effect of heat sink coefficient on temperature profile and Nusselt number decreases with increasing of Q.

Thermal enhancement in the mixed convective flow of unsteady Carreau nanofluid with slip conditions: A numerical study

Nanofluids are formed by incorporating very small sized particles consist of metals, oxides, carbides, or carbon nanotubes into base fluids like water, oil, ethylene glycol etc. Due to number of applications and amazing heat flow features of nanofluids, we are motivated to devote this article to explore the heat transform characteristics in transient flow of Carreau nanofluid over an inclined stretching cylinder. We have modeled the nonlinear mixed convection flow of Carreau nanoparticles in term of Lorentz force. Heat transfer mechanism in the flow is examined in view of nonlinear thermal radiation and non-uniform heat source/sink influences. Additionally, the effects of joule heating are also taken into account for examining the heat transport mechanism in the flow. Moreover, the effects of chemical reaction are also employed in concentration equation for investigation of mass transport phenomenon in the flow of nanofluid. To see the influence of involved physical parameters bvp4c numerical technique is employed. The numerical outcomes of physical parameters are assessed and depicted with logical discussion in the results and discussion section. The section of concluding remarks is designed to highlight the core findings of this study. It is revealed that the flow curves of nanofluid significantly grow up for escalating scales of nonlinear thermal convection constant. Moreover, an escalation is detected in the transport of thermal energy for growing scales of Eckert number and thermal radiation constant. Also, it is assessed that the flow velocity deteriorates by with an escalation in the magnitude of buoyancy force ratio parameter.

Hydrodynamic Analysis of Laminar Mixed Convective Flow of Ag-TiO2-Water Hybrid Nanofluid in a Horizontal Annulus

Nanofluids occupy a large place in many fields of technology due its improved heat transfer and pressure drop characteristics. Very recently, a new type of nanofluid, known as hybrid nanofluid, which consists of a mixture of two different nanoparticles suspended in the base fluid has been found to be the most emerging heat transfer fluid. It is well also established that entrance region effect enhances heat transfer rate. The present study deals with numerical investigations of the hydrodynamic behavior of the laminar mixed convective flow of a hybrid nanofluid in the entrance region of a horizontal annulus. A thermal boundary condition of uniform heat flux at the inner wall and an adiabatic outer wall is selected. The SIMPLER numerical algorithm is adopted in the present study. The hybrid nanofluid consists of water as base fluid and Ag-TiO2 as nanoparticles. The ratio of Ag to TiO2 is maintained as 1:3. The objective of the current study is mainly to analyze the hydrodynamic behavior hybrid nanofluid in the entrance region. The investigation reveals that the effect of the secondary flow due to the buoyancy forces is more intense in the upper part of the annular cross-section. It increases throughout the cross-section until its intensity reaches a maximum and then it becomes weak far downstream. The development of axial flow and temperature field is strongly influenced by the buoyancy forces.

Implication of fluid rheology on the Cattaneo–Christov heat flux theory for fourth grade nanofluid over a riga device with thermal radiation

This paper analyzes the influence of mixed convective fourth grade nanofluid flow by a stretchable Riga device in the presence variable thermal conductivity and mass diffusivity. Heat and mass transportation are considered with Cattaneo–Christov (CC) model. Thermal radiation and dissipation are also taken in the energy expression. Suitable transformation is employed to reduce partial differential system into nonlinear ordinary system. The governing nonlinear expression is solved via optimal homotopy analysis method. Impact of different physical variables is discussed via graphs. Velocity profile is enhanced for higher values of cross viscous parameter and fourth grade fluid variable. Fluid temperature enhances for higher estimation of thermal relaxation parameter but reverse behavior is seen for solutal concentration variable on nanoparticle concentration.

Augmentation in heat transfer for a hybrid nanofluid flow over a roughened surface

Heat transfer characteristics of mixed convective flow of a hybrid nanofluid along a wavy surface are investigated. Dimensionless equations of the problem are solved utilizing finite difference method. Numerical results revealed that for increasing the amplitude-wavelength ratio, magnetic field strength and volume fractions of Cu and Al2O3 nanoparticles, the thermal boundary-layer increases. Skin friction coefficient and local Nusselt number considerably increase owing to the increase of the volume fractions of nanoparticles and magnetic field parameter. Heat transfer for a flat surface is remarkably higher than that for a wavy surface except around the crests of it. Whatever the forced, mixed or free convection regimes, skin friction coefficient and local Nusselt number are almost linearly correlated with the volume fraction of nanoparticles. Moreover, the Cu nanoparticles provide higher heat transfer than the Al2O3 nanoparticles. It is recognized that the local Nusselt number calculated on 5% volume fraction of Cu nanoparticles is higher by 0.5%, 1.0% and 7.7% respectively for forced, mixed and free convection processes, however, when the volume fraction of nanoparticles is 8% the corresponding increments are 0.9%, 1.6% and 13.3%.

Thermal radiation effect on unsteady mixed convection boundary layer flow and heat transfer of nanofluid over permeable stretching surface through porous medium in the presence of heat generation.

Here, we study the effect of mixed convection and thermal radiation on unsteady boundary layer of heat transfer and nanofluid flow over permeable moving surface through a porous medium. The effect of heat generation is also discussed. The equations governing the system are the continuity equation, momentum equation and the heat transfer equation. These governing equations transformed into a system of nondimensional equations contain many physical parameters that describe the study. The transformed equations are solved numerically using an implicit finite difference technique with Newton's linearization method. The thermo-physical parameters describe the study are the mixed convection parameter α, , the Radiation parameter Rd, , porous medium parameter k, , the nanoparticles volume ,, the suction or injection parameter fw, , the unsteadiness parameter At, and the heat source parameter λ = 0.5 .The influence of the thermo-physical parameters is obtained analytically and displayed graphically. Comparisons of some special cases of the present study are performed with previously published studies and a good agreement is obtained.

FDM analysis for nonlinear mixed convective nanofluid flow with entropy generation

This analysis is concerned with unsteady Darcy-Forchheimer flow of nanomaterial by a stretching sheet. Heat transfer is carried out in presence of nonlinear mixed convection. Brownian motion and thermophoresis diffusion describe nanomaterial characteristics. Further magnetic field and viscous dissipation impacts are considered. By choosing suitable variables problem related expressions (PDEs) are transformed into dimensionless PDEs. These PDEs are then tackled through finite difference scheme. Entropy generation, skin friction, mass transfer rate and heat transfer rate are elaborated for involved parameters. Velocity enhances with increment in buoyancy variable and time while it reduces via higher Forchheimer number and porosity parameter. Temperature of the fluid decays with larger time while it boosts with an increment in Eckert number and nonlinear convection parameter. Higher values of Schmidt number lead to decay in concentration while it intensifies against higher thermophoretic diffusion parameter and time. Entropy production rate boosts against Prandtl and Eckert numbers while it is controlled via higher temperature ratio and volume ratio parameters.

Non-similarity solutions of radiative stagnation point flow of a hybrid nanofluid through a yawed cylinder with mixed convection

In this new-fangled research, the mixed convective stagnation point flow of a hybrid nanofluid over a yawed cylinder with radiation impact is considered. In reality, the perception of mixed convection in the study of yawed cylinder rises in heat exchangers. To explore the heat diffusion through the system of mixed convection, the mathematical problem is formed in the form of partial differential equations which are coupled and nonlinear. A solution technique is applied and described for indulgencing non-similar thermal boundary layers. The non-similar terms involving in the transformed equations are held without approximations. The non-similar equations are solved numerically using the bvp4c technique. The exploration divulges numerous significant results involving yaw angle, hybrid nanoparticle volume fraction, mixed convection, radiation, and non-similarity phenomena. The impact of the yaw angle in enhancing the velocity of the hybrid nanofluid in the span-wise and chord-wise directions in the aiding buoyancy flow and decelerating in the opposing flow, while the contrary behavior is noticed for the dimensionless temperature profile. Also, the hybrid nanoparticles reduce the velocity in both directions in case of assisting as well as opposing flow, whereas the dimensionless temperature augments.

Mathematical Analysis of Thermal Energy Distribution in a Hybridized Mixed Convective Flow

The mixed convective flow of hybrid nanofluid (SWCNT-MWCNT/EG) containing micropolar fluid past a Riga surface embedded in porous medium is explored in detail throughout this study. In the momentum equation, the Darcy Forchheimer effect is used. The heat transfer phenomenon is exploited with viscous dissipation and thermal stratification over a non-Fourier heat flux model. PDEs are transformed into the necessary governing equations using transformations. The numerical results of non-linear governing equations are collected using Matlab function bvp4c. Graphical representations of the effects of relevant parameters on velocity, skin friction, and temperature are shown. The comparison of simple nanofluid and hybrid nanofluid is discussed in graphs. The temperature field is higher for hybrid nanofluid than simple nanofluid when solid volume fraction enhances. With increasing solid volume fraction, porosity parameter, and mixed convection parameter, the axial friction factor rises. The momentum boundary layer is inversely proportional to the slip parameter, Hartman number, variable viscosity and the porosity parameter.

Closure to “Computational Analysis for Mixed Convective Flows of Viscous Fluids With Nanoparticles” (Farooq, U., Lu, D. C., Ahmed, S., and Ramzan, M., 2019, ASME J. Therm. Sci. Eng. Appl., 11(2), p. 021013)

Abstract The authors regret in the published paper referenced above and agree with the discussion by Pantokratoras (2019, “Discussion: “Computational Analysis for Mixed Convective Flows of Viscous Fluids With Nanoparticles” (Farooq, U., Lu, D. C., Ahmed, S., and Ramzan, M., 2019, ASME J. Therm. Sci. Eng. Appl., 11(2), p. 021013),” ASME J. Therm. Sci. Eng. Appl., 11(5), p. 055503). In this Closure, the non-similar mathematical model is developed to describe the mixed convective nanofluid flow over vertical sheet which is stretching at an exponential rate. In the published article referenced above, similarity transformations are utilized to convert the governing nonlinear partial differential equations (PDEs) into ordinary differential equations (ODEs). The important physical numbers such as magnetic field (M2), Brownian motion parameter (Nb), thermophoresis (Nt), Eckert number (Ec), ratio of mass transfer Grashof to heat transfer Grashof (N), buoyancy parameter (λ), and Reynolds number (Re) appearing in the dimensionless ODEs are still functions of coordinate “x”; therefore, the problem is non-similar. In this corrigendum, the non-similar model is developed by using ξ(x) as non-similarity variable and η(x, y) as pseudo-similarity variable. The dimensionless non-similar model is numerically simulated by employing local non-similarity via bvp4c. The graphical results show no change in behavior. The important thermal and mass transport quantities such as Nusselt number and Sherwood number have been computed for the non-similar model, and results are compared with the published article.

Mixed convective stagnation point flow of a hybrid nanofluid toward a vertical cylinder

PurposeThe purpose of this paper is to numerically analyze the stagnation point flow of Cu-Al2O3/water hybrid nanofluid with mixed convection past a flat plate and circular cylinder.Design/methodology/approachThe similarity equations that reduced from the boundary layer and energy equations are solved using the bvp4c solver. The duality of solutions is observed within the specific range of the control parameters, namely, mixed convection parameterλ, curvature parameterγand nanoparticles volumetric concentrationϕ1for alumina, while for copperϕ2. The stability analysis is also designed to justify the particular solutions’ stability. Additionally, the idea to obtain the solution for large value ofλandγis also presented in this paper.FindingsTwo solutions exist in opposing and assisting flows up to a critical valueλcwhereλclies in the opposing region. An upsurge of the curvature parameter tends to extend the critical value (delay the separation process), whilst increase the heat transfer performance of the working fluid. Meanwhile, the application of hybrid Cu-Al2O3/water nanofluid also can decelerate the separation of laminar boundary layer flow and produce higher heat transfer rate than the Cu–water nanofluid and pure water.Originality/valueThe results are new and original. This study benefits to the other researchers, specifically in the observation of the fluid flow characteristics and heat transfer rate of the hybrid nanofluid. Also, this paper features with the mathematical formulation for the solution with large values ofλandγ.

Mixed convective flow and heat transfer of hybrid nanofluid impinging obliquely on a vertical cylinder

Flow and heat transportation in hybrid nanofluid, impinging obliquely on a vertical cylinder, are investigated numerically in this communication. Silver and aluminium oxide nanoparticles having stable and relatively high thermal conductivity, with pure water as base fluid, are used in the analysis. The non-linear coupled partial differential equations are transformed into ordinary differential equations using suitable transformations. An implicit finite difference method is used to approximate the velocities and temperature for particular values of the various parameters and their effects are emphasised graphically. The tabular data are documented to compare the heat transfer rate for pure water silver/water nanofluid, aluminium/water nanofluid and silveraluminiumwater hybrid nanofluid. It is observed that heat transfer rate increases by increasing the curvature of the stretching cylinder and solid volume fraction of nanoparticles and for hybrid nanofluid it has a larger magnitude than that of water, nanofluid and nanofluid.

Unsteady mixed convective flow of nanofluid with arbitrary‐shaped nanoparticles over a shrinking sheet

AbstractThe present study describes the unsteady mixed convection nanofluid flow past a vertical shrinking porous surface in occurrence of slips and heat source/sink. Applying proper transformations, the foremost differential equations which are partial in nature are changed into non‐linear differential equations which are ordinary in nature. With the support of Runge–Kutta method, shooting technique is used to find out the numerical solutions of the system of equations stated above. The effects of diverse leading parameters like unsteady parameter, velocity slip parameter, suction/injection parameter, thermal slip parameter, and heat source/sink parameter are offered and explained physically. Also, the coefficient of skin friction and rates of surface heat and mass transport for a number of parameters are investigated numerically.