Convection Flow Of Nanofluid Research Articles

The use of machine learning in optimizing the height of triangular obstacles in the mixed convection flow of two-phase MHD nanofluids inside a rectangular cavity

In this article, a numerical study was conducted on the mixed convection (CNV) of nanofluid (NFD) in a two-dimensional rectangular cavity using the control volume method. The upper and lower walls of the cavity were cold and hot, respectively, and its two vertical walls were insulated. The Upper wall has constant velocity and order to create a forced CNV in the cavity. They positioned three triangle-shaped obstacles on the heated wall that were likewise hot. The velocity and temperature graph values in the cavity, the velocity and streamline contours, and the Nusselt number value were examined independently by varying the height (HIT) of each barrier. Using artificial intelligence, the best values of the parameters to have the strongest flow and the most heat transfer (HTF) were checked. Two-phase method was used to simulate NFD flow. The results of this study showed that the middle obstacle with the highest HIT had more HTF. Increasing the length of the obstacle on the right has reduced the amount of HTF and the highest HTF occurred at the lowest HIT of this obstacle. When the obstacle on the left side has the HIT, the amount of HTF is the highest, while its average value has minimized the HTF. An increase in the HIT of the right fin at different HITs of the other two fins reduces the average Nu value

Nonlinear convective nanofluid flow in an annular region of two concentric cylinders with generalized Fourier law: An application of Hamilton-Crosser nanofluid model

The current study focuses on nonlinear convective nanofluid (MoS2 vacuum pump oil) flow with different shapes in an annular region across coaxial cylinders in a permeable media. At the interface of coaxial cylinders velocity slip and temperature jump conditions are incorporated. The phenomenon of thermal transport is enhanced by amalgamating generalized Fourier law with variable thermal conductivity. The Hamilton-Crosser nanofluid flow model is adopted here. The nonlinear equations that govern the flow are simplified via a similarity transformation. For the numerical solution, the bvp4c algorithm is utilized. Graphical analysis is employed to illustrate how important factors affect the temperature and velocity fields. Computational values of the drag force coefficient and Nusselt number are summarized in tabular form. The study reveals that the velocity field upsurges on enhancing the nonlinear convective and radii ratio parameters. On amplifying the rarefaction and thermal conductivity parameters, the thermal field upsurges. Skin friction coefficient exhibits a decreasing behavior on incrementing the porosity parameter. Heat flux diminishes more rapidly by boosting the concentration of nanoparticles. A considerable correlation is apparent graphically and in tabular form by comparing the results of the current investigation with published studies.

Buoyancy Assisting and Opposing Mixed Convective MHD Flow of Nanofluid along a Vertical Stretching Sheet

Buoyancy Assisting and Opposing Mixed Convective MHD Flow of Nanofluid along a Vertical Stretching Sheet

Soret Effects on Free Convection Nanofluid Flows Due to a Stretching Sheet

This paper analyzes Nano liquids flow over a stretching sheet and the characteristics of heat and mass transfer with uniform heat generation. Cu-water and Ag-water nano liquids are considered in the study. To obtain a system of the non-linear ODEs similarity terms have been applied and an optimal homotopy asymptotic method (OHAM) have been used to work out these equations. Various parametric influences on the velocity, temperature, and mass transfer have been shown employing tables and graphs and the result we found is in excellent agreement with the previous results in the works. The homotopy asymptotic approach is used to solve these equations numerically, together with their boundary conditions and the Soret effect has been the primary subject of this article. It was displayed that the Ag-water nano liquid displays higher thermal conductivity compared to Cu-water nano liquid. In addition, the presence of a uniform heat source has a reducing effect on the concentration profile and an increasing effect on the temperature.

Single and multiple walled CNTs-TiO2 ternary hybrid nanofluid flow of Williamson fluid in an unsteady combined convective regime: An entropy analysis

A comprehensive study has been made on the unsteady combined convective flow of Williamson ternary hybrid nanofluid over a rotating sphere with multiple slips and entropy generation (EG). The carbon nanotubes with single (SWCNT) and multiwalled (MWCNT) are dispersed in the base fluid along with the titanium dioxide nanoparticles. The relevant coupled nonlinear partial differential equations (PDEs) are formulated using boundary layer approximations. The nonsimilar transformations convert the governing PDEs into nondimensional forms. The transformed equations are subjected to the Quasilinearization technique for linearization. Further, the implicit finite difference approach leads to discretizing the linearized equations. Incorporating CNTs-TiO2 ternary hybrid nanofluid leads to a higher heat transfer rate than single and two components nanofluids with the same volume fraction of 6%. The SWCNT-MWCNT Williamson hybrid nanofluid improves the energy transport rate by approximately 8% compared to the SWCNT Williamson nanofluid. The Williamson ternary hybrid nanofluid improves heat transfer strength by approximately 34% compared to the Williamson fluid. The comparison of the Newtonian ternary hybrid nanofluid with the Williamson ternary hybrid nanofluid reveals that the EG is minimum, and the Bejan number is more for the Williamson fluid than that for the Newtonian fluid. A fall in the EG is found near the sphere’s surface for higher values of temperature difference ratio and velocity slip.

The optimization of heat transfer in thermally convective micropolar-based nanofluid flow by the influence of nanoparticle’s diameter and nanolayer via stretching sheet: sensitivity analysis approach

Abstract The proposed study demonstrates the flow phenomenon and thermo-variation of a magnetized stretching sheet induced-radiative nanofluid flow. By incorporating the response surface methodology, the heat transfer rate of the thermally convective flow of nanofluid is optimized. The graphene nanomaterial is used in the water-based nanofluid. A dynamic magnetic field, thermal radiation, and the Cattaneo–Christov heat flux model have used to represent the thermal behavior of the nanofluid. The simulation utilizes experimentally estimated values for the nanomaterial’s thermal conductivity and viscosity. To further reveal the thermal enhancement of the flow, the impact of nanoparticle diameter and the solid-liquid interfacial layer is proposed at the molecular level. The response surface methodology and the sensitivity analysis has used to examine the effects of the nanoparticle volume fraction, Biot number, and magnetic parameter on the rate of heat transfer statistically. A set of equations is formed from the governing partial differential equations by implementing suitable similarity transformations. The bvp4c approach is used to solve the problem numerically. The effect of various parameters has displayed through tables, graphs, and surface plots on heat transfer, mass transfer, and the local Nusselt number. It is discovered that as the Biot number increases, so does the concentration and temperature profile. An excellent accord between the present and previously existing solutions is establishing the validity of the achieved results.

Natural convection in nanofluid flow with chemotaxis process over a vertically inclined heated surface

The thermal energy transport analysis with chemotaxis in the free convective flow of viscous nanofluid over stretchable vertically inclined heated sheet is addressed in this article. The fluid forced and free convection motion is investigated and discussed with physical reasoning. The fluid also contains microorganism heavy-bottom species, and their chemotactic motion is studied. In the light of Buongiorno model, the impact of Brownian motion and thermophoresis slip mechanism on thermal conduction in the nanofluid is analyzed. The work is based on the similarity analysis of governing partial differential equations (PDEs) which lead to non-dimensional ordinary differential equations (ODEs). The solution of resulting flow and heat equations is computed via bvp4c technique. The outcomes are represented in graphical abstract. It is noted that free convective flow field increases near to the surface of sheet then it decays to free stream exponentially. Higher magnitude of thermophoretic force boost up the thermal energy transport in nanofluid flow. The Brownian motion enhances temperature profile and lower down the convection velocity. Chemotaxis motion of species in nanofluid is increasing function of bioconvective Peclet number.

Mixed Convection Nanofluid Flow using Lie Group Scaling with the Impact of MHD Radiation Thermophoresis and Brownian Motion

The present study concerns with the mixed convection nanofluid flow across a vertical wedge with Radiation, MHD, Brownian motion, thermophoresis effects using Lie Group scaling analysis. The governing set of highly nonlinear partial differential equations are non-dimensionalized through appropriate transformations and transformed into ordinary differential equations using Lie Group Scaling, which is solved numerically using Shooting method along with bvp4c scheme. The radiation heat flux approximated with the Rosseland approximation has been implemented in the flow equations. The influence of mixed convection, magnetic, Brownian motion, radiation, Lewis number and thermophoresis parameter on the flow profiles are examined. For establishing the efficiency of our adopted numerical technique, we made comparisons with the earlier published works and we found them to be in very good agreement.

Entropy Generation of CuO-Water Nanofluid in a Cavity with an Intruded Rectangular Fin

Entropy generation and heat transfer in cavities have received significant interest due to the ever-increasing demand for enhancing thermal performances in many scientific and engineering fields. In particular, nanofluids are being used increasingly in engineering applications and real-life problems, as they exhibit significantly better thermal properties than basic heat transfer fluids, for example, water, oil, or ethylene glycol. This study investigates the entropy generation and heat transfer of a nanofluid in a confined cavity with a moving top wall and a rectangular fin at the bottom. Here, a macro-homogeneous model based on a previously developed model is employed for investigating the mixed convective flow and heat transfer of CuO-water nanofluid. Various fin geometries, Rayleigh numbers, Reynolds numbers, and nanofluid concentrations have been employed. Present results indicate that the heat transfer rate can be improved, while entropy generation can be minimized using nanofluids instead of conventional heat transfer fluids.

Analytical investigation on the combined impacts of the Soret and Dufour phenomenon in the forced convective flow of a non-Newtonian nanofluid by the movable Riga device

This paper examined the MHD flow over the Riga surface in the presence of a permeable medium with Soret and Dufour effects. The Cattaneo-Christov model is adopted to scrutinize thermal and mass diffusion. The thermal conductivity of the fluid is assumed to be varying with respect to temperature. Melting condition is also imposed. The governing system is reduced to the ordinary differential system after applying the transformation. For the analytical solution, the optimal homotopy method is used. The graphical outcomes for velocity, temperature, concentration, and entropy are plotted for different estimations of various physical variables. The velocity profile enhances for larger estimation of the fourth-grade fluid parameter but decreases for higher values of magnetic and inverse Darcy numbers. The higher values of Suret number temperature and concentration profiles show opposite results. The entropy rate enhances for radiation and Brinkman number.

Effects of natural convection flow of fractional Maxwell hybrid nanofluid by finite difference method

Heat transfer phenomenon occurs in a wide range of industrial and engineering problems. In this framework, investigating the heat transfer behavior using an efficient mathematical tool is the hot research area in the research community. Therefore, we discussed the impact of fractional Maxwell hybrid nanofluid on heat transfer under the effects of Joules Heating, Magnetic field, and viscous dissipation via porous Medium with Caputo time fractional derivative. We have considered an infinite vertical wall with adaptable temperature moving with jerked motion along -direction. Water is taken as base fluid and nano-sized particles of Copper (Cu) & Alumina are used for the preparation of nanofluid. The governing equations of nonlinear Caputo time fractional model are converted into dimensionless form. A finite difference scheme is developed and applied successfully to get numerical solutions to the problem and to examine the influence of Maxwell hybrid nanofluid, physical parameters, and fractional parameters on velocity and temperature profiles. It can also be observed that the extended finite difference algorithm is very efficient and gives the accurate solution of the discussed model. It can be extended for more numerous types of heat transfer problems arising in physical nature with complex geometry.

Turbulent forced convective flow in a conical diffuser: Hybrid and single nanofluids

Turbulent forced convective flow of hybrid and single nanofluids in a conical diffuser is investigated numerically. Simulations are conducted for various Reynolds (Re=10000-70000) and different concentrations (ϕ=0-1.5 vol%) at equal ratio of TiO2:SiO2. The impact of using theoretical and experimental correlations for dynamic viscosity and thermal conductivity on turbulent forced convection of TiO2 showed that the mean Nusselt (Nu) number is considerably reduced with the use of the experimental model. However, when the theoretical model is used, Nu varies insignificantly. Addition of TiO2 nanoparticles decreases the heat transfer inside the diffuser, whereas addition of TiO2–SiO2 nanoparticles either enhances or decreases the heat transfer rate. Compared to the pure fluid, hybrid nanofluids show a maximum enhancement of 5% and a maximum decrease of 9.7% at ϕ= 0.5 vol% and ϕ= 0.5 vol% at Re=10000, respectively. However, TiO2 nanofluids show a maximum decrease of 19% at ϕ=1.5 vol% and Re= 30000. As Re increases, the deviations between TiO2 and SiO2-TiO2 nanofluids diminish. Moreover, the Gene Expression Programming model can accurately evaluate Nu versus Re number and nanoparticle concentration.

Neural network method for quadratic radiation and quadratic convection unsteady flow of Sutterby nanofluid past a rotating sphere

In this study, the heat relocation properties of quadratic thermal radiation and quadratic convective unsteady stagnation point flow of electro-magnetic Sutterby nanofluid past a spinning sphere under zero mass flux and convective heating conditions are investigated. The governing equations are developed and expressed as partial differential equations, which are afterwards transformed into ordinary differential equations by applying similarity conversion. In the investigation, the JAX library in Python is employed with the numerical approach to artificial neural networks. It is investigated to what extent physical characteristics affect primary and secondary velocity, temperature, and concentration fields. The results demonstrate that due to increasing unsteadiness, Sutterby fluid, and magnetic field parameters, the flow of Sutterby nanofluid in the flow zone accelerates in the primary (x-direction) and slows down in the rotational (z-direction). The outcome also shows that an increase in the quadratic radiation parameter, the magnetic field constraint, and the electric field constraint induce increases in the temperature distribution of the Sutterby nanofluid. The study also shows that the concentration of nanoparticles decreases with increasing Lewis numbers and unsteadiness parameter values. Additionally, a graph illustrating the mean square error is investigated and provided.

MHD mixed convection chemically reactive nanofluid flow over a vertical plate in presence of slips and zero nanoparticle flux

The effects of slips on mixed convection nanofluid flow past a plate in the presence of first-order chemical reaction have been examined. To direct the flow, zero nanoparticle flux at the plate has been considered to advocate the rudiments missing from the plate exterior. This situation creates the replica appropriate to a variety of manufacturing divisions for submissive control of nanorudiments fraction. Using similarity transformations, the leading PDEs (partial differential equations) are reduced to odes (ordinary differential equations) and the numerical solutions of the nonlinear equations are obtained with the help of Runge–Kutta method and shooting technique. The consequences of this study have a significant impact on flow, heat and mass transport characteristics. By diminishing the width of the boundary layer, the rising velocity slip parameter causes the fluid velocity to augment while hotness reduces for rising values of velocity slip. The speed of heat transport decreases with the mounting values of thermal slip. Flow separation occurs for buoyancy-aided flow in the presence of blowing and is controlled by suction. Due to separation, significant consequences in heat and mass transport are observed. The consequences of this study expose many motivating characteristics which deserve an additional study of the problem.

A passive control strategy of a micropolar hybrid nanofluid flow over a convectively heated flat surface

In this report, the authors have presented a semi-analytical analysis on thermal convective magnetohydrodynamic flow of a water-based micropolar hybrid nanofluid comprising of Ag and CuO nanoparticles over a stagnant point region of a surface. Thermal convection and mass flux conditions are taken in flow problem. Additionally, the impacts of Brownian motion, chemical reaction, thermophoresis, heat source, and viscous dissipation are taken into account. Also, the Cattaneo-Christovo flux model is used to analyze the transportations of heat and mass. The problem formulation is transformed into dimensionless form by means of suitable similarity transformations. The homotopy analysis technique (HAM), which is semi-numerical approach that does not require small or large factors, is applied. The convergence of each profile of the flow functions are demonstrated in pictorial form. The code has been utilized in the MATHEMATICA 12.0 software. The results show that the growing micropolar factor reduces the velocity and micro-rotational distribution. Also, the coefficient of skin friction is a decreasing function of the magnetic factor. The growing magnetic factor upsurges the velocity distribution, where a dual impact of the magnetic factor on microrotation distribution is observed. The heat transfer rate is a reducing function of Eckert number, magnetic, Brownian as well as thermophoretic factors. Mass transportation rate has declined with growth in Brownian and thermophoresis factors.

LINEAR AND QUADRATIC THERMAL RADIATION INFLUENCE ON MARANGONI CONVECTIVE FLOW OF HYBRID NANOFLUID OVER A FLAT SURFACE IN A DARCY-FORCHHEIMER POROUS MEDIUM

This work investigates the MoS<sub>2</sub>-SiO<sub>2</sub>/water hybrid nanofluid flow over a flat surface with the aligned magnetic field. The novelty of the work is to analyze the heat transport phenomena of MoS<sub>2</sub>-SiO<sub>2</sub>/water hybrid nanofluid in a Darcy-Forchheimer porous medium with the Joule heating, suction/injection, viscous dissipation, Marangoni boundary conditions, and linear and quadratic thermal radiation. Utilizing the appropriate similarity transformations, the partial differential equations (PDEs) governing the heat transfer problem have been altered to ordinary differential equations (ODEs). The built-in function "bvp4c" in MATLAB was employed to find solution of the ODEs. The thermal equation has been solved for linear thermal radiation and quadratic thermal radiation. Plots are presented to show the influence of physical factors on the flow and the temperature field. The significant outcome of the present model is that with the quadratic thermal radiation, the frequency of heat flow is higher than in the linear thermal radiation. The velocity and temperature profile are augmented by an increment in the Marangoni ratio parameter, while the temperature profile decreases slightly after η = 1. Moreover, the temperature rises with an increment in the volume fraction of both the nanoparticles and the Eckert number. For the elevated numerical values of the Marangoni ratio parameter, the concentration of nanoparticles decreases.

On the Non‐Fourier’s Heat and Non‐Fick’s Mass Flux for the Quadratic Convection Flow of a Couple Stress Nanofluid with Wu’s Slip

The overall goal of this paper is to look at how non‐Fick’s and non‐Fourier’s concepts affect the quadratic convection flow of a couple stress nanofluid across an extending surface under Wu’s slip, convective heating, and convective mass transfer conditions. The governing equations in the investigation are also initially stated as higher‐order partial differential equations and thereafter rehabilitated into ordinary differential equations via similarity conversions. Finally, the numerical approach of the bvp5c solver in MATLAB R2019a is engaged to solve the resultant equations. It has been researched and shown using graphs and tables how physical characteristics affect the velocity, temperature, and concentration fields. The results show that the velocity profile along the x‐direction grows with intensifying values of the couple stress, quadratic convection, buoyancy, and third‐order slip constraints, whereas it declines with intensifying values of the fourth‐order slip and magnetic field constraints. Also, the results show that as the velocity ratio constraint is increased, the velocity field along the y‐axis increases. Furthermore, an augment in the values of the quadratic convection constraint and Schmidt number, respectively, causes a diminution in temperature and concentration distributions. The results of the current study can be used to increase lubricant production and reduce machinery deterioration. Furthermore, this theoretical and numerical deliberation has the potential to be beneficial in the field of bio‐fluid dynamics and biomedicine.

Double-diffusive stagnation point flow over a vertical surface with thermal radiation: Assisting and opposing flows.

In numerous industrial procedures, the main concern of design engineers is ensuring adequate heat and mass transfer, such as in the heating and cooling practices of solar water heaters, geothermal systems, extrusion of metal, insulation of buildings, electronics, turbines, aerodynamics, electronics, paper manufacturing, and glass fiber production. The unsteady double-diffusive mixed convection flow of boundary layer nanofluids above a vertical region near stagnation point flow is developed and examined here. The Brownian motion and thermophoresis effects are incorporated by using Buongiorno's model. In the thermal energy equations, diffusion of regular and cross types is also used. By the use of the local similarity method along with suitable similarity transformations, nonlinear unsteady partial differential equations are converted to nonlinear ordinary differential equations and are numerically solved by the Keller-Box method. The investigation expresses that these profiles of solute concentration and nanoparticle concentration, temperature, and velocity in their boundary layers, respectively, depending on several parameters. A graphic analysis of all these parameters' possessions on nature's boundary layers is depicted. The highest rate of heat transfer is obtained with negligible thermophoresis effect. Furthermore, it is perceived that an increase in Nc and Nt results in a reduction in the reduced Sherwood number of nanoparticles, whereas addition results in an increase in the Nb number. There is a reverse effect on the temperature field and layer thickness for heat generation. In the wake of the above-mentioned potential applications, the current study of fluid flow has been found to be very interesting and innovative in the analysis of the influence of Brownian motion and thermophoresis effects near stagnation point flow, which will further make revolutions in industrial fields. Moreover, Buongiorno's model predicts the characteristics of double-diffusive fluids in enhancing heat transfers. This investigation has been established as a result of the numerous industrial applications mentioned above.

MHD CONVECTIVE FLOW OF SWCNTS-WATER AND MWCNTS-WATER NANOFLUID OVER A VERTICAL CONE WITH THERMAL RADIATION AND CHEMICAL REACTION

The analysis is carried out to investigate the MHD boundary layer flow, heat, and mass transfer characteristics of two carbon nanotubes, namely single-wall carbon nanotubes (SWCNTs) and multi-wall carbon nanotubes (MWCNTs), with water as the base fluid by taking thermal radiation and chemical reaction into consideration. Suitable similarity conversions are employed to reduce non-linear partial differential equations into the system of ordinary differential equations, and these equations, together with boundary conditions, are solved numerically using the finite element method. Velocity, temperature, and concentration distributions, as well as skin-friction coefficient, Nusselt number, and Sherwood number for diverse values of influencing parameters, are examined in detail and the results are displayed graphically and in tabular form. It is found that the rate of heat transfer (-Θ'(0)) is remarkably higher in water-based, multi-wall carbon nanotubes than the single-wall carbon nanotubes as the values of nanoparticles volume fraction parameter rises in the boundary layer regime.

NUMERICAL SOLUTION ON MIXED CONVECTION FLOW OF NANOFLUID AROUND A FINNED ANGULAR SECTOR OF HEAT SINK

The aim of this study is to investigate mixed convection flow of nanofluid around a three-dimensional (3D) finned angular sector of heat sink by means of numerical simulations. The finite-volume method is used to solve the governing equations of mass, momentum, and energy conservation. The Brownian motion of the nanoparticles in the base fluid is explicitly taken into account in the thermal conductivity model (Patel model). A parametric study is carried out to examine the effects of several key parameters on the rate of heat transfer; the angular sector apex angle, the volume fraction of suspended nanoparticles (0 ≤ φ ≤ 0.09), the Richardson number (<i>Ri</i> = <i>Gr/Re</i><sup>2</sup>), and the size of the nanoparticles diameter (5, 20, 60, and 100 nm). It is shown that for a fixed low Richardson number <i>Ri</i>, the rate of heat transfer increases with the volume fraction of the nanoparticles, as forced convection mechanism is dominated. The heat-transfer enhancement is obtained for the nanofluid water/TiO<sub>2</sub> rather than the water/Cu at higher nanoparticles volume concentration and highest Richardson number. Moreover, the Maxwell thermal conductivity model resulted in a maximum enhancement in the case of nanofluid water/TiO<sub>2</sub> than that of water/Cu, whereas the nanofluid water/ Cu gives better heat-transfer enhancement at small particles than that of water/TiO<sub>2</sub>. It is observed too that the nanoparticles' diameter does not have a significant effect on the temperature field.