Influence of nonlinear thermal radiation on mixed convective hybrid nanofluid flow about a rotating sphere

The present study investigates the mixed convective hybrid nanofluid flow over a rotating sphere under the impact of nonlinear thermal radiation. A model is built to examine the heat transport performance of ferrimagnetic magnetite and copper nanoparticles over a rotating sphere. Nonsimilar transformations are used to nondimensionalize the coupled nonlinear governing equations and the flow model's boundary conditions. Furthermore, the nondimensional governing equations were solved using implicit finite difference approximation and the quasilinearization technique. The impacts of the flow regime on many controlling parameters are then thoroughly addressed. Temperature patterns improve when nonlinear thermal radiation and hybrid nanofluid values increase. The fluid velocity and skin friction coefficient increase in the streamwise direction while decreasing in the rotating direction. The separation of the boundary layer is delayed as the sphere's rotation weakens. The stationary sphere has a larger boundary layer separation than the revolving sphere. The velocity distribution improves with increasing rotation parameter values while decreasing with increasing combined convection parameter values in the rotating direction. An increase in the temperature ratio parameter makes the fluid get hotter, and the Nusselt number goes down simultaneously. Nusselt number and skin friction coefficient in the rotation direction increase, while skin friction coefficient in streamwise direction reduces for increasing values of hybrid nanofluid. The velocity of the fluid enhances in the stream-wise direction while reducing in the rotational direction with the increasing values of the combined convection parameter.     

Analysis of multilayer convective flow of a hybrid nanofluid in porous medium sandwiched between the layers of nanofluid

AgBr acts as a good sensitizer for titanium oxide, hence TiO₂–AgBr nanoparticles exhibit high photocatalytic activity which helps decompose methyl orange under visible light irradiation. Methyl orange is a chemical compound that is hard to degrade and has high stability. It is photoreactive and can capture photons from the sun and is highly used as a light harvester in solar cells, hence, it is used in solar applications. In view of this, the present article deals with the analysis of heat transfer in a multilayer flow of two immiscible nanofluids in a vertical channel that finds application in the fields of solar reactors, electronic cooling, and so on. The mathematical model involving the effect of thermal radiation and the presence of heat source is in the form of a system of ordinary differential equations. This system of equations is simplified using the differential transform method-Padé approximant and the resulting equations are solved algebraically. It is observed that the temperature of the coolant does not reach its saturation point faster due to the presence of different base fluids that differ in their thermal conductivity. This helps in maintaining the optimum temperature of the system.     

Nonlinear thermal radiation on MHD tangential hyperbolic hybrid nanofluid over a stretching wedge with convective boundary condition

In this study, two distinct nanoparticles: aluminum oxide (Al₂O₃) and copper (Cu) are chosen as nanomaterials to examine the effects of nonlinear electrically conducting magnetohydrodynamic radiation on the flow of tangential hyperbolic hybrid nanofluid across a nonlinearly stretched sheet with convective boundary conditions. The equations that regulate fluid flow are represented as partial differential equations. These equations are reduced to their equivalent ordinary differential equations, which are solved using the homotopy analysis approach with the help of similarity variables. The effect of essential physical factors on fluid velocity, temperature, skin friction coefficient, and local Nusselt number is investigated and discussed. Results ascertain that the heat transfer rate of Cu/H₂O nanofluid becomes high when equated to Cu–Al₂O₃/H₂O nanofluid. Furthermore, the temperature distribution enhances with the rise in solid volume fraction while it diminishes with improved magnetic field for both nanofluid and hybrid nanofluid.     

Electromagnetohydrodynamic boundary layer flow in hybrid nanofluid with thermal radiation effect: Numerical simulation

Hybrid nanofluid boundary layer flow past a stretching surface with zero mass flux boundary condition is explored in this article. The main aim of this article is to analyze the electromagnetohydrodynamic role in a hybrid nanofluid containing silver and molybdenum disulfide nanoparticles. The self-similar solution is embedded to reduce the governing partial differential equation into algebraic equations and a shooting algorithm is applied to obtain the solution of the resultant boundary value problem. Variation in momentum, energy, and nanoparticle concentration is explained through graphical profiles. Nusselt number and drag force coefficients are computed for various flow parameters and their impact on the nanofluid and hybrid nanofluid is computed and presented and explained in a comparative fashion. It is observed that the velocity profile shows the opposite nature with respect to the electric field and magnetic field. For electric field parameter velocity accelerates whereas for magnetic parameter velocity diminishes. Nusselt number increases with electric field parameter and nanoparticle volume fraction.     

Heat transfer enhancement in a cubical cavity filled with a hybrid nanofluid

Mixed convection heat transfer in a cubical cavity with an isothermally heated blockage inside filled with a hybrid nanofluid (HBNF) is numerically studied. The natural convection is created by the temperature difference between the hot block and the cold lateral walls, while the forced convection is generated by moving the upper wall. The influence of some variables, like the aspect ratio (0.1 ≤ r ≤ 0.5), Richardson number (0 ≤ Ri≤ 20), Reynolds number (50 ≤ Re ≤ 200), volume concentration of nanoparticles (0 ≤ ϕ ≤ 0.06), and the concentration ratio (2:8, 5:5, and 8:2) on the flow field and heat transfer is analyzed. A comparison between hybrid and mono nanofluids (NFs) is realized to investigate the energy transport enhancement. Results show that the increase of each parameter causes an increase of average Nusselt number Nu_avg and improves the heat transfer; besides the use of HBNF gives better Nu_avg values. Three correlations of the effect of r, ϕ, Ri, and Re on Nu_avg are determined for both hybrid and mono NFs.     

Heat transfer enhancement in a hybrid microchannel-photovoltaic cell using Boehmite nanofluid

Experiments were conducted to investigate the cooling performance of water-based Boehmite (AlOOH · xH₂O) nanofluid in a hybrid photovoltaic (PV) cell. A Perspex plate consists of 40 parallel rectangular microchannels with a hydraulic diameter of 783 μm, a length of 24 cm, a width of 1.8 mm and a depth of 500 μm attached to the back of the cell. Cooling performances of water, as the base fluid, and three different concentrations of nanofluid (0.01, 0.1 and 0.3 wt.%) were compared. The nanofluid thermal performance has been assessed from the obtained results for outlet flow temperature and the average PV surface temperature. The average PV surface temperature decreased from 62.29 °C to 32.5 °C at zero and 300 ml/min of flow rate for 0.01 wt.% nanofluid, respectively. Moreover, the highest improving in the electrical efficiency was achieved about 27% for 0.01 wt.% concentration of the nanofluid at this flow rate.     

Analysis of nanofluid transport through a wavy channel

Laminar forced convection of heat transfer and pressure drop of Al₂O₃ and CuO/water nanofluids flow through a horizontal tube and wavy channel under constant wall temperature boundary condition is numerically investigated. Two different models were employed in our study: single phase (homogenous and dispersion) and two phase (Lagrangian–Eulerian model or discrete-phase model (DPM) and the mixture). The effects of various parameters, such as particle concentration, particle diameter, particle type, constant or temperature-dependent properties, wave amplitude, Reynolds number and Peclet number on the thermal, and flow field of the Nanofluids are analyzed. Our results revealed that variable properties assumption play a dominant role in horizontal tubes and provide better predictions for the heat transfer enhancement. The difference between constant and variable properties becomes insignificant and can be ignored in wavy channel due to the high mixing and generated recirculation zones, whereas the difference between the DPM and the single-phase variable properties diminish as Peclet number and volume fraction increases. However, dispersion model shows an excellent agreement with the experimental data; the absence of the reference values for the adjustable factor C_d in the open literature put it in a questionable position. Therefore, DPM and homogenous single-phase model with well-chosen thermal conductivity and viscosity correlations can be considered as an accurate way and more dependable in nanofluid simulations especially the homogenous single-phase model because it requires less time, CPU, and memory usage. As expected, it is found that the heat transfer increases as the Reynolds number and particle volume fraction increases, but it is accompanied by a higher pressure drop. The obtained results have been successfully validated and compared with the experimental and numerical data available in the literature.     

Thermo-bioconvection effect on hybrid nanofluid flow over a stretching/shrinking melting wedge

The research focused on nanomaterial solutions and their flow characteristics in relation to their usage. The application of such composites in biological rheological models, in particular, has received a lot of interest. The use of nanofluids in cooling tiny electronic devices like microchips and associated devices cannot be emphasized. Our goal is to explore the influence of a binary chemical reaction and Arrhenius activation energy on a hybrid nanofluid over a melting wedge in a spongy media. It is anticipated that the water-based nanoparticle contains gyrotactic microbes. By using appropriate similarity variables, the resultant dimensional nonlinear boundary-layer model is reduced and turned into a dimensionless form. A Chebyshev spectral collocation approach is useful in solving the highly nonlinear model. In terms of physical importance, the effects of important factors on developing profiles are displayed graphically and explained. Computational outcomes are obtained via MATHEMATICA. The plot of residual error is also shown to demonstrate the method's rapid convergence. According to the study's findings, by increasing the melting parameter, the rate of heat transportation at the wall decreases greatly on the average of 12.81%, but the Sherwood number becomes effective for the chemical reaction rate with a rate of about 24.81%.     

Heat and mass transfer of water-based copper and alumina hybrid nanofluid over a stretching sheet

Hybrid nanofluids (HNFs) are vital in engineering and industrial applications due to significant effective thermal conductivity as compared with regular fluid and nanofluid (NF). The HNF is a process of the conglomeration of two or more nanoparticles of different thermophysical properties to affect the thermal transport characteristics of base fluid, particularly in gearing up heat switch charge. Further, the impact of HNF combined with stretching and squeezing of bounding surface has direct application in thinning/thickening of polymeric sheets in the chemical industry. The current study analyzes the flow of HNF over a stretching sheet under the influence of chemical reaction as well as suction/injection. We have considered water $\left({\mathrm{H}}_2\mathrm{O}\right)$ as the base fluid and copper $\left(\mathrm{Cu}\right)$, and aluminum oxide $\left({\mathrm{Al}}_2{\mathrm{O}}_3\right)$ as nanoparticles. The consequences of the magnetic field, viscous dissipation, and Joule heating are also to be investigated. The resulting partial differential equations are transformed into nonlinear ordinary differential equations using suitable similarity transformations. The numerical solutions to governing equations are obtained with the help of MATLAB software using the bvp4c solver. The important finding is: the rate of heat transfer of HNF is higher than that of NF as well as base fluid. Moreover, contributions of higher Eckert number and radiation parameter are to increase the temperature in the flow domain, whereas the Prandtl number reduces it. It is further noticed that heavier species as well as viscous dissipation decline the level of concentration across the flow field.     

Model for MHD viscoelastic nanofluid flow with prominence effects of radiation

Present phenomenon is dedicated to analyze the problem of steady state flow of an incompressible fluid model pertained to as magnetohydrodynamics viscoelastic nanofluid through a permeable plate. Continuity, momentum, energy, and concentration expressions are elaborated to comprehend nature of the fluid flow. Numerical solutions are presented. The arising mathematical problem is governed by interesting parameters which include viscoelastic parameter, magnetic field parameter, nanofluid parameter, radiation parameter, skin friction, Prandtle number, and Sherwood number. Solutions for the dimensionless velocity, temperature, and concentration fields and the corresponding skin friction, Nusselt number, and Sherwood number are determined and canvassed with the help of graphs for the distinct values of pertinent parameters.     

Thermo-electrokinetic rotating non-Newtonian hybrid nanofluid flow from an accelerating vertical surface

This paper explores the combined effects of Coriolis force and electric force on the rotating boundary layer flow and heat transfer in a viscoplastic hybrid nanofluid from a vertical exponentially accelerated plate. The hybrid nanofluid comprises two different types of metallic nanoparticles, namely silver (Ag) and magnesium oxide (MgO) suspended in an aqueous base fluid. The Casson model is deployed for non-Newtonian effects. An empirical model is implemented to determine the thermal conductivity of the hybrid nanofluid. Rosseland's radiative diffusion flux model is also utilized. An axial electrical field is considered and the Poisson–Boltzmann equation is linearized via the Debye–Hückel approach. The resulting coupled differential equations subject to prescribed boundary conditions are solved with Laplace transforms. Numerical evaluation of solutions is achieved via MATLAB symbolic software. A parametric study of the impact of key parameters on axial velocity, transverse velocity, nanoparticle temperature and Nusselt number is conducted for both the hybrid (Ag–MgO)–water nanofluid and also unitary (Ag)–water nanofluid. With increasing volume fraction of silver nanoparticles, there is a reduction in both axial velocity and temperatures, whereas there is a distinct elevation in transverse velocity for both unitary and hybrid nanofluids. Elevation in the heat absorption parameter strongly decreases axial velocity, whereas it enhances transverse velocity. Increasing the radiation parameter strongly boosts temperatures. Increasing the heat absorption parameter significantly accelerates the transverse flow. Negative values of Helmholtz–Smoluchowski velocity decelerate the axial flow whereas positive values accelerate it; the opposite behavior is observed for transverse velocity. Increasing Taylor number significantly damps both the axial (primary) and transversal (secondary) flow. Increasing thermal Grashof number strongly enhances the axial flow but damps the transverse flow. The unitary nanofluid achieves higher Nusselt numbers than the hybrid nanofluid but these are decreased with greater radiative effect (due to greater heat transport away from the plate surface), Prandtl number and heat absorption. Nusselt number is significantly reduced with greater time progression and values are consistently higher for the unitary nanofluid compared with hybrid nanofluid. The computations provide insight into more complex electrokinetic rheological nanoscale flows of relevance to biomedical rotary electro-osmotic separation devices.     

Convective heat transfer enhancement with graphene nanoplatelet/platinum hybrid nanofluid

The work here looked into heat transfer performance in addition to friction loss of graphene nanoplatelet (GNP) - Platinum (Pt) hybrid nanofluids. The experiments were performed with non-changing limit parameters of heat-flux. Nanofluid movement was turbulent at a weight percentage ranging between 0.02 and 0.1%, with the Reynold number from 5000 to 17,500. The experimental findings revealed that compared with the base liquid, all nanofluid samples had higher heat transfer abilities. Nusselt number elevation and the increment of the heat transfer coefficient were found to be dependent on Reynold number, and the weight concentration of the nanocomposite. The greatest value recorded for Nusselt number was 28.48%, accompanied by a 1.109-fold penalty. There was a rise in friction factor with regards to the highest load of nanocomposite (0.1 wt%), with the Reynolds number of 17,500.     

Mixed convection and entropy production of a hybrid nanofluid in a porous cylindrical enclosure with rotating top wall

A numerical study is carried out to investigate heat transfer and entropy production of a hybrid nanofluid in a porous cylindrical enclosure with a rotating top wall. The bottom wall of the cylinder is taken as hot, the sidewall is adiabatic, except the top wall is considered cold and rotates at an angular velocity (ΩR). The effects of a hybrid nanofluid flow on heat transfer and entropy generation are examined for an aspect ratio (H/R = 1). A FORTRAN program was elaborated for solving the governing equations based on the finite volume method. Good agreement was found when comparing results from this study against published data. Our results are presented for different Reynolds number values (100 ≤ Re ≤ 1500), nanoparticle fraction NP (0 ≤ ϕ ≤ 0.08), Darcy number (10⁻⁴ ≤ Da ≤ 10⁻¹) and porosity of the porous medium (0.2 ≤ ε ≤ 0.99) for Ri = 0.5, 1,5 and 8, where (Ri = Gr/Re2). They reveal that the heat transfer increases with Re, ϕ, Da, Ri, and decreasing ε. The simulation data were used to propose four different correlations for $\overline{\mathit{Nu}}$ and S_tot as Re, Da, Ri, ϕ, and ε.     

Triple diffusive flow of nanofluid with buoyancy forces and nonlinear thermal radiation over a horizontal plate

The present attempt is made to elaborate the features of triple diffusive convective flow of an incompressible nanoliquid induced by horizontal surface under buoyancy forces. The effect of nonlinear thermal radiation is taken into account. Heat flux model of radiation is formulated through Rosseland's approximation. The radiation phenomenon plays a key role in modern solar energy equipment's. The nondimensional variables are introduced to convert the dimensional mathematical expressions into dimensionless single independent variable. Numerical scheme is developed to obtain the solution of mathematical model. The importance of controlling constraints on flow quantities are characterized through plots. The quantities of engineering importance are computed and elaborated graphically. It is noticed that the presence of salts and nanoparticles enhance the thermal performance of base liquid. The liquid temperature and its relevant thickness of thermal layer improved significantly with an increment in the values of radiative parameter. The larger values of parameters of Brownian motion and thermophoretic correspond to higher temperature profiles.     

Flow of mixed convection for radiative and magnetic hybrid nanofluid in a porous material with Joule heating

This paper analyzes the mixed convection flow and transport of heat in a hybrid nanofluid via an exponentially extending/contracting surface. Joule heating, magnetic field, permeability of a porous medium, thermal radiation, and slip condition are taken into consideration. Magnetite (Fe₃O₄) and copper (Cu) are used as a mixture of nanoparticles while ethylene glycol as a regular liquid. The paradigm is dissolved by utilizing the method of Runge–Kutta–Fehlberg with the shooting technique in MATLAB software. The effect of controlling parameters on the coefficient of drag force, heat transfer coefficient, and the distributions of temperature and velocity for physical parameters are discussed numerically, physically, and graphically. The outcomes ended up illustrating that the transport of heat is diminished by upsurging the Joule heating and magnetic field parameters for both contracting and extending states. For larger values of permeability parameter and parameter of mixed convection, the coefficient of local skin friction upsurges in extending situations.     

Chemically reactive and radiative flow of ferro-aluminum (AA7075) hybrid nanofluid past a stretching cylinder

The present investigation throws light on the heat transfer behavior of hybridized (ferro-aluminum alloy [AA7075]) nanofluid. In addition to that, influences of thermal radiation, magnetic effect, and chemical reaction are also considered for the exploration. Here, the flow is deliberated due to a porous stretching cylinder. The equations that portray the fluid flow are transfused to simple ordinary differential equations by applying similarity elements. Then, the procured equations have been solved by adopting the Runge–Kutta–Fehlberg 4th–5th order tool. The extracted solution are exported to plot graphs for velocity, thermal, and solutal profiles with the concerned parameters, and using these plots, the discussion has been produced for the behavior of all flow fields. The behavior of the thermal profile shows substantial enhancement with an increase in the solid volume fraction of hybrid nanofluid. The velocity and concentration panel de-escalates for larger values of Reynolds number. A significant discussion on the skin friction drag, Nusselt number, and Sherwood number has been produced.     

Heat and mass transfer characteristics of radiative hybrid nanofluid flow over a stretching sheet with chemical reaction

Unsteady magnetohydrodynamic heat and mass transfer analysis of hybrid nanoliquid flow over a stretching surface with chemical reaction, suction, slip effects, and thermal radiation is analyzed in this study. A combination of alumina (Al₂O₃) and titanium oxide (TiO₂) nanoparticles are taken as hybrid nanoparticles and water is considered as the basefluid. Using the similarity transformation method, the governing equations are changed into a system of ordinary differential equations. These equations together with boundary conditions are numerically evaluated by using the Finite element method. The influence of various pertinent parameters on the profiles of fluids concentration, temperature, and velocity is calculated and the outcomes are plotted through graphs. The values of nondimensional rates of heat transfer, mass transfer, and velocity are also analyzed and the results are depicted in tables. Temperature sketches of hybrid nanoliquid intensified in both the steady and unsteady cases as the volume fraction of both nanoparticles rises.