The study of heat transfer phenomena in non-similar flow of nanofluid is the subject of this investigation. The external retarded flow past a flat plate is considered which does not allow the self-similarity solution. To enhance the heat transfer rate nanofluid has been considered instead of the pure fluid. The nanoparticles of Aluminum Oxide are disseminated in the Water, being base fluid, to form the nanofluid. The consideration of nanofluid results in a substantial heat transfer augmentation along with the skin friction coefficient and both are observed to be further enhanced with higher concentration of nanoparticles. Almost 48% and 36% of gain in heat transfer rate and skin friction coefficient, respectively, have been observed in the 20% nanoparticle concentration at the downstream location where separation is occurring. However, a 67% gain in skin friction coefficient is observed for other downstream locations. The effect of nanoparticle concentration on the separation phenomena has also been investigated carefully and it is found that the concentration of nanoparticle does not delay the flow separation in this case. The effect of nanoparticle concentration on velocity and temperature profiles and their gradients is depicted and discussed through several graphs.

The natural convection of TiO₂-Water-Nanofluid in a cubic cavity, containing a hot block under the influence of the magnetic field was studied numerically. The verticals walls are cold, the bottom wall is hot and the other walls (top, front and rear) are adiabatic. This work aims to visualize the importance of taking into account the three-dimensionality of the flow in the presence of magnetic field as well as the impact of the addition of nanoparticles on heat exchange rate evolution. The governing equations are solved using the finite volume method and the SIMPLER algorithm is used for pressure-velocity coupling. The problem was simulated at different Rayleigh numbers (10³ ≤ Ra ≤ 10⁶), Hartmann numbers (0 ≤ Ha ≤ 90) and inclination angles of the magnetic field (0 ≤ ω ≤ 135°) as well as nanoparticles volume fraction (φ = 0%, φ = 5%) with fixed Prandtl number (Pr = 7). The thermal conductivity and dynamic viscosity of the nanofluid are estimated by taking into account temperature-dependent properties, using Corcione’s correlations. Based on the cooling optimization of cold walls along with comparative analysis between 3D cavity and 2D cavity, the obtained results show that the buoyancy force enhances the heat exchange, while the magnetic field produces opposite effects. When the buoyancy force is dominated, the intensification of heat transfer becomes large, compared to the case where conduction is dominant. The qualitative difference between a 3D and 2D configuration is remarkable for higher Ra, and becomes smaller when the magnetic field is applied horizontally or vertically with relatively high intensity. But, quantitatively, the 3D flow is far from being considered as a 2D flow for all pertinent parameters control. Finally, adding nanoparticles enhances heat transfer for both configurations, the best transfer rate is obtained for ω = 0.

Conventional investigations on fluid flows are undertaken with an assumption of constant fluid properties. But in reality, the properties such as viscosity and thermal conductivity vary with temperature. In such cases, considering these variabilities aids in modelling the flows with accuracy. Particularly, studying the flow of graphene based nanofluids with variable properties makes the best of both the advantageous thermophysical properties of graphene nanoparticles in heat transfer and the variable fluid properties in accuartely modelling the flow. In this article, the flow of graphene oxide nanofluid along a linearly stretching cylinder under no-slip and convective boundary conditions is investigated, by taking the base fluid viscosity to be a temperature dependant function. Buongiorno model is adapted to develop the flow of graphene nanofluids including the influence of variable heat source, cross-diffusion effects and the effects of nanoparticle characteristics such as thermophoresis and Brownian motion. The modelled equations are transformed and are numerically solved using linearization method. The impacts of embedded parameters including the Dufour and Soret numbers on temperature, concentration and velocity profiles of the chosen nanofluid and their consequent impacts on the predominant cause for the generated entropy are studied. The obtained results are depicted and interpreted in detail. From the tabulated values of skin friction and the values of Sherwood and Nusselt numbers, it is inferred that the conductive heat and mass transfer can be enhanced by variable viscosity parameter and skin friction can be reduced by Soret number. Furthermore, entropy generation is analysed and Bejan number is calculated to be lesser than 0.5, thus demonstrating the dominance of irreversibilty to fluid friction and mass transfer.

This paper is centered on the numerical and analytical solution of a non-Newtonian Casson nanofluid flow problem in the presence of vertical magnetic field. Brownian motion and thermophoretic forces are introduced due to the addition of nanoparticles and; the magnetic field adds an extra Lorentz’s force term along with Maxwell’s equations. Using Normal mode technique, the system of PDEs with the corresponding boundary conditions is reduced to a system of ODEs. The Galerkin-type weighted residual method is used to get a numerical solution for the formulated differential system. Numerical simulation is carried out to make the investigation helpful for practical applications like nano-drug delivery systems as in clinical and medical research, magnets are extremely important to create three-dimensional images of anatomical and diagnostic importance from nuclear magnetic resonance signals. Comparisons of the numerical results with previously published results are made and fine agreements are noted for the considered values of the parameters. The impact of magnetic field, Casson parameter and nanoparticle parameters are discussed for different types of boundary conditions (free–free, rigid-free and rigid–rigid). The system is found to be the most stable for more realistic rigid–rigid boundaries out of three different boundaries. For the purpose of numerical computations, blood has been considered as the Casson nanofluid. The novelty of the work lies in the fact that the strong stabilizing influence of Lorentz force on blood-based Casson nanofluid enables the red blood cells to pass through the blood in a more streamlined fashion which may play a significant role in human health, more specifically in the cardiovascular system. Further, although the Casson parameter hastens the onset of convection yet Casson fluids are more stable as compared to regular fluids.

The characteristics of hybrid nanofluid flow contained copper (Cu) and cobalt ferrite (CoFe₂O₄) nanoparticles (NPs) across a squeezing plate have been computationally evaluated in the present report. In biomedical fields, in very rare cases fluid flow through a static channel. Similarly in industrial sights, we are also often observed that the fluid flows through comprising plates rather than fixed plates (flow in vehicle’s engine between nozzles and piston). CoFe₂O₄ and Cu nanoparticles are receiving huge attention in medical and technical research due to their broad range of applications. For this purpose, the phenomena have been expressed in the form of the system of PDEs with the additional effect of suction/injection, heat source, chemical reaction, and magnetic field. The system of PDEs is simplified to the dimensionless set of ODEs through similarity replacements. Which further deals with the computational approach parametric continuation method. For the validity and accuracy of the outcomes, the results are confirmed with the existing works. The results are displayed and evaluated through Figures. It is detected that the hybrid nanoliquid has a greater ability for the velocity and energy conveyance rate as related to the nanofluid. Furthermore, the energy profile declines with the consequences of unsteady squeezing term, while enhances with the effects of suction factor, heat absorption and generation, and lower plate stretching sheet.

Numerical simulations of water-Al₂O₃ nanofluid flow in a rectangular channel with two trapezoidal obstacles have been studied, which has rmarkable effect in various engineering applications. The governing equations have been solved using SIMPLEC algorithm and FLUENT software has been used to visualize the simulation results. Motivation of this work is to examine the dynamic behavior of laminar water-Al₂O₃ nanofluid flow for volume fraction, ψ = 0%, 2%, and 4%. The present study analyzes different hydrothermal flow phenomena with the variation in obstacle height and ψ. Moreover, the simulation results, such as the profiles of velocity, normalized temperature (θ), poiseuille number (C_fRe), local Nusselt number (Nu), average Nusselt number (Nu_avg) and friction factor (f) have been portrayed with the variations in ψ and Reynolds number (Re). It has been observed that the obstacles increase the convective heat transfer (HT) significantly. At Re = 100, for all the configurations it has been found that the velocity profile become more pronounced for ψ = 4% as compared to ψ = 0%. A linear relationship has been found between the values of f and ψ. It is also found that an increase in Re increases vortex length. It is also shown that variation of volume fraction (ψ) and obstacle height resulted in an indicative change in the normalized temperature and velocity along the center line. In type-1 obstacle configuration, it has been found that Nu_avg increases by 6.6% at ψ = 2%, and the same increases by 10.73% at ψ = 4% as compared to that at ψ = 0%. Moreover, it has been found that in type-2 obstacle configuration, value of f increases by approximately 7.9% at ψ = 2% and 13.84% at ψ = 4% as compared to that at ψ = 0%.

This paper presents a numerical analysis study of the dynamic and thermal performance of a convective flow of water-copper nanofluids in a double-pass flat solar collector. The flow inside the confined space between the glazing and the insulation is governed by the continuity, momentum, and energy equations. The problem addressed is solved via a CFD ANSYS code using the finite volume method to discretize the equations of the mathematical model. The dynamic and thermal fields are obtained for different values of the volume fraction (φ = 0%, φ = 3%, and φ = 8%). These results are compared with other results mentioned in the literature. The results obtained allowed us to define the influence of these different parameters on the convective nanofluid flow in the solar collector. The increase in the volume fraction further promotes heat transfer. The presence of nanoparticles expects a critical part of the convective heat exchange.

The article widely reviewed the variation of the heat transfer characteristics and fluid flow of various nanofluids based on physical and chemical parameters like velocity, geometry, viscosity, friction factor, and pressure drop. It also shed light on the stability of these nanofluids in various conditions. The article mainly focuses on the effects on Reynolds number and Nusselt number, thermal changes in the environment and the cooling solution used for nanofluids, and the dependency of concentration of nanoparticles in the working fluid. Apart from this, it also discusses the geometry in which the fluid is kept and the motion or forces it experiences and simulations to observe and analyse the flow of fluid and heat through these nanofluids. Also, this article presents the improvement in the pool boiling heat transfer rates through nanofluids with twisted tapes and corrugated patterns such as corrugated double-tube exchangers. This article concluded with the results obtained from experimental analysis and numerical methods. According to the study, as nanofluids get bigger, their velocity increases. When particle size is increased from 10 nm to 100 nm, the alumina-water nanofluid’s velocity rises by 22.22%. For Al₂O₃/water nanofluid with a particle size of 10 nm, the rate of expansion in wall shear stress when concentration is raised from 0% to 5% is 75%. The geometry of the tubes affects the properties of heat transport. When a triangular tube having a twisted tape is utilized in the system, the Nusselt number is enhanced by 34.7% and 52.5% in turbulent and laminar flow respectively.

Combined effects of the magnetic field, heat source/sink, and homogeneous–heterogeneous chemical reaction on the three-dimensional fluid flow over a stretching sheet have been examined in this paper. For originality and practicality, the influence of non-linear convection on hybridised nanoparticles of titanium dioxide (TiO₂) and silver (Ag) in the non-Newtonian engine oil (EO) are introduced into the governing equations, which are then dimension-free by utilizing appropriate transformations. Williamson fluid model has been employed to determine the rheological features of the considered fluid mixture. MATLAB inbuilt bvp4c solver and Keller box method are proposed for the numerical solution of current fluid theories. Physical elaboration of the graphs is given to recognize the influence on fluid flow and heat transport mechanism in different rising conditions. Based on results, the implication of magnetic field and Williamson parameters restrict the fluid flow for both nanofluid (TiO₂/EO) and hybrid nanofluid (TiO₂ + Ag/EO). Special case studies of the shape factor effect show more enhancement in heat transfer rate for cylindrically shaped nanoparticles 25.8162% followed by brick-shaped 20.3286% and spherical-shaped 17.0583%. This study will provide better insight into applications including aircraft refrigeration, lubrication, plastic processing, engine and generator cooling, and so forth.

In this research paper, the study focuses on results of heat radiation on Casson fluid flowing in three dimensions toward a linearly stretched sheet packed with porous media when a magnetic field is present, as well as when Prandtl number effects when there is a porous medium involved. The Roseland approximation, which integrates a heat radiation’s impact into the energy equation, is used to incorporate thermal radiation into this research endeavour. To be used in this fluid flow the basic governing partial equations for this fluid flow were changed from linear ordinary differential equations by converting non-linear partial equations with similarity variables are utilised. The numerical solutions to the resultant linear ordinary duality equations are obtained by the use of the finite element approach. Graphical representations of the effectiveness and accuracy of this finite element approach are provided for a variety of characteristics as the permeability (K), Casson fluid (β), and magnetic field (M) parameters Stretching sheet parameter (C), Prandtl number (Pr) and Thermal radiation component (R). and conditions. A comparison of our numerical findings with previously published data (S. Nadeem, R. U. Haq, N. S. Akbar, and Z. H. Khan, Alexandria Eng. J. 52, 577 (2013)) reveals a a high level of consistency among the two sets of data.