Heat Transfer Of Hybrid Nanofluid Research Articles

Optimizing heat transfer with nano additives: A mathematical approach

This study is carried out to investigate heat transfer of hybrid nanofluid between two concentric cylinders using the fractional Maxwell model. The fractional model is solved numerically; fractional derivatives are integrated using the L1 algorithm of Caputo derivative and the integer order derivatives are discretized using the Crank–Nicolson numerical method. The findings show that skin friction decreases when the relaxation time parameter increases. The thermal performance of the working fluid increased up to 5% when hybrid nanoparticles were suspended to it.

Stagnation Point Flow and Heat transfer of Hybrid Nanofluid over a Stretching/Shrinking Cylinder with Suction/Injection Effects

The focus of this research is to observe how suction/injection affects the stagnation point flow and heat transfer in a hybrid nanofluid over stretching/shrinking cylinder. Silver (Ag) and copper oxide (CuO) nanoparticles are dispersed in pure water to create a hybrid nanofluid. By using similarity transformations, the governing partial differential equations are turned into a ordinary differential equations which are then solved by implementing bvp4c function in MATLAB software. The influence of the nanoparticle volume fraction, magnetic parameter, curvature parameter and suction/injection parameter, on velocity and temperature profiles, local skin friction and local Nusselt number are discussed and presented in graphical forms. The results indicate that all of the problems have dual solutions for a given range of parameters. It is noticed that with the suction effect, energy losses is reduced, thus the heat transfer increases and decreases the boundary layer separation. Furthermore, the presence of curvature parameter and suction effect expand the range of dual solutions. In addition, the rate of heat transfer for hybrid nanofluid was higher than viscous fluid and nanofluid.

Significance of quadratic radiation and variable thermal conductivity on heat transfer of hybrid nanofluid using Xue model: A Legendre wavelet approach

Carbon nanotubes have a broad spectrum of applications in thermal management, enhanced cooling, lubricants, sensors and detections, environmental remediation, biomedical, and drug delivery. Motivated by its industrial applications, this work analyses the effects of nonuniform heat source/sink and quadratic thermal radiation on the thermal characteristics of hybrid nanofluid flow over a curved stretching sheet using the Legendre wavelet collocation technique (LWCT). The base fluid is found to be composed of ethylene glycol and water in the ratio of 30:70, and the nanoparticles are taken as single-wall carbon nanotube (SWCNT) and multi-wall carbon nanotube (MWCNT) in the ratio of 2% each. The thermal conductivity models, namely Xue, modified Maxwell and Hamilton-Crosser, are compared for heat transfer enhancement. From the results up to 5% volume fraction, the Xue model shows the maximum rate of heat transfer enhancement, while the above 5% Hamilton-Crosser model shows the maximum rate of heat transfer enhancement. The temperature profiles of existing hybrid nanofluid are increased with a heat source, radiation and variable thermal conductivity. Moreover, the graphs describing the local Nusselt number display the heat transfer rate depreciation with an increase in variable thermal conductivity and radiation parameters.

Turbulent Heat Transfer of Hybrid Nanofluid with Nano-Encapsulated Phase Change Material in a Square Channel

Investigation of turbulent mixed convection of different working fluids, namely, pure water, CuO/water nanofluid, n-octadecane/water nanofluid (or slurry), and a hybrid water-based suspension of CuO and n-octadecane nanoparticles in a uniformly heated vertical square channel is carried out. The shear stress transport/kappa-omega model is applied to simulate the turbulent flow. Eulerian–Lagrangian two phase model and homogeneous model are employed to simulate the nanofluid flow. It is shown that Eulerian–Lagrangian two-phase model predicts higher Nusselt number and friction factor than single-phase model and the results of two-phase model are closer to experimental data. It is found that a new hybrid nanofluid with dispersed nano-encapsulated phase change material particles provides better thermal and hydrodynamic performances compared to other nanofluids. Slurry containing 5% n-octadecane provides an improvement of nearly 37.2%, while hybrid nanofluid (1% CuO + 5% n-octadecane) offers added convective heat transfer enhancement of almost 60%. With increasing volume fraction, friction factor becomes slightly larger than that of pure water. For 5% n-octadecane/water and 1% CuO + 5% n-octadecane/water nanofluids, friction factor increases by 2.5% and 1.7%, respectively. Due to dominance of thermal entropy generation, total entropy generation reduces by increasing Reynolds number and volume fraction.

EHD flow and heat transfer of hybrid nanofluid in a free surface cavity fitted with an internal hot obstacle

The objective of this study is to numerically investigate the effects of electrohydrodynamics (EHD) on coupled free convective thermocapillary flow. The study focuses on a free-surface cavity filled with a hybrid nanofluid (MWCTN- Fe3O4-thermal oil) and containing a hot rigid obstacle. An electric field is applied between the obstacle and the lower cavity wall to induce additional instabilities in this region. This technique aims to eliminate the dead zone typically present in traditional natural convection and is expected to greatly improve heat transfer efficiency. To achieve this objective, the equations governing the EHD phenomenon, as well as the equations defining the physicochemical properties of the hybrid nanofluid, are solved using the finite volume method (FVM) coupled with a blocked-off region procedure. A parametric study is conducted, involving the Marangoni number (surface tension), the thermal Rayleigh number (buoyancy force), the electrical Rayleigh number (electrical force), the nanoparticle concentration, the size and the position of the obstacle. It has been demonstrated that applying of an electric field to the convective-thermocapillary flow of the nanofluid (combining two enhancement techniques) significantly enhances heat transfer, resulting in a more than 230 % increase in the Nusselt number.

Flow and Heat transfer of Hybrid nanofluid past an Exponentially Stretched Porous surface

This research looks at the flow and heat conduction properties of a hybrid nanofluid formed by an exponentially stretched porous surface. Over the last decade, there has been a substantial increase in research on nanofluids. Despite several contradictions in the published results and a poor understanding of the heat transmission mechanism in nanofluids, this fluid has emerged as a viable heat transfer medium. It takes longer for the combination nanofluid to make heat than it does for ordinary nanofluid. It has also been shown through simulations that the mixed nanofluid has better temperature performance than the nanofluid. Using the similarity transformation approach, the governing equations of the issue are turned to similarity equations. To convert nonlinear partial differential equations (PDEs) to ordinary differential equations (ODEs), the Keller Box approach is used. This strategy for solving these ODEs has been shown to be quite successful. The effects of several targeted parameters on physical quantities are shown, and the comparison of findings for validation is also recorded. The study's findings are provided as graphs, demonstrating the strong influence of the targeted elements on both nanofluid and hybrid nanofluid. Because of the existence of hybrid nanofluid, the velocity and temperature profiles have improved. Variations in the amount of Copper (Cu) nanoparticles, in particular, cause dramatic variations in the velocity and temperature profiles of the hybrid nanofluid. Furthermore, a lower Prandtl number is shown to reduce temperature and thermal boundary layer thickness. The graphical representations also show how porosity affects temperature and velocity profiles.

Numerical Study of Unsteady Magnetohydrodynamics Flow and Heat Transfer of Hybrid Nanofluid Induced by a Slendering Surface with Suction and Injection Effects

Since the last two decades, most of the researchers have concentrated on the nanofluids boundary layer flow over a surface of even thickness or flat surface. This article deals with a mathematical model, which describe the hybrid nanofluid (SiO2–MoS2/water) flow over a slendering surface (surface of uneven thickness). The novelty is to study the effects of natural convection and porous medium. The analysis of heat transfer is also accomplished and for the same purpose, the viscous dissipation, heat source/sink, ohmic heating and thermal radiation effects are incorporated. The velocity slip and thermal slip boundary conditions with suction/injection effects are applied. Similarity transformations are utilized to change the prevailing PDEs to ODEs. Numerical investigation is performed to solve the equations. The MATLAB in built function “bvp4c solver” is employed for finding the solution. The velocity and temperature profile were found higher for the injection case in comparison to the suction. The effect of power law index parameter and unsteadiness parameter is to aid the flow velocity. The heat generation parameters, Eckert number and volume fraction of nanoparticles act to augment the flow temperature. For the suction and injection case, the radiation parameter has positive correlation with the heat transfer rate.

Assessment of Effectiveness Amount of Heat Absorption/Production and Magnetic Field on Entropy Generation During Conjugate Heat Transfer of Hybrid Nanofluid

Assessment of Effectiveness Amount of Heat Absorption/Production and Magnetic Field on Entropy Generation During Conjugate Heat Transfer of Hybrid Nanofluid

Impact of wavy porous layer on the hydrodynamic forces and heat transfer of hybrid nanofluid flow in a channel with cavity under the effect of partial magnetic field

Abstract This computational analysis focuses on the effects of porous layer on the flow dynamics, heat transfer and hydrodynamic forces of hybrid nanofluid in a channel having an open cavity fixed with bottom wall in the presence of partial magnetic field. The set of PDEs governing the dynamics has been transformed to dimensionless form and simulated using higher order finite element method. In particular, P 3 / P 2 ${\mathbb{P}}_{3}/{\mathbb{P}}_{2}$ finite element pair is employed for the spatial discretization and Crank–Nicolson approach is utilized for the temporal discretization. The obtained equations has been linearized with adaptive Newtons method and linearized systems have been computed using the geometric multi-grid technique. The impact of parameters, for instance, Richardson number, thickness of porous layer and nanoparticle fraction is analyzed in the presence of partial magnetic field and porous layer on the hydrodynamic forces like lift and drag forces on the submerged bodies, being the important part of the fluid flow and heat transfer are also be analysed. It is noticed that the drag and lift coefficients are reduced as the nanoparticle fraction is altered while the local- and average-Nusselt number get higher values.

Numerical analysis of heat transfer of hybrid nanofluid in a porous sinusoidal channel with magnetic field and an alternating heat flux

Recently, a great amount of research was done on wavy conduits due to the importance of heat and flow transfer in wavy channels and conduits, and their special use in various industries. The improvement of heat transfer in these ducts attracted the attention of many researchers, and experimental and numerical studies are devoted. The effect of the presence of a porous medium and magnetic field on forced convection heat transfer and a nanofluid flow in a complex wave-shaped channel with a special boundary condition (Non-uniform with respect to location) was studied for the first time. For this purpose, the heat transfer of a nanofluid in a two-dimensional sinusoidal channel containing a porous medium in the attendance of a magnetic field was analyzed. First, the nanoparticles were optimized using the design of the experiment method, and then modeling was performed using selected optimal particles. To improve heat transfer in a sinusoidal channel, the factors like the injection of optimized nanoparticles, porous medium, and magnetic field usage were used. The equations were discretized using the Fluent software with a finite volume method. The validation of problem outcomes was done using experimental and numerical studies. Porous medium in four different Darcys (10−5, 10−4, 10−3, and 10−2), and applying magnetic fields in four different Hartman (0, 4, 7, and 10) were examined. The results show that the channel wave, and magnetic field intensity improved heat transfer. Furthermore, using a porous medium with high Darcy can increase the Nusselt number. Hence, in the same conditions (Re = 500, Ha = 10) with Darcy number increasing from 10−5 to 10−2, Nu becomes equal to 5.011. This proposed system is an industrial-utility system that can increase heat transfer efficiency.

The effect of hybrid nanofluid CuO-TiO2 on radiator performance

This study aims to improve the performance of the vehicle's cooling system called the radiator, which is part of increasing energy efficiency. Research has been done to investigate the convective heat transfer of hybrid nanofluid, using CuO and TiO2 nanoparticles and water-ethylene glycol (RC) as base fluids on a radiator. The mass concentration of the hybrid nanoparticles varied from 0.25 %, 0.30 %, and 0.35 %. For the preparation of the hybrid nanofluid through a two-step method, by mixing dry samples of CuO and TiO2 nanoparticles (50:50) and then the mixture of radiator coolant, RC (60 % water and 40 % ethylene glycol). The fluid flow varies from 20 liters per minute to 28 liters per minute. Temperature variations range from 70 °C to 90 °C by using controlled heating. Four thermocouples measure the inlet and outlet hot fluid flow and the airflow before and after the radiator. The experiment showed that the overall heat transfer coefficient increases remarkably with the increase of the hybrid nanoparticle concentration under various flow rate values. The maximum overall heat transfer coefficient increases by about 83 % compared to pure radiator coolant under 0.35 % mass concentration at a flow rate of 22 liters per minute and a temperature of 70 °C. It has also been found that the heat transfer rate is highly dependent on the radiator's mass fraction and flow rate. Increasing the mass concentration shows maximum enhancement in heat transfer rate. Inlet temperature also enhances the heat transfer rate, but its effect is small compared to nanofluid's mass concentration and flow rate. This study reveals that hybrid nanofluids can be suitable as a working fluid, especially in small-scale heat transfer devices.

Role of copper and alumina for heat transfer in hybrid nanofluid by using Fourier sine transform

The convection, thermal conductivity, and heat transfer of hybrid nanofluid through nanoparticles has become integral part of several natural and industrial processes. In this manuscript, a new fractionalized model based on hybrid nanofluid is proposed and investigated by employing singular verses and non-singular kernels. The mathematical modeling of hybrid nanofluid is handled via modern fractional definitions of differentiations. The combined Laplace and Fourier Sine transforms have been configurated on the governing equations of hybrid nanofluid. The analytical expression of the governing temperature and velocity equations of hybrid nanofluid have been solved via special functions. For the sake of thermal performance, dimensional analysis of governing equations and suitable boundary conditions based on Mittage-Leffler function have been invoked for the first time in literature. The comparative analysis of heat transfer from hybrid nanofluid has been observed through Caputo-Fabrizio and Atangana-Baleanu differential operators. Finally, our results suggest that volume fraction has the decelerated and accelerated trends of temperature distribution and inclined and declined profile of heat transfer is observed copper and alumina nanoparticles.

Numerical study of heat transfer in hybrid nanofluid flow over permeable nonlinear stretching curved surface with thermal slip

The hybrid nanofluid flow past a permeable curved surface with nonlinear stretching is considered in this analysis. Here two kinds of particles considered to examine the flow field over the exponentially curved surface with a porous medium. The mathematical model underflow assumptions are developed by using the Navier-Stokes equations. The mathematical model in terms of partial differential equations is reduced to a system of nonlinear ordinary differential equations through suitable transformations. The reduced system in terms of ordinary differential equations is solved by using the numerical scheme bvp4c method. The effects of involved physical parameters on velocity and temperature profiles are highlighted through tables and graphs. The major focus of this work is to compare the hybrid nanofluid heat transfer scale to the simple nanofluid. Two cases namely suction and injection are debated. The obtained results are validated by developing comparison with existing literature. Temperature profile exhibits declining behavior for improving the values of solid nanoparticle concentration in injection case while temperature profile is increasing towards higher values of solid nanoparticle concentration in case of suction. Rate of heat transfer achieved lesser by hybrid nanofluid when compared to simple nanofluid. The positive curvature parameter enhanced the momentum boundary layer thickness for both cases injection and suction. On increasing solid nanoparticle concentration, the velocity profile enhanced for the case of suction and injection case.

Entropy optimized radiative heat transfer of hybrid nanofluid over vertical moving rotating disk with partial slip

Hybrid nanofluids are a mixture of two types of nanomaterials in the base fluid. These nanofluids have novel characteristics that benefit many industrial applications like fuel cells, refrigerators, heat exchangers, etc. The present study examined entropy optimized Cu−TiO2/Water flow over vertically moving rotating disk with thermal radiation and partial slip. Also, Dufour and Soret’s effects are utilized in the modeling of the energy equation. The highly non-linear system of differential equations is solved by the BVP Midrich scheme employed in Maple software. The effects of embedded non-dimensional parameters on velocity, concentration, and temperature profiles are analyzed graphically along with the examination of entropy generation. It is observed that vertical disk movement and rotation have a contrasting impact on velocity, concentration, and temperature profiles compared to existing literature. Also entropy rate rises with radiation parameter, diffusion factor and temperature ratio parameter but declines with slip coefficient. The local skin friction coefficients, Nusselt number and Sherwood number are plotted with respect to different involved parameters. The current work can be utilized in various engineering applications to improve their efficiency.

Thermal Enhancement Effects of Buoyancy-Driven Heat Transfer of Hybrid Nanofluid Confined in a Tilted U-Shaped Cavity

In this manuscript, the analysis of buoyancy-driven heat transfer of copper-alumina/water hybrid nanofluid in a U-shaped enclosure under the influence of cavity inclination is extensively studied numerically. The dimensionless governing equations are formed by using dimensionless variables. The domain is discretized to a finite number of the Lagrange three-node triangular element, and the finite element method is employed with the Galerkin-weighted residual algorithm to compute and solve the problem. The Newton-Raphson method is employed as a convergence criterion for each iteration. Numerical and experimental validation of the previously published data is conducted with the present results to verify the stability and reliability of the numerical procedure and results. The effect of the lid tilting angle on the heat transfer performance of the enclosure is extensively explored in the manuscript. The streamlines, isotherms, local and average Nusselt numbers as well as the vertical and horizontal velocity of the fluid are plotted for a variation of the Rayleigh number up to 106. The analysis of the effect of fluid velocity on the fluid flow and thermal distribution pattern are discussed with relation to the overall heat transfer capability within the domain. It is found that hybrid nanofluid enhances the heat transfer rate within the enclosure. The highest heat transfer performance is at an inclination angle of 40°≤Θ≤ 60°. The results presented in the manuscript will be useful in the manufacturing processes involving electronics such as laptops and smartphones.

RETRACTED: Aqueous aluminium–copper hybrid nanofluid flow past a sinusoidal cylinder considering three-dimensional magnetic field and slip boundary condition

We analyzed the problem of the steady general three-dimensional magnetohydrodynamics stagnation-point boundary layer flow past an impermeable wavy circular cylinder considering aluminium–copper/water hybrid nanofluid as the working fluid and velocity slip as well as temperature jump boundary conditions. The induced magnetic field effect was also taken into account. The analytical procedure is based on the model that implements the nanoparticles and base fluid masses to formulate the equivalent volume fraction, equivalent density, and equivalent specific heat at constant pressure which is then substituted in the chosen single-phase thermophysical properties. Then, the foregoing relations were used in basic governing PDEs (partial differential equations), according to Tiwari–Das nanofluid scheme. It is worth mentioning that the bvp4c code from MATLAB software that is a famous finite-difference method has been exploited for solving the final similarity ODEs (ordinary differential equations). Results demonstrate that the developed mass-based model can be successfully employed with great confidence to study the flow and heat transfer of hybrid nanofluid in other similar problems. Moreover, it is proved that the nodal stagnation points possess higher values of skin friction coefficients and local Nusselt numbers relative to those for the saddle stagnation points. Besides, enhancing the second nanoparticle's mass leads to increase in all parameters of engineering interest including skin friction coefficients along x and y directions as well as local Nusselt number.

Heat Transfer Enhancement and Boundary Layer Separations for a Hybrid Nanofluid Flow past an Isothermal Cylinder

Unsteady magnetohydrodynamic mixed convection flow of an incompressible hybrid nanofluid (Cu-Al2O3/water) past an isothermal cylinder with thermal radiation effect has been studied. Appropriate non-dimensional variables are initiated to reduce the governing equations into a convenient form. By utilizing the procedure of finite difference, reduced equations are then solved for all time. Besides, series solutions are obtained using perturbation technique for short time and asymptotic method for long time which agree with the acquired numerical solution up to a good accuracy. When the mixed convection parameter Ri, radiation conduction parameter Rd, magnetic field parameter M and the volume fractions of nanoparticles ϕ1 and ϕ2 are increased, the local skin friction coefficient and the local Nusselt number are found to increase. Results revealed that the hybrid nanofluid (Cu-Al2O3/water) enhances the heat transfer about 28.28% in comparison to the Al2O3-water nanofluid and about 51.15% than the pure fluid. Contrary to this, the heat transfer of hybrid nanofluid is augmented about 41.76% than the Cu-water nanofluid and 71.41% than the base fluid. The streamlines and isotherms reveal that higher values of Ri, M and Rd delay the boundary layer separation and accordingly shrink the vortices. Moreover, the thermal boundary layer is thickened for the increment of aforesaid quantities. The surface temperature parameter augments the local skin friction coefficient, however, the reverse characteristic is observed for the local Nusselt number.

MHD Flow and Heat Transfer of Hybrid Nanofluid over an Exponentially Shrinking Surface with Heat Source/Sink

In nanotechnology research, nanofluid technology contributes many applications to engineering applications and industry, such as power generation, solar collection, heat exchangers for cooling, and many more. However, there are still a few constraints in terms of heat transfer enhancement, although nanofluid properties show the best heat transfer rate compared with conventional fluids. Thus, this study was conducted for the purpose of investigating the behaviors of flow and heat transfer of hybrid nanofluid with carbon nanotubes (CNTs) on a permeable exponentially shrinking surface, as well as investigating the effects of a magnetic field and heat source/sink. This study was conducted by developing a mathematical model, which was the Tiwari–Das model for momentum and energy equations, and then transforming the model’s partial differential equations (PDEs) to ordinary differential equations (ODEs) using a similarity solution. Next, these equations were solved numerically using the MATLAB bvp4c boundary value problem solver. The authors particularly explored these behaviors with a few variations. Based on the results obtained, it was found that dual solutions exist in a specific range of the shrinking case, λc<λ<−λ and that the critical point λc also exists in a range of −1.5 < λc < −1 with different parameters. For the heat source/sink effect, the Nusselt number was higher when heat sink case ε < 0, whereas it decreased when the heat source case ε > 0. Therefore, this study deduced that the heat transfer rate of hybrid nanofluid (CNTs/Cu–water) is better than regular nanofluid (CNT–water) and conventional fluid (water). The present study took into consideration the problem of MHD flow and heat transfer analysis of a hybrid nanofluid towards an exponentially shrinking surface with the presence of heat source/sink and thermal radiation effects. The authors show that dual solutions exist within a specific range of values due to the shrinking case. The current work is predicted to have numerous benefits in equivalent real-world systems.

Nanoparticle shape effect on the natural-convection heat transfer of hybrid nanofluid inside a U-shaped enclosure

The effect of nanoparticle shape on the natural-convection heat transfer of Cu-Al2O3-water hybrid nanofluid inside a U-shaped enclosure is presented in this paper. The governing equations are transformed into the dimensionless form using dimensionless variables. A three-node triangular finite element method is used with the Newton-Raphson method to solve the problem numerically. The streamlines and isotherms as well as the local and average Nusselt numbers are presented for the fluid-flow with Rayleigh number of 104 to 106. It is found that blade nanoparticle shape produces the highest heat transfer rate while sphere is the lowest.

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.