Computational analysis of water based Cu - Al2O3/H2O flow over a vertical wedge

Theoretical and numerical investigation of the fluctuating mixed convection of hybrid nanofluid flow over a vertical Riga wedge is considered in this analysis. Two kinds of solid nanoparticles with base fluid at vertical Riga wedge is studied. Thermal and velocity slip impacts on vertical Riga wedge are investigated in the current study. We discussed both the unsteady and steady cases. The water has low thermal conductivity. We added the nanoparticle [Formula: see text] and [Formula: see text] which increases the thermal conductivity of the base fluid. This phenomena increase the heat transfer rate at the surface Riga plate. Partial differential equations are reduced into an ordinary differential equation by means of dimensionless similarity variables. The resulting ordinary differential equations are further solved through numerical and perturbation methods. Thickness of momentum boundary layer is reduced because of the solid nanoparticle rises in all cases of [Formula: see text], [Formula: see text], [Formula: see text]and[Formula: see text]. Our results are more agreeing with the decay results of Bachok et al. and Yacob et al. when rest of the physical parameters dimensions.

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Approximate Analytical Analysis of Unsteady MHD Mixed Flow of Non-Newtonian Hybrid Nanofluid over a Stretching Surface

Fluids ◽

10.3390/fluids6040138 ◽

2021 ◽

Vol 6 (4) ◽

pp. 138

Author(s):

Ali Rehman ◽

Zabidin Salleh

Keyword(s):

Heat Transfer ◽

Differential Equations ◽

Base Fluid ◽

Research Work ◽

Hybrid Nanofluid ◽

Stretching Surface ◽

Optimal Homotopy Analysis Method ◽

Analytical Analysis ◽

Transfer Ratio ◽

The Impact

This paper analyses the two-dimensional unsteady and incompressible flow of a non-Newtonian hybrid nanofluid over a stretching surface. The nanofluid formulated in the present study is TiO2 + Ag + blood, and TiO2 + blood, where in this combination TiO2 + blood is the base fluid and TiO2 + Ag + blood represents the hybrid nanofluid. The aim of the present research work is to improve the heat transfer ratio because the heat transfer ratio of the hybrid nanofluid is higher than that of the base fluid. The novelty of the recent work is the approximate analytical analysis of the magnetohydrodynamics mixed non-Newtonian hybrid nanofluid over a stretching surface. This type of combination, where TiO2+blood is the base fluid and TiO2 + Ag + blood is the hybrid nanofluid, is studied for the first time in the literature. The fundamental partial differential equations are transformed to a set of nonlinear ordinary differential equations with the guide of some appropriate similarity transformations. The analytical approximate method, namely the optimal homotopy analysis method (OHAM), is used for the approximate analytical solution. The convergence of the OHAM for particular problems is also discussed. The impact of the magnetic parameter, dynamic viscosity parameter, stretching surface parameter and Prandtl number is interpreted through graphs. The skin friction coefficient and Nusselt number are explained in table form. The present work is found to be in very good agreement with those published earlier.

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Synthesis of hybrid nanofluid with two-step method

E3S Web of Conferences ◽

10.1051/e3sconf/20186703057 ◽

2018 ◽

Vol 67 ◽

pp. 03057 ◽

Cited By ~ 1

Author(s):

Wayan Nata Septiadi ◽

Ida Ayu Nyoman Titin Trisnadewi ◽

Nandy Putra ◽

Iwan Setyawan

Keyword(s):

Thermal Conductivity ◽

Base Fluid ◽

Volume Fraction ◽

Heat Transfer Fluid ◽

Hybrid Nanofluid ◽

Test Results ◽

Step Method ◽

Fluid Mixture ◽

High Level ◽

Better Than

Nanofluid is a liquid fluid mixture with a nanometer-sized solid particle potentially applied as a heat transfer fluid because it is capable of producing a thermal conductivity better than a base fluid. However, nanofluids have a weakness that is a high level of agglomeration as the resulting conductivity increases. Therefore, in this study, the synthesis of two nanoparticles into the base fluid called hybrid nanofluids. This study aims to determine the effect of nanoparticle composition on the highest thermal conductivity value with the lowest agglomeration value. This research was conducted by dispersing Al2O3-TiO2 nanoparticles in water with volume fraction of 0.1%, 0.3%, 0.5%, 0.7% in the composition of Al2O3-TiO2 ratio of 75%:25%, 50%:50%, 25%:75%. The synthesis was performed with a magnetic stirrer for 30 minutes. The tests were carried out in three types: thermal conductivity testing with KD2, visual agglomeration observation and absorbance measurements using UV-Vis, wettability testing with HSVC tools and Image applications. The test results showed that the ratio composition ratio of 75% Al2O3-25% TiO2 with a volume fraction of 0.7% resulted in an increase in optimum thermal conductivity with the best wettability and the longest agglomeration level.

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Thermal conductivity enhancement in gold decorated graphene nanosheets in ethylene glycol based nanofluid

Scientific Reports ◽

10.1038/s41598-020-71740-1 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

M. C. Mbambo ◽

M. J. Madito ◽

T. Khamliche ◽

C. B. Mtshali ◽

Z. M. Khumalo ◽

...

Keyword(s):

Thermal Conductivity ◽

Ethylene Glycol ◽

Base Fluid ◽

Graphene Nanosheets ◽

Synthesis Method ◽

Particle Diameter ◽

Laser Wavelength ◽

Hybrid Nanofluid ◽

Average Particle ◽

Conductivity Enhancement

Abstract We report on the synthesis and thermal conductivity of gold nanoparticles (AuNPs) decorated graphene nanosheets (GNs) based nanofluids. The GNs-AuNPs nanocomposites were synthesised using a nanosecond pulsed Nd:YAG laser (wavelength = 1,064 nm) to ablate graphite target followed by Au in ethylene glycol (EG) base fluid to obtain GNs-AuNPs/EG hybrid nanofluid. The characterization of the as-synthesised GNs-AuNPs/EG hybrid nanofluid confirmed a sheet-like structure of GNs decorated with crystalline AuNPs with an average particle diameter of 6.3 nm. Moreover, the AuNPs appear smaller in the presence of GNs which shows the advantage of ablating AuNPs in GNs/EG. The thermal conductivity analysis in the temperature range 25–45 °C showed that GNs-AuNPs/EG hybrid nanofluid exhibits an enhanced thermal conductivity of 0.41 W/mK compared to GNs/EG (0.35 W/mK) and AuNPs/EG (0.39 W/mK) nanofluids, and EG base fluid (0.33 W/mK). GNs-AuNPs/EG hybrid nanofluid displays superior enhancement in thermal conductivity of up to 26% and this is due to the synergistic effect between AuNPs and graphene sheets which have inherent high thermal conductivities. GNs-AgNPs/EG hybrid nanofluid has the potential to impact on enhanced heat transfer technological applications. Also, this work presents a green synthesis method to produce graphene-metal nanocomposites for various applications.

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Unsteady Stagnation Point Flow of Hybrid Nanofluid Past a Convectively Heated Stretching/Shrinking Sheet with Velocity Slip

Mathematics ◽

10.3390/math8101649 ◽

2020 ◽

Vol 8 (10) ◽

pp. 1649

Author(s):

Nurul Amira Zainal ◽

Roslinda Nazar ◽

Kohilavani Naganthran ◽

Ioan Pop

Keyword(s):

Heat Transfer ◽

Differential Equations ◽

Skin Friction ◽

Stagnation Point ◽

Volume Fraction ◽

Velocity Slip ◽

Slip Condition ◽

Stagnation Point Flow ◽

Shrinking Sheet ◽

Hybrid Nanofluid

Unsteady stagnation point flow in hybrid nanofluid (Al2O3-Cu/H2O) past a convectively heated stretching/shrinking sheet is examined. Apart from the conventional surface of the no-slip condition, the velocity slip condition is considered in this study. By incorporating verified similarity transformations, the differential equations together with their partial derivatives are changed into ordinary differential equations. Throughout the MATLAB operating system, the simplified mathematical model is clarified by employing the bvp4c procedure. The above-proposed approach is capable of producing non-uniqueness solutions when adequate initial assumptions are provided. The findings revealed that the skin friction coefficient intensifies in conjunction with the local Nusselt number by adding up the nanoparticles volume fraction. The occurrence of velocity slip at the boundary reduces the coefficient of skin friction; however, an upward trend is exemplified in the rate of heat transfer. The results also signified that, unlike the parameter of velocity slip, the increment in the unsteady parameter conclusively increases the coefficient of skin friction, and an upsurge attribution in the heat transfer rate is observed resulting from the increment of Biot number. The findings are evidenced to have dual solutions, which inevitably contribute to stability analysis, hence validating the feasibility of the first solution.

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Radiative Boundary Layer Flow of Casson Fluid Over an Exponentially Permeable Slippery Riga Plate with Viscous Dissipation

Journal of Advanced Research in Applied Sciences and Engineering Technology ◽

10.37934/araset.21.1.4151 ◽

2020 ◽

Vol 21 (1) ◽

pp. 41-51

Author(s):

Nur Syamila Yusof ◽

Siti Khuzaimah Soid ◽

Mohd Rijal Illias ◽

Ahmad Sukri Abd Aziz ◽

Nor Ain Azeany Mohd Nasir

Keyword(s):

Magnetic Field ◽

Boundary Layer ◽

Differential Equations ◽

Viscous Dissipation ◽

Velocity Slip ◽

Casson Fluid ◽

Numerical Results ◽

Thermal Slip ◽

Slip Parameter ◽

Riga Plate

This study is aimed to analyze the steady of stagnation point flow and radiative heat transfer of a non-Newtonian fluid which is Casson fluid passing over an exponentially permeable slippery Riga plate in presence of thermal radiation, magnetic field, velocity slip, thermal slip, and viscous dissipation effects. The governing partial differential equations are transformed into ordinary differential equations by using similarity transformation then solved numerically by boundary value problem solver (BVP4C) in MATLAB software package. The numerical results are evaluated with previous researches to reach an agreement with the parameters of the current study. This study is discussing the behavior of the velocity and temperature profiles as well as skin friction coefficient and local Nusselt number for various physical parameters such as magnetic field, radiation, suction, thermal slip, velocity slip, Prandtl number, Eckert number and modified Hartmann number. Numerical results are shown graphically for each parameter with different values. It is found that the momentum boundary layer thickness increases with increasing the values of Casson parameter. The temperature decreases when the velocity slip parameter and thermal slip parameter are increased.

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Radiative Magnetohydrodynamics Casson Nanofluid Flow and Heat and Mass Transfer past on Nonlinear Stretching Surface

10.3762/bxiv.2021.65.v1 ◽

2021 ◽

Author(s):

Gurrala Thirupathi ◽

Kamatam Govardhan ◽

Ganji Narender

Keyword(s):

Differential Equations ◽

Velocity Slip ◽

Convective Boundary Condition ◽

Skin Friction Coefficient ◽

Physical Parameters ◽

Stretching Surface ◽

Nanofluid Flow ◽

Convective Boundary ◽

Casson Nanofluid ◽

Order Four

The magnetohydrodynamics (MHD) stagnation point Casson nanofluid flow towards stretching surface with velocity slip and convective boundary condition has been investigated in this article. Effects of thermal radiation, viscous dissipation, heat source and chemical reaction have also been incorporated. Using appropriate similarity transformation Partial Differential Equations (PDEs) are converted into Ordinary Differential Equations (ODEs) and shooting technique along with Adams–Moulton method of order four has been used to obtain the numerical results. Different physical parameters effects on velocity, temperature and concentration of nanofluid flow have been presented graphically and discussed in detail. Numerical values of the skin friction coefficient, Nusselt number and Sherwood number are also and discussed.

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Role of Brownian Motion and Thermophoresis Effects on Hydromagnetic Flow of Nanofluid Over a Nonlinearly Stretching Sheet with Slip Effects and Solar Radiation

International Journal of Applied Mechanics and Engineering ◽

10.2478/ijame-2019-0031 ◽

2019 ◽

Vol 24 (3) ◽

pp. 489-508

Author(s):

S.P. Anjali Devi ◽

S. Mekala

Keyword(s):

Brownian Motion ◽

Differential Equations ◽

Stretching Sheet ◽

Volume Fraction ◽

Nonlinear Partial Differential Equations ◽

Velocity Slip ◽

Physical Parameters ◽

Nonlinear Thermal Radiation ◽

Hydromagnetic Flow ◽

Nonlinearly Stretching Sheet

Abstract Hydromagnetic flow of water based nanofluids over a nonlinearly stretching sheet in the presence of velocity slip, temperature jump, magnetic field, nonlinear thermal radiation, thermophoresis and Brownian motion has been studied. The article focuses on Cu water nanofluid and Ag water nanofluid. The similarity transformation technique is adopted to reduce the governing nonlinear partial differential equations into nonlinear ordinary differential equations and then they are solved numerically utilizing the Nachistem – Swigert shooting method along with the fourth order Runge Kutta integration technique. The influence of physical parameters on the flow, temperature and nanoparticle volume fraction are presented through graphs. Also the values of the skin friction coefficient at the wall and nondimensional rate of heat transfer are given in a tabular form. A comparative study with previous published results is also made.

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Entropy Generation in Cu-Al2O3-H2O Hybrid Nanofluid Flow over a Curved Surface with Thermal Dissipation

Entropy ◽

10.3390/e21100941 ◽

2019 ◽

Vol 21 (10) ◽

pp. 941 ◽

Cited By ~ 10

Author(s):

Muhammad Idrees Afridi ◽

Tawfeeq Abdullah Alkanhal ◽

Muhammad Qasim ◽

Iskander Tlili

Keyword(s):

Differential Equations ◽

Entropy Generation ◽

Numerical Results ◽

Curvilinear Coordinates ◽

Curved Surface ◽

Thermal Dissipation ◽

Solid Boundary ◽

Radius Of Curvature ◽

Physical Parameters ◽

Hybrid Nanofluid

Heat transfer and entropy generation in a hybrid nanoliquid flow caused by an elastic curved surface is investigated in the present article. To examine the effects of frictional heating on entropy generation, the energy dissipation function is included in the energy equation. The Tiwari and Dass model for nanofluid is used by taking water as a base fluid. A new class of nanofluid (hybrid nanofluid) with two kinds of nanoparticles, Copper (Cu) and Aluminum oxide (Al2O3), is considered. Curvilinear coordinates are used in the mathematical formulation due to the curved nature of the solid boundary. By utilizing similarity transformations, the modelled partial differential equations are converted into ordinary differential equations. Shooting and the Runge-Kutta-Fehlberg method (FRKM) have been used to solve the transformed set of non-linear differential equations. The expression for entropy generation is derived in curvilinear coordinates and computed by using the numerical results obtained from dimensionless momentum and energy equations. Comparisons of our numerical results and those published in the previous literature demonstrate excellent agreements, validating our numerical simulation. In addition, we have also conducted parametric studies and find that entropy generation and temperature suppress with increasing values of dimensionless radius of curvature. Furthermore, it is found that less entropy is generated in regular nanofluid as compare to hybrid nanofluid. To examine the influences of a set of embedding physical parameters on quantities of interest, different graphs are plotted and discussed.

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Effects of Oil-Based Nanofluid on a Stretching Surface with Variable Suction and Thermal Conductivity

Diffusion Foundations ◽

10.4028/www.scientific.net/df.11.99 ◽

2017 ◽

Vol 11 ◽

pp. 99-109 ◽

Cited By ~ 2

Author(s):

Christian John Etwire ◽

Ibrahim Yakubu Seini ◽

Rabiu Musah

Keyword(s):

Thermal Conductivity ◽

Boundary Layer ◽

Differential Equations ◽

Ordinary Differential Equations ◽

Base Fluid ◽

Stretching Surface ◽

Third Order ◽

Suction Parameter ◽

Layer Flow ◽

Porous Stretching Surface

The combined effect of suction and thermal conductivity on the boundary layer flow of oil–based nanofluid over a porous stretching surface has been investigated. Similarity techniques were employed in transforming the governing partial differential equations into a coupled third order ordinary differential equations. The higher third order ordinary differential equations were then reduced into a system of first order ordinary differential equations and solved numerically using the fourth order Runge-Kutta algorithm with a shooting method. The results were presented in tabular and graphically forms for various controlling parameters. It was found that increasing the thermal conductivities of the base fluid (oil) and nanoparticle size (CuO) of the nanofluid did not affect the velocity boundary layer thickness but depreciates with suction and permeability. The suction parameter and thermal conductivity of the base fluid also made the thermal boundary layer thinner.

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Dual solution of boundary-layer flow driven by variable plate and streaming-free velocity

Advances in Mechanical Engineering ◽

10.1177/1687814020930849 ◽

2020 ◽

Vol 12 (7) ◽

pp. 168781402093084

Author(s):

M Ferdows ◽

Faris Alzahrani ◽

Shuyu Sun

Keyword(s):

Heat Transfer ◽

Thermal Conductivity ◽

Boundary Layer ◽

Differential Equations ◽

Skin Friction ◽

Numerical Study ◽

Velocity Ratio ◽

Dual Solutions ◽

Physical Parameters ◽

Branch Solution

This article presents a numerical study to investigate boundary-layer heat transfer fluid associated with a moving flat body in cooperation of variable plate and streaming-free velocity along the boundary surface in the laminar flow. The thermal conductivity is supposed to vary linearly with temperature. Similarity transformations are applied to render the governing partial differential equations for mass, momentum and energy into a system of ordinary differential equations to reveal the possible existence of dual solutions. MATLAB package has been used to solve the boundary value problem numerically. We present the effects of various parameters such as velocity ratio, thermal conductivity and variable viscosity on velocity and temperature distribution. The analysis of the results concerning Skin friction and Nusselt number near the wall is also presented. It is focused on the detection and description of the dual solutions. The study reveals that the undertaken problem admits dual solutions in particular range of values of different physical parameters. It can be seen that for the first branch solution, the fluid velocity decreases near the sheet, but it increases far away from the sheet for velocity ratio parameter, whereas the opposite effect is induced for second branch solution. Skin friction coefficient and rate of heat transfer increase due to increase in thermal conductivity parameter.

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