scholarly journals Entropy Analysis of Carbon Nanotubes Based Nanofluid Flow Past a Vertical Cone with Thermal Radiation

Entropy ◽  
2019 ◽  
Vol 21 (7) ◽  
pp. 642 ◽  
Author(s):  
Ramzan ◽  
Mohammad ◽  
Howari ◽  
Chung
Keyword(s):  
Carbon Nanotubes ◽  
Friction Coefficient ◽  
Differential Equations ◽  
Thermal Radiation ◽  
Skin Friction ◽  
Skin Friction Coefficient ◽  
Vertical Cone ◽  
Multi Walled Carbon Nanotubes ◽  
Mass Transfers ◽  
Walled Carbon Nanotubes

Our objective in the present study is to scrutinize the flow of aqueous based nanofluid comprising single and multi-walled carbon nanotubes (CNTs) past a vertical cone encapsulated in a permeable medium with solutal stratification. Moreover, the novelty of the problem is raised by the inclusion of the gyrotactic microorganisms effect combined with entropy generation, chemical reaction, and thermal radiation. The coupled differential equations are attained from the partial differential equations with the help of the similarity transformation technique. The set of conservation equations supported by the associated boundary conditions are solved numerically with the bvp4c MATLAB function. The influence of numerous parameters on the allied distributions is scrutinized, and the fallouts are portrayed graphically in the analysis. The physical quantities of interest including the skin friction coefficient and the rate of heat and mass transfers are evaluated versus essential parameters, and their outcomes are demonstrated in tabulated form. For both types of CNTs, it is witnessed that the velocity of the fluid is decreased for larger values of the magnetic and suction parameters. Moreover, the value of the skin friction coefficient drops versus the augmented bioconvection Rayleigh number. To corroborate the authenticity of the presented model, the obtained results (under some constraints) are compared with an already published paper, and excellent harmony is achieved in this regard.

scholarly journals Unsteady MHD Bionanofluid Flow in a Porous Medium with Thermal Radiation near a Stretching/Shrinking Sheet

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
M. Irfan ◽  
M. Asif Farooq ◽  
A. Mushtaq ◽  
Z. H. Shamsi
Keyword(s):  
Porous Medium ◽  
Friction Coefficient ◽  
Differential Equations ◽  
Thermal Radiation ◽  
Skin Friction ◽  
Internal Heat ◽  
Skin Friction Coefficient ◽  
Shrinking Sheet ◽  
Physical Parameters ◽  
The Impact

This research aims at providing the theoretical effects of the unsteady MHD stagnation point flow of heat and mass transfer across a stretching and shrinking surface in a porous medium including internal heat generation/absorption, thermal radiation, and chemical reaction. The fundamental principles of the similarity transformations are applied to the governing partial differential equations (PDEs) that lead to ordinary differential equations (ODEs). The transformed ODEs are numerically solved by the shooting algorithm implemented in MATLAB, and verification is done from MATLAB built-in solver bvp4c. The numerical data produced for the skin friction coefficient, the local Nusselt number, and the local Sherwood number are compared with the available result and found to be in a close agreement. The impact of involved physical parameters on velocity, temperature, concentration, and density of motile microorganisms profiles is scrutinized through graphs. It is analyzed that the skin friction coefficient enhances with increasing values of an unsteady parameter A , magnetic parameter M , and porosity parameter Kp . In addition, we observe that the density of a motile microorganisms profile enhances larger values of the bioconvection Lewis number Lb and Peclet number Pe and decreases with the increasing values of an unsteady parameter A .

Ohmic Heating of Magnetohydrodynamic Viscous Flow over a Continuous Moving Plate with Viscous Dissipation Buoyancy and Thermal Radiation

2019 ◽  
Vol 392 ◽  
pp. 73-91
Author(s):  
K.S. Adegbie ◽  
Damilare J. Samuel ◽  
Babatunde O. Ajayi
Keyword(s):  
Friction Coefficient ◽  
Differential Equations ◽  
Thermal Radiation ◽  
Skin Friction ◽  
Viscous Dissipation ◽  
Ohmic Heating ◽  
Mathematical Formulation ◽  
Skin Friction Coefficient ◽  
Radiative Heat Loss ◽  
Moving Plate

This study extends previous investigation on ohmic heating of magnetohydrodynamic viscous fluid flow over a continuous moving plate to include radiative heat-loss, viscous dissipation and buoyancy effects. The mathematical formulation representing the modified physical model involves a system of three partial differential equations, which are transformed into a system of two coupled non-linear ordinary differential equations using suitable dimensionless variables. Thereafter, the resulting dimensionless system of equations governing modified model are solved via Homotopy Analysis Method (HAM). The accuracy and convergence of solutions are validated by comparing the results obtained with those in literature and they are in good agreement. Parametric study is performed to illustrate the effects of emerging parameters on fluid velocity and temperature, skin friction coefficient and Nusselt number. It is found that the impacts of pertinent parameters due to the extensions are significant and these are presented in graphs and tables. The results indicate that the skin friction coefficient and the heat transfer rate increase with the increasing values of thermal radiation and decrease with the increasing value of viscous dissipation parameter.

scholarly journals Significance of Velocity Slip in Convective Flow of Carbon Nanotubes

Symmetry ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 679 ◽  
Author(s):  
Ali Saleh Alshomrani ◽  
Malik Zaka Ullah
Keyword(s):  
Carbon Nanotubes ◽  
Nusselt Number ◽  
Skin Friction ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Velocity Slip ◽  
Rotating Disk ◽  
Skin Friction Coefficient ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The present article inspects velocity slip impacts in three-dimensional flow of water based carbon nanotubes because of a stretchable rotating disk. Nanoparticles like single and multi walled carbon nanotubes (CNTs) are utilized. Graphical outcomes have been acquired for both single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). The heat transport system is examined in the presence of thermal convective condition. Proper variables lead to a strong nonlinear standard differential framework. The associated nonlinear framework has been tackled by an optimal homotopic strategy. Diagrams have been plotted so as to examine how the temperature and velocities are influenced by different physical variables. The coefficients of skin friction and Nusselt number have been exhibited graphically. Our results indicate that the skin friction coefficient and Nusselt number are enhanced for larger values of nanoparticle volume fraction.

Stability and statistical analysis on melting heat transfer in a hybrid nanofluid with thermal radiation effect

2021 ◽  
pp. 095440892110331
Author(s):  
Md Faisal Md Basir ◽  
Joby Mackolil ◽  
B Mahanthesh ◽  
Kottakkaran S Nisar ◽  
Taseer Muhammad ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Friction Coefficient ◽  
Differential Equations ◽  
Thermal Radiation ◽  
Skin Friction ◽  
Transfer Rate ◽  
Skin Friction Coefficient ◽  
Hybrid Nanofluid ◽  
Melting Heat ◽  
Melting Heat Transfer

The dual solutions for the stagnation point flow in a cobalt–CeO2/kerosene hybrid nanofluid with melting heat transfer and thermal radiation are analyzed. The partial differential equations are solved by the conversion of the partial differential equations into nonlinear ordinary differential equations by utilizing suitable scaling group transformations. Numerical solutions are obtained by employing the built-in function in the MATLAB software (bvp4c). Physically recoverable solutions are found employing stability analysis. The factor variables of interest (melting parameter, the nanoparticle volume fraction of cobalt and CeO2) are then further analyzed by utilizing the sensitivity analysis (based on the response surface methodology model) for heat transfer rate, as well as the skin friction coefficient. It is found that the heat transfer and skin friction tend to be significantly higher in a hybrid nanofluid due to the radiation and melting heat transfer. The lower branch is found to be unstable, whereas the upper branch is found to be stable. Also, the heat transfer rate and skin friction coefficient are found to be negatively sensitive toward the melting parameter. The model in this study can be applied for microscopic propulsion systems and the nano-electromechanical systems integrated with a nano-based system.

scholarly journals Comparison between multi-walled carbon nanotubes and titanium dioxide nanoparticles as additives on performance of turbine meter oil nano lubricant

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hadi Pourpasha ◽  
Saeed Zeinali Heris ◽  
Yaghob Mohammadfam
Keyword(s):  
Carbon Nanotubes ◽  
Titanium Dioxide ◽  
Friction Coefficient ◽  
Pressure Drop ◽  
Mass Fraction ◽  
Viscosity Index ◽  
Wear Depth ◽  
Nano Lubricant ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

AbstractThis research aims of compare the impact of the mass fraction of multi-walled carbon nanotubes (MWCNTs) and titanium dioxide (TiO2) nano additive on the tribological and thermophysical attributes of turbine meter oil. These attributes include the average friction coefficient, pressure drop, wear, flash point, pour point, relative viscosity, kinematics viscosity, and viscosity index. The pressure drops and the average friction coefficient inside the copper tube were simulated and compared with experimental results. In this study, for the synthesis of nano lubricants from turbine meter oil as a pure fluid and from MWCNTs and TiO2 as nano additives in the mass fraction of 0.05, 0.1, 0.2, 0.3, and 0.4 wt.% and from oleic acid and Triton x100 as surfactants were utilized. The results illustrated that the wear depth of copper pins in the presence of nano lubricant with 0.4 wt.% of MWCNTs and 0.1 wt.% TiO2 was improved by 88.26% and 71.43%, respectively. Increasing 0.3 wt.% of TiO2 and MWCNTs into the oil caused to improvement in viscosity index. The simulation data and experimental data for the pressure drop were closer together and indicated a minor error that the maximum error is less than 10%.

Entropy generation analysis in flow of thixotropic nanofluid

2019 ◽  
Vol 29 (12) ◽  
pp. 4507-4530 ◽  
Author(s):  
Muhammad Ijaz Khan ◽  
Salman Ahmad ◽  
Tasawar Hayat ◽  
M. Waleed Ahmad Khan ◽  
Ahmed Alsaedi
Keyword(s):  
Friction Coefficient ◽  
Differential Equations ◽  
Skin Friction ◽  
Entropy Generation ◽  
Hartmann Number ◽  
Convective Boundary Condition ◽  
Skin Friction Coefficient ◽  
Convective Boundary ◽  
Content Type ◽  
Flow Variables

Purpose The purpose of this paper is to address entropy generation in flow of thixotropic nonlinear radiative nanoliquid over a variable stretching surface with impacts of inclined magnetic field, Joule heating, viscous dissipation, heat source/sink and chemical reaction. Characteristics of nanofluid are described by Brownian motion and thermophoresis effect. At surface of the sheet zero mass flux and convective boundary condition are considered. Design/methodology/approach Considered flow problem is mathematically modeled and the governing system of partial differential equations is transformed into ordinary ones by using suitable transformation. The transformed ordinary differential equations system is figure out by homotopy algorithm. Outcomes of pertinent flow variables on entropy generation, skin friction, concentration, temperature, velocity, Bejan, Sherwood and Nusselts numbers are examined in graphs. Major outcomes are concluded in final section. Findings Velocity profile increased versus higher estimation of material and wall thickness parameter while it decays through larger Hartmann number. Furthermore, skin friction coefficient upsurges subject to higher values of Hartmann number and magnitude of skin friction coefficient decays via materials parameters. Thermal field is an increasing function of Hartmann number, radiation parameter, thermophoresis parameter and Eckert number. Originality/value The authors have discussed entropy generation in flow of thixotropic nanofluid over a variable thicked surface. No such consideration is yet published in the literature.

scholarly journals Stagnation-point flow past a shrinking sheet in a nanofluid

Open Physics ◽  
2011 ◽  
Vol 9 (5) ◽  
Author(s):  
Roslinda Nazar ◽  
Mihaela Jaradat ◽  
Norihan Arifin ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Friction Coefficient ◽  
Nonlinear System ◽  
Differential Equations ◽  
Skin Friction ◽  
Stagnation Point ◽  
Volume Fraction ◽  
Skin Friction Coefficient ◽  
Stagnation Point Flow ◽  
Shrinking Sheet

AbstractIn this paper, the stagnation-point flow and heat transfer towards a shrinking sheet in a nanofluid is considered. The nonlinear system of coupled partial differential equations was transformed and reduced to a nonlinear system of coupled ordinary differential equations, which was solved numerically using the shooting method. Numerical results were obtained for the skin friction coefficient, the local Nusselt number as well as the velocity and temperature profiles for some values of the governing parameters, namely the nanoparticle volume fraction φ, the shrinking parameter λand the Prandtl number Pr. Three different types of nanoparticles are considered, namely Cu, Al2O3 and TiO2. It was found that nanoparticles of low thermal conductivity, TiO2, have better enhancement on heat transfer compared to nanoparticles Al2O3 and Cu. For a particular nanoparticle, increasing the volume fraction φ results in an increase of the skin friction coefficient and the heat transfer rate at the surface. It is also found that solutions do not exist for larger shrinking rates and dual solutions exist when λ < −1.0.

scholarly journals Magnetohydrodynamic Flow and Heat Transfer Over an Exponentially Stretching/Shrinking Sheet in Ferrofluids

2021 ◽  
Vol 29 (3) ◽  
Author(s):  
Nurfazila Rasli ◽  
Norshafira Ramli
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Friction Coefficient ◽  
Differential Equations ◽  
Skin Friction ◽  
Skin Friction Coefficient ◽  
Magnetohydrodynamic Flow ◽  
Shrinking Sheet ◽  
Flow And Heat Transfer ◽  
Exponentially Stretching

In this research, the problem of magnetohydrodynamic flow and heat transfer over an exponentially stretching/shrinking sheet in ferrofluids is presented. The governing partial differential equations are transformed into nonlinear ordinary differential equations by applying suitable similarity transformations. These equations are then solved numerically using the shooting method for some pertinent parameters. For this research, the water-based ferrofluid is considered with three types of ferroparticles: magnetite, cobalt ferrite, and manganese-zinc ferrite. The numerical solutions on the skin friction coefficient, Nusselt number, velocity and temperature profiles influenced by the magnetic parameter, wall mass transfer parameter, stretching/shrinking parameter, and volume fraction of solid ferroparticle are graphically displayed and discussed in more details. The existences of dual solutions are noticeable for the stretching/shrinking case in a specific range of limit. For the first solution, an increasing number in magnetic and suction will also give an increment of skin friction coefficient and Nusselt number over stretching/shrinking sheet. For the skin friction coefficient only, it is showed a decreasing pattern after the intersection. Besides, the presence of ferroparticles in the fluids causes a high number of the fluid’s thermal conductivity and heat transfer rate.

scholarly journals Micropolar ferrofluid flow via natural convective about a radiative isoflux sphere

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199439
Author(s):  
Saber EL-Kabeir ◽  
Ahmed Rashad ◽  
Waqar Khan ◽  
Zeinab Mahmoud Abdelrahman
Keyword(s):  
Nusselt Number ◽  
Friction Coefficient ◽  
Thermal Radiation ◽  
Skin Friction ◽  
Magnetic Force ◽  
Volume Fraction ◽  
Skin Friction Coefficient ◽  
Temperature Fields ◽  
Partial Slip ◽  
Convection Flow

Current investigation scrutinizes the magnetohydrodynamic (MHD) natural convection flow of micropolar ferrofluid across an isoflux sphere with the impacts of thermal radiation and partial slip. Cobalt-nanoparticles with kerosene as the base fluid are considered. The governing partial differential conservation equations and convenient boundary conditions are rendered into a nondimensional form. The finite difference method (FDM) is then applied to determine the solution of a collection of resultant equations. The outcomes obtained by FDM have also compared with cited investigation. Illustrations describing influences of prominent parameters which provides physical interpretations of velocity, angular velocity, and temperature fields as well as the skin friction coefficient and Nusselt number are examined in detail with the help of graphical representations. This investigation determined that the skin-friction coefficient and heat transport rate reduced along with augmentation in the magnetic force and micropolar parameter, while opposite performance is adhered with elevating in the thermal radiation. Moreover, the boosted nanoparticle volume fraction reduced the skin friction coefficient and improved the Nusselt number.

scholarly journals Comparison between multi-walled carbon nanotubes and Titanium dioxide nanoparticles as additives on performance of Turbine meter oil nano lubricant

2020 ◽  
Author(s):  
Hadi Pourpasha ◽  
Saeed Zeinali Heris ◽  
Yaghob Mohammadfam
Keyword(s):  
Carbon Nanotubes ◽  
Titanium Dioxide ◽  
Friction Coefficient ◽  
Pressure Drop ◽  
Mass Fraction ◽  
Viscosity Index ◽  
Nano Lubricant ◽  
Multi Walled Carbon Nanotubes ◽  
Nano Additives ◽  
Walled Carbon Nanotubes

Abstract This research work purpose to compare the impact of the mass fraction of multi-walled carbon nanotubes (MWCNTs) and Titanium dioxide (TiO2) nano additive on the tribological and thermophysical attributes of turbine meter oil. These attributes are including the average friction coefficient, pressure drop, wear, flash point, pour point, relative viscosity, kinematics viscosity, and viscosity index. Also, the pressure drops and the average friction coefficient inside the copper tube were simulated and compared with experimental results. In this study, for the synthesis of nano lubricants from turbine meter oil as a pure fluid and from MWCNTs and TiO2 as nano additives in the mass fraction of 0.05, 0.1, 0.2, 0.3, and 0.4 wt.% and from oleic acid and Triton x100 as surfactants were utilized. The diameter of MWCNTs and TiO2 nano additives were ranging from 5 nm to 16.1 nm and 7.9 nm to 13.9 nm, respectively. The average particle size of TiO2 and MWCNTs nano additives in 0.4 wt.% in the pure lubricant were 221 nm and 320 nm, respectively. The results illustrated that the wear depth of copper pins in the presence of nano lubricant with 0.4 wt.% of MWCNTs and 0.1 wt.% TiO2 was improved by 88.26% and 71.43%, respectively. Nano lubricants with 0.3 wt.% of TiO2 and 0.4 wt.% of MWCNTs nano additives illustrated the maximum improvement in the flash point temperature with enhancement 4 °C and 10 °C. By increasing of 0.3 wt.% of TiO2 and MWCNTs into the pure oil caused to improve in viscosity index with enhancement 6.68% and 2.43% compared to the pure lubricant, respectively. The simulation data and experimental data for the pressure drop were closer together and indicated a minor error that the maximum error is less than 10%.

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