scholarly journals Effects of Second-Order Slip Flow and Variable Viscosity on Natural Convection Flow of CNTs − Fe 3 O 4 /Water Hybrid Nanofluids due to Stretching Surface

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Ayele Tulu ◽  
Wubshet Ibrahim
Keyword(s):  
Volume Fraction ◽  
Local Heat Transfer ◽  
Velocity Slip ◽  
Local Heat ◽  
Second Order ◽  
Hybrid Nanoparticles ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Hybrid Nanofluids ◽  
Dependent Viscosity

This study deals with natural convection unsteady flow of CNTs − Fe 3 O 4 /water hybrid nanofluids due to stretching surface embedded in a porous medium. Both hybrid nanoparticles of SWCNTs − Fe 3 O 4 and MWCNTs − Fe 3 O 4 are used with water as base fluid. Effects of hybrid nanoparticles volume friction, second-order velocity slip condition, and temperature-dependent viscosity are investigated. The governing problem of flow is solved numerically employing spectral quasilinearization method (SQLM). The results are presented and discussed via embedded parameters using graphs and tables. The results disclose that the thermal conductivity of CNTs − Fe 3 O 4 / H 2 O hybrid nanofluids is higher than that of CNTs − H 2 O nanofluids with higher value of hybrid nanoparticle volume fraction. Also, the results show that momentum boundary layer reduces while the thermal boundary layer gros with higher values of temperature-dependent viscosity and second-order velocity slip parameters. The skin friction coefficient improves, and the local heat transfer rate decreases with higher values of nanoparticle volume fraction, temperature-dependent viscosity, and second-order velocity slip parameters. Furthermore, more skin friction coefficients and lower local heat transfer rate are reported in the CNTs − Fe 3 O 4 / H 2 O hybrid nanofluid than in the CNTs − H 2 O nanofluid. Thus, the obtained results are promising for the application of hybrid nanofluids in the nanotechnology and biomedicine sectors.

Crosswise stream of methanol–iron oxide (CH3OH–Fe3O4) with temperature-dependent viscosity and suction/injection effects

2019 ◽  
Vol 233 (5) ◽  
pp. 1013-1023 ◽  
Author(s):  
Rabil Tabassum ◽  
R Mehmood
Keyword(s):  
Heat Transfer ◽  
Volume Fraction ◽  
Treatment Plant ◽  
Exponential Model ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Coating Materials ◽  
Similarity Transformations ◽  
Dependent Viscosity ◽  
Energy Equations

Manufacturing of modern coating materials doped with magnetic nanoparticles has arisen as an exciting new area of materials processing fluid dynamics. Methanol is primarily used in chemical manufacturing, specialized vehicles fuel, energy carrier, as an antifreeze in pipelines, in wastewater treatment plant, and many more. In this article, a mathematical model is therefore developed to study crosswise flow of methanol-based ferromagnetic fluid through a permeable medium with suction/injection effects. Temperature-dependent viscosity is taken with Reynolds exponential model. The Tiwari–Das and Maxwell–Garnett nanofluid models are used, which alters the electrical conductivity, density, and thermal conductivity properties with nanoparticle volume fraction. The two-dimensional mass, momentum, and energy equations are normalized into nonlinear system comprising ordinary differential equations via appropriate similarity transformations. The solution of the emerging physical problem is attained by shooting scheme in MATLAB symbolic software. Validation of the results is presented through comparison with previously reported literature in the limiting sense. The influence of pertinent parameters on the flow and heat transfer characteristics is revealed through graphs. It is found that velocity profiles are suppressed with greater magnetic parameter and porosity parameters but temperature profile is enhanced. Velocity and temperature profiles for injection case are higher when compared with the suction phenomenon. Shear stress at the wall is decreased with volume fraction. Heat transfer gradient at the wall is significantly enhanced with volume fraction.

Effects of Varying Viscosity and Mixed Convection on Nanotubes-water Flow With Reactions by a Stretching Cylinder: a Comparative Study

2021 ◽  
Author(s):  
Zakir Hussain ◽  
Tasawar Hayat ◽  
Ahmed Alsaedi
Keyword(s):  
Fluid Flow ◽  
Comparative Study ◽  
Mixed Convection ◽  
Heat Generation ◽  
Volume Fraction ◽  
Liquid Volume ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Magnetic Parameters ◽  
Dependent Viscosity

Abstract The addressed work explains SWCNT (Single walled carbon nanotubnes) and MWCNT (Multi walled carbon nanotubnes) nanofluid flow under the influences of temperature dependent viscosity and mixed convection. Comparative study of SWCN-T and MWCNT suspended in base liquid is presented. Further heat and mass transfer are addressed for nanofluid effected by radiation, heat generation/absorption and diffusion species. Mathematical development of problem is taken in cylindrical coordinates. System of highly nonlinear differential equations are constructed via appropriate transformations. The system of equations are tackled numerically by bvp4c MATLAB solver. The findings of the study show that volume fraction contributes to decline the fluid flow by cylindrical shaped nanoparticles. In addition, fluid flow decelerates via curvature and magnetic parameters while it boots by Grashof number and volume fraction. Further more, temperature dependent viscosity variable corresponds to decrease the temperature close to the surface and it develops away from the surface. The temperature advances in MWCNT-liquid than SWCNT-liquid. Volume fraction and magnetic parameters correspond to skin friction coefficient enhancement. Heat transfer rate increases for larger curvature and heat generation parameters and reverse trend holds against radiation parameter.

scholarly journals Numerical Study of Free Convection inside the Differentially Heated Cavity incorporating Variable Property Al2O3-H2O Nanofluid

2021 ◽  
Author(s):  
Bishwajit Sharma ◽  
◽  
Md. Feroz Alam ◽  
Mayur Krishna Bora ◽  
Rabindra Nath Barman ◽  
...  
Keyword(s):  
Free Convection ◽  
Volume Fraction ◽  
Numerical Study ◽  
Particle Diameter ◽  
Nano Particle ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Percentage Concentration ◽  
Prandtl Numbers ◽  
Dependent Viscosity

This paper investigates free convection in a partially heated square cavity filled with alumina-water nanofluid. The investigation is carried out at the three-volume fraction of nanoparticles (0, 0.03, 0.05), two Prandtl numbers (2.66, 6), and constant Grashof number (105) with three shapes of insulating obstacles (Square, Circular, and Rectangular). The results show that the nanofluid volume fraction and Prandtl number significantly enhance the heat transfer. The user-defined function (UDF) is developed and computed to investigate the effect of nanoparticle diameter and its temperature-dependent viscosity on convection. The average Nusselt number (Nu) increased with the temperature-dependent viscosity model and by increasing the percentage concentration of the nanoparticles. For all obstacle shapes, the thermal performance improved with increase in the nano-particle diameter.

Transient Magneto-Squeezing Flow of NaCl-CNP Nanofluid over a Sensor Surface Inspired by Temperature Dependent Viscosity

2018 ◽  
Vol 387 ◽  
pp. 600-614 ◽  
Author(s):  
Manoj Kumar Nayak ◽  
M. Mubashir Bhatti ◽  
Oluwole Daniel Makinde ◽  
Noreen Sher Akbar
Keyword(s):  
Volume Fraction ◽  
Variable Viscosity ◽  
Mhd Flow ◽  
Linearization Method ◽  
Squeeze Flow ◽  
Squeezing Flow ◽  
Sensor Surface ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Dependent Viscosity

Present study is to a great extent explains the time dependent squeezing magneto-hydrodynamic flow of Sodium Cloride-Carbon nanopowder nanofluid past a sensor surface. The current study is all about the influence of temperature dependent viscosity represented by Reynolds model and Vogel’s model on the MHD flow of the nanofluid considered. Successive Taylor series linearization method has been implemented in order to obtain the numerical solution of the transformed non-linear governing equations. It is very important to mention that irrespective of whether it is NaCl-Graphite or NaCl-Carbon Black or NaCl-Carbon nanopowder, the presence of magnetic field strength contributes the impede movement of the fluid while enhancement in the volume fraction, Reynolds model and Vogel’s model viscosity parameters exhibit the diametrically opposite trend. Keywords: NaCl-CNP nanofluid; MHD; Variable viscosity; Unsteady Squeeze flow; Sensor surface.

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