scholarly journals Mixed convective flow of CNTs nanofluid subject to varying viscosity and reactions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zakir Hussain ◽  
Tasawar Hayat ◽  
Ahmed Alsaedi ◽  
Muhammad Shoaib Anwar

AbstractThe addressed work explains SWCNTs (Single walled carbon nanotubnes) and MWCNTs (Multi walled carbon nanotubnes) nanofluid flow under the influences of temperature dependent viscosity and mixed convection. Comparative study of SWCNTs and MWCNTs 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 larger volume fraction $$\left( \phi \right)$$ ϕ contributes to enhance the nanoliquid flow. The velocity by submerging MWCNTs is noted higher than SWCNTs. Furthermore, the relationship between the viscosity variable $$\left( \theta _{r}\right)$$ θ r and the temperature is such that the temperature near the surface decreases with increase in $$\left( \theta _{r}\right)$$ θ r , while at the same time the temperature away from the surface increases. Subsequently, higher temperature is observed in SWCNTs-liquid compared to the MWCNTs-liquid to the similar values of $$\left( \theta _{r}\right)$$ θ r . Further, heat transfer is an increasing function of varying viscosity variable $$\left( \theta _{r}\right)$$ θ r .

Author(s):  
M. S. Alqarni ◽  
Hassan Waqas ◽  
Sumeira Yasmin ◽  
Taseer Muhammad

The prime aim of this investigation is to discuss the two-dimensional steady analysis of hybrid nanoliquids in the existence of magnetohydrodynamics (MHD), thermally radiation and viscous dissipation effects over a linear stretchable sheet. Carbon nanotubes (SWCNT and MWCNT) with copper (Cu) are comprised in the propylene glycol-based fluid. The significance of propylene glycol-based fluid is affected under the exponential space-based heat source phenomenon. The remarkable role of propylene glycol on thermal transport of hybrid nanoliquids is influenced in the presence of temperature-dependent viscosity. The highly nonlinear governing partial differential structures are reduced to nonlinear ODEs by using suitable transformations. The transformed nonlinear ODEs of flow problem have been solved numerically by employing bvp4c (shooting) scheme with Lobatto-IIIA formula in MATLAB. The physical outcomes of involved parameters are obtained by utilizing the graphical and tabular data. The heat transport rate and the skin friction under the numerical data are also presented. From the results, we concluded that the velocity of fluid is declined for higher nanoparticles volume fraction. Velocity of fluid is declined with growing magnetic parameter. Furthermore, the temperature is upgraded with the growing thermal Biot number.


2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Ayele Tulu ◽  
Wubshet Ibrahim

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.


Author(s):  
Rabil Tabassum ◽  
R Mehmood

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.


2021 ◽  
Author(s):  
Zeeshan Khan ◽  
Prof. Dr. Ilyas Khan

Abstract The convective heat and mass propagation inside dies are used to determine the characteristics of coated wire products. As a result, comprehending the properties of polymerization mobility, heat mass transport, and wall stress concentration is crucial. The wire coating procedure necessitates an increase in thermal performance. As a result, this research aims to determine how floating nanoparticles affect the mass and heat transport mechanisms of third-grade fluid in the posttreatment for cable coating processes. For nanofluids, the Buongiorno model is used, including variable viscosity. The model equations are developed using continuity, momentum, energy, and nanoparticle volume fraction concentration. We propose a few nondimensional transformations that are relevant. The numerical technique Runge-Kutta fourth method is used to generate numerical solutions for nonlinear systems. Pictorial depictions are used to observe the influence of various factors in the nondimensional flow, radiative, and nanoparticle concentration fields. Furthermore, the numerical results are also verified analytically using Homotopy Analysis Method (HAM). The analytical findings of this investigation revealed that within the Reynolds modeling, the stress on the whole wire surface combined with shear forces at the surface predominates Vogel's model. The contribution of nanomaterials upon force on the entire surface of wire and shear forces at the surface appears positive. A non-Newtonian feature can increase the capping substance's velocity. This research could aid in the advancement of wire coating technologies.For the first instance, the significance of nanotechnology during wire coating evaluation is explored utilizing Brownian motion with generation/absorption slip processes. For time-dependent viscosity, two alternative models are useful.


PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0249434
Author(s):  
Anwar Saeed ◽  
Wajdi Alghamdi ◽  
Safyan Mukhtar ◽  
Syed Imad Ali Shah ◽  
Poom Kumam ◽  
...  

The present article provides a detailed analysis of the Darcy Forchheimer flow of hybrid nanoliquid past an exponentially extending curved surface. In the porous space, the viscous fluid is expressed by Darcy-Forchheimer. The cylindrical shaped carbon nanotubes (SWCNTs and MWCNTs) and Fe3O4 (iron oxide) are used to synthesize hybrid nanofluid. At first, the appropriate similarity transformation is used to convert the modeled nonlinear coupled partial differential equations into nonlinear coupled ordinary differential equations. Then the resulting highly nonlinear coupled ordinary differential equations are analytically solved by the utilization of the “Homotopy analysis method” (HAM) method. The influence of sundry flow factors on velocity, temperature, and concentration profile are sketched and briefly discussed. The enhancement in both volume fraction parameter and curvature parameter k results in raises of the velocity profile. The uses of both Fe3O4 and CNTs nanoparticles are expressively improving the thermophysical properties of the base fluid. Apart from this, the numerical values of some physical quantities such as skin friction coefficients, local Nusselt number, and Sherwood number for the variation of the values of pertinent parameters are displayed in tabular forms. The obtained results show that the hybrid nanofluid enhances the heat transfer rate 2.21%, 2.1%, and 2.3% using the MWCNTs, SWCNTs, and Fe3O4 nanomaterials.


2021 ◽  
Author(s):  
Zakir Hussain ◽  
Tasawar Hayat ◽  
Ahmed Alsaedi

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.


2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Oluwole Makinde ◽  
Oswald Franks

AbstractThis study is devoted to investigate the effect of magnetic field on a reactive unsteady generalized Couette flow with temperature dependent viscosity and thermal conductivity. It is assumed that conducting incompressible fluid is subjected to an exothermic reaction under Arrhenius kinetics, neglecting the consumption of the material. The model nonlinear differential equations governing the transient momentum and energy balance are obtained and tackled numerically using a semi-discretization finite difference technique coupled with Runge-Kutta Fehlberg integration scheme. Important properties of the velocity and temperature fields including thermal stability conditions are presented graphically and discussed quantitatively.


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