Influence of carbon nanotubes on heat transfer in MHD nanofluid flow over a stretchable rotating disk: A numerical study (original) (raw)
Related papers
Entropy, 2019
The impact of nonlinear thermal radiations rotating with the augmentation of heat transfer flow of time-dependent single-walled carbon nanotubes is investigated. Nanofluid flow is induced by a shrinking sheet within the rotating system. The impact of viscous dissipation is taken into account. Nanofluid flow is assumed to be electrically conducting. Similarity transformations are applied to transform PDEs (partial differential equations) into ODEs (ordinary differential equations). Transformed equations are solved by the homotopy analysis method (HAM). The radiative source term is involved in the energy equation. For entropy generation, the second law of thermodynamics is applied. The Bejan number represents the current investigation of non-dimensional entropy generation due to heat transfer and fluid friction. The results obtained indicate that the thickness of the boundary layer decreases for greater values of the rotation parameter. Moreover, the unsteadiness parameter decreases t...
International Communications in Heat and Mass Transfer, 2010
⎯A numerical study of a laminar mixed convection problem in a ventilated square cavity partially heated from bellow is carried out. The fluid in the cavity is a water-based nanofluid containing Cu nanoparticles. The effects of monitoring parameters, namely, Richardson number, Reynolds number, and solid volume fraction on the streamline and isotherm contours as well as average Nusselt number along the two heat sources are analyzed. The computation is performed for Richardson number ranging from 0.1 to 10, Reynolds number from 10 to 500, and the solid volume fraction from 0 to 0.1. The results show that by adding nanoparticles to the base fluid and increasing both Reynolds and Richardson numbers the heat transfer rate is enhanced. It is also found, regardless of the Richardson and Reynolds numbers, and the volume fraction of nanoparticles, the highest heat transfer enhancement occurs at the left heat source surface.
Mathematical Problems in Engineering
This article deals with carbon nanoliquid flow due to stretchable rotating disk with the effect of Cattaneo–Christov heat flux model. Both SWCNTs and MWCNTs are considered with ethylene glycol as the base fluid. The effects of nanoparticle volume friction, normally applied magnetic field, stretching factor, velocity, and thermal slip factors are examined. The fundamental flow governing equations are transformed into dimensionless system of coupled nonlinear ordinary differential equations, and they are solved numerically using spectral quasi-linearization method (SQLM). Employing graphs and tables, the results of velocity and temperature fields as well as skin friction coefficient and local heat transfer rate are analyzed and presented via embedded parameters. The results reveal that higher velocity fields and lower temperature fields are noticed in the MWCNT nanofluids than SWCNT nanofluids. The higher incidence of magnetic field improves the thermal boundary layer thickness. A gro...
Procedia Technology, 2014
Numerical investigation of heat transfer phenomena over an isothermal cylinder, for low Reynolds number flow of nanofluid is presented. Conservation equation of mass, momentum and energy under steady state have been solved using finite volume method. Heat transfer characteristic and flow over the stationary cylinder has been studied for water based copper nano fluid with different solid fraction values. Local Nusselt number over the cylinder surface has been found to increase with increase in nano particle fraction as well as increase in flow strength, though, the physics behind the rise in two cases is entirely different. Local heat flux drops along the cylinder wall and increases with increase in nano particle fraction as well as Reynolds number. Neglecting buoyancy effect, flow separation angle is not affected by presence of nano particles in the base fluid.
Solid metallic and non-metallic materials such as copper, silver, iron, alumina, copper oxide, Silicon carbide and carbon nanotubes have much higher thermal conductivities than fluids. Thermal conductivity of conventional heat transfer fluids can be improved by adding solid nanoparticles to fluids. The heat transfer enhancement of many industrial coolants by adding solid nanoparticles to liquids has attracted much attention in last few years. This work focuses on the satisfactory enhancement in heat transfer of industrial coolant by adding CNT nanoparticles (Sigma-Aldrich USA Product No. 636398). Many reports are available on studies of nanofluid at high temperature but practically none at lower temperature (below room temperature). In addition this work takes into account the change in flow properties of nanofluid due to temperature variation. Theoretical and numerical models have been proposed to predict the thermal conductivity and viscosity of nanofluid in the literature. The nanofluid heat transfer in laminar flow conditions have been explained in this study.
Scientific reports, 2017
This article investigates heat transfer enhancement in free convection flow of Maxwell nanofluids with carbon nanotubes (CNTs) over a vertically static plate with constant wall temperature. Two kinds of CNTs i.e. single walls carbon nanotubes (SWCNTs) and multiple walls carbon nanotubes (MWCNTs) are suspended in four different types of base liquids (Kerosene oil, Engine oil, water and ethylene glycol). Kerosene oil-based nanofluids are given a special consideration due to their higher thermal conductivities, unique properties and applications. The problem is modelled in terms of PDE's with initial and boundary conditions. Some relevant non-dimensional variables are inserted in order to transmute the governing problem into dimensionless form. The resulting problem is solved via Laplace transform technique and exact solutions for velocity, shear stress and temperature are acquired. These solutions are significantly controlled by the variations of parameters including the relaxatio...
International Journal of Numerical Methods for Heat & Fluid Flow, 2020
Purpose In this article, we consider the magnetohydrodynamic (MHD) nanofluid flow over a rotating stretchable disk through porous medium. For porous medium, Darcy’s relation is used. It also encompassed the impact of nanoparticles shape on MHD nanofluid flow and heat transfer. The effect of thermal radiation and Joule heating is also being considered. Design/methodology/approach Three categories of nanoparticles are taken into deliberation, i.e. copper, silver and titanium oxide. The nanofluid is made of pure water and various types of sphere- and lamina-shaped nanoparticles. By using appropriate similarity transformation, the governing partial differential equations are transformed to ordinary one. The coupled ordinary differential equations system is tackled numerically by bvp4c method. Findings The impact of various pertinent parameters, i.e. solid volume fraction, Hartman number, thermal radiations parameter, Reynolds number, Eckert number, porosity parameter and ratio parameter...
Numerical Modeling of Fluid Flow and Thermal Behavior of Different Nanofluids on a Rotating Disk
Heat Transfer-Asian Research, 2014
The thermal and velocity profiles of various nanofluid systems on a rotating disk are simulated. Finite difference method, the orthogonal collocation method, and the differential quadrature method (DQM) of numerical approaches are used to solve the governing equations and are compared to determine the faster and more accurate solution procedure. Five nanoparticles Al, Al 2 O 3 , Cu, CuO, and TiO 2 solved in three base fluids water, ethylene glycol, and engine oil are considered to be used on the disk at different volume fractions. A new general algorithm is presented for solving equations of a rotating-disk problem quickly and accurately and it is found that the DQM method is the best approach for this numerical simulation. Heat transfer performance of a rotating disk would be much better enhanced with water based Al nanofluid. A wide range of results for different base-fluid combinations with nanoparticles is presented with untransformed 3D results and effects of the variation of different parameters provides comprehensive insight and prevents inaccurate deductions.
Rotating Flow in a Nanofluid with CNT Nanoparticles over a Stretching/Shrinking Surface
Mathematics
The steady three-dimensional rotating flow past a stretching/shrinking surface in water and kerosene-based nanofluids containing single and multi-walled carbon nanotubes (CNTs) is investigated. The governing equations are converted to similarity equations, and then numerically solved using MATLAB software. The impacts of rotational, suction, and nanoparticle volume fraction on the flow and the thermal fields, as well as velocity and temperature gradients at the surface, are represented graphically and are analyzed. Further, the friction factor and the heat transfer rate for different parameters are presented in tables. It is found that the heat transfer rate increases with increasing nanoparticle volume fraction as well as suction parameter in water and kerosene-based nanofluids of single and multi-walled CNTs. However, the increment in the rotating flow parameter decreases the rate of heat transfer. Multi-walled carbon nanotubes and kerosene-based nanofluid contribute to heat trans...
Malaysian Journal of Applied Sciences, 2021
This study investigates the mathematical modelling of heat generation/absorption effect on the convective flow of single wall carbon nanotube-copper (SWCNT-Cu)/water hybrid nanofluid towards a stagnation point past a stretching sheet with Newtonian heating. The set of governing equations in the form of non-linear partial differential equations are first transform using the similarity transformation technique then solved numerically by the Runge-Kutta-Fehlberg (RKF45) method in Maple software. The numerical solutions were obtained for the surface temperature, the heat transfer coefficient and the skin friction coefficient as well as the velocity and the temperature profiles. The features of the flow and heat transfer characteristics for various values of the stretching parameter, the conjugate parameter, the nanoparticle volume fraction parameter and the heat source/sink parameter are analyzed and discussed. It is found that effects of hybrid nanoparticles are more significant for lo...