393 publications from this institution
The objective of present attempt is to investigate electric field effect in Fe3O4–ethylene glycol nanomaterial force convective heat transfer. Viscosity of nanomaterial depends upon electric field effect. Relevant mathematical formulation is completed. Control volume based finite element method (CVFEM) is employed for the numerical simulation. Emphasis is given to the outcomes of nanofluid volume fraction, supplied voltage and Reynolds number. Clearly flow pattern depends upon supplied voltage and such effect for low Reynolds number is more sensible. Thermal layer thickness close to bottom is thinner for larger Reynolds number. Heat transfer rate is increasing function of both supplied voltage and Reynolds number.
Many phenomena in viscoelasticity, fluid mechanics, biology, chemistry, acoustics, control theory, psychology, and other areas of science can be successfully modeled by the use of fractional order derivatives. That is because of the fact that, a realistic modeling of a physical phenomenon having dependence not only at the time instant, but also the previous time history can be successfully achieved by using fractional calculus. Some mechanical problems such as eigenvalue problem, higher-order initial problems, fractional integro-differential equations, etc., the governing equations are some complicated and cannot be solved by the traditional differential transformation method (DTM). This chapter introduces DTM for advance problems and contains the following sections: 2.1 Introduction 2.2 Differential Transformation Method for Higher-Order Initial Value Problems 2.3 Fractional Differential Transform Method 2.4 Differential Transformation Method for Integro-Differential Equation 2.5 Differential Transformation Method for Eigenvalue Problems 2.6 Two-Dimensional Differential Transformation Method for Fractional Order Partial Differential Equations 2.7 Reduced Differential Transform Method 2.8 Modified Differential Transformation Method
In this paper, magneto-hydrodynamic (MHD) Jeffery–Hamel nanofluid flow in non-parallel walls is investigated analytically using different analytical methods. Different base fluids and nanoparticle are used. The effective thermal conductivity and viscosity of nanofluid are calculated by the Maxwell–Garnetts (MG) and Brinkman models, respectively. Comparison between Differential Transformation Method (DTM), DTM–Padé and Least square method (LSM) show that LSM is more accurate than other methods. The influence of the nanofluid volume friction, Reynolds number, Hartmann number and Angle of the channel on velocity profiles are investigated. Also it can be found that skin friction coefficient is an increasing function of Reynolds number, opening angle and nanoparticle volume friction but a decreasing function of Hartmann number.
No abstract is provided for this article.
In this study magnetohydrodynamic effect on natural convection heat transfer of Cu–water nanofluid in an enclosure with hot elliptic cylinder is investigated. The governing equations of fluid motion and heat transfer in their vorticity stream function form are used to simulate the nanofluid flow and heat transfer. Control Volume based Finite Element Method (CVFEM) is applied to solve these equations. The effective thermal conductivity and viscosity of nanofluid are calculated using the Maxwell–Garnetts (MG) and Brinkman models, respectively. The calculations are performed for different governing parameters such as the Hartmann number, Rayleigh number, nanoparticle volume fraction and inclined angle of inner cylinder. Also a correlation of average Nusselt number corresponding to active parameters is presented. The results indicate that Nusselt number is an increasing function of nanoparticle volume fraction, Rayleigh numbers and inclination angle while it is a decreasing function of Hartmann number. Also it can be found that increasing Rayleigh number leads to decrease heat transfer enhancement while opposite trend is observed with augment of Hartmann number.
Natural convection heat transfer is an important phenomenon in engineering and industry with widespread applications in diverse fields, such as geophysics, solar energy, electronic cooling, and nuclear energy. Nanofluid can be used to enhance rate of heat transfer. Two common methods can be used to simulate nanofluid flow and heat transfer: single-phase model and two-phase model. Influence of active parameters has been examined.
The thermal radiation has an important role in the overall surface heat transfer when the convection heat transfer coefficient is small. It is well known that the effect of thermal radiation is important in space technology and high temperature processes. Thermal radiation also plays an important role in controlling heat transfer process in polymer processing industry. In this chapter, nanofluid hydrothermal behavior in the presence of thermal radiation is investigated.
No abstract is provided for this article.
In this study natural convection heat transfer of Cu–water nanofluid in a cold outer circular enclosure containing a hot inner sinusoidal circular cylinder in the presence of horizontal magnetic field is investigated numerically using the Control Volume based Finite Element Method (CVFEM). Both circular enclosure and inner cylinder are maintained at constant temperature. The governing equations of fluid motion and heat transfer in their vorticity stream function form are used to simulate the fluid flow and heat transfer. The effective thermal conductivity and viscosity of nanofluid are calculated using the Maxwell–Garnetts (MG) and Brinkman models, respectively. The calculations were performed for different governing parameters such as the Hartmann number, Rayleigh number, values of the number of undulations of the inner cylinder and nanoparticle volume fraction. The results indicate that in the absence of magnetic field, enhancement ratio decreases as Rayleigh number increases while an opposite trend is observed in the presence of magnetic field. Also it is found that the average Nusselt number is an increasing function of nanoparticle volume fraction, the number of undulations and Rayleigh numbers while it is a decreasing function of Hartmann number.
Three dimensional problem of steady nanofluid deposition on an inclined rotating disk is illustrated. The important effects of Brownian motion and thermophoresis have been included in the model of nanofluid. The basic partial differential equations are reduced to ordinary differential equations which are solved numerically using the fourth-order Runge–Kutta method. The numerical investigation is carried out for different governing parameters namely: Normalized thickness, Schmidt number, Brownian parameter and thermophoretic parameter. Results show that Nusselt number is an increasing function of each active parameter. Latent heat has direct relationship with Schmidt number, Brownian parameter and thermophoretic parameter but it has reverse relationship with Normalized thickness.
No abstract is provided for this article.
This study is applied Lattice Boltzmann Method to investigate the natural convection flow utilizing nanofluids in a concentric annulus. A numerical strategy presents for dealing with curved boundaries of second order accuracy for both velocity and temperature fields. The fluid between the cylinders is a water-based nanofluid containing different types of nanoparticles: copper (Cu), alumina (Al2O3), titanium oxide (TiO2) and silver (Ag). The nanofluid is a two component mixture modeled as a single-phase incompressible fluid with the different thermophysical properties. This investigation compared with other experimental and found to be in excellent agreement. Result shows The type of nanofluid is a key factor for heat transfer enhancement. In this study the highest values of percentage of heat transfer enhancement are obtained when using silver nanoparticle.
In this research, second law and exergy analysis for nanofluid turbulent flow due to inserting modified turbulators has been studied. Nanofluid behavior is predicted via single phase model. Finite volume method is considered to model the governing equations. Exergy loss and second law performance were calculated for various values of revolution angle and Reynolds number. Also good correlations have been offered according to outputs. Results indicate that second law performance is an augmenting function of revolution angle. Exergy loss enhances with decrease of revolution angle and Reynolds number.
Impact of nanofluid natural convection due to magnetic field in existence of melting heat transfer is simulated using CVFEM in this research. KKL model is taken into account to obtain properties of CuO–H 2 O nanofluid. Roles of melting parameter ( δ ), CuO–H 2 O volume fraction ( ϕ ), Hartmann number (Ha), and Rayleigh (Ra) number are depicted in outputs. Results depict that temperature gradient improves with rise of Rayleigh number and melting parameter. Nusselt number detracts with rise of Ha. At the end, a comparison as a limiting case of the considered problem with the existing studies is made and found in good agreement.
CuOH2O nanofluid hydrothermal analysis in a complex geometry is presented using CVFEM. Brownian motion influence on properties of CuOH2O is considered. In order to eliminate pressure gradient source terms, vorticity stream function method has been applied. The homogenous model has been utilized for simulation of H2OCuO nanofluid. Effects of number of undulations, volume fraction of nanofluid and Rayleigh number on hydrothermal treatment are examined. Results indicate that temperature gradient enhances with augment of number of undulations.
