S.M. Seyyedi

Bio: S.M. Seyyedi is an academic researcher from Islamic Azad University. The author has contributed to research in topics: Nusselt number & Rayleigh number. The author has an hindex of 13, co-authored 25 publications receiving 745 citations. Previous affiliations of S.M. Seyyedi include Babol Noshirvani University of Technology.

Natural convection of nanofluids in an enclosure between a circular and a sinusoidal cylinder in the presence of magnetic field

Abstract: 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.

Application of LBM in simulation of natural convection in a nanofluid filled square cavity with curve boundaries

Abstract: A two-dimensional numerical study has been performed to investigate natural convection in a square cavity with curve boundaries filled with Cu–water nanofluid. Lattice Boltzmann Method (LBM) is used to simulate this problem. The effective thermal conductivity and viscosity of nanofluid are calculated by the Maxwell–Garnetts (MG) and Brinkman models, respectively. This investigation was compared with other numerical methods and was found to be in excellent agreement. Effects of nanoparticle volume fraction, Rayleigh numbers and inclination angle on flow and heat transfer are considered. The results proved that the change of inclination angle has a significant impact on the thermal and hydrodynamic flow fields. Also it can be found that maximum values of enhancement are obtained at Ra = 103 and Ra = 105 for γ > 0° and γ

CVFEM analysis for Fe3O4–H2O nanofluid in an annulus subject to thermal radiation

Abstract: Colloidal nanoparticles suspensions (nanofluids) are the materials of consideration for thermal engineering due to their typically enhanced heat transportation characteristics in comparison to base liquid. Nanoliquids have utilizations in transportation, solar absorption, nuclear systems chilling, friction reduction and energy storage etc. Besides, magnetic nanoliquids are utilized in the cancer therapeutics via implementation of drug delivery and cancer imaging. Thus, in view of such utilizations, here modeling and simulations are presented to scrutinize the natural convective Fe 3 O 4 -water nanoliquid flow in an annulus between a triangle and a rhombus enclosures. Thermal radiation aspect is considered for formulation. CVFEM is implemented for computations of numerical outcomes. Impacts of embedding variables on the flow and heat transfer features have been perused. Furthermore a correlation for average Nusselt number is established in terms of energetic parameters. The obtained results portray that average Nusselt number rises subjected to Rayleigh number, radiation parameter and volume fraction of nanofluid while it diminishes when Hartmann number is increased.

Radiative nanofluid flow and heat transfer between parallel disks with penetrable and stretchable walls considering Cattaneo–Christov heat flux model

Abstract: Young Researchers and Elite Club, Aliabad Katoul Branch, Islamic Azad University, Aliabad Katoul, Iran Mechanical Engineering Department, Prince Sultan Endowment for Energy and Environment, Prince Mohammad Bin Fahd University, Al-Khobar, 31952, Saudi Arabia RAK Research and Innovation Center, American University of Ras Al Khaimah, Ras Al Khaimah, United Arab Emirates Department of Mechanical Engineering, Aliabad Katoul Branch, Islamic Azad University, Aliabad Katoul, Iran Mechanical Engineering Department, Babol Noshirvani University of Technology, Babol, Iran Correspondence A.S. Dogonchi, Young Researchers and Elite Club, Aliabad Katoul Branch, Islamic Azad University, Aliabad Katoul, Iran. Email: Sattar.Dogonchi@yahoo.com Abstract In this work, we explore the unsteady squeezing flow and heat transfer of nanofluid between two parallel disks in which one of the disks is penetrable and the other is stretchable/shrinkable, in the presence of thermal radiation and heat source impacts, and considering the Cattaneo–Christov heat flux model instead of the more conventional Fourier's law of heat conduction. A similarity transformation is utilized to transmute the governing momentum and energy equations into nonlinear ordinary differential equations with the proper boundary conditions. The achieved nonlinear ordinary differential equations are solved by the Duan–Rach Approach (DRA). This method modifies the standard Adomian Decomposition Method by evaluating the inverse operators at the boundary conditions directly. The impacts of diverse active parameters, such as the suction/injection parameter, the solid volume fraction, the heat source parameter, the thermal relaxation parameter,

Natural convection heat transfer under constant heat flux wall in a nanofluid filled annulus enclosure

Abstract: In this investigation, the Control Volume based Finite Element Method (CVFEM) is used to simulate the natural convection heat transfer of Cu–water nanofluid in an annulus enclosure. The Maxwell–Garnetts (MG) and Brinkman models are also employed to estimate the effect of thermal conductivity and viscosity of nanofluid. The governing parameters are the Rayleigh number, nanoparticle volume fraction and the aspect ratio (ratio of the outer radius to the inner one). Results are presented in the form of isotherms, streamlines, local and average Nusselt numbers. The results indicate that increment of the aspect ratio increases the value of average Nusselt number. Moreover, the angle of turn for the boundary condition of the inner cylinder significantly affects the values of local Nusselt number, average Nusselt number, streamlines and isotherms.

A review on the visible light active titanium dioxide photocatalysts for environmental applications

Abstract: Fujishima and Honda (1972) demonstrated the potential of titanium dioxide (TiO2) semiconductor materials to split water into hydrogen and oxygen in a photo-electrochemical cell. Their work triggered the development of semiconductor photocatalysis for a wide range of environmental and energy applications. One of the most significant scientific and commercial advances to date has been the development of visible light active (VLA) TiO2 photocatalytic materials. In this review, a background on TiO2 structure, properties and electronic properties in photocatalysis is presented. The development of different strategies to modify TiO2 for the utilization of visible light, including non metal and/or metal doping, dye sensitization and coupling semiconductors are discussed. Emphasis is given to the origin of visible light absorption and the reactive oxygen species generated, deduced by physicochemical and photoelectrochemical methods. Various applications of VLA TiO2, in terms of environmental remediation and in particular water treatment, disinfection and air purification, are illustrated. Comprehensive studies on the photocatalytic degradation of contaminants of emerging concern, including endocrine disrupting compounds, pharmaceuticals, pesticides, cyanotoxins and volatile organic compounds, with VLA TiO2 are discussed and compared to conventional UV-activated TiO2 nanomaterials. Recent advances in bacterial disinfection using VLA TiO2 are also reviewed. Issues concerning test protocols for real visible light activity and photocatalytic efficiencies with different light sources have been highlighted.

MHD free convection of Al2O3–water nanofluid considering thermal radiation: A numerical study

Abstract: This article explores the effect of thermal radiation on Al2O3–water nanofluid flow and heat transfer in an enclosure with a constant flux heating element. KKL (Koo–Kleinstreuer–Li) correlation is used for simulating effective thermal conductivity and viscosity of nanofluid. The governing equations are solved via control volume based finite element method. The effects of Rayleigh number, Hartman number, viscous dissipation parameter, radiation parameter and volume fraction of nanoparticle on the flow and heat transfer characteristics have been examined. Results show that enhancement in heat transfer has direct relationship with Hartman number, viscous dissipation parameter and radiation parameter but it has reverse relationship for Rayleigh number. It is also observed that Nusselt number is an increasing function of Rayleigh number, volume fraction of nanoparticle and radiation parameter while it is a decreasing function of viscous dissipation parameter and Hartman number.

Ferrohydrodynamic and magnetohydrodynamic effects on ferrofluid flow and convective heat transfer

Abstract: In this paper, influence of an external magnetic field on ferrofluid flow and heat transfer in a semi annulus enclosure with sinusoidal hot wall is investigated. The governing equations which are derived by considering the both effects of FHD (Ferrohydrodynamic) and MHD (Magnetohydrodynamic) are solved via CVFEM (Control Volume based Finite Element Method). The effects of Rayleigh number, nanoparticle volume fraction, Magnetic number arising from FHD and Hartmann number arising from MHD on the flow and heat transfer characteristics have been examined. Results show that Nusselt number increases with augment of Rayleigh number and nanoparticle volume fraction but it decreases with increase of Hartmann number. Magnetic number has different effect on Nusselt number corresponding to Rayleigh number. Also it can be found that for low Rayleigh number, enhancement in heat transfer is an increasing function of Hartmann number and decreasing function of Magnetic number while opposite trend is observed for high Rayleigh number.

Heat transfer of Cu-water nanofluid flow between parallel plates

Abstract: Heat transfer of a nanofluid flow which is squeezed between parallel plates is investigated analytically using homotopy perturbation method (HPM). Copper as nanoparticle with water as its base fluid has been considered. The effective thermal conductivity and viscosity of nanofluid are calculated by the Maxwell–Garnetts (MG) and Brinkman models, respectively. This investigation is compared with other numerical methods and they were found to be in excellent agreement. The effects of the squeeze number, the nanofluid volume fraction and Eckert number and δ on Nusselt number are investigated. The results show that Nusselt number has direct relationship with nanoparticle volume fraction, δ, the squeeze number and Eckert number when two plates are separated but it has reverse relationship with the squeeze number when two plates are squeezed.

Simulation of MHD CuO–water nanofluid flow and convective heat transfer considering Lorentz forces

Abstract: Magnetic field effect on CuO–water nanofluid flow and heat transfer in an enclosure which is heated from below is investigated. Lattice Boltzmann method is applied to solve the governing equations. The effective thermal conductivity and viscosity of nanofluid are calculated by KKL (Koo–Kleinstreuer–Li) correlation. In this model effect of Brownian motion on the effective thermal conductivity is considered. Effect of active parameter such as: Hartmann number, heat source length, nanoparticle volume fraction and Rayleigh numbers on the flow and heat transfer characteristics have been examined. The results reveal that the enhancement in heat transfer increases as Hartmann number and heat source length increase but it decreases with increase of Rayleigh number. Also it can be found that effect of Hartmann number and heat source length is more pronounced at high Rayleigh number.