Radiative Mixed Convection over an Isothermal Cone Embedded in a Porous Medium with Variable Permeability

The interaction of mixed convection with thermal radiation of an optical dense viscous fluid adjacent to an isothermal cone imbedded in a porous medium with Rosseland diffusion approximation incorporating the variation of permeability and thermal conductivity is numerically investigated. The transformed conservation laws are solved numerically for the case of variable surface temperature conditions. Numerical results are given for the dimensionless temperature profiles and the local Nusselt number for various values of the mixed convection parameter , the cone angle parameter , the radiation-conduction parameter , and the surface temperature parameter

Stefan blowing, navier slip and radiation effects on thermo-solutal convection from a spinning cone in an anisotropic porous medium

Thermal radiation features in many high temperature materials processing operations. To evaluate the influence of radiative flux on spin coating systems, we consider herein the thermo-solutal (coupled heat and mass transfer) in steady laminar boundary layer natural convection flow from a rotating permeable vertical cone to an anisotropic Darcian porous medium. Surface slip effects are also included in the model presented. The conservation equations are rendered into self-similar form and solved as an ordinary differential two-point boundary value problem with surface and free stream boundary conditions using MAPLE 17 software. The transport phenomena are observed to be controlled by ten parameters, viz primary and secondary Darcy numbers (Dax and Da), rotational (spin) parameter (NR), velocity slip parameter (a), suction/injection parameter (S), thermal slip parameter (b), mass slip parameter (c) buoyancy ratio parameter (N), and conduction-radiation parameter (Rc). Tangential velocity and temperature are observed to be enhanced with greater momentum slip whereas swirl velocity and concentration are reduced. Increasing swirl Darcy number strongly accelerates both the tangential and swirl flow and also heats the regime whereas it decreases concentrations. Conversely a rise in tangential Darcy number accelerates only the tangential flow and decelerates swirl flow, simultaneously depressing temperatures and concentrations. Increasing thermal slip accelerates the swirl flow and boosts concentration but serves to retard the tangential flow and decrease temperatures. With higher radiation contribution (lower Rc values) temperatures are elevated and concentrations are reduced. Verification of the MAPLE 17 solutions is achieved using a Keller-box finite difference method (KBM). A number of interesting features in the thermo-fluid and species diffusion characteristics are addressed. Key words: Stefan blowing; Spinning cone; MAPLE 17; Anisotropi

MHD free convection-radiation interaction in a porous medium - part I : numerical investigation

A numerical investigation of two dimensional steady magnetohydrodynamics heat and mass transfer by laminar free convection from a radiative horizontal circular cylinder in a non-Darcy porous medium is presented by taking into account the Soret/Dufour effects. The boundary layer conservation equations, which are parabolic in nature, are normalized into non-similar form and then solved numerically with the well-tested, efficient, implicit, stable Keller–Box finite-difference scheme. We use simple central difference derivatives and averages at the mid points of net rectangles to get finite difference equations with a second order truncation error. We have conducted a grid sensitivity and time calculation of the solution execution. Numerical results are obtained for the velocity, temperature and concentration distributions, as well as the local skin friction, Nusselt number and Sherwood number for several values of the parameters. The dependency of the thermophysical properties has been discussed on the parameters and shown graphically. The Darcy number accelerates the flow due to a corresponding rise in permeability of the regime and concomitant decrease in Darcian impedance. A comparative study between the previously published and present results in a limiting sense is found in an excellent agreement

Effects of Soret, Dufour, chemical reaction, thermal radiation and volumentric heat generation/absorption on mixed convection stagnation point flow on an Iso-thermal vertical plate in porous media

A mathematical model is analyzed in order to study the effects of Soret, Dufour, chemical reaction, thermal radiation and volumentric heat generation/absorption on mixed convection stagnation point flow on an Iso-thermal vertical plate in a porous media. The governing partial differential equations are transformed into set of coupled ordinary differential equations, which are solved numerically using Runge-Kutta sixth order method along with shooting technique. The physical interpretation to this expression is assigned through graphs and tables for the wall shear stress , Nusselt number and Sherwood number . Results were compared with the existing literature and showed a perfect agreement. Similarly, results showed that the fields were influenced appreciably by the effects of the governing parameters: Soret number Sr, Dufour number Df, chemical reaction parameter γ, thermal radiation parameter Ra, order of reactions n, thermal Grashof number GT, solutal Grashof number GC, Prandtl number Pr, permeability parameter K, rate of heat generation/absorption parameter S, and magnetic field strength parameter M. It was evident that for some kind of mixtures such as the light and medium molecular weight, the Soret and Dufour’s effects should be considered as well

Numerical study of radiative Maxwell viscoelastic magnetized flow from a stretching permeable sheet with the Cattaneo–Christov heat flux model

In this article, the Cattaneo-Christov heat flux model is implemented to study non-Fourier heat and mass transfer in the magnetohydrodynamic (MHD) flow of an upper convected Maxwell (UCM) fluid over a permeable stretching sheet under a transverse constant magnetic field. Thermal radiation and chemical reaction effects are also considered. The nonlinear partial differential conservation equations for mass, momentum, energy and species conservation are transformed with appropriate similarity variables into a system of coupled, highly nonlinear ordinary differential equations with appropriate boundary conditions. Numerical solutions have been presented for the influence of elasticity parameter (), magnetic parameter (M2), suction/injection parameter (λ), Prandtl number (Pr), conduction-radiation parameter (Rd), sheet stretching parameter (A), Schmidt number (Sc), chemical reaction parameter (γ_c), modified Deborah number with respect to relaxation time of heat flux (i.e. non-Fourier Deborah number) on velocity components, temperature and concentration profiles using the successive Taylor series linearization method (STSLM) utilizing Chebyshev interpolating polynomials and Gauss-Lobatto collocation. The effects of selected parameters on skin friction coefficient, Nusselt number and Sherwood number are also presented with the help of tables. Verification of the STSLM solutions is achieved with existing published results demonstrating close agreement. Further validation of skin friction coefficient, Nusselt number and Sherwood number values computed with STSLM is included using Mathematica software shooting quadrature

Radiation and Chemical Reaction Effects on MHD Thermosolutal Nanofluid Flow over a Vertical Plate in Porous Medium

In this study we discussed the influence of radiation and chemical reaction on MHD thermosolutal nanofluid convective slip flow over a vertical plate in porous medium in presence of thermophoresis and Brownian motion effects. The governing boundary layer partial differential equations are transformed into system of ordinary differential equations by using similarity transformation and then solved numerically using bvp5c Matlab package. The effects of dimensionless governing parameters on the flow, heat and mass transfer was discussed and presented through graphs. Also, the skin friction coefficient and local Nusselt and Sherwood numbers are computed and discussed. Results indicate that an increase in chemical reaction parameter enhances the mass transfer rate. Keywords: MHD, Radiation, Chemical Reaction, Nanofluid, Convection

On Dissipative Radiative MHD Boundary Layer Flow in a Porous Medium Over a Non Isothermal Stretching Sheet

The paper aims at investigating the effects of Ohmic and viscous dissipations on the steady two-dimensional radiative boundary-layer flow of an incompressible, viscous, electrically conducting fluid caused by a linearly stretching sheet placed at the bottom of fluid saturated porous medium in the presence of uniform transverse magnetic field. The radiative heat flux is assumed to follow Rosseland approximation. The governing system of partial differential equations are converted to ordinary differential equations by using the similarity transformations, which are then solved numerically using shooting method with fourth order Runge-Kutta scheme. The dimensionless temperature distribution is computed for different thermo-physical parameters and presented graphically. The temperature gradient at the sheet and skin friction coefficient are derived numerically and presented through graph

MHD Mixed Convection Flow of Casson Fluid over a Moving Wedge Saturated in a Porous Medium in the presence of Chemical Reaction and Convective Boundary Conditions

This work concerned to hydromagnetic mixed convection flow of Casson fluid over a wedge. It is assumed that the wedge is moving inside a porous medium. The effects of chemical reaction, slip and convective boundary conditions at velocity, temperature and concentration walls are also considered. The governing partial differential equations are converted into ordinary differential equations using similarity transformations, and then solved by implicit finite difference scheme. Comparisons with the existing literature are performed and good agreement is achieved. The influence of physical parameters on flow fields are illustrated graphically. It is observed that the velocity rises with the increment in Casson fluid parameter and magnetic parameter. It is also noticed that thickness of thermal boundary layer grows with the increase of radiation. The skin friction coefficient enhances with the increase of porosity parameter while reduces as Casson fluid and moving wedge parameters increase. Increase in heat and mass transfer rate is noticed to be enhanced with the increase in radiation and chemical reaction parameters, respectively

Finite element simulation of twist forming process to study twist springback pattern

Springback is one of the most common defects found in the metal forming of automotive parts. There are three conditions which can be considered as springback i.e. flange angle change, sidewall curl and twist springback and among them, twist springback is the most complicated problem. This study will focuses on the development of finite element simulation model of the twist forming process. The main aim of this project is to investigate the parameters that may affect the twist springback. Few parameters including twist angle, hardening constant and thickness are explored using finite element (FE) software ANSYS Workbench (16.0). The rectangular mild strips are used to form the twist forming. The standard material properties and stress-strain curve of mild steel had been used to get the springback prediction. The results of springback were measured by the difference of the bending angles before and after unloading process. The results were then be validated with the research made of Dwivedi et al., (2002). The results show that the springback angle reduces as the thickness of strips are increased and also as the angle of twist increases

Effect of porosity on unsteady MHD convection flow Past a moving vertical plate with ramped wall temperature

The unsteady MHD convective flow of an electrically conducting fluid embedded in a porous medium along moving infinite vertical plate with ramped wall temperature and radiation in a rotating system is investigated here. The fluid taken is incompressible and viscous. The governing PDE’s of the model are solved by using integral transform method. The analytical solutions for the velocity, concentration and temperature are obtained. The expressions for skin friction, rate of mass transfer and heat transfer near the plate are obtained. The effects of various parameters like porosity of the medium, magnetic field, Soret number, thermal radiation, rotation, radiation and Hall current on the flow field are discussed. It is observed that velocity increases with the increase in the porosity parameter K. It reveals that a porous medium having large permeability supports the movement of the fluid in the system. Also, it is noticed that Hall parameter reduces the resistive effect of the applied magnetic field. Such a study assumes importance because both rotation and Hall current induce secondary flow in the flow-field. The results of the research may be useful in many industrial applications