Heat Transfer in Unsteady Squeezing Flow Between Parallel Plates

In this study, we investigated an unsteady MHD flow between parallel plates in the presence of viscous dissipation. The transformed governing equations are solved numerically using bvp5c Matlab package. The impact of different non-dimensional parameters on velocity and temperature profiles along with the local Nusselt number is discussed graphically. It is observed that the Nusselt number is a decreasing function of the radiation parameter and Hartmann number but it is an increasing function of squeeze number and Eckert number. Keywords:MHD, viscous dissipation, squeeze number, radiatio

Influence of SORET on Unsteady MHD of Kuvshinshiki Fluid Flow With Heat and Mass Transfer Past a Vertical Porous Plate With Variable Suction

No Abstrac

Personality and learning styles towards the practical-based approach

An enduring question for educational research is the result of individual deviations in the efficacy of learning. The individual learning differences that have been much explored relate to differences in personality, learning styles, strategies and conceptions of learning. This article studies the personality and the learning style profile exhibited by students in a practical based approach of vocational courses. The relationship between personality and learning styles among students was assessed as the students got along through the curriculum. The analysis show that students are more oriented towards an active learning mode in a practical-based approach. Given a specific instruction, some people will learn more effectively than others due to their individual personality and learning styles. This study will help a vocational instructor and advisors to understand their students and to design instruction that can benefit students to accomplish a respectable performance in their learning process

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

Unsteady reactive magnetic radiative micropolar flow, heat and mass transfer from an inclined plate with joule heating: a model for magnetic polymer processing

Magnetic polymer materials processing involves many multi-physical and chemical effects. Motivated by such applications, in the present work a theoretical analysis is conducted of combined heat and mass transfer in unsteady mixed convection flow of micropolar fluid over an oscillatory inclined porous plate in a homogenous porous medium with heat source, radiation absorption and Joule dissipation. A first order homogenous chemical reaction model is used. The transformed non-dimensional boundary value problem is solved using a perturbation method and Runge-Kutta fourth order numerical quadrature (shooting technique). The emerging parameters dictating the transport phenomena are shown to be the gyro-viscosity micropolar material parameter, magnetic field parameter, permeability of the porous medium, Prandtl number, Schmidt number, thermal Grashof number, species Grashof number, thermal radiation-conduction parameter, heat absorption parameter, radiation absorption parameter, Eckert number, chemical reaction parameter and Eringen coupling number (vortex viscosity ratio parameter). The impact of these parameters on linear velocity, microrotation (angular velocity), temperature and concentration are evaluated in detail. Results for skin friction coefficient, couple stress coefficient, Nusselt number and Sherwood number are also included. Couple stress is observed to be reduced with stronger magnetic field. Verification of solutions is achieved with earlier published analytical results

Mixed convection dissipative viscous fluid flow over a rotating cone by way of variable viscosity and thermal conductivity

AbstractThe effects of temperature-dependent viscosity and thermal conductivity on the flow and heat transfer characteristics of a viscous fluid over a rotating vertical cone are premeditated. The properties of the fluid are assumed to be constant except for the density difference with the temperature. Also, the effect of viscous dissipation is considered in the energy equation. The highly nonlinear unsteady equations are converted into a system of nonlinear ordinary differential equations which is solved by using Homotopy analysis method. The interesting findings for different pertinent parameters on momentum, energy, skin friction coefficient and local Nusselt number are demonstrated in the form of graphs and tables. A comparison has been made with literature as a limiting case of the well-chosen unsteady problem

Theoretical Investigation of Magnetohydrodynamic Radiative Non-Newtonian Fluid Flow over a Stretched Surface

The aim of this study is to investigate the heat and mass transfer in magnetohydrodynamic Newtonian and non-Newtonian fluid flow over a stretched domain in the presence of thermal radiation, chemical reaction, Soret and Dufour effects. In addition to this, we also considered the aligned magnetic field (i.e. the magnetic field applied at different angles) along the flow direction and dual solutions are executed for the transverse and aligned magnetic field cases. The governing system of equations is transformed as the system of ODEs with the help of suited similarity transforms. The resulting equations are solved numerically with the aid of the shooting process. The graphical and tabular results are explored to discuss the flow, thermal and concentration behavior along with the heat and mass transfer rate. Keywords: MHD, Aligned Magnetic field, Soret and Dufour effects, Radiation, Chemical reaction

Mathematical models for heat and mass transfer in nanofluid flows.

Doctoral Degree. University of KwaZulu-Natal, Pietermaritzburg.The behaviour and evolution of most physical phenomena is often best described using mathematical models in the form of systems of ordinary and partial differential equations. A typical example of such phenomena is the flow of a viscous impressible fluid which is described by the Navier-Stokes equations, first derived in the nineteenth century using physical approximations and the principles of mass and momentum conservation. The flow of fluids, and the growth of flow instabilities has been the subject of many investigations because fluids have wide uses in engineering and science, including as carriers of heat, solutes and aggregates. Conventional heat transfer fluids used in engineering applications include air, water and oil. However, each of these fluids has an inherently low thermal conductivity that severely limit heat exchange efficiency. Suspension of nanosized solid particles in traditional heat transfer fluids significantly increases the thermophysical properties of such fluids leading to better heat transfer performance. In this study we present theoretical models to investigate the flow of unsteady nanofluids, heat and mass transport in porous media. Different flow configurations are assumed including an inclined cylinder, a moving surface, a stretching cone and the flow of a polymer nanocomposite modeled as an Oldroyd-B fluid. The nanoparticles assumed include copper, silver and titanium dioxide with water as the base fluid. Most recent boundary-layer nanofluid flow studies assume that the nanoparticle volume fraction can be actively controlled at a bounding solid surface, similar to temperature controls. However, in practice, such controls present significant challenges, and may, in practice, not be possible. In this study the nanoparticle flux at the boundary surface is assumed to be zero. Unsteadiness in fluid flows leads to complex system of partial differential equations. These transport equations are often highly nonlinear and cannot be solved to find exact solutions that describe the evolution of the physical phenomena modeled. A large number of numerical or semi-numerical techniques exist in the literature for finding solutions of nonlinear systems of equations. Some of these methods may, however be subject to certain limitations including slow convergence rates and a small radius of convergence. In recent years, innovative linearization techniques used together with spectral methods have been suggested as suitable tools for solving systems of ordinary and partial differential equations. The techniques which include the spectral local linearization method, spectral relaxation method and the spectral quasiliearization method are used in this study to solve the transport equations, and to determine how the flow characteristics are impacted by changes in certain important physical and fluid parameters. The findings show that these methods give accurate solutions and that the speed of convergence of solutions is comparable with methods such as the Keller-box, Galerkin, and other finite difference or finite element methods. The study gives new insights, and result on the influence of certain events, such as internal heat generation, velocity slip, nanoparticle thermophoresis and random motion on the flow structure, heat and mass transfer rates and the fluid properties in the case of a nanofluid

Transient Magnetohydrodynamic Free Convective Heat and Mass Transfer Flow with Thermophoresis past a Radiate Inclined Permeable Plate in the Presence of Variable Chemical Reaction and Temperature Dependent Viscosity

In the present study, an analysis is carried out to investigate the effects of variable chemical reaction, thermophoresis, temperature-dependent viscosity and thermal radiation on an unsteady MHD free convective heat and mass transfer flow of a viscous, incompressible, electrically conducting fluid past an impulsively started infinite inclined porous plate. The governing nonlinear partial differential equations are transformed into a system of ordinary differential equations, which are solved numerically using a sixth-order Runge-Kutta integration scheme with Nachtsheim-Swigert shooting method. Numerical results for the non-dimensional velocity, temperature and concentration profiles as well as the local skin-friction coefficient, the local Nusselt number and the local Stanton number are presented for different physical parameters. The results show that variable viscosity significantly increases viscous drag and rate of heat transfer. The results also show that higher order chemical reaction induces the concentration of the particles for a destructive reaction and reduces for a generative reaction

Magnetohydrodynamic radiative Casson fluid flow over a semi-infinite vertical plate: An analytical approach

In this study, we analyzed the heat transfer nature of the magnetohydrodynamic Casson fluid flow over a semi-infinite porous vertical plate in the presence of thermal radiation and heat source/sink with buoyancy effect. The governing partial differential equations are transformed as non-dimensional equations using suitable transformation and resulting equations are solved using Perturbation technique. The effect of non-dimensional parameters namely thermal radiation, heat source/sink, Grashof number, porosity parameter and magnetic field parameter on the flow and heat transfer is analyzed for both Casson and Newtonian fluid cases. Also discussed the friction factor and local Nusselt number for both cases. It is found that momentum and thermal boundary layers of Casson and Newtonian fluids are non-uniform. Keywords: Casson fluid, MHD, thermal radiation, heat source/sink, buoyancy effect