scholarly journals Influence of Heat Generation/Absorption on Mixed Convection Flow Behaviour in the Presence of Lorentz Forces in a Vertical Micro Circular Duct Having Time Periodic Boundary Conditions: Steady Periodic Regime

2020 ◽  
Vol 25 (4) ◽  
pp. 1-21
Author(s):  
B. Aina ◽  
S. Isa

AbstractThe problem of mixed convection flow of a heat generating/absorbing fluid in the presence existence of Lorentz forces in a vertical micro circular subjected to a periodic sinusoidal temperature change at the surface has been studied taking the first-order slip and jump effects into consideration. The research analysis is carried out by considering a fully developed parallel flow and steady periodic regime. The governing equations, together with the constraint equations which arise from the definition of mean velocity and temperature, are written in a dimensionless form and mapped into equations in the complex domain. One obtains two independent boundary value problems, which provide the mean value and the oscillating term of the velocity and temperature distributions. These boundary value problems are solved analytically. A parametric study of some of the physical parameters involved in the problem is conducted. The results of this research revealed that the magnetic field has a damping impact on the flow and results in decreases in fluid velocity for both air and water. Furthermore, the presence of the heat generation parameter is seen to enhance the temperature distribution and this is reflected as an increase in the magnitude of the oscillation dimensionless velocity, whereas in the presence of heat absorption a reversed trend occurs.

2013 ◽  
Vol 18 (4) ◽  
pp. 1151-1164 ◽  
Author(s):  
G.V.R. Reddy ◽  
B.A. Reddy ◽  
N.B. Reddy

Abstract The effects of thermal radiation and mass transfer on an unsteady hydromagnetic boundary layer mixed convection flow along a vertical porous stretching surface with heat generation are studied. The fluid is assumed to be viscous and incompressible. The governing partial differential equations are transformed into a system of ordinary differential equations using similarity variables. Numerical solutions of these equations are obtained by using the Runge-Kutta fourth order method along with the shooting technique. Velocity, temperature, concentration, the skin-friction coefficient, Nusselt number and Sherwood number for variations in the governing thermo physical parameters are computed, analyzed and discussed.


2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Salaika Parvin ◽  
Nepal Chandra Roy ◽  
Rama Subba Reddy Gorla

AbstractIn this study, the ignition characteristics and the flow properties of the mixed convection flow are presented. Detailed formulations of the forced, natural and mixed convection problems have been discussed. In order to avoid inconvenient switch between the forced and natural convection we introduce a continuous transformation in the mixed convection. We make a comparison between these situations which reveal a good agreement. For mixed convection flow, the ignition distance is explicitly expressed as a function of the Prandtl number, reaction parameter and wall temperature. It has been observed that owing to the increase of the aforesaid parameters, the thermal ignition distance is reduced. Numerical results are illustrated for velocity, temperature, and concentration for different physical parameters. Furthermore, the development of combustion is presented by using streamlines, isotherms and isolines of fuel and oxidizer.


2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Khilap Singh ◽  
Manoj Kumar

A numerical model is developed to examine the effects of thermal radiation on unsteady mixed convection flow of a viscous dissipating incompressible micropolar fluid adjacent to a heated vertical stretching surface in the presence of the buoyancy force and heat generation/absorption. The Rosseland approximation is used to describe the radiative heat flux in the energy equation. The model contains nonlinear coupled partial differential equations which have been converted into ordinary differential equation by using the similarity transformations. The dimensionless governing equations for this investigation are solved by Runge-Kutta-Fehlberg fourth fifth-order method with shooting technique. Numerical solutions are then obtained and investigated in detail for different interesting parameters such as the local skin-friction coefficient, wall couple stress, and Nusselt number as well as other parametric values such as the velocity, angular velocity, and temperature.


2010 ◽  
Vol 6 (2) ◽  
pp. 84-93 ◽  
Author(s):  
N Ananda Reddy ◽  
SVK Varma ◽  
MC Raju

Thermo diffusion and chemical effects on heat transfer in MHD mixed convection flow and masstransfer past an infinite vertical plate with Ohmic heating and viscous dissipation have beenstudied. Approximate solutions have been derived for velocity, temperature, concentration profiles,skin friction, rate of heat transfer and rate of mass transfer using perturbation technique. Theobtained results are discussed with the help of graphs to observe the effect of various parameterslike Schmidt number (Sc), Prandtl number (Pr), Magnetic parameter (M),Soret number (So) andchemical parameter (K), taking two cases viz. Case I: when Gr > 0 (flow on cooled plate) and CaseII: Gr < 0 (flow on heated plate). Thermal diffusion causes both the fluid velocity and temperature tofall due to the presence of the chemical effect. Velocity and temperature profiles are higher formercury than electrolytic solution. Soret effect increased the concentration of the fluid while chemicaleffect decreased.Keywords: Chemical effect; thermo diffusion; magnetic field; heat-mass transfer.DOI: 10.3329/jname.v6i2.3761


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