TRANSIENT MIXED CONVECTION IN A PLANE VERTICAL CHANNEL

2014 ◽  
Author(s):  
Nadim El Wakil ◽  
Jacques Padet ◽  
Renato M. Cotta
Keyword(s):  
Mixed Convection ◽  
Vertical Channel

Mixed convection flow of an electrically conducting fluid in a vertical channel with boundary conditions of the third kind

2014 ◽  
Vol 92 (11) ◽  
pp. 1387-1396 ◽  
Author(s):  
J.C. Umavathi ◽  
A.J. Chamkha
Keyword(s):  
Mixed Convection ◽  
Average Velocity ◽  
Vertical Channel ◽  
Perturbation Parameter ◽  
Conducting Fluid ◽  
Integration Scheme ◽  
Electrically Conducting ◽  
Nusselt Numbers ◽  
Electrically Conducting Fluid ◽  
External Fluid

In this study, the effects of viscous and Ohmic dissipation in steady, laminar, mixed, convection heat transfer for an electrically conducting fluid flowing through a vertical channel is investigated in both aiding and opposing buoyancy situations. The plates exchange heat with an external fluid. Both conditions of equal and different reference temperatures of the external fluid are considered. First, the simpler cases of either negligible Brinkman number or negligible Grashof number are addressed with the help of analytical solutions. The combined effects of buoyancy forces and viscous dissipation are analyzed using a perturbation series method valid for small values of the perturbation parameter. To relax the conditions on the perturbation parameter, the governing equations are also evaluated numerically by a shooting technique that uses the classical explicit Runge–Kutta method of four slopes as an integration scheme and the Newton–Raphson method as a correction scheme. In the examined cases of velocity and temperature fields, the Nusselt numbers at both the walls and the average velocity are explored. It is found that the velocity profiles for an open circuit (E > 0 or E < 0) lie in between the short circuit (E = 0). The graphical results illustrating the effects of various parameters on the flow as well as the average velocity and Nusselt numbers are presented for open and short circuits. In the absence of electric field load parameter and Hartmann number, the results agree with Zanchini (Int. J. Heat Mass Transfer, 41, 3949 (1998)). Further, the analytical and numerical solutions agree very well for small values of the perturbation parameter.

Heat and mass transfer in binary film evaporation and condensation in vertical channel

2015 ◽  
Vol 4 (1) ◽  
pp. 214
Author(s):  
Abdelaziz Nasr ◽  
Abdulmajeed S. Al-Ghamdi
Keyword(s):  
Mass Transfer ◽  
Ethylene Glycol ◽  
Mixed Convection ◽  
Liquid Film ◽  
Vertical Channel ◽  
Vapor Concentration ◽  
Evaporation And Condensation ◽  
Film Evaporation ◽  
Binary Liquid ◽  
Water Condensation

Evaporation and condensation in the presence of binary liquid film flowing on one of two parallel vertical plates by mixed convection have been studied numerically. The first plate is adiabatic and wetted by a binary liquid film while the second one is dry and isothermal. The results concern the effects of the inlet parameters on the ethylene glycol evaporation and on the water condensation. Results obtained show that the increase of the inlet vapor concentration of water benefits its condensation and the increase of the inlet vapor concentration of ethylene glycol inhibits its evaporation.

scholarly journals Flow Reversal of Fully Developed Mixed Convection in a Vertical Channel with Chemical Reaction

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Habibis Saleh ◽  
Ishak Hashim ◽  
Sri Basriati
Keyword(s):  
Mixed Convection ◽  
Chemical Reaction ◽  
Buoyancy Force ◽  
Vertical Channel ◽  
Critical Values ◽  
Flow Reversal ◽  
Governing Equations ◽  
Reversed Flow ◽  
Exothermic Chemical Reaction

The present analysis is concerned with the criteria for the onset of flow reversal of the fully developed mixed convection in a vertical channel under the effect of the chemical reaction. The governing equations and the critical values of the buoyancy force are solved and calculated numerically via MAPLE. Parameter zones for the occurrence of reversed flow are presented. The exothermic chemical reaction is found to enhance the flow reversal and made flow reversal possible for symmetrical walls temperature.

Sign in / Sign up

Export Citation Format

Share Document