Effect of Radiation on Hydromagnetic Mixed Convective Flow in a Vertical Channel Filled With Porous Media: A Thermal Nonequilibrium Approach

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
K. M. Renu ◽  
Ashok Kumar

Abstract This work addresses the magnetic and radiation effects on the fully developed mixed convective flow in a vertical channel occupied by a porous medium with the thermal nonequilibrium state. The assumption that the fluid is electrically conducted is taken into account and permitted by a uniform transversal magnetic field while the temperature of the wall is changing linearly with the direction of the fluid flow. The spectral collocation technique is used for the numerical solution, whereas the analytical solution is governed for the special case when the drag force F* and the ratio of porosity-scaled thermal conductivity γ are zero. It is observed that, in the buoyancy assisted case, the fluid flow for Ra<102, (Nuf) increased near the wall with increasing the Hartmann number (M). Beyond this when Ra≥102, (Nuf) is decreased with increasing M. It is also perceived that there exists an interval [0,H0] in which (Nuf) increases with increasing M as well as increasing radiation parameter Rd, furthermore beyond the value of H0, Nuf decreasing asymptotically. While for the buoyancy opposed case, the flow separation and inflection point appear in the velocity profile for different values of M, further both the flow separation and inflection point are dying out as M increases. Overall, for the both cases, the magnetic and radiation parameters are stabilizing the flow in the system.

2019 ◽  
Vol 23 (3 Part B) ◽  
pp. 1861-1873
Author(s):  
Thangavelu Mahalakshmi ◽  
Nagarajan Nithyadevi ◽  
Hakan Oztop

This present numerical study explores the MHD mixed convective flow and heat transfer analysis in a square porous enclosure filled with nanofluid having center thin heater. The left and right walls of the enclosure are maintained at temperature T . The bottom wall is c considered with a constant heat source whereas the remaining part of bottom wall and top wall are kept adiabatic. The finite volume method based on SIMPLE algorithm is used to solve the governing equations in order to investigate the effect of heater length, Hartmann, Richardson, and Darcy numbers on the fluid-flow and heat transfer characteristics inside the enclosure. A set of graphical results are presented in terms of streamlines, isotherms, mid height velocity profiles and average Nusselt numbers. The results reveal that heat transfer rate increases as heater length increases for increasing Darcy and Richardson numbers. Among the two positions of heaters, larger enhancement of heat transfer is obtained for horizontal heater of maximum length. It is observed that, Hartmann number is a good control parameter for heat transfer in fluid-flow through porous medium in enclosure. Moreover, Ag-water nanofluid has greater merit to be used for heat transfer enhancement. This problem may be occurred in designing cooling system for electronic equipment to maximize the efficiency with active and secured operational conditions.


2010 ◽  
Vol 40 (1) ◽  
pp. 1-25 ◽  
Author(s):  
J. Prathap Kumar ◽  
J.C. Umavathi ◽  
Basavaraj M. Biradar

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