scholarly journals The Role and Effects of Thermal Radiation on the Non-equilibrium Heat Transfer in a Porous Filled Enclosure

2021 ◽  
Vol 692 (2) ◽  
pp. 022053
Author(s):  
Yiwei Chen ◽  
Yuanyuan Chen ◽  
Xuecheng Xu
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zehba Raizah ◽  
Abdelraheem M. Aly ◽  
Noura Alsedais ◽  
Mohamed Ahmed Mansour

AbstractThe current study treats the magnetic field impacts on the mixed convection flow within an undulating cavity filled by hybrid nanofluids and porous media. The local thermal non-equilibrium condition below the implications of heat generation and thermal radiation is conducted. The corrugated vertical walls of an involved cavity have $${T}_{c}$$ T c and the plane walls are adiabatic. The heated part is put in the bottom wall and the left-top walls have lid velocities. The controlling dimensionless equations are numerically solved by the finite volume method through the SIMPLE technique. The varied parameters are scaled as a partial heat length (B: 0.2 to 0.8), heat generation/absorption coefficient (Q: − 2 to 2), thermal radiation parameter (Rd: 0–5), Hartmann number (Ha: 0–50), the porosity parameter (ε: 0.4–0.9), inter-phase heat transfer coefficient (H*: 0–5000), the volume fraction of a hybrid nanofluid (ϕ: 0–0.1), modified conductivity ratio (kr: 0.01–100), Darcy parameter $$\left(Da: 1{0}^{-1}\,\mathrm{ to }\,1{0}^{-5}\right)$$ D a : 1 0 - 1 to 1 0 - 5 , and the position of a heat source (D: 0.3–0.7). The major findings reveal that the length and position of the heater are effective in improving the nanofluid movements and heat transfer within a wavy cavity. The isotherms of a solid part are significantly altered by the variations on $$Q$$ Q , $${R}_{d}$$ R d , $${H}^{*}$$ H ∗ and $${k}_{r}$$ k r . Increasing the heat generation/absorption coefficient and thermal radiation parameter is improving the isotherms of a solid phase. Expanding in the porous parameter $$\varepsilon$$ ε enhances the heat transfer of the fluid/solid phases.


Author(s):  
A Mahdy ◽  
RA Mohamed ◽  
FM Hady ◽  
Omima A Abo Zaid

Heat transfer due to a square Darcy porous cavity in the presence of dust particles and thermal radiation effect by applying the thermal non-equilibrium model is investigated numerically in the current paper. The square cavity is maintained at a hot temperature at the left side wall, and the right side wall is maintained at cold temperature. While the bottom and top walls of the cavity are considered adiabatic. The impact of governing physical parameters on the streamlines, isotherms contours for the fluid and dust phases and isotherms for the solid phase are tested and represented through Graphic. In addition, the profiles of the average Nusselt numbers for solid and fluid phases and the total average Nusselt number are presented. The finite difference method is convenient to obtain a numerical analysis of the non-dimensionalized equations via the influence of mass concentration of the dust particles, fluid-particle interaction parameter for velocity, fluid-particle interaction parameter for temperature, Eckert number, radiation parameter, Rayleigh number, modified conductivity ratio, and inter-phase heat transfer coefficient. The results urge that the presence of dust particles leads to reduces the heat transfer rate at the left wall of the enclosure.


Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 10
Author(s):  
Muhammad Amer Qureshi

In this paper, heat transfer and entropy of steady Williamson nanofluid flow based on the fundamental symmetry is studied. The fluid is positioned over a stretched flat surface moving non-uniformly. Nanofluid is analyzed for its flow and thermal transport properties by consigning it to a convectively heated slippery surface. Thermal conductivity is assumed to be varied with temperature impacted by thermal radiation along with axisymmetric magnetohydrodynamics (MHD). Boundary layer approximations lead to partial differential equations, which are transformed into ordinary differential equations in light of a single phase model accounting for Cu-water and TiO2-water nanofluids. The resulting ODEs are solved via a finite difference based Keller box scheme. Various formidable physical parameters affecting fluid movement, difference in temperature, system entropy, skin friction and Nusselt number around the boundary are presented graphically and numerically discussed. It has also been observed that the nanofluid based on Cu-water is identified as a superior thermal conductor rather than TiO2-water based nanofluid.


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