![Fig. 5. Temperature profiles along the vertical central line at various dimensionless time: solid lines-present results, dots-solutions in Ref.[32].](/figures/fig-5-temperature-profiles-along-the-vertical-central-line-vfsqgj9h.webp)
Q2. What are the future works mentioned in the paper "Conjugate natural convection heat transfer in an open-ended square cavity partially filled with porous media" ?
Finally, it has been demonstrated that the present model can be used for unsteady conjugate heat transfer problems, which will be considered in their future work.
Q3. What is the important challenge for traditional numerical techniques?
For traditional numerical techniques, to appropriately treat conjugate heat transfer across fluid/porous interface is a great challenge, especially for complicate geometry [14].
Q4. What is the dominant heat transfer mechanism in the porous layer?
the dominant heat transfer mechanism in the porous layer is heat conduction as the isotherms in the porous zone are nearly parallel with the vertical hot wall, especially for a very thin porous layer (e.g. d/L = 0.1).
Q5. What is the effect of the permeability of the porous zone on the flow pattern?
When the permeability of the porous zone is high (e.g. Da = 10−1), the cold fluid from the environment can successfully penetrate the interface and form a large clockwise vortex.
Q6. What is the effect of the drag resistance on the porous layer?
For a poor permeable porous layer (e.g. Da = 10−5), as the drag resistance is large and the saturating fluid moves slowly, heat conduction dominates the porous zone.
Q7. What is the effect of the permeability of the porous layer on the heat transfer?
for a porous layer with low permeability (e.g. Da = 10−5), the intensity of heat transfer will monotonically decrease against the height of the hot wall.
Q8. What is the effect of Rk on the heat transfer?
Compared with the thickness of the porous layer, the intensity of heat transfer is more sensitive to effective thermal conductivity of the porous layer, especially when Rk is lessthan unity.
Q9. What is the effect of Rk on the thermal resistance of the porous layer?
the temperature gradient in the porous zone is slight and the distribution of temperature looks very uniform within the porous layer.
Q10. What is the governing equation for heat transfer in an open-ended enclosure?
The governing equations for heat transfer in an open-ended enclosure, where porous media and pure fluid coexist, can be written as [14,25]∂αuα = 0, (1)∂tuα + uβ∂β uα ε = −∂αεp+ ∂βνe(∂αuβ + ∂βuα) +
Q11. What is the common type of solar energy receiver?
In a lot of practical applications, an enclosure is usually partially filled with porous media, e.g. a room with multi-layer building materials[12] or a new type of solar energy receiver [13] .
Q12. what is the effective thermal diffusivity of a fluid?
(12)and the effective thermal diffusivity κe is given byκe = σ0(τT − 1/2)c2sΔt. (13)According to Eq.(13), it is clear that in the present model the effective thermal diffusivity depends on σ0 , rather than σ in Guo’s model (c.f. Eq.(30) in [37]).
Q13. how does the permeability of porous media affect the efficiency of a solar thermal receiver?
In addition, according to the presentwork, one must pay high attention to the effect of permeability of porous media on the uniform of temperature distribution in a solar thermal receiver, as seriously non-uniform temperature distribution will damage its life and overall efficiency.
Q14. What is the effect of a thicker porous layer on the circulation in the fluid zone?
according to this figure, one can observe that a thicker porous layer will suppress the circulation in the fluid zone while enhance the circulation within the porous area as establishment and development of free convectional flow require sufficient space.
Q15. What is the effect of the Darcy number on the flow pattern of a porous?
In this subsection the authors set ε = 0.6, Ra = 105, σporous = 1.0, d/L = 0.3 and Rk = 1, while the Darcy number varies over a wide range 10−1 ≤ Da ≤ 10−5.
Q16. How does the effect of porous to fluid thermal conductivity ratio differ from open-ended cavities?
5.2 Effect of porous-to-fluid thermal conductivity ratioIn order to reveal the effect of porous-to-fluid thermal conductivity ratio Rk, in this subsection the authors set Da = 10−3, ε = 0.6, Ra = 105, σporous = 1.0 and d/L = 0.3, while Rk varies between 0.1 and 10.
Q17. what is the key to model conjugate heat transfer across fluid/porous interface?
As shown below, it is the key to model conjugate heat transfer across fluid/porous interface with arbitrary heat capacitance ratio (i.e. σporous = 1 in Eq.(6)).
Q18. How was the effect of magnetic force on natural convection in an open-ended cavity investigated?
Natural convection in a horizontal open-ended axisymmetric cavity was investigated experimentally by the holographic interferometry technique [5].