Coupled radiation and natural convection within an inclined sinusoidal solar collector heated from below
The main objective of this article is to study the effect of coupled mode free convection with surface radiation on the fluid flow behavior inside a tilted solar collector having a flat glass cover and a wavy bottom absorber. The cavity is subject to vertical gradient temperature while its top sidewalls remain thermally insulated. The dimensionless governing equations under Boussinesq approximation are coupled with a radiative model through the boundary conditions and solved by the Finite Volume Method. The numerical results are discussed in terms of streamlines, isotherms, convective and radiative Nusselt number along the cover plate for various aspect ratios, inclination angle, emissivity and Rayleigh number. These results highlighted the condition of the enclosure performance and revealed that the heat and fluid flow fields are affected by surface radiation and the above parameters. In the end, correlations for predicating the convection heat loss in term of averaged Nusselt numbers are developed in both pure free convection and coupled convection surface radiation modes.