Modeling and Analysis of an Efficient Porous Media for a Solar Porous Absorber With a Variable Pore Structure

A theoretical mathematical model that considers the continuous linear porosity or pore diameter distribution is established to develop a novel porous absorber with variable pore structure, which will result in a thermopressure drop improvement. Efficient performance can be achieved based on reconstruction of the velocity, temperature, and radiation fields. Collimated and diffusive radiative heat fluxes and the heat loss mechanism from the irradiated surface are analyzed in the presence of the volumetric effect. This study analyzes three typical linear pore structure distributions: increasing (I), decreasing (D), and constant (C) types, respectively. In general, the D type porosity (φ) layout combined with the I type pore diameter (d_p) distribution would be an excellent pore structure layout for a porous absorber.