Tomography-Based Heat And Mass Transport Characterization Of Complex Porous Materials For Solar Power And Fuel Generation

Transport phenomena in porous media are pertinent to thermal and thermochemical processes for power and fuel generation using concentrated solar energy. The porous media serve as insulator, radiant absorbers, heat exchangers, catalyst carriers, reactants, and/or reaction sites. Volume-averaging models for porous media, commonly applied for process simulations and optimization, rely heavily on the a-priori determination of their effective transport properties, which in turn depend strongly on the morphology of the porous media. A combined experimental-numerical methodology is applied to accurately determine these effective properties. The exact 3D geometrical structure is obtained by computed tomography and applied in subsequent direct pore-level numerical simulations of heat and mass transfer using Monte Carlo and finite volume techniques. Three examples of materials widely used in solar applications are selected: (i) a reacting packed bed of carbonaceous materials undergoing solardriven gasification; (ii) a ceramic foam for a solar pressurized air receiver coupled to a gas turbine; and (iii) an anisotropic ceramic foam for a solar H2O/CO2-splitting thermochemical cycle. A comprehensive characterization of morphology and heat/mass transport properties is accomplished via Monte Carlo and finite volume techniques.