(67c) Influences of Geometric Factors on a Solar Thermochemical Reactor for Two-Step CO2 Splitting

Solar thermochemical processes utilize the inexhaustible solar energy as thermal driving force to provide heat and motivate the reactions, which offer pathways to store solar energy to chemical fuels. Some elevated temperature reactions, like synthesis of syngas and methane reforming, are anticipating to accomplish in solar reactors, which have the ability to provide extremely high temperatures. Presently, the dominating factors in the design of solar reactors are heat and mass transfer with reaction mechanisms. A novel partition cavity-receiver reactor concept is proposed in this paper. For the purpose to provide a longer pathway of interaction between catalyst and reactants, a partition is introduced in this cavity-receiver reactor. A numerical computational fluid dynamics (CFD) analysis is performed to study on the influences of geometric factors, like length-diameter ratio, partition length and thickness, the transparency of partition, to fluid flow and heat transfer under constant solar power input for both two-dimensional and three-dimensional models. A two-step solar thermochemical redox reaction using ceria as catalyst to split CO₂ is modeled in the partition cavity-receiver reactor to investigate the relationship between geometric factors and reaction rates. Based on the comparisons and analysis of results, optimized geometric factors and corresponding operating conditions are discussed.