Eulerian method for flow and heat transfer characteristics in an internally circulating fluidized bed reactor driven by solar energy with initial situation

A coupled simulation of flow, heat transfer, and reaction processes in an internally circulating fluidized bed reactor with solar energy application is conducted. Using the Euler-Euler model, the influence of varying inlet gas velocities and radiation fluxes on particle dynamics and reactor performance is analyzed. This study presents the first detailed coupling of radiation flux, inlet gas velocity, and particle volume fraction in the modeling of solar-assisted internally circulating fluidized bed reactors. The results show that increasing the inlet velocity enhances particle fluidization, accelerates particle circulation, and improves heat transfer between particles and gas. The calcium carbonate mass fraction exhibits a more uniform horizontal distribution at higher velocities or radiation intensities, spreading from the center toward the sidewalls. Particle velocity profiles reveal a core-annular structure, with higher velocities in the center and lower near the wall, a trend that intensified with increasing inlet speed. In contrast, both particle and gas temperatures exhibit higher values near the walls than in the center. Radiation energy peaks at the reactor center but distributes more evenly with increasing inlet velocity. These findings provide valuable insights into multiphase transport and heat-reaction coupling for the design and optimization of solar-assisted fluidized bed reactors.