Numerical simulation and experimental studies of external flow field in FCC feed nozzle

摘要

The present paper focus on spray characteristics and droplet distribution by using the discrete phase model of CFD method for external flow field simulation of fluid catalytic cracking feed nozzle. A two-fluid Euler-Lagrange approach is selected for modeling the aforementioned phenomenon referring to influence of the gas-liquid two phase pressure on atomizing performance, then the two-phase flow taking place inside the mixing chamber and the exterior region near the outlet of the nozzle has been simulated. The results attained by numerical simulation shows that the atomizing particle size decreased with the increase of axial distance, and it obviously decreased near the outlet of nozzle, and then leveled off. In view of the initial structure of catalytic cracking feed atomizing nozzle, the experiment setup was established, experimental results showed that the average atomizing diameter increased with the increase of liquid flow rate and it decreased with the increase of gas supply pressure, the atomizing particle size tend to level off while the gas phase pressure increases to a certain value. Under the operating parameters of that gas phase pressure is 1 bar (0.1MPa) and water flow rate is 16.7g/s, both the numerical simulation and experimental data with a good agreement. The study was of certain referring value on the structure design and operating parameters optimization of catalytic cracking feed nozzle.