Investigation of flow characteristics and mixing of liquid hydrogen within a premixing swirl tube for the turbine engine combustor

Abstract

This article explores the flow characteristics and fuel mixing in a premixed tube leading to the combustion chamber, focusing on hydrogen fuel. A CFD simulation utilizing a discrete phase model (DPM) was conducted to investigate the impact of spray angle, spray pressure, and fuel-to-air ratio on fuel atomization, fragmentation, and fuel-air mixing efficiency. The findings highlight the critical role of the spray angle in fuel atomization and breakup. Increasing the spray angle enhances atomization, resulting in smaller fuel droplet sizes and improved fuel-air mixing. The particle diameters ranged from 165 μm to 117 μm for spray angles of 15°–60°, respectively. Additionally, spray pressure significantly influences particle diameter, velocity, and turbulent kinetic energy. Higher spray pressures promote efficient atomization, fragmentation, and smaller particle sizes, enhancing fuel dispersion and mixing. The fuel-to-air ratio also plays a crucial role, with lean mixtures (0.0003 kg/s of fuel flow rate) facilitating increased fuel-air mixing and smaller droplet sizes. Furthermore, the swirl motion induced by airflow and lower fuel-to-air ratios enhances fuel atomization and breakup, resulting in finer spray characteristics. These insights contribute to optimizing spray angle, pressure, and fuel-to-air ratio, ultimately improving fuel injection systems, combustion efficiency, and emissions reduction across various applications.