Numerical simulation of combustion in a multi-component two-phase flow by lattice Boltzmann method

This study presents a numerical study of combustion process in a multi-component two-phase flow using the lattice Boltzmann method. The research primarily focuses on the combustion process within liquid propellant rocket engines using monomethyl hydrazine (MMH) and nitrogen tetroxide (NTO) as droplets. Building upon our previous work [Latifiyan et al., Acta Mech. 233, 4817–4849 (2022)], which enables concurrent phase transition modeling for both fuel and oxidizer droplets, the droplet combustion and diffusive flame development are simulated using the model of Ashna et al. [Phys. Rev. E 95(5), 053301 (2017)], incorporating temperature-based thermophysical characteristics. The developed biphasic model is verified by simulating n-decane droplet combustion, showing reasonable agreement with experimental data despite minor discrepancies. Additionally, the multi-component model is validated by comparing MMH and NTO droplet combustion with classical numerical results, demonstrating acceptable agreement. The combustion characteristics of the MMH and NTO droplets are explored, followed by investigating the fluctuations in the diffusion flame temperature and fuel evaporation rate by altering the relevant parameters. The results indicate that an increase in the gas phase velocity, NTO droplet diameter, ambient temperature, and reduction in droplet spacing is associated with an elevated flame temperature and a fuel evaporation rate.