Computational study of aluminum droplet combustion in different atmospheres
Résumé
Combustion of a single aluminum droplet in different atmospheres is simulated using a 1D approach, recently developed at ONERA, with detailed models for the gas-phase and surface chemistry as well as molecular transport. The reacting flow around a droplet is treated as spherically symmetric and quasi-steady-state by assuming that the droplet regression is slow with respect to the convective and diffusive transport in the surrounding gases. The 1D combustion model is first validated with respect to the 2D axisymmetric approach. It is demonstrated that with the 1D approach, it is possible to take into account the effect of oxidizer convection and obtain parameter profiles closely corresponding to the 2D results. The results of both simulations are found in good agreement with available experimental data for an O2/Ar atmosphere. Using the 1D approach, an important parametric study has been conducted by simulating steady combustion of droplets with different diameters D ≤ 400 µm in three atmospheres (O2/Ar, pure H2O and CO2) at two pressure levels (1 and 10 atm). Effects due to the surface chemistry model and the reversibility of the gas-phase reactions producing Al2O3(L) have been investigated. The burning time and exponent of the law are evaluated for the considered physical conditions and modeling options. Profiles of temperature and mole fractions of important species are presented and analyzed.
Origine : Accord explicite pour ce dépôt