Communication Dans Un Congrès Année : 2025

Characterization of the impact of oxygen concentration on the alumina cloud surrounding a burning aluminum droplet

Résumé

The high energetic density of aluminum makes it a relevant choice as an energetic additive in the propulsion field. Mainly added to solid fuels, its use improves the global performance of the rocket due to its high combustion temperature. Moreover, aluminum is gaining consideration as a potential clean energy carrier. Indeed, its availability, ease of transportation or capacity to recycle are characteristics that are sought after. During the combustion of an aluminum particle in the gas phase regime, aluminum reacts with the available oxygen in a region separate from the particle, resulting in the formation of alumina through a highly exothermic reaction. Upon formation, alumina instantly condenses into nanodroplets. These droplets can then coagulate or aggregate upon cooling, forming the primary condensed combustion products (CCPs). In the military or space explorations fields, characterizing these CCPs is essential, as it directly affects rocket efficiency through thermoacoustic oscillations or two-phase ejection losses. This characterization is also vital for aluminum recycling, as alumina must be recovered and reduced to form aluminum again. Therefore, assessing the characteristics of alumina around a burning aluminum droplet is of utmost importance. While numerical studies remain scarce and present discrepancies in the results, the methods developed allow for the non-intrusive determination of in situ alumina size, concentration, temperature and gaseous emission profiles during the combustion of a levitating aluminum droplet in a chosen environment. While results in the case of air have already been published, the impact of oxygen concentration of the combustion parameters needs to be understood. In this work, a light extinction method (LEM) combined with a modulated absorption emission (MAE) method is applied to the case of an aluminum droplet burning in an O2/Ar mixture at 1 bar. To grasp the impact of oxygen concentration, the results for a 21%O2/79%Ar(vol.) are compared to those for a 30%O2/70%Ar(vol.) mixture. The size, concentration and temperature profiles of alumina nanoparticles are obtained for a 70 micron diameter aluminum particle.

Fichier non déposé

Dates et versions

hal-05190947 , version 1 (29-07-2025)

Identifiants

  • HAL Id : hal-05190947 , version 1

Citer

H. Keck, C. Chauveau, G. Legros, S. Gallier, F. Halter, et al.. Characterization of the impact of oxygen concentration on the alumina cloud surrounding a burning aluminum droplet. 30th International Colloquium on the Dynamics of Explosions and Reactive Systems (ICDERS 2025), IDERS, Jul 2025, Ottawa, Canada. ⟨hal-05190947⟩
93 Consultations
0 Téléchargements

Partager

  • More