Influence of nitrogen in aluminum droplet combustion

Aluminum combustion in wet and dry CO2: Consequences for surface reactions

“…The first stage of Al droplet combustion was already described in [2,19]. The preheating phase corresponds to a partial oxidation of the droplet surface ( Fig.…”

“…The experimental setup was detailed previously [2,19]. A 3-mm aluminum droplet is maintained contactless in an aerodynamic levitation system and is heated by a continuous CO 2 laser.…”

“…It was also observed that the presence of nitrogen promotes the oxide cap formation, while the addition of inert gases (Ar, He) seems to inhibit it [3,17,18]. In [2,19], it was shown that the oxide cap size decreases during Al burning in watercontaining atmospheres; an oxide cap regression rate was estimated in analogy to the burning rate, and was correlated with the droplet temperature, suggesting a chemical decomposition process of alumina by liquid aluminum into gaseous species.…”

“…Because of its high energetic properties, aluminum powder allows a significant increase of the specific impulse of the propellant. For this reason, the combustion of aluminum particles has been strongly studied for these last 40 years [1,2]. However, some phenomena are not yet clearly understood such as the existence of an oxide cap on the Al surface [1][2][3][4][5][6][7][8][9], or possible fragmentation of the aluminum particle [1,3,4,[9][10][11][12][13][14].…”

“…Apart from the oxide cap, other phases may appear on the Al surface such as the formation of aluminum nitride (AlN) and oxynitride (AlON) during the combustion in N 2 -containing atmospheres [2]. The dissolution process of oxygen and carbon inside the particle is also significant.…”