Effect of acceleration on agglomeration of aluminum particles during combustion of composite solid propellants

Abstract

The effect of the normal acceleration (g-load) on formation of agglomerates and their distribution function is examined within the framework of the statistical model of aluminum agglomeration. A parametric study of aluminum agglomeration with different values of normal g-loads is performed. The theory developed predicts a new effect, namely, a nonmonotonic dependence of the mean-mass size of agglomerates leaving the burning surface on the magnitude of normal g-loads: with increasing g-load, the mean-mass size of agglomerates can increase if the g-loads are low or moderate and decrease if the g-loads are high; in the latter case, the size distribution of agglomerates becomes less spread and more stable.

Aluminum particle agglomeration characteristics and suppression method during the combustion of aluminum‐based solid propellants: A review

“…The propellant's own formulation includes Al particle size [28], content [44], grade [10]; oxidizer particle size [1], content [45], grade [46], type [45]; binder type [21], etc. External environmental factors include pressure [24], atmosphere [47], acceleration [48], etc.…”

“…Glotov [47] has experimentally found that the combustion environment (nitrogen and helium) has little effect on agglomerate size and only has some effect on the size distribution of smoke oxide particles (0.1–3 μm). Rashkovskii [48] has used a mathematical model to predict the effect of acceleration on the size distribution of agglomerates. The results showed that the acceleration and the average mass size of agglomerates show a nonlinear relationship, i. e., when the acceleration is small, the average mass size of agglomerates increases with the acceleration; when the acceleration is large, the average mass size of agglomerates decreases with the acceleration and the agglomerate size distribution becomes more concentrated and stable.…”

Investigation of the agglomeration reduction mechanism of the aluminized HTPB propellant containing ferric perfluorooctanoate [Fe(PFO)3]

“…In addition, hightemperature condensed phase products in the combustion chamber and the nozzle throat can possibly destroy the internal insulation layer of the rocket motor during high-speed motion and cause serious ablation of the nozzle or even blockage of the nozzle throat. 8,9 These defects limit the application of the propellants containing high contents of Al powder.…”

Oxidation Dynamics of Aluminum Nanorods

“…It is well known that during the combustion of aluminum powder propellant, particles could initially melt and coalesce into large agglomerates [4,5]. There are various possible mechanisms of adhesion between the initial aluminum particles and the agglomerates [6,7].…”