Experimental Study on the Influence of Different Oscillation Amplitude on the Combustion Characteristics of Aluminum Particles

Combustion instability is one of the most frequently stated problems with the reliability of the entire flight system. On one hand, aluminum powder can suppress combustion instability in solid rocket motors(SRMs). On the other hand the distributed combustion caused by aluminum may drive the acoustic oscillation. In order to simulate the oscillation of the engine and obtain the comprehensive effect of aluminum on combustion instability, It is essential for understanding the gain and damping factors of combustion instability to study the combustion characteristics of aluminum powder under different oscillation amplitudes. In this study, high-speed photography and digital in-line holography (DIH) are used simultaneously to diagnose the combustion characteristics of aluminized AP/HTPB composite propellant. The experimental results indicate that the flame of aluminum agglomeration particles fluctuates periodically under the acoustic oscillation, and the range and magnitude of flame fluctuation grows as the oscillation amplitude increases. There is a significant difference in the particle size distribution at different oscillation amplitudes, when the oscillation amplitude increases, the mean diameter and agglomeration particle size (Dagg) and agglomeration fraction (fagg) all increase.