Effect of Magnalium on Burning Rate and Agglomeration Size of Composite Propellant

抄録

This study experimentally investigates the effects of magnalium on the burning rate and agglomeration size of aluminized composite propellants. Decreasing the size of agglomerations on the burning surface can reduce slag formation in a solid rocket motor. Magnalium, an alloy of magnesium and aluminum, can serve this purpose owing to its excellent ignitability and combustion properties. However, it also increases the burning rate and diminishes motor performance. Therefore, the effects of magnalium on the burning rate and agglomeration size should be investigated. Propellants (15 wt% HTPB, 17 wt% metal, and 68 wt% AP) whose compositions vary only in terms of their metal content are tested. The metallic component used is a mixture of aluminum and magnalium (aluminum 50 wt%: magnesium 50 wt%), and the magnalium ratios are 0, 0.25, 0.5, and 1.0. Combustion tests were conducted using an N₂-flashed strand burner and an agglomeration collector. The propellant strands were burned at pressures ranging from 0.1 to 5 MPa. The burning rate increased with increasing magnalium content. The agglomerations of composite propellants were collected, and their sizes and size distributions were measured. De Brouckere's mean diameter D₄₃ of the agglomerations decreases with the addition of magnalium and a decrease in ambient pressure.