Carbon fibers as additives to engineer agglomeration and propagation of aluminized propellants

A major challenge in the application of aluminum (Al) in solid propellants lies in the incomplete combustion and severe agglomerations of Al particles that cause two-phase flow loss in aluminized solid rocket motor. In this work, 2.5 wt% carbon fibers embedded into Al/AP/HTPB solid propellant shows a ∼ 25 % enhancement in burn rate. In-situ microscopic observation and thermal imaging of combustion find that carbon fibers intercept ejected hot agglomerates near the burning surface and enhance heat feedback to the unreacted material. The post-combustion products were also collected and analyzed, confirming that polyacrylonitrile (PAN)-based carbon fibers keeps their integrity during the combustion, thus can efficiently catch the hot agglomerates and promote the heat feedback. This study outlines how these approaches may enhance the propagation and reduce the two-phase flow losses in solid propulsion.