Impact of Nanoscale Aluminum on the Burn Rate of Composite Propellants Manufactured using Conventional Mixing Techniques

摘要

Several HTPB/AP/Al-based composite propellant mixtures were prepared with and without the addition of small percentages of nanoscale aluminum and burned in a strand burner at pressures up to 5000 psi. The effect of monomodal versus bimodal AP particle size, course aluminum particle size, nano aluminum particle size, and course-to-fine ratios on burn rate and manufacturability were explored. A significant conclusion of the present study is that the addition of nano-sized aluminum does not necessarily increase a propellant's burn rate when prepared using conventional methods. It was observed that, over the range of mixtures and pressures explored, a bimodal oxidizer is required for the nanoscale Al to affect the burning rate, and that a monomodal oxidizer tended to nullify any influence. In some cases, the addition of nano-sized aluminum actually decreased the burn rate. The level of burn rate increase or decrease depended on the bimodal or monomodal AP particle sizes, the coarse Al particle size, and the pressure range.