ADN Solid Propellants with High Burning Rates as Booster Material for Hypersonic Applications

Abstract

RAM-and SCRAM-Jet engines can not generate static thrust and only work at high speeds. This starting velocity of the motor v 0 is usually generated by carrier rockets or boosters, which mostly use solid propellants based on ammonium perchlorate (AP) and hydroxyl-terminated polybutadiene (HTPB). Modern solid propellants based on ammonium dinitramide (ADN) and Glycidyl Azide Polymer (GAP) have significant advantages in terms of environmental compatibility and thermodynamic performance. In the present work, it is shown that the already high burning rate of ADN solid propellants can be more than doubled by means of metallic fibers, which significantly increases the thrust of such engines. In order to achieve such results, 3 wt% of AlÀ Mg alloy fibers are added to the propellant. A formulation with 3 mm long fibres shows the highest burning rate with 84.0 mm/s at 26.5 MPa. Small scale motor tests confirm these investigations. The burning mechanism is studied by SEM/EDX investigations and by measuring the thermal conductivity. These show that the fibres remain on the burning surface and thus transfer the heat from the flame to the depth of the propellant. The thermal conductivity of samples with AlMg5 fibers is about 22 % higher than the reference.

Combustion of ammonium dinitramide based solid propellant with PBT as energetic binders

“…[11] and Vogelsanger et al. [25] and ADN/GAP propellants (the content of ADN was 70 wt%) measured by Sims [26] were shown in Figure 11 as well.…”

Research progress on the catalytic and thermal decomposition of ammonium dinitramide (ADN)

“…Compared to AP, ADN exhibits signicant advantages, including a higher enthalpy of formation, faster-burning rate, higher specic impulse, and no toxic gas HCl is formed during combustion, substantially rendering ADN one of the most promising oxidizers. [21][22][23][24] So far, the synthesis processes for ADN are quite mature. Chen et al 25 summarized several methods (aminopropionitrile method, urea method, carbamate method, and sulfamate method) in their work, which lays the foundation for the scaled-up application of ADN in the future.…”

“…28,29 Solid propellants do not require a complex fuel supply and combustion control systems, which makes solid thrust systems more reliable. 23 As a result, ADN can also be used as an oxidizer and mixed with fuels, binders, and plasticizers to prepare solid composite propellants, which makes it promising to replace the traditional oxidant AP. However, ADN-based solid propellants still have some shortcomings.…”

Characterization of Electrospinning Prepared Nitrocellulose (NC)-Ammonium Dinitramide (ADN)-Based Composite Fibers

“…The utilization of the high energetic oxidizer, such as ammonium dinitramide (ADN), gives several desirable characteristics when employed in solid rocket propellants and explosives. In this work, ADN [ 34 , 35 ], one kind of green oxidizer with high energy and an OB of 25.8%, was introduced into the NC matrix to compose a system with high reactivity that behaves in the way that thermite does. Additionally, the high explosives RDX and CL-20 were also introduced to improve the total energy.…”