Additive Manufactured Thermoplastic-Aluminum Nanocomposite Hybrid Rocket Fuel Grain and Method of Manufacturing Same

摘要

A hybrid rocket solid fuel grain having a cylindrical shape and defining a center port is additive manufactured from a compound of thermoplastic fuel and passivated nanocomposite aluminum additive. The fuel grain comprises a stack of fused layers, each formed as a plurality of fused abutting concentric circular beaded structures of different radii arrayed defining a center port. During operation, an oxidizer is introduced along the center port, with combustion occurring along the exposed port wall. Each circular beaded structure possesses geometry that increases the surface area available for combustion. As each layer ablates the next abutting layer, exhibiting a similar geometry is revealed, undergoes a gas phase change, and ablates. This process repeats and persists until oxidizer flow is terminated or the fuel grain material is exhausted. To safety achieve this construction, a fused deposition additive manufacturing apparatus, modified to shield the nanocomposite material from the atmosphere is used.

主权项

1. A method of making a fuel grain for use in a hybrid rocket engine, the method comprising:
compounding a first material suitable as a hybrid rocket fuel and a second energetic and pyrophoric nanoscale metallic material according to a predetermined mixture ratio to form a third material; the third material serving as feedstock material for use in an additive manufacturing apparatus; and operating the additive manufacturing apparatus using the feedstock material to fabricate a fuel grain comprising a plurality of fused stacked layers of solidified fuel grain material, each layer of the plurality of layers comprising a plurality of bonded and concentric substantially circular ring-shaped beads of different radii and defining a center combustion port.