液体内包式ハイブリッドロケット燃料の構想と3D プリンタによる試作

抄録

Hybrid rockets have the advantages of safety propulsion system and low cost fuel compared to liquid rockets and solid rockets, but improving the burning rate of fuels is a major issue, and various approaches have been taken for fuel properties and combustion methods. The author devised a liquid-encapsulated fuel as a measure to improve the burning rate of the hybrid rocket. The liquid-encapsulated fuel is containing the liquid fuel in the solid fuel. At the burning surface, liquid fuel is directly supplied to the combustion area and the surface without melting process or gasification process of usual hybrid rocket fuels. Also it is possible to control the burning rate by the shape, position, and number of containing the liquid. In order to demonstrate the production of the liquid-encapsulated fuel, the author prototyped a solid fuel containing liquid fuel with a size of 10 mm×10 mm×100 mm using a stereolithography 3D printer with a liquid resin. And the liquid-encapsulated fuels were prototyped, but the bubbles were generated inside the liquid. After investigating the cause, the author sought an appropriate curing process of 3D printer and shape design guidelines that suppress the generation of bubbles, and succeeded in prototyping a liquid-encapsulated fuel without bubbles.