Influence of Fuel Shape of Hybrid Rocket Engine on Thrust

A hybrid rocket is equipped with an engine consisting of two types of propellants with different phases. It is common to use liquid oxygen for the liquid oxidizer and acrylic for the solid fuel. A hybrid rocket has merits including low cost, safety and environment-friendly. This is because no gunpowder for the propellant. However, it has a weakness of low thrust due to difficulty of burning fuel. The final objective of this research is to develop engines with a higher thrust. For this reason, research has been conducted to burn fuel more efficiently, nevertheless, it has not been commercialized yet. In this study, we used gaseous oxygen for oxidizer and acrylic for fuel. Firing test was carried out with three kinds of fuel; single-port type, convergent type, and divergent type. We studied the influence of acrylic fuel shape on thrust of hybrid rocket engine. As a result, as the contact area of the flame and the fuel increased, the thrust was improved for the convergent type and the divergent type compared to the single-port type.