Study on the Regression Rate of Paraffin-Based Hybrid Rocket Fuels

The most important issue with a conventional hybrid rocket is its very low fuel regression rate. However, paraffin-based fuels are known to have a much higher regression rate. It was determined theoretically that materials with low surface tension and melt-layer viscosity, such as paraffin-based fuels, generate more entrainment and increase the regression rate. This was a very interesting theory. It was therefore decided to prove it experimentally by observing burning fuels in a visualization chamber. This experiment revealed the high regression rate of paraffin-based fuels. Changing the melting paraffin-based fuel viscosity by adding ethylene-vinyl acetate copolymer was found to be successful. The regression rates of these fuels were measured and determined the relation between the regression rates and the viscosities of the melting fuels. It has been considered that this relation proves the high regression rate theory.