Experimental investigation of fuel composition and mix-enhancer effects on the performance of paraffin-based hybrid rocket motors

Experimental investigations have been performed for a lab-scale hybrid rocket motor with hydrogen peroxide and paraffin-based propellants. A new paraffin-based solid fuel with favorable mechanical strength, consisting of 50 wt% paraffin, 20 wt% PE wax, 18 wt% EVA, 10 wt% SA and 2 wt% carbon, was proposed. The thermal properties of the proposed paraffin-based fuel and its components were firstly evaluated using TG/DTG measurements. It was found that the decomposition rates of each of the components of this paraffin-based fuel follow the order SA > pure paraffin > paraffin-based fuel blends > PE > EVA. Measurements of the regression rate of this paraffin-based fuel were performed and compared with results found in the literature. This showed that the regression rate of this paraffin-based fuel is much higher than that of traditional polymer solid fuels such as HTPB fuels. Finally, by adding a protrusion, a cavity and swirl blades at the end and in the middle of the combustion chamber, experimental investigations into the effects of a mix-enhancer on the paraffin-based hybrid rocket motor were performed. These investigations are discussed in detail.