Evaluation of Paraffin–Polyethylene Blends as Novel Solid Fuel for Hybrid Rockets

A novel paraffin-based blends fuel prepared from pure paraffin wax of the alkane family with polyethylene of the alkene family is proposed and tested in a slab motor to visualize the droplet entrainment mechanism followed by a hybrid rocket motor test to analyze its combustion characteristics. The mechanical strength of the proposed blended fuel is investigated by increasing the polyethylene weight percent. The overall regression rate of 5 wt % of polyethylene with 95 wt % of pure paraffin is found to be 3.9 factors higher than that of a pure polyethylene. Improved combustion efficiency under the condition of a similar oxidizer mass flow rate range is achieved with respect to pure paraffin fuel in which performance gain is comparable to that of the SP-1a fuel of Stanford University. Spectrum analysis of the chamber pressure shows no critical instability mode for the range of this study. The blend fuel is found to be comparatively effective for the hybrid rocket fuel in terms of mechanical strength, combustion efficiency, combustion instability, and combustion performance.