A Parametric Study of the Effect of Liquid Fuel Entrainment on the Combustion Characteristics of a Paraffin-Based Hybrid Rocket Motor

The interaction between a melting hybrid rocket fuel grain and the combustion processes inside the combustion chamber of a hybrid rocket motor was investigated using a CFD model, ultimately evaluating how this affects the motor’s performance. The motor’s working conditions were simulated by changing the global oxidizer to fuel mass flow ratio, the fraction of the total fuel entrained by the oxidizer, and the size distribution of the entrained droplets. Due to the transport of the fuel droplets the reaction zones are extended farther downstream, which results in an incomplete evaporation and causes significantly lower combustion efficiency comparing to the ideal well-mixed mixture

A wide characterization of paraffin-based fuels mixed with styrene-based thermoplastic polymers for hybrid propulsion

In the framework of a long-term research activity focused on the development of high-performance solid fuels for hybrid rockets, paraffin-based fuels were investigated and characterized using two different pure paraffinic waxes and a styrene-based thermoplastic elastomer as strengthening material. The fuels were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis / differential thermal analysis (TGA-DTA). The viscosity of the melt layer, responsible for the entrainment effect, was investigated using a Couette viscosimeter. The storage modulus (G′) was analyzed using a parallel-plate rheometer. The chemical composition of the pure paraffinic materials was studied using gas chromatography / mass spectrometry (GC-MS), while mechanical properties were investigated through uniaxial tensile tests