Beeswax material: Non-conventional solid fuel for hybrid rocket motors

Abstract

Traditional solid fuel for Hybrid Rocket Motor (HRM) is characterized as a low regression rate, aiming to develop a new generation of solid fuel material that combines at the same time good ballistic properties, easy manufacture, safe exhaust emission and low cost. Beeswax as bio-derived hydrocarbon fuel has been evaluated to be used as solid fuel in HRM. Firing tests are carried out at the average pre-chamber pressure of 2.90 bar, the oxidizer mass flow rate of 9.34 g/s and the regression rate of 1.5 mm/s at combustion efficiency reaches 60.3%. Beeswax as pure solid fuel grain at 7 mm active channel port with 100 mm length is tested with gaseous oxygen (gO2) as oxidizer and it showed a regression rate at least three times as high as traditional hybrid propellant, such as Polymethyl methacrylate (PMMA) and Polyethylene (PE)/gO2. This provides a promise for high performance parameters with a special regression rate to overcome the main drawbacks of traditional hybrid propellant. Experimental evaluation parameters (regression rate, fuel mass flow rate and combustion efficiency) are carried out for beeswax/gO2. Combustion shows fairly successful results for lab scale testing but it needs further enhancement, especially in combustion efficiency and theoretical studies for combustion efficiency.