Utilization of Mechanically Activated Aluminum in Hybrid Rockets

摘要

Polytetrafluoroethylene is known to enhance the reactivity of aluminum. The enhancement in the reactivity isproduced by mechanically activating the aluminum using polytetrafluoroethylene. In this study,mechanicallyactivated aluminum powder is used along with paraffin wax as the fuel grain for a hybrid propellant. Here,gaseousoxygen is used as oxidizer. To achieve an optimum composition for the best specific impulse,the aluminum fraction inthe composition is restricted to 50% of the base fuel composition along with 50% wax/ethylene vinyl acetate(combination of wax and ethylene vinyl acetate,in a ratio of 4:1). The polytetrafluoroethylene in mechanicallyactivated aluminum powder is added at the expense of wax/ethylene vinyl acetate in the fuel composition. Whencompared with the composition having pyral aluminum powder (which has flake like particles of very nigh specificsurface area),mechanically activated powder increases the fuel regression rate by 40% at an oxidizer mass flux of35/cni--s. It is also observed that the combustion efficiency of the hybrid motor is 59% with the use of mechanicallyactivated aluminum powder in comparison to 39% obtained with micron-sized aluminum powder.