GLYCIDYL AZIDE POLYMER AND POLYETHYLENE GLYCOL MIXTURES AS HYBRID ROCKET FUELS

Abstract

Two types of hybrid rocket motors that use mixtures of glycidyl azide polymer (GAP) and polyethelene glycol (PEG) as the solid fuel are proposed and the combustion characteristics are presented. GAP and PEG mixtures in which the PEG concentrations are lower than a critical value between 40 and 50 mass% can sustain self-combustibility and can be used as a solid fuel for gas hybrid rocket systems, while mixtures with higher PEG concentrations and without self-combustibility can be employed as a solid fuel for traditional hybrid rockets. Thrust control and tailoring using changes in both the oxidizer/fuel (O/F) ratio and grain composition were investigated for the gas hybrid system, and successful control was accomplished in experiments. Firing tests were conducted of a traditional hybrid rocket motor as functions of the oxygen mass flux and burning pressure. The effect of GAP is obvious, and GAP enhances the regression rates of the solid fuel grain, and an effect of pressure was also found. The distributed flame model is discussed briefly here to explain the regression rate increase by GAP.