抄録
During development of a large size CAMUI-type hybrid rocket motor in 2006, anomalous combustion associated with large pressure spike frequently occurred. After troubleshooting, low temperature of the fuel was found to have caused anomalous combustion. Because a cryogenic liquid oxygen tank is around the motor, polyethylene fuel grain is cooled to liquid oxygen temperature. The anomalous combustion was duplicated with a downsized motor. The size of the fuel grain was 2/5 of large size motor. Because Damkohler number is proportional to the ratio of pressure and oxygen mass flux, the ratio for the subscale motor was conformed to that for the full-scale motor. In a reproductive experiment, pressure spike also appeared. This result suggests that blow-off occurs before the pressure spike. After the blow-off, gas mixture in the chamber may ignite to cause the pressure spike.
