High Pressure Fuel Regression Characteristics of Axial-Injection End-Burning Hybrid Rockets

Abstract

This study is an investigation of axial-injection end-burning hybrid rockets aimed at revealing fuel regression characteristics under relatively high-pressure conditions. Firing tests are conducted using gaseous oxygen as the oxidizer at chamber pressures and oxidizer port velocities ranging from 0.22 to 1.05 MPa and 31 to , respectively. The results of 15 static firing tests show that the fuel regression rate increases as the chamber pressure increases, and regression rates range from approximately at 0.25 MPa to at 0.90 MPa. Furthermore, it is observed that the pressure exponent of the fuel regression rate is 1.05 and the fuel regression rate is not influenced by the oxidizer port velocity in this study. The model explains that the backfiring problem tends to occur in relatively high-pressure conditions, and it leads to the conclusion that increasing the nozzle throat diameter is an effective means of preventing backfiring from occurring.