Effect of velocity ratio on combustion process gas-gas injector

In order to develop the gas-gas injector for full flow staged combustion cycle engine, hot fire tests were conducted on shear coaxial injector that utilized gaseous oxygen and gaseous hydrogen as propellants. Through measurements of chamber pressure and wall temperature, the effects of hydrogen to oxygen velocity ratio on combustion efficiency as well as the combustor heat load were investigated. The results show that the combustion efficiency was affected by both the injecting velocity ratio of hydrogen to oxygen and the absolute velocity of propellants. The combustor heat load increases with increasing velocity ratio. A low oxygen pressure drop and an appropriate velocity ratio are the preferable choice for shear coaxial gas-gas injector.