Design and experimental investigation of ejector rocket chamber for RBCC propulsion system

A GO₂/kerosene ejector rocket chamber was designed and tested to meet the requirements of the RBCC propulsion system. It was required to operate at chamber pressure 2 MPa and 1.6 mixture ratio, while the mass flow rate of the rocket was changed from 95 g/s to 285 g/s. The mass flow rate controlling, ignition, injection and thermal protection of the faceplate and chamber body have achieved reasonably good performance during the reacting flow tests and non-reacting flow tests. Then the performance of the rocket was investigated in the RBCC combined tests. As the results shown, the rocket has achieved efficiency 88%~98% C^*, and it is influenced by the mass flow rate, mixture ratio, momentum flux ratio and pressure decrease of the rocket. The higher momentum flux ratio and pressure decrease in a suitable range, the better performance of the atomizing, mixing and burning will attain. Although the pressure decrease of the kerosene is only 11% of the design value, the GO₂/kerosene Gas Center Swirl Coaxial (GCSC) injector can achieve efficienicy at least 88% C^* by effective aerodynamic effects. The purge flow should be controlled in tests and taken into account when the performance of the rocket is analyzed, as there will be efficiency decrease by 3% C^* when the purge flow reaches 5% of the rocket mass flow rate. When the performance of the rocket is compared in the separate tests and combined tests, the rocket is found to attain almost efficiency 7% higher C^* in combined test, because of its longer characteristic length.