A Parametric Study of Gas-Centered Liquid-Swirl Coaxial Injector under Supercritical Conditions

Gas-centered, liquid-swirl coaxial injector has been adopted in many modern propulsion engines. In the present work, the flow dynamics of gas-centered, liquid-swirl coaxial injectors are numerically investigated at supercritical conditions using large-eddy-simulation techniques. Gaseous oxygen is injected axially into the center post at a temperature of 687.7K, while kerosene is introduced tangentially into the coaxial annulus at a temperature of 492.2K. The operating pressure is 25.3 MPa, well above the thermodynamic critical points of propellants. Key flow characteristics are identified and analyzed in detail. These key dynamic processes include longitudinal acoustic waves in the center post and recess region, vortex shedding near the injection slit, the Kelvin-Helmholtz instability in the recess region and vortical expansion and amalgamation in the taper region. The influence of the recess length on flow dynamics are also explored in depth. Further details will be presented at the meeting.