Simulation of Mixing in Rocket Engine Injectors under In-Space Conditions

Shear layer mixing between two coaxial jets of different density gases has been examined to simulate and analyze mixing and ignition between fuel and oxidizer from a single element injector of a rocket engine. An experimental combustion facility has been designed and fabricated to simulate the behavior of single element coaxial injector. The flow and mixing characteristics of this injector are examined under non-reacting conditions at normal atmospheric pressure. PIV (Particle Image Velocimetry) diagnostics is used to obtain the flowfield distribution of two different density gases that simulates the behavior of gaseous H2/O2 flows from the injector. The results are then used to validate the calculated results obtained from a CFD -model. A RANS type code has been used to simulate the dynamics of the 2-D axisymmetric simulated coaxial injector used in rocket combustors. The model can predict flowfield, turbulence characteristics and species distribution inside the combustor for a range of operating conditions. The code is then used to obtain the flow dynamic behavior as well as species distribution of H2/O2 flows inside a combustion chamber under sub-atmospheric conditions. These results provide useful information on the mixing, ignition and combustion for in-space combustion conditions. The model can be extended to include more realistic operational conditions for the injector as well as the injector-wall interactions.