Sensitivity Study on a Low Order Model for the Analysis of Transverse Combustion Instability

The present paper investigates transverse combustion instability in multi-injector engines using a low-order modeling approach. It combines one-dimensional injector modeling, three-dimensional combustion chamber modeling, and a response function that mimics the fuel accumulation mechanism sustaining instability in liquid rocket engines with coaxial injectors. The analysis focuses primarily on the impact of the response function parameters on the resulting limit cycle frequency and amplitude. Experimental data from an 82-injector LOX/Methane engine afflicted by transverse instability are used to this goal. The study also explores the possible damping of thermoacoustic phenomena through the use of baffles. Results yield valuable insights into the response function behavior in geometrically complex scenarios and highlight the effectiveness of low-order models as design tools for liquid rocket engines.