Simulating Acoustic Combustion Chamber Eigenmodes to Facilitate Combustion Stability in Rocket Engines

R. Kaess [1], J. Braun [1],
[1] Airbus Safran Launchers, Ottobrunn, Germany
Published in 2016

Airbus Safran Launchers is the market leader in Space Launch services. Rocket engines are among the most powerful machines that exist. The core of the rocket engine is the combustion chamber where in the case of liquid propellant rocket engines, fuel and oxidizer are injected, mixed and burnt and where, consequently, the energy release takes place. The hot combustion gases are accelerated in a convergent – divergent nozzle to supersonic speed. Acoustically, the combustion chamber represents a fairly closed volume with low dissipation. Thermo-acoustic instabilities can have detrimental consequences for the engine. Therefore, an approach for simulating the acoustic combustion chamber eigenmodes is presented. The knowledge of the eigenmodes allows for avoiding interactions with other components and facilitates the design of countermeasures, such as baffles or acoustic absorbers.