Mean Flow Augmented Acoustics in Rocket Systems

S. Fischbach[1]
[1]NASA Marshall Space Flight Center / Jacobs ESSSA Group, Huntsville, AL, USA
Published in 2014

Combustion instability in solid rocket motors and liquid engines has long been a subject of concern. Recent advances in energy based modeling of combustion instabilities require accurate determination of acoustic frequencies and mode-shapes. Of particular interest is the acoustic mean flow interactions within the converging section of a rocket nozzle, where gradients of pressure, density, and velocity become large. The expulsion of unsteady energy through the nozzle of a rocket is identified as the predominate source of acoustic damping for most rocket systems. An approach to address nozzle damping with mean flow effects was implemented by French [1]. The present study aims to implement the French model within the COMSOL Multiphysics® framework and analyzes two of the authors presented test cases.