A low order modeling approach to transverse combustion instability

A low order modeling approach to the problem of the transverse combustion instability in liquid propellant rocket engines is presented and applied. The model is based on a val- idated approach for the one-dimensional study of longitudinal combustion instability. The one-dimensional technique is used here to simulate the injector behavior and is suitably cou- pled with a three-dimensional model aiming to simulate the combustion chamber domain. The two models work in synergy. The 3D tool is in charge of the combustion modeling and of mul- tidimensional wave propagation, while the 1D one cares about dynamics of the shear-coaxial injectors. Such dynamics includes a coupling function describing the unsteady mass addition caused by the acoustic propagation which closes, in fact, the instability feedback loop. In both one- and three-dimensional domains multispecies inviscid unsteady Euler equation are solved. Results obtained with the present approach on literature test cases are presented: the full unstable solution for a single injector longitudinally unstable test case and the preliminary analysis of a 3D instability test case.