Numerical Investigation of Flame-Acoustic Interaction at Resonant and Non-Resonant Conditions in a Model Combustion Chamber

Abstract

This paper investigates flame-acoustic interaction in a model combustion chamber using detached-eddy simulation methods (DES) in three different setups. We present simulation results for a new load point of combustion chamber H from DLR Lampoldshausen and explore the flame response to resonant and non-resonant external excitation. The first part of the paper shows results for the steady-state flow field without siren excitation. These results are used to determine the combustion chamber eigenmodes by means of an impulse-response approach and we compare the results to experimental data and Helmholtz modes. In the second part of this paper, numerical results with transversal excitation at non-resonant conditions are compared to the steady-state eigenmodes and it is argued that the nonresonant excitation is a more realistic representation of the experimental situation than the unexcited steady-state simulation. The last part of the paper compares non-resonant and resonant simulations and reports a strong influence of resonant siren excitation on the shape and length of the dense LOx cores and the flame field which confirms previous studies of similar configurations.