Control effects of perforated liner on combustion instability based on nonlinear flame modles

Combustion instabilities are undesirable for the performance of power devices, such as rocket engines, aeroengines and furnaces. High-amplitude pressure oscillations will cause mechanical and thermal stress to the combustor and lead to structural damage in severe cases. Therefore, it is essential to prevent the onset of combustion instabilities or at least suppress finite-amplitude oscillations in the nonlinear limit cycles. In this paper, the control effects of the perforated liners on the combustion instabilities based on nonlinear flame models are investigated using analytical approach. The approach is based on the network model and transfer element method (TEM). The TEM is used to describe the acoustics in the lined section that is influenced by the perforated liners. To establish an eigenvalue problem, appropriate matching and boundary conditions are applied. It is found that the limit cycles are suppressed with the control effect of the perforated liner. Meanwhile, the stability map is markedly different with the heat source position and the velocity amplitude when the perforated liners come into play. And the acoustic resistance and the acoustic reactance play different roles in changing the stability map.