Clean combustion, such as hydrogen combustion for the reduction of NOx emissions, is prone to thermo-acoustic instabilities which may cause structural vibrations and equipment failures. In the present work, an adjoint-based sensitivity analysis is applied to a low-order thermo-acoustic model. A structural sensitivity analysis is conducted first to evaluate the effects of a generic feedback mechanism on eigenvalues of concern. It is found that the most stabilizing feedback mechanism is the addition of mass, in a quantity which is proportional to the pressure perturbation right downstream of the flame. Sensitivity of the eigenvalues to base flow modifications is also assessed. Such analyses provide gradient information for optimization techniques to mitigate or cancel such instabilities with quick and low-cost calculations.
Adjoint-based sensitivity of a thermo-acoustic system
Wei J.;Pralits J. O.;Bottaro A.
2022-01-01
Abstract
Clean combustion, such as hydrogen combustion for the reduction of NOx emissions, is prone to thermo-acoustic instabilities which may cause structural vibrations and equipment failures. In the present work, an adjoint-based sensitivity analysis is applied to a low-order thermo-acoustic model. A structural sensitivity analysis is conducted first to evaluate the effects of a generic feedback mechanism on eigenvalues of concern. It is found that the most stabilizing feedback mechanism is the addition of mass, in a quantity which is proportional to the pressure perturbation right downstream of the flame. Sensitivity of the eigenvalues to base flow modifications is also assessed. Such analyses provide gradient information for optimization techniques to mitigate or cancel such instabilities with quick and low-cost calculations.
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