APS -70th Annual Meeting of the APS Division of Fluid Dynamics- Event - An adjoint-based sensitivity analysis of thermoacoustic network models

摘要

Thermoacoustic instability is a phenomenon that occurs in numerouscombustion systems, from rockets to land-based gas turbines. Theacoustic oscillations of these systems are of significant importanceas they can result in severe vibrations, thrust oscillations, thermalstresses and mechanical loads that lead to fatigue or even failure. Inthis work we use a low-order network model representation of acombustor system where linear acoustics are solved together with theappropriate boundary conditions, area change jump conditions, acousticdampers and an appropriate flame transfer function. Special emphasisis directed towards the interaction between acoustically driveninstabilities and flame-intrinsic modes. Adjoint methods are used toperform a sensitivity analysis of the spectral properties of thesystem to changes in the parameters involved. An exchange of modalidentity between acoustic and intrinsic modes will be demonstrated andanalyzed. The results provide insight into the interplay betweenvarious mode types and build a quantitative foundation for the designof combustors.