Investigation of heat transfer at the outer combustor wall on self-sustained thermoacoustic oscillations in a Rijke tube

Abstract

Thermoacoustic oscillations have plagued combustion systems for decades and are becoming increasingly relevant as engines become more powerful, more compact, and more eco-friendly. These oscillations arise from constructive coupling between unsteady heat release and acoustic pressure waves, and result in strong pressure oscillations that can inhibit flame stability and induce component failure. In this work, a simple numerical model is used to study the effects of the temperature distribution of the outer combustor wall on the thermoacoustic stability of a Rijke tube. A Galerkin series expansion of the linearized acoustic governing equations is coupled with a classical G-equation premixed flame model to determine the minimum energy required to maintain stability for various system configurations, and results are compared against computational fluid dynamics simulations for select cases.