Exergy as Lyapunov Function for Studying the Dynamic Stability of a Flow, Reacting to Self-Oscillation Excitation

Abstract

This article introduces a new, physically-based Lyapunov function definition that can be used as acoustic energy for finite-amplitude pressure oscillations in reacting systems, especially in combustion chambers. Reacting flow is seen as an open, non-equilibrium (parameters are distributed unevenly locally) thermodynamic system. This Lyapunov function is defined as the maximum mechanical work that could be extracted by a heat engine from the studied system if this system were disconnected from the inlet and outlet and from any other surrounding environment and the engine could transfer to the surrounding environment only mechanical work.

Keywords

• reacting flow stability
• self-sustained oscillations
• combustion instability
• finite amplitude acoustic