Rate-dependent bifurcation dodging in a thermoacoustic system driven by colored noise

TL;DR

This paper investigates how changing the rate of bifurcation parameters and noise characteristics can prevent thermoacoustic instability in engines, providing a mathematical framework and control insights.

Contribution

It introduces a stochastic model of thermoacoustic systems driven by colored noise and analyzes how parameter change rate and noise correlation influence instability dodging.

Findings

Faster parameter changes help dodge instability

Longer noise correlation time is beneficial

Higher noise intensity hampers instability avoidance

Abstract

Tipping in multistable systems occurs usually by varying the input slightly, resulting in the output switching to an often unsatisfactory state. This phenomenon is manifested in thermoacoustic systems. This thermoacoustic instability may lead to the disintegration of rocket engines, gas turbines and aeroengines, so it is necessary to design control measures for its suppression. It was speculated that such unwanted instability states may be dodged by changing quickly enough the bifurcation parameters. Thus, in this work, based on a fundamental mathematical model of thermoacoustic systems driven by colored noise, the corresponding Fokker-Planck-Kolmogorov equation of the amplitude is derived by using a stochastic averaging method. A transient dynamical behavior is identified through a probability density analysis. We find that the rate of change of parameters and the correlation time of the noise are helpful to dodge thermoacoustic instability, while a relatively large noise intensity is a disadvantageous factor. In addition, power-law relationships between the maximum amplitude and the noise parameters are explored, and the probability of successfully dodging a thermoacoustic instability is calculated. These results serve as a guide to the design of engines and to propose an effective control strategy, which is of great significance to aerospace-related fields.