Development of Segmented Dynamic Combustion Model to Investigate Instability of Gas Turbine

Abstract

This paper presents a dynamic combustion model with 10 segmented well-stirred reactors which thermo-acoustic instability of gas turbine is able to be evolved. Because combustion instability in gas turbine results in serious damage to the combustor system, it is inevitable to understand the physics of instability. In this study, segmented dynamic combustion model and thermo-acoustic instability model has been developed in Matlab/Simulink® platform. The dynamic segmented model is developed to understand the consumption of fuel and oxidizer and the volume segmentation is discretized by finite difference method. The thermo-acoustic instability model is based on the wave equation to describe the pressure fluctuation. Model is validated with reference experiment which shows that frequency of pressure appears 430Hz, 630Hz under the low-speed and high-speed range respectively. Also fluctuations of speed and temperature corresponding to the two input condition in the chamber were presented. As a result, reliable combustor simulation model has been developed to analyze combustion characteristics under the operating condition.