Combustion Oscillation Analysis of Premixed Flames at Elevated Pressures

Abstract

A new analytical time lag flame model based on Bloxidge’s flame model was introduced for calculating combustion oscillation of premixed flame to take into account the distribution of heat release rate and flame speed which was calculated by analytical formulas dependent on pressure, temperature, fuel-to-air ratio and velocity. The transfer matrix technique using the new flame model was applied to the calculation of acoustic resonance. To verify the model, combustion oscillation experiments were performed for methane-air premixed flames stabilized by a swirl burner at elevated pressures between 0.6–0.9MPa. Fluctuating pressure had the maximum peak at the specific value of fτf. Here f is the frequency of resonance and τf is the passing time of premixed gas through flame length. The analysis could simulate the dependency of fuel-to-air ratio and static pressure for dynamic pressure local peak.