화염 길이가 저차원 열음향 모델에 미치는 영향에 대한 수치적 연구

Abstract

The thermoacoustic network model is a low-order modeling approach used to analyze and predict thermoacoustic instabilities arising from the positive interaction between unsteady heat release and a combustor’s acoustic field. In this study, we question the conventional assumption of a compact flame in thermoacoustic network models by systematically analyzing the effect of flame length on this low-order framework. We first compare the growth rates and mode frequencies of thin and long flames using a three-dimensional analysis tool, revealing a clear discrepancy between the two cases. We then evaluate a one-dimensional network modeling strategy that segments the flame. The results indicate that both the thin-flame assumption and the segmented-flame approach fail to reproduce the full thermoacoustic dynamics within the combustor. We also investigate the influence of varying gain and time delay parameters on growth rates and mode frequencies. The findings of this study demonstrate that flame length has a significant impact on thermoacoustic behavior, and this influence should be appropriately incorporated into low-order thermoacoustic models. Based on these observations, we suggest future research directions for improving existing thermoacoustic network models.