Predicting lean blow-off limit of gas turbine combustors based on Damköhler number and detailed atomization information

Abstract

A hybrid lean blow-off prediction method based on Damköhler ( Da) number was proposed in the authors’ previous study. However, the uniform model for fuel drop size distribution cannot fully reflect the actual atomization quality under lean blow-off conditions, which has negative effects on prediction accuracy. In the current study, atomization experiments are conducted under different fuel supply pressure. The atomization quality is described by Rosin–Rammler model and is integrated into numerical simulation. The calculation method of chemical time scale ( τc) is improved by accurately differentiating the inlet and outlet surface of reaction zone. After the improvement, the Da number under lean blow-off conditions mainly lies between 0.3 and 0.8, while under the designing condition, the Da number is about 20. Compared with the former method, the optimized method in the present article can distinguish stable combustion states markedly from lean blow-off states. Through the introduction of detailed atomization information and the improvement of time scale calculation, lean blow-off prediction accuracy in the present work is efficiently improved, which can provide powerful technical support for engineering applications.