유동섭동에 의한 난류예혼합화염의 열방출 모델에 관한 연구

Abstract

The unsteady heat release characteristics play a significant role in combustion instabilities often observed in low emissions gas turbine combustors. Such combustion instabilities are often caused by coupling mechanisms between unsteady heat release rates and acoustic perturbations. A generalized model of the flame response to acoustic perturbations, including mixture ratio perturbations, is analytically formulated to extend the prior models by considering a distributed heat release along the mean flame front and using the flame’s kinematic model that incorporates the turbulent flame development. A specific example for the flame transfer function due to flame area fluctuation showed that, when a developing flame speed is used, the transfer function magnitude decreases faster at low Strouhal number and the transfer function phase increases more rapidly, as compared to the results with a constant flame speed. The results from both types of flame speed observe a well known n-τ model.