FAST INFRARED IMAGING TO STUDY BURNER FLUCTUATIONS

Numerous experimental studies and numerical models were developed to understand the behavior of gas turbines with LPP technology; in particular several researches are undergoing to better understand fuel/air interaction in the premixing duct, upstream of the combustion chamber. In this paper, studies were performed on kerosene lean premixed flames in a LPP burner by mean of PLLS and a new technology such as FAst IR Imaging varying the Air Fuel Ration (AFR). Both techniques evidenced oscillation frequencies around 100 Hz both under cold conditions and combustion. Typical frequencies bias toward combustion were identified. The FAIRI technique allowed to identify higher frequencies (up to several kHz) in the 2D dimensions. The investigation also evidenced that the typical frequencies shift up while increasing AFR. Finally, the analysis of the frequency slope allowed to characterize the turbulence levels along the flame.