562015-03-24 , 法政大学大学院理工学・工学研究科
The present paper describes an attempt to develop a testing technology to understand correlation between fuel/air mixing characteristics inside the pre-mixing duct of a lean staging burner for an aero engine and resulting combustion characteristics in the combustion chamber downstream. Laser induced fluorescence (LIF) of OH radicals and of kerosene was chosen as a visualization method for this purpose. In addition to the side wall of the optical combustor, the outer-wall of the burner was also made of transparent quartz to realize optical access. The experiments were conducted at high temperature and high pressure burning conditions to simulate a realistic operating condition of the aero-engine. The results revealed time-averaged three-dimensional structure on the development of fuel/air mixing in the pre-mixing duct in the streamwise direction with effects of swirling air, and on the relationship between spatial distributions of OH radicals and of fuel concentrations. Furthermore, instantaneous inter-relation of their planar spatial distributions was also obtained by simultaneous application of the two LIF techniques. In summary, the present approach was proven to be effective, which is also potentially capable of being applied as a diagnostic tool to unsteady combustion behaviors such as combustion oscillations.