基于高速化学发光测量的超声速燃烧室振荡特性统计学分析

To analyze the oscillation behavior of the flame in a supersonic combustor fueled with hydrogen, high-speed chemiluminescence images were recorded under two different equivalence ratios (Φ). A series of statistical analysis were performed, including the time-averaging of the images, the RMS variation, the proper orthogonal decomposition (POD) and the oscillation of the flame edge speed at the shear layer, to study the overall and transient behaviors of the flame instabilities. The results show that the flame is stabilized in the cavity in both fuel lean and fuel rich conditions, and the anchor position and flame surface area are similar in both cases. In fuel rich case, the flame was observed also in the main supersonic flow region which is attributed to the bow shock formed by the fuel jet. Via POD analysis, the main flame oscillation modes in the cavity combustor are the alternative oscillation along the flow direction and the alternative oscillation between the shear layer and the recirculating zone in the cavity. The fluctuation of the flame brush edge speed under the condition of Φ=0.2 is 2 times larger than that of Φ=0.3.