Time-frequency domain analysis study on dynamic response characteristics of kerosene-fueled scramjet combustor

Scramjet combustor states parameters dynamic characteristics study have great importance in scramjet accuracy thermodynamics regulations. In this investigation the dynamic response characteristics of kerosene-fueled scramjet combustor wall pressures are studied by time-frequency domain analysis method. Firstly, the dynamic response of scramjet combustor wall pressure is stimulated by step input of kerosene under different fuel equivalence ratio by using the direct-connected test facility. Secondly, the time-frequency spectrum of the dynamic response data are analyzed by using Hilbert-Huang transform (HHT) method. In HHT analysis, the raw experiment response data are filtered and decomposed into intrinsic mode functions (IMF) in time domain by the Empirical mode decomposition (EMD), then Hilbert spectral analysis (HSA) examine each IMF's instantaneous frequency as functions of time. Finally, time-frequency domain character distributions with different fuel equivalence ratio(ER) and wall pressure measurement location are given and analyzed by comparison study.