离心-温度复合装置的自学习切换控制方法研究

在发动机试验中，推力室脉动压力数据是研究发动机性能、判断不稳定燃烧的重要依据。针对发动机试验脉动压力数据的特点和传统傅里叶变换在时频分析领域的不足，根据经验模态分解（Empirical Mode Decomposition， EMD）方法良好的自适应特征、瞬时频率的精确定位能力、局部瞬时表达能力以及提取信号分量的优点，对发动机试验脉动压力数据进行分析。介绍了采用EMD方法对脉动压力数据进行分析的方法和步骤。分别采用FFT方法、EMD分解和基于不同小波基函数的小波分析方法分析脉动压力数据，总结了FFT和小波分析两种方法对非线性非平稳数据进行分析的不足。研究的结果显示，EMD方法能够较好地分析非线性非平稳脉动压力数据，且对研究、分析发动机试验脉动压力数据的频谱特征和不稳定燃烧具有重要的应用和推广价值。

Analysis of engine fluctuating pressure data based on empirical mode decomposition

In the engine test, the fluctuating pressure data of the thrust chamber is an important basis for studying the performance of the engine and judging the unstable combustion. In view of the characteristics of engine test fluctuating pressure data and the shortcomings of traditional fourier transform in the field of time?frequency analysis, the engine test fluctuating pressure data are analyzed according to the advantages of empirical mode decomposition (EMD) method, such as good adaptive characteristics, accurate positioning of instantaneous frequency, local instantaneous expression ability and extraction of signal components. The method and steps of analyzing fluctuating pressure data by EMD method are introduced. FFT method, EMD decomposition and wavelet analysis method based on different wavelet basis functions are used to analyze fluctuating pressure data respectively. The shortcomings of FFT and wavelet analysis methods in analyzing nonlinear and non-stationary data are summarized. The results show that the EMD method can well analyze the nonlinear and non-stationary data of fluctuating pressure. This method has important application and popularization value for studying and analyzing the frequency spectrum characteristics of engine test fluctuating pressure data and unstable combustion.