气固流化床压力脉动信号的频域熵分析

Frequency-Domain Entropy Analysis of Pressure Fluctuations in a Gas-solid Fluidized Bed

对气固流化床风室内的压力脉动信号进行频域变换,使用三种熵分析方法,研究了一个内径150 mm、高2.5m流化床不同静床高工况下的流动特性和流型特征。实验结果表明:这三个方法得到的特性曲线可以较好地判别固定/鼓泡/湍动床三个流型;在确定从鼓泡床向湍动床转变的转变点上,DFT熵方法优于小波熵和小波包熵方法,物理意义更明确且计算更快捷。

The pressure signals measured in the plenum of a fluidized bed （i.d. 150 mm, height 2.5 m） were transformed into frequency-domain contents which were analyzed by three entropy methods in order to study the characteristic of flow dynamics and flow regimes. It shows that： the three entropy characteristic curves can distinguish the three flow regimes （i.e. fixed/bubbling/turbulent） well; The DFT Shannon entropy does better than wavelet entropy and wavelet packet entropy on marking the transition point from the bubbling bed to the turbulent bed, and it has clearer physical meaning and less computation time.