(189aj) Characterization of Turbulent Fluidization Regime with Geldart Group B Particles by Wavelet Analysis of Pressure Fluctuation Signals

Authors: 
Leu, L., National Taiwan University
Yu, Y., National Taiwan University


The pressure fluctuation signals were measured in a 0.108 m i.d. × 7m high circulating fluidized bed for using Geldart group B powders. By means of the multi-resolution analysis of wavelet transform, the wavelet energy distribution profile of absolute and differential pressure fluctuations in three fluidization regimes were calculated. In bubbling and turbulent fluidization, the energy distribution was dominated by detail signals D6 and D7. Moreover, when the superficial gas velocity reached the transition velocity Uc, the wavelet energy distribution at D6 + D7 reached the maximum value. In the dense lower section of fast fluidization regime, the energy distribution was dominated by detail signals D8 and S8; in the dilute upper section of fast fluidization regime, the energy distribution was dominated by detail signals D4 and D5. When the superficial gas velocity reached the transition velocity Uk, the value of the wavelet energy distribution at D6 + D7 decreased quickly. When the superficial gas velocity exceeded the transition velocity Uk, the energy distribution was dominated by detail signals D6 + D7 or D8 + S8. In this way the regime transition could be found by wavelet analysis.