Investigation of Macro-instability in a Stirred Vessel Using the Combined Approach of Power Spectral Density and Wavelet Analysis
应用功率谱密度与小波分析组合法研究搅拌槽内宏观不稳定性

Experiments were carried out in a flat-bottom cylindrical stirred tank with 0.476 m in diameter.The digital-signal processing approaches for macro-instability were analyzed and the combined approach of power spectral density and wavelet analysis was proved to be suitable for analyzing one-dimensional low-frequency signal with noise and peak value.The torque of the impeller was measured by torque transducer and analyzed by using the combined approach.The results show that there are macro-instabilities in the stirred vessel. The dimensionless macro-instability frequency(f/N) obtained by the combined approach was in good agreement with those from the literature.The combined approach of power spectral density and wavelet analysis was proved to be a useful tool for the investigation of macro-instability phenomenon.