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SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2021, Vol. 32 ›› Issue (4): 87-99.DOI: 10.1016/j.cjche.2020.09.042

• Fluid Dynamics and Transport Phenomena • 上一篇    下一篇

Time-series analysis of the characteristic pressure fluctuations in a conical fluidized bed with negative pressure

Sheng Fang1,2, Yanding Wei1,2, Lei Fu3, Geng Tian1,2, Haibin Qu4   

  1. 1 The State Key Laboratory of Fluid Power and Mechatronic Systems, College of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China;
    2 Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province, College of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China;
    3 College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310023, China;
    4 Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
  • 收稿日期:2020-04-20 修回日期:2020-07-31 出版日期:2021-04-28 发布日期:2021-06-19
  • 通讯作者: Yanding Wei, Haibin Qu
  • 基金资助:
    This work was supported by the National Standardization Project of TCM (ZYBZH-C-TJ-55) and National Science and Technology Major Project (2018ZX09201011-002). We thank American Journal Experts (AJE) for English language editing.

Time-series analysis of the characteristic pressure fluctuations in a conical fluidized bed with negative pressure

Sheng Fang1,2, Yanding Wei1,2, Lei Fu3, Geng Tian1,2, Haibin Qu4   

  1. 1 The State Key Laboratory of Fluid Power and Mechatronic Systems, College of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China;
    2 Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province, College of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China;
    3 College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310023, China;
    4 Pharmaceutical Informatics Institute, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
  • Received:2020-04-20 Revised:2020-07-31 Online:2021-04-28 Published:2021-06-19
  • Contact: Yanding Wei, Haibin Qu
  • Supported by:
    This work was supported by the National Standardization Project of TCM (ZYBZH-C-TJ-55) and National Science and Technology Major Project (2018ZX09201011-002). We thank American Journal Experts (AJE) for English language editing.

PDF (PC)

摘要： The negative pressure conical fluidized bed is widely used in the pharmaceutical industry. In this study, experiments based on the negative pressure conical fluidized bed are carried out by changing the material mass and particle size. The pressure fluctuation signals are analyzed by the time and the frequency domain methods. A method for absolutely characterizing the degree of the energy concentration at the main frequency is proposed, where the calculation is to divide the original power spectrum by the average signal power. A phenomenon where the gas velocity curve temporarily stops growing is observed when the material mass is light, and the particle size is small. The standard deviation and kurtosis both rapidly change at the minimum fluidization velocity and thus can be used to determine the flow regime, and the variation rule of the kurtosis is independent of both the material mass and particle size. In the initial fluidization stage, the dominant pressure signal comes from the material movement; with the increase in the gas velocity, the power of a 2.5 Hz signal continues to increase. A method of dividing the main frequency by the average cycle frequency can conveniently determine the fluidized state, and a novel concept called stable fluidized zone proposed in this paper can be obtained. Controlling the gas velocity within the stable fluidized zone ensures that the fluidized bed consistently remains in a stable fluidized state.

关键词: Conical fluidized bed, Negative pressure, Pressure fluctuation, Time-series analysis, Characteristic value, Fluidized state

Abstract: The negative pressure conical fluidized bed is widely used in the pharmaceutical industry. In this study, experiments based on the negative pressure conical fluidized bed are carried out by changing the material mass and particle size. The pressure fluctuation signals are analyzed by the time and the frequency domain methods. A method for absolutely characterizing the degree of the energy concentration at the main frequency is proposed, where the calculation is to divide the original power spectrum by the average signal power. A phenomenon where the gas velocity curve temporarily stops growing is observed when the material mass is light, and the particle size is small. The standard deviation and kurtosis both rapidly change at the minimum fluidization velocity and thus can be used to determine the flow regime, and the variation rule of the kurtosis is independent of both the material mass and particle size. In the initial fluidization stage, the dominant pressure signal comes from the material movement; with the increase in the gas velocity, the power of a 2.5 Hz signal continues to increase. A method of dividing the main frequency by the average cycle frequency can conveniently determine the fluidized state, and a novel concept called stable fluidized zone proposed in this paper can be obtained. Controlling the gas velocity within the stable fluidized zone ensures that the fluidized bed consistently remains in a stable fluidized state.

Key words: Conical fluidized bed, Negative pressure, Pressure fluctuation, Time-series analysis, Characteristic value, Fluidized state

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