Statistical and frequency analysis of the pressure fluctuation in a fluidized bed of non-spherical particles--颗粒学报PARTICUOLOGY

He, H., Lu, X., Shuang, W., Wang, Q., Kang, Y., Yan, L., Ji, X., Luo, G., & Liu, H. (2014). Statistical and frequency analysis of the pressure fluctuation in a fluidized bed of non-spherical particles. Particuology, 16, 178–186. https://doi.org/10.1016/j.partic.2014.02.004

Statistical and frequency analysis of the pressure fluctuation in a fluidized bed of non-spherical particles

Honghao He ^a *, Xiaofeng Lu ^a *, Wei Shuang ^a, Quanhai Wang ^a, Yinhu Kang ^a, Liyun Yan ^a, Xuanyu Ji ^a, Guangyu Luo ^b, Hai Liu ^b

a Key Laboratory of Low-grade Energy Utilization Technologies and Systems (Chongqing University), Ministry of Education, Chongqing 400044, China
b Sichuan Nanxi Boiler Ltd., Sichuan 644100, China

10.1016/j.partic.2014.02.004

Volume 16, October 2014, Pages 178-186

Received 8 October 2013, Revised 28 December 2013, Accepted 3 February 2014, Available online 4 April 2014.

E-mail: hto119@gmail.com; xfluke@cqu.edu.cn

Highlights

• Standard deviation of pressure fluctuation was investigated as a function of gas velocity.

• The results revealed different dynamic behavior for particles of different sphericities.

• Power spectral density was estimated with autoregressive model.

• A potential method for determining U_k was proposed based on power spectral analysis.

Abstract

In this paper, the pressure fluctuation in a fluidized bed was measured and processed via standard deviation and power spectrum analysis to investigate the dynamic behavior of the transition from the bubbling to turbulent regime. Two types (Geldart B and D) of non-spherical particles, screened from real bed materials, and their mixture were used as the bed materials. The experiments were conducted in a semi-industrial testing apparatus. The experimental results indicated that the fluidization characteristics of the non-spherical Geldart D particles differed from that of the spherical particles at gas velocities beyond the transition velocity U_c. The standard deviation of the pressure fluctuation measured in the bed increased with the gas velocity, while that measured in the plenum remained constant. Compared to the coarse particles, the fine particles exerted a stronger influence on the dynamic behavior of the fluidized bed and promoted the fluidization regime transition from bubbling toward turbulent. The power spectrum of the pressure fluctuation was calculated using the auto-regressive (AR) model; the hydrodynamics of the fluidized bed were characterized by the major frequency of the power spectrum of the pressure fluctuation. By combining the standard deviation analysis, a new method was proposed to determine the transition velocity U_k via the analysis of the change in the major frequency. The first major frequency was observed to vary within the range of 1.5 to 3 Hz.

Graphical abstract

Keywords

Fluidized bed; Non-spherical particles; Pressure fluctuation; Transition velocity

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