Study of the Power Spectrum of Acoustic Emission (AE) by Accelerometers in Fluidized Beds

Jiang, Xiaojing; Wang, J. D.; Jiang, Binbo; Yang, Yongrong; Hou, Lei

doi:10.1021/ie070457i

Cited by 40 publications

(40 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As stated above, only a few examples can be found in the literature (Jiang et al, 2007;Leach et al, 1978) that provide information to generate some understanding of the carrier frequency band properties characterizing the measured accelerometer signal.…”

Section: Flow-induced Vibration In Fluidized Bedsmentioning

confidence: 99%

“…A model developed in (Jiang et al, 2007) based on the relationship between particle collisions and acoustic signals dealt with the measurement of the elastic waves produced by the particle-particle and particle-wall collisions. Consequently, the expected carrying resonant frequency band had considerably high frequency values, requiring the use of very high sampling frequencies ranging from 100 kHz to 500 kHz (Jiang et al, 2007;Tsujimoto et al, 2000). Even though several reports suggested that these high frequency methods can be tuned to serve for some fluidized bed applications, the sampling frequencies on the order of hundreds of kHz considerably can increase the computational costs needed to handle the monitoring problem.…”

Section: Flow-induced Vibration In Fluidized Bedsmentioning

confidence: 99%

“…As discussed in the example shown below for the vibration induced by the pressure time series, this information may be used to assess the "quality" of the FB dynamic information contained in the measured accelerometer signal. In spite of the great differences with the sampling frequencies chosen to measure the accelerometer signals (Table 2), both approaches reported in Cody et al (1996) and Jiang et al (2007) assumed that the particle-particle and particle-wall collisions were the single sources for the measured "Acoustic Emissions". This apparent inconsistency disappeared within the present approach, with the existing pressure wave pattern dominated by either the compression or the elastic waves.…”

Section: Vibration Induced By Pulse-type Excitationmentioning

confidence: 99%

“…flow induced vibration) resulted from the particleparticle and particle-wall collisions, suggesting that an "impact model" can account for the elastic waves resulting from these particle collisions. These methods should have provided a reliable estimation of the carrier frequency component of the measured accelerometer signal for measurements in the ultrasonic range (Jiang et al, 2007). One of the main drawbacks of this approach results from the high computational cost of sampling at those high frequencies, as the great number of data in each sample complicates the measurement process, limiting the number of time series analysis techniques that can be used to handle the data.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Characterization of flow-induced vibrations in gas–solid fluidized beds: Elements of the theory

Briongos

Sobrino

Gómez-Hernández

et al. 2013

Chemical Engineering Science

View full text Add to dashboard Cite

Abstract:This paper revisits the basic hypothesis underlying the measurement of flow-induced vibration in fluidized beds. A novel theoretical approach based on the standing pressure field characterizing the bed dynamics is proposed to link the pressure fluctuations to the measured accelerometer signals. The model provides a reliable prediction of the carrying frequency band and helps in designing the accelerometer measurement process.The model was tested with previous results reported in the literature as well as with piezoelectric accelerometer measurements collected from a lab-scale experimental facility. A study on accelerometer measurements was conducted to identify the main limitations expected for measuring flow-induced vibrations in a gas-solid fluidized bed.The structural response of the vessel to flow-induced vibration was mostly determined by the "bed acoustics" that can be dominated by either elastic or compression waves.Finally, the survival of an envelope process on the measured accelerometer signal guaranteed the quality of the flow dynamical information collected during the measurement process.

show abstract

Section: Flow-induced Vibration In Fluidized Bedsmentioning

confidence: 99%

Section: Flow-induced Vibration In Fluidized Bedsmentioning

confidence: 99%

Section: Vibration Induced By Pulse-type Excitationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Characterization of flow-induced vibrations in gas–solid fluidized beds: Elements of the theory

Briongos

Sobrino

Gómez-Hernández

et al. 2013

Chemical Engineering Science

View full text Add to dashboard Cite

show abstract

“…In other words, AE signal is sensitive and selective to the movement of the particles. Many recent publications on the applications [19][20][21][22][23][24][25][26] of AE measurement indicate that they lead to reliable quantitative results and do not function just as qualitative indicators, as was the case in the beginning phases of AE-based applications in nondestructive testing. 19 In this work, we for the first time developed and applied a passive acoustic emission (AE) technique, to investigate the flow regime and fluidization condition of polyethylene particles in a gas-solid fluidized bed.…”

Section: Introductionmentioning

confidence: 99%

Characterization of flow regime transition and particle motion using acoustic emission measurement in a gas‐solid fluidized bed

2009

View full text Add to dashboard Cite

Particle motion is a major determinant of the dynamical performance of a fluidized bed. It plays an important role in determining and optimizing the complex correlation of fluidization condition between particle-particle and particle-environment in a system. A passive acoustic emission (AE) technique is applied to monitor, characterize, and control the fluidization condition of polyethylene particles in a gas-solid fluidized bed. Experimental results show that AE signals are very sensitive to the particle movements by analyzing energy distribution, which can help to understand the status of the system. The AE energy temporal analysis is further used to identify the transition of flow regimes. Moreover, the activity of particle motion can be quantitatively determined by using a combination of granular temperature and AE spatial energy analysis. This work provides valuable insights into the dynamic behavior of particles in a gassolid fluidized bed based on AE technique.

show abstract

Resolution of structure characteristics of AE signals in multiphase flow system—From data to information

Wang

Cao

et al. 2009

AIChE Journal

View full text Add to dashboard Cite

This investigation was performed to study the underlying structure characteristics of acoustic emission (AE) signals, which could be helpful not only to understand a relatively complete picture of hydrodynamics in multiphase flow systems, but also to extract the most useful information from the original signals with respect to a particular measurement requirement. However, due to AE signals are made up of emission from many acoustic sources at different scales, the resolution of AE signals is often very complicated and appears to be relatively poorly researched. In this study, the structure characteristics of AE signals measured both in gas-solid fluidized bed and liquid-solid stirred tank were researched in detail by resorting to wavelet transform and rescaled range analysis. A general criterion was proposed to resolve AE signals into three physicalrelated characteristic scales, i.e., microscale, mesoscale, and macroscale. Multiscale resolution of AE signals implied that AE signals in microscale represented totally the dynamics of solid phase and could be applied to measure particle-related properties. Furthermore, based on the structure characteristics of AE signals, useful features related to particles motion were extracted to establish two new prediction models, one for on-line measurements of particle size distribution (PSD) and average particle size in gas-solid fluidized bed and the other for on-line measurement of the suspension height in liquid-solid stirred tank. The prediction results indicated that (1) measurements of PSD and average particle size using AE method showed a fairly good agreement with that using sieve method both for laboratory scale and plant scale fluidized beds, and (2) measurements of the suspension height using AE method showed a fairly good agreement with that using visual method. The results thus validated that the extracted features based on analyses of structure characteristics of AE signals were very useful for establishing effective on-line measurement models with respect to some particular applications.

show abstract

Study of the Power Spectrum of Acoustic Emission (AE) by Accelerometers in Fluidized Beds

Cited by 40 publications

References 8 publications

Characterization of flow-induced vibrations in gas–solid fluidized beds: Elements of the theory

Characterization of flow-induced vibrations in gas–solid fluidized beds: Elements of the theory

Characterization of flow regime transition and particle motion using acoustic emission measurement in a gas‐solid fluidized bed

Resolution of structure characteristics of AE signals in multiphase flow system—From data to information

Contact Info

Product

Resources

About