Documents disponibles écrits par cet auteur

Characterization of particle fluidization pattern in a gas solid fluidized bed based on acoustic emission (AE) measurement / Wang Jingdai in Industrial & engineering chemistry research, Vol. 48 N° 18 (Septembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8508–8514 Titre : Characterization of particle fluidization pattern in a gas solid fluidized bed based on acoustic emission (AE) measurement Type de document : texte imprimé Auteurs : Wang Jingdai, Auteur ; Ren Congjing, Auteur ; Yongrong Yang, Auteur Année de publication : 2010 Article en page(s) : pp. 8508–8514 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Fluidized  bed  Acoustic  emission  measurement Résumé : Flow pattern of the fluidized bed is a key factor for heat transfer and the design of a new reactor. It is important to comprehend the fluidization conditions because the complex correlation between particle−particle and particle−environment in the reactor. In this study, we applied acoustic emission (AE) measurement in monitoring the particle fluidization pattern in a gas−solid bed fluidized with different sorts of particles classified by Geldart. With AE axial time average energy analysis, the flow structure of polyethylene particles was investigated both in the laboratory and plant apparatus. The results showed that the fluidization pattern in the bed is multicirculation, including the main-circulation zone, subcirculation zone, and the stagnant zone. Moreover, the influence of operating variables, such as particle size, superficial gas velocity, static bed height, and particle sorts had also been considered. It was found that the particle size, gas velocity, and particle sorts have significant impacts to the fluidization pattern. In contrast, the height of the stagnant zone did not show direct relation to the static bed height. AE measurement was proved to be reliable for understanding the dynamical features that affect the behavior of the fluidized bed. This can be useful guidance for an industrial process and help improve the process operation and the design of the new reactor. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8018774 [article] Characterization of particle fluidization pattern in a gas solid fluidized bed based on acoustic emission (AE) measurement [texte imprimé] / Wang Jingdai, Auteur ; Ren Congjing, Auteur ; Yongrong Yang, Auteur . - 2010 . - pp. 8508–8514. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8508–8514 Mots-clés : Fluidized  bed  Acoustic  emission  measurement Résumé : Flow pattern of the fluidized bed is a key factor for heat transfer and the design of a new reactor. It is important to comprehend the fluidization conditions because the complex correlation between particle−particle and particle−environment in the reactor. In this study, we applied acoustic emission (AE) measurement in monitoring the particle fluidization pattern in a gas−solid bed fluidized with different sorts of particles classified by Geldart. With AE axial time average energy analysis, the flow structure of polyethylene particles was investigated both in the laboratory and plant apparatus. The results showed that the fluidization pattern in the bed is multicirculation, including the main-circulation zone, subcirculation zone, and the stagnant zone. Moreover, the influence of operating variables, such as particle size, superficial gas velocity, static bed height, and particle sorts had also been considered. It was found that the particle size, gas velocity, and particle sorts have significant impacts to the fluidization pattern. In contrast, the height of the stagnant zone did not show direct relation to the static bed height. AE measurement was proved to be reliable for understanding the dynamical features that affect the behavior of the fluidized bed. This can be useful guidance for an industrial process and help improve the process operation and the design of the new reactor. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8018774

Characterization of particle fluidization pattern in a gas solid fluidized bed based on acoustic emission (AE) measurement / Wang Jingdai in Industrial & engineering chemistry research, Vol. 48 N° 18 (Septembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8508–8514 Titre : Characterization of particle fluidization pattern in a gas solid fluidized bed based on acoustic emission (AE) measurement Type de document : texte imprimé Auteurs : Wang Jingdai, Auteur ; Ren Congjing, Auteur ; Yongrong Yang, Auteur Année de publication : 2010 Article en page(s) : pp. 8508–8514 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Fluidized  bed  Acoustic  emission  measurement Résumé : Flow pattern of the fluidized bed is a key factor for heat transfer and the design of a new reactor. It is important to comprehend the fluidization conditions because the complex correlation between particle−particle and particle−environment in the reactor. In this study, we applied acoustic emission (AE) measurement in monitoring the particle fluidization pattern in a gas−solid bed fluidized with different sorts of particles classified by Geldart. With AE axial time average energy analysis, the flow structure of polyethylene particles was investigated both in the laboratory and plant apparatus. The results showed that the fluidization pattern in the bed is multicirculation, including the main-circulation zone, subcirculation zone, and the stagnant zone. Moreover, the influence of operating variables, such as particle size, superficial gas velocity, static bed height, and particle sorts had also been considered. It was found that the particle size, gas velocity, and particle sorts have significant impacts to the fluidization pattern. In contrast, the height of the stagnant zone did not show direct relation to the static bed height. AE measurement was proved to be reliable for understanding the dynamical features that affect the behavior of the fluidized bed. This can be useful guidance for an industrial process and help improve the process operation and the design of the new reactor. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8018774 [article] Characterization of particle fluidization pattern in a gas solid fluidized bed based on acoustic emission (AE) measurement [texte imprimé] / Wang Jingdai, Auteur ; Ren Congjing, Auteur ; Yongrong Yang, Auteur . - 2010 . - pp. 8508–8514. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 18 (Septembre 2009) . - pp. 8508–8514 Mots-clés : Fluidized  bed  Acoustic  emission  measurement Résumé : Flow pattern of the fluidized bed is a key factor for heat transfer and the design of a new reactor. It is important to comprehend the fluidization conditions because the complex correlation between particle−particle and particle−environment in the reactor. In this study, we applied acoustic emission (AE) measurement in monitoring the particle fluidization pattern in a gas−solid bed fluidized with different sorts of particles classified by Geldart. With AE axial time average energy analysis, the flow structure of polyethylene particles was investigated both in the laboratory and plant apparatus. The results showed that the fluidization pattern in the bed is multicirculation, including the main-circulation zone, subcirculation zone, and the stagnant zone. Moreover, the influence of operating variables, such as particle size, superficial gas velocity, static bed height, and particle sorts had also been considered. It was found that the particle size, gas velocity, and particle sorts have significant impacts to the fluidization pattern. In contrast, the height of the stagnant zone did not show direct relation to the static bed height. AE measurement was proved to be reliable for understanding the dynamical features that affect the behavior of the fluidized bed. This can be useful guidance for an industrial process and help improve the process operation and the design of the new reactor. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8018774

Determination of critical speed for complete solid suspension using acoustic emission method based on multiscale analysis in stirred tank / Ren Congjing in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5323–5327 Titre : Determination of critical speed for complete solid suspension using acoustic emission method based on multiscale analysis in stirred tank Type de document : texte imprimé Auteurs : Ren Congjing, Auteur ; Xiaojing Jiang, Auteur ; Wang Jingdai, Auteur ; Yongrong Yang, Auteur Année de publication : 2008 Article en page(s) : p. 5323–5327 Note générale : Bibliogr. p. 5327 Langues : Anglais (eng) Mots-clés : Solid  suspension;  Acoustic  emission;  Stirred  tank;  Multiscale  analysis Résumé : According to the mechanism that acoustic emission (AE) signals with different frequency ranges were emitted when solid particles impacted the wall, a characteristic scale (S1) of the AE signals representing the movement of solid particles was obtained by using wavelet transform and Hurst analysis. A regular evolution behavior of energy fraction on each frequency with the increasing impeller speeds was observed. A new method to determine critical impeller speed was presented by analyzing the relationship between energy fraction in S1 scale and the impeller speed. The critical impeller speed was associated with the emergence of steady state in energy fractions in the S1 scale. The method was further verified with four groups of experiments with the particle sizes of 0.5 mm and 0.7 mm by comparing experimental results with that from the conventional visual method for a water and glass beads system. The average relative errors were no more than 4.28%. It is a fast, nonintrusive, and accurate method to investigate the Njs by multiscale analysis of acoustic energy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714347 [article] Determination of critical speed for complete solid suspension using acoustic emission method based on multiscale analysis in stirred tank [texte imprimé] / Ren Congjing, Auteur ; Xiaojing Jiang, Auteur ; Wang Jingdai, Auteur ; Yongrong Yang, Auteur . - 2008 . - p. 5323–5327. Bibliogr. p. 5327 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5323–5327 Mots-clés : Solid  suspension;  Acoustic  emission;  Stirred  tank;  Multiscale  analysis Résumé : According to the mechanism that acoustic emission (AE) signals with different frequency ranges were emitted when solid particles impacted the wall, a characteristic scale (S1) of the AE signals representing the movement of solid particles was obtained by using wavelet transform and Hurst analysis. A regular evolution behavior of energy fraction on each frequency with the increasing impeller speeds was observed. A new method to determine critical impeller speed was presented by analyzing the relationship between energy fraction in S1 scale and the impeller speed. The critical impeller speed was associated with the emergence of steady state in energy fractions in the S1 scale. The method was further verified with four groups of experiments with the particle sizes of 0.5 mm and 0.7 mm by comparing experimental results with that from the conventional visual method for a water and glass beads system. The average relative errors were no more than 4.28%. It is a fast, nonintrusive, and accurate method to investigate the Njs by multiscale analysis of acoustic energy. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie0714347

Distribution of electrostatic potential in a gas-solid fluidized bed and measurement of bed level / Wang Fang in Industrial & engineering chemistry research, Vol. 47 N° 23 (Décembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9517–9526 Titre : Distribution of electrostatic potential in a gas-solid fluidized bed and measurement of bed level Type de document : texte imprimé Auteurs : Wang Fang, Auteur ; Wang Jingdai, Auteur ; Yongrong Yang, Auteur Année de publication : 2009 Article en page(s) : p. 9517–9526 Note générale : Chemistry engineering Langues : Anglais (eng) Mots-clés : Electrostatic  potential  Gas-solid  fluidized  Bed  level Résumé : A theory on the electrostatic charge distribution in gas−solid fluidized beds was proposed. It consists of an interpretation of the causes of bipolar charging, the charging mechanisms in the fluidized bed, and the relationship between charge distribution and particle-size distribution in fluidized beds. Experiments were performed in a three-dimensional column gas−solid fluidized bed to measure the electrostatic charge distribution. It was found that the electric field inside the bed was nonuniform. If there was a distinct interface between the dilute and dense phases, the voltage polarity would reverse near the bed level, resulting in a Z-shaped axial profile of potential. The heights where voltage polarity reversal happened rose with the increase of gas velocity and static bed height. It was also found that the electrostatic voltage rose with increasing radial distances from the axis of the column. To sum up, the voltage at any axial cross section of the bed showed double saddles, with bed level as the interface. Accordingly, three special zones to be emphasized were identified: distributor, stagnant, and bed level zones, of which the latter two have high voltages and are more readily disturbed by particle/wall adhesion and even wall sheets. Based on the characteristics of axial profile of electrostatic potential in the fluidized bed, a new technique that could successfully predict bed level was developed. Good agreement was observed between visual measurements of bed level and predictions by the electrostatic method, with maximum relative error of 4.08% and mean relative error of 2.02%. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800805t [article] Distribution of electrostatic potential in a gas-solid fluidized bed and measurement of bed level [texte imprimé] / Wang Fang, Auteur ; Wang Jingdai, Auteur ; Yongrong Yang, Auteur . - 2009 . - p. 9517–9526. Chemistry engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9517–9526 Mots-clés : Electrostatic  potential  Gas-solid  fluidized  Bed  level Résumé : A theory on the electrostatic charge distribution in gas−solid fluidized beds was proposed. It consists of an interpretation of the causes of bipolar charging, the charging mechanisms in the fluidized bed, and the relationship between charge distribution and particle-size distribution in fluidized beds. Experiments were performed in a three-dimensional column gas−solid fluidized bed to measure the electrostatic charge distribution. It was found that the electric field inside the bed was nonuniform. If there was a distinct interface between the dilute and dense phases, the voltage polarity would reverse near the bed level, resulting in a Z-shaped axial profile of potential. The heights where voltage polarity reversal happened rose with the increase of gas velocity and static bed height. It was also found that the electrostatic voltage rose with increasing radial distances from the axis of the column. To sum up, the voltage at any axial cross section of the bed showed double saddles, with bed level as the interface. Accordingly, three special zones to be emphasized were identified: distributor, stagnant, and bed level zones, of which the latter two have high voltages and are more readily disturbed by particle/wall adhesion and even wall sheets. Based on the characteristics of axial profile of electrostatic potential in the fluidized bed, a new technique that could successfully predict bed level was developed. Good agreement was observed between visual measurements of bed level and predictions by the electrostatic method, with maximum relative error of 4.08% and mean relative error of 2.02%. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800805t