Critical comparison of electrostatic effects on hydrodynamics and heat transfer in a bubbling fluidized bed with a central jet

• Published in: Chemical engineering science Vol. 191; pp. 156 - 168
• Main Authors: Wang, Haotong, Hernández-Jiménez, Fernando, Lungu, Musango, Huang, Zhengliang, Yang, Yao, Wang, Jingdai, Yang, Yongrong
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 14.12.2018
• Subjects: Bubble behavior; Electrostatics; Fluidization; Heat transfer; Particle fluctuation; Fluidization; Particle fluctuation; Electrostatics; Heat transfer; Bubble behavior
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2018.06.069

•Phase fraction, bubble properties were compared in the charged and uncharged system.•Jet region, bubble generation region and free space were found in the simulation.•Interphase heat transfer coefficient was gained by corrected gas throughflow.•Charged system had weaker particle fluctuation velocity and more chaotic behavior. In many industrial processes, electrostatic charges are inevitable and affect the hydrodynamic behavior and heat transfer ability of chemical equipment. A comprehensive study of the electrostatic effect on bubble behavior, particle fluctuation velocity and heat transfer coefficient in the fluidized bed with a central jet has been evaluated in this paper by Eulerian-Eulerian two-fluid model coupled with electrostatic model and energy model. The simulated voidage profiles at different positions, bubble detachment time and initial bubble diameter are compared with experimental results from the literature without charge. The bubble behaviors including bubble frequency and bubble numbers, combined with particle fluctuation parameters are analyzed in both charged and uncharged system. The electrostatic effect on two kinds of heat transfer coefficients is quantitatively compared, namely bubble to emulsion phase heat transfers based on the gas throughflow velocity and gas-solid local heat transfer coefficient. Simulation results show that electrostatic charges decrease bubble numbers and granular temperature, whereas the averaged heat transfer coefficients are enhanced. Overall, the electrostatic effect on the hydrodynamic and heat transfer characteristics can be revealed.