Effect of non-uniform electric field on bubble dispersion characteristics in high-viscosity fluid
Electric field enhanced multiphase flow technology for interphase dispersion and mass transfer is widely used in chemical production.The size and dispersion behavior of bubbles and the physical properties of the continuous phase are important factors affecting the mass transfer efficiency in multiphase flow systems.In this study,a charged liquid-gas dispersion experimental platform was designed and built to visually study the dispersion behavior of bubbles in a high-viscosity fluid under the action of a non-uniform electric field.The morphological characteristics of the bubbles during the growth and dispersion process were recorded,and the effects of electric field strength and gas flow rate on the bubble dispersion behavior and bubble size were analyzed.The experimental results indicated that with the increase of electric field intensity,the dispersion behavior of air in glycerol underwent transitions from dripping mode to bead mode when the electric Bond number(BoE)reached 4.5.After reaching 8.7,it further transformed into mixed mode and finally corona mode when the electric Bond number reached 17.8.The bubble diameter decreased significantly with increasing electric field strength.Compared to the bubble size under no electric field,the bubble diameter decreased by 80％when the electric Bond number reached 6.4.In the mixed mode,the bubbles broke into numerous microbubbles,with microbubble diameters below 100µm.This effectively increased the interface area between the gas and liquid phases.Meanwhile,the study showed that the transition of the bubble dispersion mode mainly depended on the electric field strength,and the increase of the gas flow rate had little effect on the transition of the bubble dispersion mode and the bubble diameter.Based on the existing data,bubble diameter prediction model related to the electric Bond number in the range 0＜BoE＜16 was established.The results of this study could provide reference for the growth and dispersion behavior of bubbles in complex fluids under the action of electric fields.
non-uniform electric fieldbubble patternsbubble sizeviscous fluidelectro-hydro dynamics(EHD)
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