Bubble-Rise Velocity in AC and DC Electrofluidized Beds

The behavior of a single injected bubble in a rectangular air-fluidized bed of glass microspheres has been studied experimentally for the ac and dc applied electric field cases. An empirical dimensionless equation for bubble-rise velocity and bubble volume is reviewed for application below a critical ac electric field strength for significant electromechanical effects. As observed previously, dc experiments in electrofluidized beds are more sensitive to time dependence and to hysteresis effects than are ac experiments, as densely spaced particles tend to become immobilized in the presence of dc electric fields.