The effect of van der Waals and charge induced forces on bed modulus of elasticity in ac/dc electrofluidized beds of fine powders—a unified theory

Computational fluid dynamics and electrostatic modeling of polymerization fluidized-bed reactors

“…It was shown in their study that when the electric field is three times the gravity the bed expansion decreased and solids volume fraction increased. Colver [25] applied perturbation theory on an ac electrofluidized bed of fine powder using electric field bubble control. They observed that at room temperature the bed modulus of elasticity increased linearly with the applied electric field for glass beads fluidized by argon.…”

Effect of particle size polydispersity on the yield stress of magnetofluidized beds as depending on the magnetic field orientation

“…In this stable fluidization regime (similar to Geldart A fluidization), the attractive forces between magnetized particles are strong enough for permanent interparticle contacts to partially support the bed weight giving rise to an expanded jammed state. The induced interparticle forces provide the MFB with an effective elastic modulus that stabilizes it against small disturbances and precludes the growth of large gas bubbles [102,103,3,35]. Thus, the solid-plastic behavior of MFBs [83] resembles the behavior of magnetorheological fluids -MFRs-(and the analogous electrorheological fluids, ERFs), which usually consist of a concentrated suspension of solid, micron-sized, highly magnetizable particles in a non-magnetizable liquid [104][105][106][107].…”

Experimental Study on the Entrainment Characteristics of Ultrafine Powder in a Fluidized Bed with Vibrator and Agitator

“…10 A series of methods have been developed to improve the fluidization characteristics, including addition of coarse particles, 11,12 fine powder coating, 13 vibration, 14−16 agitation, 17 sound waves, 18,19 and magnetic 20 and electric fields. 21 In this work, a combination of vibration, agitation, and coarse particles was introduced into fluidized bed feeder, and the effects on entrainment characteristics were investigated.…”

“…It is well-known that fine power belongs to group C in Geldart’s classification, which is difficult to be fluidized or conveyed because of the considerable interparticle forces, such as London–van der Waals, electrostatic interactions and liquid bridging forces. , The interparticle forces put forward many problems in the fluidization and entrainment of group C particles, such as channeling, slugging, and spouting . A series of methods have been developed to improve the fluidization characteristics, including addition of coarse particles, , fine powder coating, vibration, − agitation, sound waves, , and magnetic and electric fields . In this work, a combination of vibration, agitation, and coarse particles was introduced into fluidized bed feeder, and the effects on entrainment characteristics were investigated.…”