Levitation of Discrete Particles

A simplified analysis (Deng and Kwauk, 1990) of solids levitation led to the following ordinary differential equation involving three parameters, ux, dujdx, and d2ujd2x, to be determined from experiments  

The frequency of fluid oscillation at which levitation takes place is plotted in Fig. 40 against the corresponding amplitude A of oscillation, the asymmetry factor ka or ratio of the duration of the downstroke to that of the upstroke, and the resin particle diameter d. From these experimental data, the three parameters of the equation were correlated to the particle diameter  

Curves computed from the equation using these empirically correlated parameters are also shown in Fig. 40, indicating acceptable agreement. 

Trajectories of a single resin particle computed from the equation are shown in Fig. 41, indicating that at/= 4.5 Hz the particle sinks, while at /= 7.5 Hz rising levitation takes place. 

---