抄録
We experimentally investigate the velocity of free falling powder jet and entrained air near the hopper exit. A phase-Doppler anemometer(P.D.A.) is used for the measurement of their velocities. We found that the relative velocity between particle and air is so small that the center-line velocity of powder jet is close to the falling velocity of a single particle in disregard of the fluid drag. We obtaind that the dimensionless velocity profiles of powder jet are similar and independent of the falling distance. The volumetric flow rate of entrained air is increased with an increasing falling distance.
