Entrained Air Flow Characteristics due to the Powder Jet [Translated]†

Abstract

We experimentally and numerically examine the flow characteristics of powder jet and entrained air. A phase-Doppler anemometer is used for the measurement of axial velocity profiles of particle and entrained air. It is found that the axial velocity profile of the entrained air takes a maximum at the center-line and decreases toward outer edge. A flow region of the entrained air extends transversely into a particle free region. The center-line velocity of entrained air at first increases with increasing distance from the orifice outlet and then decreases after it remains a plateau. The transverse dispersion of the entrained air is very small as compared with that of a single-phase turbulent jet. The numerical simulation is performed based on the Lagrangian modeling for particles and Eulerian modeling for air flow. We consider particle-particle collision, gravity force, drag force and transverse force due to the particle spin and to the velocity gradient of airflow, and apply a k-ε model. The present simulation qualitatively explains our measurement in terms of velocity profiles and dispersion ofparticle and air.† This report was originally printed in J. Soc. Powder Technology, Japan. 37(3), 160-167 (2000) in Japanese, before being translated into English by KONA Editorial Committee with the permission of the editorial committee of the Soc. Powder Technology, Japan.

Keywords

• multi-phase flow
• entrained air
• powder jet
• phase-doppler anemometer measurement
• numerical simulation