Journal of Fluid Mechanics

LDV measurements of an air-solid two-phase flow in a vertical pipe

Yutaka  Tsuji a1, Yoshinobu  Morikawa a1 and Hiroshi  Shiomi a1
a1 Faculty of Engineering, Osaka University, Osaka, Japan

Article author query
tsuji y   [Google Scholar] 
morikawa y   [Google Scholar] 
shiomi h   [Google Scholar] 


Measurements of air and solid-particle velocities were made in a vertical pipe two-phase flow by the use of a laser-Doppler velocimeter (LDV). Five kinds of plastic particles, diameters of which ranged from about 3 mm to 200 μm, were transported in a vertical pipe of 30 mm inner diameter. It was found that, the smaller the particle size, the flatter was the mean air velocity distribution for the same mass flow ratio of solids to air. Large particles increased air turbulence throughout the pipe section, while small particles reduced it. Both effects of promotion and suppression of turbulence were observed at the same time in the presence of particles of medium size, that is, the turbulence was increased around the pipe centre and reduced near the wall. The frequency spectrum of air turbulence normalized by the turbulence intensity was not changed by the large particles. In the presence of the small particles, the higher-frequency parts of the spectrum increased.

(Published Online April 20 2006)
(Received April 25 1983)