LDA measurements of near wall powder velocities in a high shear mixer
Artikel i vetenskaplig tidskrift, 2007

In this study, a new method has been developed to measure particle velocity distributions in the near wall region of a high shear mixer by using Laser Doppler Anemometry (LDA). The velocities along the side of the granulator have been measured at different impeller speeds and it has been found that it is possible to obtain tangential and axial velocity data in the dense powder flow up to 4 mm in depth. Moreover, it has been found that the tangential velocity component increases slightly with distance from the wall in the near wall region, indicating a partial slip boundary condition for the solid phase at the vessel wall. It is also shown that the tangential velocity decreases with increased vertical distance to the impeller. The velocity fluctuations, represented by root mean square (rms) velocities, also decrease with increased vertical distance to the impeller and the tangential and axial rms components are found to be of the same order of magnitude.

multiphase flows

soil mechanics

powder technology

granulation

Laser Doppler Anemometry (LDA)

Författare

Anders Darelius

Chalmers, Kemi- och bioteknik, Kemisk apparatteknik

Anders Rasmuson

Chalmers, Kemi- och bioteknik, Kemisk apparatteknik

Ingela Niklasson Björn

AstraZeneca AB

Staffan Folestad

AstraZeneca AB

Chemical Engineering Sciences

0009-2509 (ISSN)

Vol. 62 21 5770-5776

Ämneskategorier

Kemiteknik

DOI

10.1016/j.ces.2007.06.015