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LDA measurements of near wall powder velocities in a high shear mixer

Anders Darelius (Institutionen för kemi- och bioteknik, Kemisk apparatteknik) ; Anders Rasmuson (Institutionen för kemi- och bioteknik, Kemisk apparatteknik) ; Ingela Niklasson Björn ; Staffan Folestad
Chemical Engineering Science (0009-2509). Vol. 62 (2007), 21, p. 5770-5776.
[Artikel, refereegranskad vetenskaplig]

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.

Nyckelord: Laser Doppler Anemometry (LDA); powder technology; soil mechanics; granulation; multiphase flows



Denna post skapades 2008-01-10. Senast ändrad 2016-08-15.
CPL Pubid: 65514

 

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Institutioner (Chalmers)

Institutionen för kemi- och bioteknik, Kemisk apparatteknik (2005-2014)

Ämnesområden

Kemiteknik

Chalmers infrastruktur