Abstract
Qualitative and quantitative studies of laminar mixing in a corotating disk processor chamber were carried out experimentally and theoretically. Theoretical study of the flow field in a parallel chamber indicates the presence of an orthogonal circulation flow pattern with a double circulation pattern at constant radii. A color tracer was used for studying experimentally the laminar mixing. The experiments verified the theoretically predicted flow fields and showed that the two orthogonal flow patterns bring about a composition randomization throughout the volume. Quantitative measurement of interfacial area evolution helped in characterizing the laminar mixing behaviour of such a configuration.
Nomenclature
- A
interfacial area after mixing, m2
- Ao
interfacial area before mixing, m2
- H
separation between parallel disks, m
- Hd
separation between wedge shape disks at r = Rd, m
- L
average pool length, m
- m
Power Law model parameter (consistency index)
- n
Power Law exponent
- nt
number of rotations of the disk assembly
- N
frequency of disk rotation, rev/s
- P
hydrostatic pressure, N/m2
- Q
volumetric flow rate, m3/s
- Qd
volumetric drag flow rate, m3/s
- Qp
volumetric pressure flow rate, m3/s
- r
radial co-ordinate in cylindrical coordinates, m
- rc
critical radius below which net backflow occurs, m
- r*
radius at which back velocities exist at the centre of the gap separation, m
- Rs
disk radius at the root of the channel, m
- Rd
inner radius of the barrel, m
- R
mean radius, (Rs + Rd)/2, m
- S
reciprocal of the power law exponent, 1/n
- UΦ
dimensionless tangential velocity in the Φ direction
- VΦ
tangential velocity in the Φ direction, m/s :
- Z
coordinate in cylindrical coordinates
- α
ratio of shaft to disk radii, Rs/Rd
-
mean strain, s–1
-
dimensionless z-coordinate, 2 z/H
- P
dimensionless radial coordinate, r/Rs
- Φ
angle in cylindrical coordinates, rad
-
angular pressure gradient, N/m2/rad
Acknowledgements
The authors wish to thank the Farrel Co. for donating the experimental equipment for this study, and Ms. T. Sapir for her help and contribution to some of the computations.
Reference
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© 1988 Hanser Publishers, Munich
