Chapter 10
Dynamics of Separation Characteristics
of Sieving and Flow Classification
Processes
Martin Weers, Annett Wollmann, Ulrich Teipel, and Alfred P. Weber
Abstract In spite of the broad range of applications of flow and sieve classification,
the physical phenomena for higher particle loadings are not completely understood.
As a starting point, common models such as the one of Molerus may be used and
optimized to include particle-particle and particle-wall collisions. In this contribution, it is investigated to which extent single particle models may be employed to
describe the performance of a deflector wheel classifier and a circular vibratory
screening machine at higher loadings. For the sieving process, the Molerus model
was modified with a selectivity parameter, while for the deflector wheel, a differentiation of particles with low and high Stokes numbers was made. For high Stokes
numbers, in a first approximation, the particularities of the airflow can be neglected,
but the impaction behavior on the wheel blades needs to be taken into account. With
the detailed knowledge of the mean airflow, a much better prediction of the separation curve can be obtained. In particular, the dynamic aspects of flow and sieving
classification have been studied.
Nomenclature
T (x)
Separation efficiency (–)
x
Particle size (m)
x
Dimensionless particle size (–)
M. Weers (B) · A. Wollmann · A. P. Weber
Institute of Particle Technology, Technical University of Clausthal, Clausthal-Zellerfeld, Germany
e-mail: martin.weers@tu-clausthal.de
A. Wollmann
e-mail: annett.wollmann@tu-clausthal.de
A. P. Weber
e-mail: weber@mvt.tu-clausthal.de
U. Teipel
Institute of Particle Technology and Raw Material Innovation, TH Nürnberg, Nuremberg,
Germany
e-mail: ulrich.teipel@th-nuernberg.de
© Springer Nature Switzerland AG 2020
S. Heinrich (ed.), Dynamic Flowsheet Simulation of Solids Processes,
https://doi.org/10.1007/978-3-030-45168-4_10
349
Dynamics of Separation Characteristics
of Sieving and Flow Classification
Processes
Martin Weers, Annett Wollmann, Ulrich Teipel, and Alfred P. Weber
Abstract In spite of the broad range of applications of flow and sieve classification,
the physical phenomena for higher particle loadings are not completely understood.
As a starting point, common models such as the one of Molerus may be used and
optimized to include particle-particle and particle-wall collisions. In this contribution, it is investigated to which extent single particle models may be employed to
describe the performance of a deflector wheel classifier and a circular vibratory
screening machine at higher loadings. For the sieving process, the Molerus model
was modified with a selectivity parameter, while for the deflector wheel, a differentiation of particles with low and high Stokes numbers was made. For high Stokes
numbers, in a first approximation, the particularities of the airflow can be neglected,
but the impaction behavior on the wheel blades needs to be taken into account. With
the detailed knowledge of the mean airflow, a much better prediction of the separation curve can be obtained. In particular, the dynamic aspects of flow and sieving
classification have been studied.
Nomenclature
T (x)
Separation efficiency (–)
x
Particle size (m)
x
Dimensionless particle size (–)
M. Weers (B) · A. Wollmann · A. P. Weber
Institute of Particle Technology, Technical University of Clausthal, Clausthal-Zellerfeld, Germany
e-mail: martin.weers@tu-clausthal.de
A. Wollmann
e-mail: annett.wollmann@tu-clausthal.de
A. P. Weber
e-mail: weber@mvt.tu-clausthal.de
U. Teipel
Institute of Particle Technology and Raw Material Innovation, TH Nürnberg, Nuremberg,
Germany
e-mail: ulrich.teipel@th-nuernberg.de
© Springer Nature Switzerland AG 2020
S. Heinrich (ed.), Dynamic Flowsheet Simulation of Solids Processes,
https://doi.org/10.1007/978-3-030-45168-4_10
349