166
D. Markauskas and H. Kruggel-Emden
of the relevant screening subprocesses are derived and available process models as
introduced in Sects. 3.2.1–3.2.3 are benchmarked for both continuous and discontinuous processes. In Sect. 4.3 results for discontinuous screening under the influence
of moisture are validated against experiments. Thereafter process models as derived
in [123] and stated in Sect. 3.2.4 are benchmarked against the obtained DEM results.
4.1 Continuous Screening
As a first case screening of a polydisperse feed material is investigated by the DEM
in a continuously operated screen apparatus as shown in Fig. 9a. In Sect. 4.1.1 the
numerical setup is described and the required simulation parameters are outlined. In
Sect. 4.1.2 the results are presented as obtained from the DEM (section “Numerical
Investigations”) and the process models (Section “Benchmarking of Steady State
Separation Curve Screening Models”).
4.1.1 Numerical Setup and Simulation Parameters
The considered apparatus is equipped with a wire screen of 0.35 m x 0.1 m size.
The square aperture size is 4.9 mm while the wire diameter is 1 mm. In the initial
configuration, the apparatus is vibrated with 27.6 Hz with a stroke angle of 45° to the
horizontal at an amplitude of 1.76 mm (Fig. 9a). The mass flow of the polydisperse
feed material amounts to 0.1 kg/s in the initial setup. The material comprises of
particles with a density of 2700 kg/m
3 subdivided equally into 100 size classes ranging from 2.4 mm to 7.35 mm. Besides spheres, cylinder-like and double cone-like
particles are studied in this investigation (see Fig. 9b). The non-spherical particles
(shapes (2) and (3)) have an aspect ratio of 1.55. The cylindrical particles (shape
(2)) are volume equivalent to the spherical particles and have a hemispherical termination at both ends. The double cones (shape (3)) have the same minor dimension
as the spheres. If needed for analysis or as a parameter for a screening model, the
a
b
a = 4.9 mm
w = 1 mm
l = 0.35 m
0.07 m
Vibration amplitude 1.76 mm
and frequency 27.6 Hz
0.035 m
0.1 m
2
1
3
45°
Fig. 9 a Continuous screening apparatus with wire structure; b Considered particle shapes. Reprint
with permission from [109]
D. Markauskas and H. Kruggel-Emden
of the relevant screening subprocesses are derived and available process models as
introduced in Sects. 3.2.1–3.2.3 are benchmarked for both continuous and discontinuous processes. In Sect. 4.3 results for discontinuous screening under the influence
of moisture are validated against experiments. Thereafter process models as derived
in [123] and stated in Sect. 3.2.4 are benchmarked against the obtained DEM results.
4.1 Continuous Screening
As a first case screening of a polydisperse feed material is investigated by the DEM
in a continuously operated screen apparatus as shown in Fig. 9a. In Sect. 4.1.1 the
numerical setup is described and the required simulation parameters are outlined. In
Sect. 4.1.2 the results are presented as obtained from the DEM (section “Numerical
Investigations”) and the process models (Section “Benchmarking of Steady State
Separation Curve Screening Models”).
4.1.1 Numerical Setup and Simulation Parameters
The considered apparatus is equipped with a wire screen of 0.35 m x 0.1 m size.
The square aperture size is 4.9 mm while the wire diameter is 1 mm. In the initial
configuration, the apparatus is vibrated with 27.6 Hz with a stroke angle of 45° to the
horizontal at an amplitude of 1.76 mm (Fig. 9a). The mass flow of the polydisperse
feed material amounts to 0.1 kg/s in the initial setup. The material comprises of
particles with a density of 2700 kg/m
3 subdivided equally into 100 size classes ranging from 2.4 mm to 7.35 mm. Besides spheres, cylinder-like and double cone-like
particles are studied in this investigation (see Fig. 9b). The non-spherical particles
(shapes (2) and (3)) have an aspect ratio of 1.55. The cylindrical particles (shape
(2)) are volume equivalent to the spherical particles and have a hemispherical termination at both ends. The double cones (shape (3)) have the same minor dimension
as the spheres. If needed for analysis or as a parameter for a screening model, the
a
b
a = 4.9 mm
w = 1 mm
l = 0.35 m
0.07 m
Vibration amplitude 1.76 mm
and frequency 27.6 Hz
0.035 m
0.1 m
2
1
3
45°
Fig. 9 a Continuous screening apparatus with wire structure; b Considered particle shapes. Reprint
with permission from [109]