10
S. Sander et al.
the gas stream by means of a nozzle. The system is operated in the suction mode.
The compressor at the end of the system can handle maximum volume flow rates
of 1700 m
3 /h. This flow rate leads to mean velocities in the flow channel (cross
Sect. 30 cm × 50 cm) of max. 3 m/s. The dispersed particles are accelerated with
the gas flow into the channel through a honeycomb flow straightener.
Not separated particles are detected at the outlet of the ESP by an aerosol spectrometer (GRIMM). The exiting flow from the ESP, directly connected to the channel,
is cleaned of the remaining particles in the gas stream. Therefore, the gas stream first
passes through a cyclone. Here the particles larger than 5 microns are deposited. The
gas then passes through a cartridge filter and a filter cloth. The air is not returned but
escapes through a vent to the outside (Fig. 3).
2.7 Flow Field Analysis: PIV-System
To measure the particle velocities along the channel of the electrostatic precipitator,
Particle Imaging Velocimetry (PIV) is used (see also [26, 27]). A flexible shielded
laser arm leads the laser beam to the inlet of the flow channel. A beam expander at
the output of the arm widens the beam. The laser light section then propagates in the
direction of flow perpendicular to the deposition anodes as shown in Fig. 4.
With the PIV measuring system, the flow of particles in a 2d plane is measured.
The measurements are used to derive instantaneous and average velocity profiles of
the particles in a section of the separator.
2.8 Particle Layer Measurement
For analyzing the deposited particle layer at the ESP wall, specific small targets
(round stubs) are placed in the channel walls that easily could be removed from the
walls. Three stubs with a diameter of 20 mm are mounted into the collection anode
at a height of 0.15 m and lengthwise to the second electrode. The particle layers
formed on these stubs are examined with a microscope to determine the thickness of
the deposit. Figure 5 shows the test set-up used to determine the deposit thicknesses.
In addition to the stubs another layer sample is collected on a copper plate with
the size of 20 cm × 20 cm. This sample is used for offline characterization of the
layer dustiness.
2.9 Coupled CFD-Modeling
Numerical simulation studies of electrostatic precipitation (EPS’s) of dust particles
from exhaust gases have been carried out. In ESP’s particle separation from exhaust
S. Sander et al.
the gas stream by means of a nozzle. The system is operated in the suction mode.
The compressor at the end of the system can handle maximum volume flow rates
of 1700 m
3 /h. This flow rate leads to mean velocities in the flow channel (cross
Sect. 30 cm × 50 cm) of max. 3 m/s. The dispersed particles are accelerated with
the gas flow into the channel through a honeycomb flow straightener.
Not separated particles are detected at the outlet of the ESP by an aerosol spectrometer (GRIMM). The exiting flow from the ESP, directly connected to the channel,
is cleaned of the remaining particles in the gas stream. Therefore, the gas stream first
passes through a cyclone. Here the particles larger than 5 microns are deposited. The
gas then passes through a cartridge filter and a filter cloth. The air is not returned but
escapes through a vent to the outside (Fig. 3).
2.7 Flow Field Analysis: PIV-System
To measure the particle velocities along the channel of the electrostatic precipitator,
Particle Imaging Velocimetry (PIV) is used (see also [26, 27]). A flexible shielded
laser arm leads the laser beam to the inlet of the flow channel. A beam expander at
the output of the arm widens the beam. The laser light section then propagates in the
direction of flow perpendicular to the deposition anodes as shown in Fig. 4.
With the PIV measuring system, the flow of particles in a 2d plane is measured.
The measurements are used to derive instantaneous and average velocity profiles of
the particles in a section of the separator.
2.8 Particle Layer Measurement
For analyzing the deposited particle layer at the ESP wall, specific small targets
(round stubs) are placed in the channel walls that easily could be removed from the
walls. Three stubs with a diameter of 20 mm are mounted into the collection anode
at a height of 0.15 m and lengthwise to the second electrode. The particle layers
formed on these stubs are examined with a microscope to determine the thickness of
the deposit. Figure 5 shows the test set-up used to determine the deposit thicknesses.
In addition to the stubs another layer sample is collected on a copper plate with
the size of 20 cm × 20 cm. This sample is used for offline characterization of the
layer dustiness.
2.9 Coupled CFD-Modeling
Numerical simulation studies of electrostatic precipitation (EPS’s) of dust particles
from exhaust gases have been carried out. In ESP’s particle separation from exhaust