INVESTIGATION OF THE INFLUENCE OF ELECTRIC
AND MAGNETIC FIELDS ON THE EVOLUTION OF AEROSOL
SYSTEMS IN A LIMITED VOLUME VIA LASER LIGHT
DISPERSION
K.S. Damov* , A.S. Antonov**
*Mathematics and Natural Sciences Department, South-West University
“Neofit Rilsky”, 66 Ivan Mihailov Str., Blagoevgrad-2700, Bulgaria
E-mail: krasi_damov@abv.bg
**Institute of Nuclear Research and Nuclear Energy - Bulgarian Academy
of Sciences, 72 Tsarigradsko Chausee Blvd., Sofia-1784, Bulgaria
E-mail: asantonov@abv.bg
Abstract
The present paper discusses the influence of electric and magnetic fields on the
evolution of aerosol systems in a limited volume. The change in their mass density
distribution is studied (the spectra of state under such influence). The density is
measured according to the method of free aerosol outflow. Experimentally obtained
spectra of state of some aerosol systems are presented with and without the influence
of electric and magnetic fields. Comparisons with control spectra are drawn.
1. INTRODUCTION
Aerosol systems in limited volume are the object of research in a number of
papers [1-3], including some previous papers of ours [4-7]. We created a highly
sensitive method for determining the mass density of such aerosol systems. The
method is based on the free outflow of aerosol under the influence of its own
hydrostatic pressure [8-10].
The influence of electric fields on the aerosol system is based on the availability
of static charges in the aerosol particles caused by various mechanisms. The latter are
discussed in detail by P. Reist [11]. At that paper the mechanism of the origin of
static charge in the aerosol particles is connected with their seizure of ions from the
air. This is due to the fact that the mass density of the aerosol phase is far smaller than
the mass of air filling the same volume. This fact was asserted in our previous papers
[8, 9].
9
It should be noted that in the references there are no data for the influence of
magnetic fields on the aerosol systems. Such influence shouldn’t be expected, unless
the aerosol systems are made up of finely dispersed ferromagnetic materials. In this
sense the results we present for the influence of magnetic fields on aerosol systems
(cigarette smoke) are quite unexpected. Moreover, the aerosol particles we study are
diamagnetic in essence.
Evaluation of the change in the density of the aerosol phase after the impact of
electric or magnetic field is made by means of the function of density distribution
f (  ) . We called this function “spectrum of the state of the aerosol system” [8, 10]
and it is a general characteristic of the latter. It contains the array of all density values,
obtained during its time evolution (from 0 to 10 min) in different aerosol volumes.
2. EXPERIMENTAL RESULTS
2.1 Change in the density distribution of the aerosol phase after impact with
electric field
Electrically charging of the aerosol occurs before filling the aerosol chamber
when it passes through an electric chamber – Fig.1. It consists of two parallel
electrodes – a flat one C, and a crested one A. Voltage of 2 kV is passed to them
while the positive pole is connected with the crested electrode A. By means of a
resistor the maximum current is limited to 1 mA. The created corona discharge
(positive stable current corona) enriches the passing aerosol with positive and
negative ions.
Ф-8
A
3
20
B
C
10
15
60
86
Figure 1. Electric chamber for enriching the passing aerosol with ions.
All dimensions are in mm.
10
5
15
Fig.2 shows the spectra of the state of an aerosol system, smoke from Arda
cigarettes (a packet) without impact (“Arda-Cl” – a thick line) and after impact of
electric field (“Arda-EF” – a dotted line).
Arda-C1
f (  ), ( m 3 / kg)
Arda_EF
100
80
60
40
20
0
0
5
10
15
20
25
30
35
40
45
50
55
60
Figure 2. Spectra of the state of an aerosol system, smoke from Arda cigarettes (a packet).
The thick line marks the control (“Arda-Cl”). The dotted line marks the corresponding
spectrum when the aerosol has passed through the positive stable current corona
(“Arda-EF”).
Table 1. Statistical data for the spectra of the state of aerosol systems – smoke from cigarettes
Arda and Fenix, before and after passing through the positive stable current corona. We have presented
in succession the mean arithmetic value of the mass density, the standard deviation, the minimum and
maximum value within the whole array, the maximum f (  )  max and the semi-width of the function
f ( ) .
Density of aerosols - cigarette smoke
Arda-C1 Arda-EF
№
Fenix-C1
Fenix-EF
_
1
 ( 103 kg / m3 )
22,5
15,6
26,3
23,3
2
  (10 kg / m )
0.5
0,3
0,6
0,4
3
 min (10  3 kg / m 3 )
4,3
2,1
8,8
8,1
50,6
31,5
54,1
48,4
70
84
50
80
11
10
20
12
3
4
5
6
 max (10
3
3
3
kg / m )
f (  ), ( m 3 / kg)
  0 . 5 ( 10  3 kg / m 3 )
11
The shift of spectrum is to the left, in the direction of decrease of the mass density.
The dispersion also decreases – Table 1. Obviously, the corona discharge strongly
influences the rougher fraction of the aerosol.
Fig.3 and Table 1 show the same dependences for Fenix cigarettes (a packet).
The curves look a bit different but the tendency remains the same – the spectrum is
shifted to the left (the mean value decreases correspondingly) and the dispersion also
decreases.
Fenix_C1
f (  ), ( m 3 / kg)
Fenix_EF
100
80
60
40
20
0
0
5
10
15
20
25
30
35
40
45
50
55
60
Figure 3. Spectra of the state of an aerosol system, smoke from Fenix cigarettes (a packet).
The thick line is the control (“Fenix-C1”). The dotted line is the corresponding
spectrum after the smoke has passed through the positive stable current corona
(“Fenix-EF”).
2.2 Change in the density distribution of the aerosol phase after impact with
magnetic field
The impact of magnetic fields on the aerosol occurs by means of a system of
magnets before filling the aerosol chamber – Fig.4. The system comprises three pairs
of circular constant magnets with an opening in the middle. They are situated in a
parallel manner, their opposing poles facing each other. The tube with aerosol passes
through them. The magnetic induction along their axis is strongly inhomogeneous
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with a changing direction and with a maximum value of about 0.05 T. Similar
systems are used for activation of liquids (water and water systems) [12, 13].
10
50
10
12
50
10
S
S
N
N
10
50
S
S
N
N
S
S
N
55
Ф-45
N
Ф-15
Figure 4. A system of three pairs of constant magnets which exercise influence on the aerosol
passing through the tube. All dimensions are given in mm.
Fig.5 shows the spectra of the state of an aerosol system, smoke from Arda
cigarettes, without impact (“Arda-C1” – the thick line) and after the impact of
magnetic field (“Arda-3M” – the dotted line). The shift of spectrum is to the right, in
the direction of increase of the mass density. The dispersion also increases
(cf.
Table 2).
Arda_C1
f (  ), ( m 3 / kg)
Arda_3M
100
80
60
40
20
0
0
5
10
15
20
25
30
35
40
45
50
55
60
Figure 5. Spectra of the state of an aerosol system, smoke from Arda cigarettes (a packet).
The thick line is the control (“Arda-C1”). The dotted line is the corresponding spectrum
but after impact of magnetic field (“Arda-3M”).
13
Table 2. Statistical data for spectra of the state of aerosol systems – smoke from cigarettes Arda
and Fenix before and after impact with magnetic field. We have presented in succession the mean
arithmetic value of the mass density, the standard deviation, the minimum and maximum values within
the whole array, the maximum f (  )  max and the semi-width of the function f (  ) .
Density of aerosols - cigarette smoke
№
Arda-C1
Arda-3M
Fenix-C2
Fenix-3M
22,5
25,1
21,0
27,3
0.5
0,6
0,3
0,5
4,3
3,7
10,4
12,8
50,6
50,6
30,1
49,9
70
55
77
74
11
17
11
13
_
1
2
3
4
 ( 103 kg / m3 )
  (10 3 kg / m 3 )
 min (10  3 kg / m 3 )
 max (10
3
kg / m 3 )
f (  ), ( m / kg)
3
5
6
  0 . 5 ( 10  3 kg / m 3 )
Fig.6 and Table 2 show the same dependences for the smoke of Fenix cigarettes.
The shift of the spectrum is also to the right, in the direction of increase of the mass
density. The dispersion also grows, i.e. the tendency remains the same.
Fenix_C2
f (  ), ( m 3 / kg)
Fenix_3M
100
80
60
40
20
0
0
5
10
15
20
25
30
35
40
45
50
55
60
Figure 6. Spectra of the state of an aerosol system, smoke from Fenix cigarettes (a packet).
The thick line is the control (“Fenix-C2”). The dotted line is the corresponding,
spectrum but after impact with magnetic field (“Fenix-3M”).
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3. CONCLUSIONS AND DISCUSSIONS
During the experiments we conducted with electrically charging of aerosol
systems with positive stable current crown the aerosol particles turn into ions of
Langevin [11, p.157]. They have an average life span of about 103 s. During the
investigation of the aerosol systems we applied detention times (evolution time) up
to 600 s. It can be assumed that all aerosol particles have kept their charge during the
process of investigation. When the average size of aerosol particles is about 0.16  m
[13, p.357] the charge of one particle is about 1 e [11, p.159, Table 10-5]. Therefore
the change of mass density distribution we obtained is due to the enlargement of the
aerosol particles and faster sedimentation as a result of recombination of the positive
and negative charges of the aerosol particles.
To our knowledge this paper represents the first attempt to establish
experimentally the change of mass density distribution of the aerosol phase when the
aerosol passes through strongly inhomogeneous magnetic field. It can be assumed
that this effect is due to the collective character of the interacting aerosol particles. An
analogy can be drawn with water which is a collective system of molecules connected
by hydrogen bonds. This system is influenced (it changes its structure) when it passes
through an inhomogeneous magnetic field [12 - 14].
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15
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