CC BY
7
УДК 551.594.2
Khuchunaev B.M.
Doctor of Physical and Mathematical Sciences, Head of Laboratory of cloud microphysics, Federal State Budgetary Institution «High-Mountain Geophysical Institute»,
Nalchik, Russian Federation Gekkieva S.O.
Candidate of Physical and Mathematical Sciences, Senior Researcher Department of cloud physics, Federal State Budgetary Institution «High-Mountain Geophysical Institute»,
Nalchik, Russian Federation
Budaev A.Kh.
Junior Researcher, Department of cloud physics, Federal State Budgetary Institution «High-Mountain Geophysical Institute»,
Nalchik, Russian Federation
EQUIPMENT, TECHNIQUE AND PRELIMINARY RESULTS OF SPECIFIC CHARGE MEASUREMENT ON REAGENT PARTICLES FORMED DURING THE SUBLIMATION OF PYROTECHNIC COMPOSITIONS
Abstract
Until now the issues related to the influence of the electric field on their ice-forming properties have not been fully studied. Studies conducted in this direction show that the growth of ice nuclei depends on the electric field strength, the charge of the crystallizing nucleus and on the implementation of a particular growth mechanism [1]. The presence of an electric field in clouds and a charge on reagent particles can affect the specific yield of ice-forming nuclei during work on weather modification [2,3].
This article discusses the issues of determining the charge on AgI particles that are formed during the sublimation of the AD-1 pyrotechnic composition.
Keywords:
electricity, cloud, reagent, pyrotechnic composition, sublimation, charge.
Equipment for determining the charge on reagent particles from the AD-1 pyrotechnic composition of using a bipolar rectifier
The results of the analysis of published works on this topic show that none of them fully addresses the issues of methodology and special equipment for measuring the specific charge on reagent particles formed during the sublimation of pyrotechnic compositions [4,5].
To study the formation of an electric charge on reagent particles, a special set of equipment was created, which includes a device for measuring the charge on particles, a microscope, a high-voltage rectifier, a video camera.
To isolate AgI particles from the totality of the sublimation products that are formed during the dispersion of the AD-1 pyrotechnic composition, millipore filters were fixed on each plate, onto particles of the sublimation products are deposited. Subsequently, they appeared on the instrument table of the thermoelectric diffusion chamber «Grad-3» (Fig.1).
Electronic scales were used to weigh the pyrotechnic composition. The flow rate in the trap block was determined using a digital anemometer.
Fig. 1 - Thermoelectric diffusion chamber «Grad-3» 1 - thermoelectric unit, 2 - power supply unit, 3 - temperature control unit, 4 - digital voltmeter, 5 - illuminator, 6 - microscope, 7 - combined cooling radiator
Technique for determining the charge on reagent particles from pyrotechnic composition
A certain amount of pyrotechnic composition is weighed on electronic scales. It is loaded onto the metal boat of the reagent sublimation device. A high voltage is applied to the capacitor plates from a high-voltage rectifier. The sublimation of the composition begins after a voltage is applied to the contacts of the reagent sublimation device. When the pyrotechnic composition is sublimated, the flow velocity is measured with an anemometer and continuous video recording is conducted. The flow of the sublimation products is partially deflected and deposited on the capacitor plates. The degree of deflection of particles in an electric field is determined by video data.
The equation of particle motion in the electric field of a flat capacitor was used to calculate the specific charge on the particles:
Q = Q / m = 2xv2 / y2 E,
where Q - the specific charge of the reagent particle, Q - the charge of the reagent particle, m - the
mass of the reagent particle, E- the electric field intensity, X - the path traversed by the particle perpendicular to the flow, V - the velocity of the particle, y - the path traveled by the particle from the beginning of the capacitor plate to the collision with the plate along the plates.
Results of experiments to determine the specific charge on reagent particles
A series of experiments was carried out to determine the specific charge on AgI particles formed during the sublimation of the AD-1 pyrotechnic composition.
Figure 4 shows a photograph of the deflection of the sublimation particles in an electric field created by unipolar rectifiers A with poles «0» and «+» and B with poles «0» and «-». When using a rectifier with poles «0» and «+» (Fig. 2, A), the total charge is positive, and when using a rectifier with polarity «0» and «-» (Fig. 2, B), the total charge is negative. This is due to the fact that during the movement of the sublimation particle in the electric field of a unipolar capacitor, the particles have time to recharge.
Fig. 2 - Deviation of the particle flow from the AD-1 pyrotechnic composition in the electric field of unipolar rectifiers with polarity «0», «+» (A), with polarity «0», «-» (B)
Table 1 and figure 3 show the distribution of charged particles by specific charges.
Table 1
Distribution of reagent particles formed during the sublimation of the AD-1 pyrotechnic
composition by specific charges
Specific charge (q/m), C/kg Percentage of negatively charged particles, n./N, % Percentage of positively charged particles, n+/N, %
145-10-4 29 12
16-10-4 22 10
5,8-10-4 19 8
where N — the total amount of charged particles of the reagent; n — the amount of negative charged particles on the plate; n — the amount of negative charged particles on the plate.
Fig. 3 — Distribution of reagent particles by specific charges formed during the sublimation
of the AD-1 pyrotechnic composition
The X-axis represents the specific charge of reagent particles (q/m), 10-4, C/kg. The Y-axis represents the specific concentration of charged reagent particles on the plate, n / N, %. As can be seen from the table 1 and the figure 3, there is a significant difference in the results obtained, which, apparently, is due to not taking into account the mobility of positively and negatively charged ions. This problem is the subject of further research. Conclusion
The equipment and technique for studying the charge on reagent particles from pyrotechnic compositions based on the use of rectifiers of different polarities have been developed.
It was revealed that when the composition of AD-1 is sublimated, the particles are charged both positively and negatively. The ratio between negatively and positively charged particles is 7:3.
Preliminary research results have shown that the specific charge during the sublimation of pyrotechnic composition varies from 0 C/kg to 0.0145 C/kg.
It is shown that when a reagent particle moves in an electric field, the particle acquires an additional charge, which may be greater than the initial charge.
References:
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4. Choi E.M., Yoon Y.H., Lee S. Kang H. Freezing Transition of Interfacial (2005). Water at Room Temperature under Electric Fields // Phys. Rev. Lett. 95. D085701, doi: 10.1103/PhysRevLett.95.085701
5. Barthe C., Chong M., Pinty J., Bovalo C., Escobar J. (2012). CELLS v1.0: Updated and Parallelized Version of an Electrical Scheme to Simulate Multiple Electrified Clouds and Flashes over Large Domains // Geoscientific Model Development. V. 5, issue 1.P. 167- 184. DOI: 10.5194/gmd-5-167-2012
© Khuchunaev B.M., Gekkieva S.O., Budaev A.Kh., 2022
