ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 10, pp. 1871–1873. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © I.V. Krauklish, I.Yu. Rodionov, V.A. Sirotko, 2008, published in Zhurnal Prikladnoi Khimii, 2008, Vol. 81, No. 10, pp. 1751–1753.
Conditions of Liquid Phase Formation in Operation
of Fire-Extinguishing Aerosol Generators
I. V. Krauklish, I. Yu. Rodionov, and V. A. Sirotko
St. Petersburg State Institute of Technology (Technical University), St. Petersburg, Russia
Ustinov Voenmekh Baltic State Technical University, St. Petersburg, Russia
Received May 16, 2008
Abstract—Reasons for formation of the liquid phase in operation of fire-extinguishing aerosol generators were
examined. The amount of the melt formed depends on the particle size and on the inclination angle and length
of the cylindrical generator.
Fire safety is currently a pressing problem. Despite
the overall decrease in the number of fires in the past
three years, the total damage, according to the Emergency
Ministry data, increased by more than 20%. One of the
most efficient and economical means for fire control is
the use of fire-extinguishing aerosol generators. However,
they have certain drawbacks. In particular, formation of
not only a solid, but also a liquid phase in the course of
generator operation impairs the generator performance
and causes additional damage to the materials being
treated. The goal of this study was to elucidate the reasons
for formation of the liquid phase.
Experiments were performed in a model cylindrical
generator with an outer diameter of 0.85 and an inner
diameter of 0.8 m, made of St.10 steel [GOST (State
Standard) 8733–74]. We used two cylinders of different
lengths, 0.82 and 1.64 m. Charges were prepared by
dead pressing on a PSU-125 hydraulic press at a com-
paction pressure of 200 MPa. Charges of two types were
used: with an internal channel 0.04 m in diameter and
without it. The charge length in both cases was 0.20 m,
and the outer diameter, 0.078 m. To protect the generators
from burning-through of the side surface, the charges
were twice coated with a mixture of liquid glass and
iron(III) oxide. To prevent an uncontrollable increase
in the combustion rate, the charge was wrapped with
a 0.002-m layer of a heat-insulating material (mica).
To measure the temperature, we used standard
TKhA thermocouples in a porcelain sheath [Chromel
(90.5% Ni + 9.5% Сr)–Alumel (94.5% Ni + 5.5% Al,
Si, Mn, Co)], 0.001 m in diameter, with the upper tem-
perature measurement limit of 1300 K. The junctions
of some of the thermocouples were fixed at hollows on
the generator housing, and some of the thermocouples
were inserted through apertures in the housing to re-
cord the aerosol temperature.
The model generator was tested on a special instal-
lation consisting of a computer, analog–digital con-
verter, amplifier, and thermocouples. The installation
allows on-line monitoring of changes in the tempera-
tures of both the generator walls and the aerosol flow.
Data obtained in the course of the tests were treated
with a computer in the Microsoft Windows 2000 envi-
ronment and were recorded using a specially devel-
oped software. The test results are listed in Table 1.
Table 1. Results of generator tests
Charge without channel 0.83 1.2 0.22 983 1083 69 5
1.63 1.2 0.22 798 943 77 0
Double charge without channel 1.63 2.4 0.42 1118 1228 150 16
Charge with channel 1.63 1.5 0.42 943 1054 145 0