EPNM -2010
Detonation Chambers for
Synthesis of Nanodiamonds and
Another Explosive Technologies
A.F. Cherendin, V.G. Galutsky, K.V. Kulik,
Yu.P. Meshcherjakov*, A.A. Pikarevsky,
O.I. Stojanovsky
Design and Technology Branch of Lavrentyev Institute of
Hydrodynamics SB RAS, Tereshkovoi Street 29, 630090
Novosibirsk, Russia
* ura@kti-git.nsc.ru
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EPNM -2010
Introduction
Designing of industrial detonation (explosion) chambers with a long service time meets
certain difficulties. Presently there is no comprehensive engineering method for reliable
calculation of dynamic stresses in different points of chamber body with arbitrary shape.
Different numerical methods concerning the dynamic loading of structures need to be verified
experimentally.
If to analyze the published works, next conclusions can be made. In [1] only ideal shapes like
sphere and cylinder are considered and derived formulas are suitable for the preliminary
estimations only. Some investigations show that stresses can differ substantially (in 2 – 2.5
times) in different points of a chamber body [2, 3]. The other works also have shown the
existence of stress concentration in a chamber shell during the explosive loading [4-6].
1. Demchuk A.F., Isakov V.P. Metallic detonation chambers. – Krasnoyarsk: publishing of Krasnoyarsk University, 2006
2. V.V. Adishev, V.M. Kornev. On calculations of explosion chamber shell //Combustion, Explosion, and Shock Waves (Fizika
Goreniya i Vzryva). 1979, vol.15, No. 6, p. 108-114.
3. A. I. Abakumov, V.V. Egunov, A.G. Ivanov , et all. Calculating-and-Experimental Investigation of Deformation in Explosion
Chamber // Journal of Theoretical and Applied Mechanics. 1984, No. 3, p.127-130.
4. V. M. Kornev, V.V. Adishev, A.N. Mitrofanov, V.A. Grekhov. Experimental investigation and analysis of explosion chamber
shell vibrations // Combustion, Explosion, and Shock Waves (Fizika Goreniya i Vzryva). 1979, vol.15, No.6, p.155-157.
5. V.V. Silvestrov , A.V. Plastinin, N.N.Gorshkov, O.I. Stoyanovsky. Response of real explosion chamber shell on inner pulse
loading // Combustion, Explosion, and Shock Waves (Fizika Goreniya i Vzryva). 1994. No.2, p.95-102.
6. V.V. Silvestrov , A.V. Plastinin, N.N.Gorshkov . Influence of explosive charge surrounding media on a response of explosion
chamber shell // Combustion, Explosion, and Shock Waves (Fizika Goreniya i Vzryva).1994. vol.30, No.2.
Introduction
EPNM -2010
In this presentation we show how the problem of stress concentration is considered
in DTB of LIH with the use theoretical calculations and experimental measurements
of stresses arising in a chamber shell.
Examples of detonation chambers produced in DTB of LIH are given
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Strain measurement technique
numerical calculation
Detonation Chamber
Block board data collection
(Switching card,
Configuration block,
PSU,
Data collection board:
64 channels, scan rate
3 MHz )
Personal
PC
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Strain measurement technique
and numerical calculation II
• Coefficient of strain sensor sensitivity – 183±3%
• Resistance of strain sensors – 10 kΩ
• The temperature dependence of the coefficient of strain sensor sensitivity–
0.29%/°С
• Time period of studied process – 10-20 ms
• Measurement error – less than 10%
Results of strain measurements are compared with numerical calculation results. These
calculations are usually made at the stage of chamber design. Numerical calculations are
performed using one of the modifications of finite element method developed by Y.P.
Mesheryakov *.
Boundary conditions :
The pressure Р=0 at the outer boundary of the shell
The specific impulse J is applied at the inner boundary of the shell
*Y.P. Meshcheryakov, N.M. Bulgakova. Thermoelastic modeling of microbump and nanojet formation on nanosize gold
films under femtosecond laser irradiation. Appl. Phys. A, 2006, v.82, pp.363-368.
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Testing of the KIP-02 detonation chamber
(example of chamber designing using calculation+measurement approach)
List of simbols
«r» - longitudinal axis of the sensor lies in the cross
sectoin plane of shell
«f» - the axis of the sensor which is located
perpendicularly to the «r» direction
1r, 9r - sensors located at the chamber’s poles
With the help of the sensor 7 the greatest stress in a
cylindrical shell was measured.
With the help of other sensors №№ 2,3,4,5,6,8 the
stresses were measured at the specific points of
chamber body.
In KIP-0.2 chamber stress concentration was
decreased substantially
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Determination of equivalent
stresses
In compliance with measured deformations εr(t) и εf(t) , with main directions r и f, stressstrained state was determined by formulas :
σr = E(εr + μ εf)/(1- μ), σf = E(εf + μ εr)/(1- μ);
Equivalent stress : σэ=( σr² + σf² - σr·σf)¹′²
Sperical air-blast impulse: J=2ρ0·r(2Q)/3R².
ρ0 - charge density, r - sperical charge radius , m – charge mass, Q - specific heat energy
Peak stress at point 9(r) according to (Мещеряков Ю.П. , Стояновский О.И. Расчет
максимальных напряжений в металлических дисках, возникающих в результате
воздействия импульсных нагрузок./ Известия ВолгГТУ №3 (41), Волгоград, 2008, 144с.)
(σr,u)мах. =1.24·J·a0·r/2h²,
r - disk radius, a0 - sound speed in metal, h – disk thickness, J - specific impulse
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Dependence of stress in the cover of the
chamber on the mass of explosive charge
If the charge mass is m = 0.2 kg than
calculated stress in the center of the
cover is (σr,u)мах.=115 MPa.
Measured value is σэ=101 MPa.
The difference between the
measured values was 14%, that
under the made assumptions
and measurement errors can be
considered to be satisfactory.
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Dependence of stress in the chamber
bottom on the mass of explosive charge
Calculated value s in the point 1(r)
obtained by finite element method
exceed the measured value by 10%. In
spite of the fact, that there was made
the increasing of the bottom thickness
(1.75 times more comparing with
ellipsoid thickness), stresses are still
maximum for shell
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Dependence of stress in the chamber bottom on
the mass of explosive charge(edge of the
thickness change , point 2)
The purpose of measuring stress in point
2(r,f) was to made sure that the thickness
decrease on the edge of the disc didn’t lead
to stress increase above the legitimate
value. Values of the hoop stresses σf are
less by 10-25 MPa against to largest in this
point radial stresses σr and equivalent
stresses σэ are between of them what
indicates that the maximum stress values σr
and σf take place when the corresponding
waves of the shell oscillation does not in
antiphase.
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Superimposition of the sensors data 7(r), 7(f).
Stress dependence on charge mass (point 7)
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Equivalent stresses in point 7(r,f)
One can see the typical oscillation of
amplitudes - the superposition of
oscillations leads to a periodic increase in
the amplitudes on the background of the
waves attenuation. Distinctly seen 5 such
amplitudes with period T=1.7·10-4 s.
Between them we can see about 10
oscillations with lesser amplitude and
period is about T=1.7·10-4 s, which
correspond to wave-length L= T· a= 0.85
m (here a= 5·103 m/s – sound speed), i.e.
chamber’s body length in longitudinal
section between flange and disc. One
can suppose, that there is the oscillation
superposition at «r» and «f» dimensions
with close frequencies
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Stress in point 6 (r,f)
compared with calculated value in point 6(r,f)
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Equivalent stresses at specific points of
chamber body
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Conclusion
Analysis of the stress-strained state of the detonation chamber “KIP-02” shows:
1. Maximum stresses arise on the poles of the cylindrical (short cylinder)
detonation chamber and in the central section of the cylindrical shell. Despite
the fact that there is the thickening in the center of the elliptic bottom, which
thickness at 1.75 times more than thickness of the cylinder, stress in the center
reaches 150 MPa, that 1.5 times more than stress in the lock’s cover and in the
middle part of the cylinder.
2. The results of numerical calculations of the stresses were obtained ( without
product pipeline) for the points of elliptical bottom and poles of cylindrical chamber.
The calculated data is reasonably well approved by the results of measurements.
3. Investigations of the stress condition of the shell near the orifice, thickened bottom
disc and in the place where the cylinder runs into the ellipsoidal head showed that
these particularities led to rising of stress values not more than 25%. Maximum
stress near the product pipeline is in the point, located more closer to chamber
pole.
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Industrial detonation chamber "Alpha-2» designed for
production of diamond-graphite product by explosion
1–chamber’s body; 2–cover; 3–charge; 4–tap; 5–container; 6–chassis;
7–filter; 8–pipe line; 9–container; 10–service area.
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Specification of the detonation chamber
"Alpha-2"
Chamber type – Cylindrical vertical with elliptic bottom
Chamber’s overall dimensions, mm:
height
- 4505
bottom
- 2000x2500
Chamber’s body mass, kg
- 6800
Chamber’s inner volume, м³.
-2
Maximum charge mass (TNT equivalent), kg
-2
Work cycle time, min
- 10-15
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Laboratory explosive chambers
• B
Сферический
корпус наиболее
предпочтителен с
точки зрения
равнопрочности .
Цилиндрический
корпус с
эллиптическими
днищами более
предпочтителен с
точки зрения
изготовления.
Explosive chamber KV-0.2
Camber mass 1.3 t,
overall sizes 1800 x
1200 x 1630 mm
Explosive chamber DVK-0.2
Chamber mass 2.7 t,
Overall sizes 2185 х 1630
х 2150 mm.
Designed for investigation
of detonation process
using synchrotrone
radiation
Laboratory explosive chambers
Explosive chamber KIP-0.2
Chamber is made from stainless steel. It is
used in experiments on explosive
synthesis of ultrafine diamonds
Chamber mass 0.85 t
Overall sizes
1030 х 850 х 1400 мм
Explosive chamber for 2 kg HE
Designed for explosive working of
materials. Can be used for utilization
of explosives.
.
Explosive chamber for 2 kg HE
Chamber sealing system eliminates
outflow of detonation products and
permits evacuation of air and filling of
chamber volume with desired gas.
Explosive chamber KVG-8
Chamber mass 48 t
Overall dimensions
16360 x 2200 x
2460 мм.
Explosive chamber KVG-16
Chamber mass 76 t ,
Overall sizes 27210
x 2200 x 2460 mm
Explosive chamber KVG-16
Chamber consists of massive body of 13 m in length and 1.76 m in diameter.
Work table of 10 m in length moves on rails. Explosive charge mass 2 kg per 1
meter. Designed firstly for explosive hardening of railway crossings. Can be
used for utilization of explosives.
Explosive chamber KVG-16
Chamber was supplied to Chech Republic and was used for utilization
of pyrotechnic substances. During approximately two years 15
thousand explosions were made and 300 t of pyrotechnic materials
were utilized.
The slide is presented by OZM Company
Thank your for your attention!
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