Transcript On possibility of detonation products temperature measurements of

XII International Symposium on Explosive Production of
New Materials: Science, Technology, Business, and
Innovations (EPNM-2014), May 25-30, 2014, Krakow, Poland
On Possibility of Detonation Products
Temperature Measurements
of Emulsion Explosives
Victor V. Sil’vestrov, S.A. Bordzilovskii,
S.M. Karakhanov, and A.V. Plastinin
Lavrentyev Institute of Hydrodynamics
Novosibirsk, Russia
Goals
1. Measurements of the detonation front
temperature of emulsion explosives (EMX)
2. Why?
–
The temperature is the most sensitive detonation
parameter to the EOS
–
Development & calibration of EOS of detonation
products for EMX, decomposition kinetics.
–
Application of EMX to the delicate explosive
welding is the reality today (thin foils, low-meltingpoint metals, tube plates and others).
3. Better knowledge of the EMX’s properties is
needed.
EMX’s Temperature. Review
Numerical calculations:
• Yoshida M., et al.; Tanaka K.: 1985, 8th IDS –
Kihara-Hikita EOS, 1900-2100 К
• Odinzov et al.; Alymova et al.: 1994, Chemical
Reports, BKW EOS; Combustion, Explosion,
and Shock Waves, thermodynamic code, 10001700 К
• Tanaka, 2005, APS-2005, KHT EOS, 1700 К
Experiment: single article Lefrancois A., et al. / 12th
Symp. (Intern.) on Detonation, 2002. Nitram explosive
(based on AN emulsion) – Tb = 4179 K (?)
3
EMX composition
• Oxidizer – water solution of mixture AN & SN
nitrates, 94 wt. %
• Fuel – liquid hydrocarbon + emulsifier, 6 wt. %
• Sensitizer – glass microballoons 60 μm in size,
from 1 to 50 wt. % above an emulsion weight
• EMX parameters: density 0.5 – 1.3 g/cc,
detonation pressure 0.7 – 11 GPa, VOD 2.1 – 6
km/s, critical diameter 5 – 38 mm
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Measuring procedure
• Self-made four channel fiber optical pyrometer
with quartz fiber 0.4/0.8 mm in diameter and up to 15 m
in length
• Basis – Planck’ distribution and Black body
approximation
• Brightness temperature at 630(20) & 660(120) nm
• FMP – spectral range 300 ÷ 750 nm
• Calibration before each shot, lamp 1100 – 2350 K
and interpolation to higher temperature
• Accuracy  50-150 K
• Testing – PMMA, epoxy resin, PTFE at 1500-3000 K
• Details in Vestnik NSU, 2011, 6(1), 116-122 (in Russian)
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Experimental setup – window technique
1 – HV detonator, 2 – 5% EMX primer, 3 – emulsion explosive
Ø55x250 mm (at max density Ø105x400 mm), 4 – polypropylene
tube with 5 mm wall, 5 – contact pin, 6 – PVF2 or manganin
pressure gauge, 7 – Plexiglas window 15 mm in thick, 8 – mask
Ø6 mm, 9 – optical fiber with 0.4 mm quartz core (to pyrometer) or
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Visar probe
Luminosity signal interpretation
Purpose – the choose a point to measure the Temperature of
Detonation Products according the classic ZND model
Main idea
Correlation of three profiles
0.7 GPa
tR
Registered profile (1) = hot spot (3) +
detonation temperature (2)
1880 K
Temperature (1), pressure (2),
particle velocity (3)
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Luminosity (1) & Temperature (2)
2140 K
1940 K
mcs
PD = 4.4 GPa
tR = 0.65 μs
PD = 10.7 GPa
tR = 1.3 μs
t1 – detonation reaches the EMX/window interface
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Brightness temperature of detonation front
vs detonation pressure
(experiment)
3500
Т, К
Hot spots
T hs
2500
Tb
Detonation front
Γ = 0.8
TCJ,
calculation
Correction
P   model
1500
Γ = 0.4
EMX – low-temperature explosive
~ 2000
K
7
8
PPd,d,GPa
ГПа
500
0
4
8
12
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Comparison with calculations
EMX based on AN/SN emulsion
2500
experiment
Т, К
2000
1500
calculations
1000
1
3
6
7
ГПа
PPdd,, GPa
500
0
4
8
12
10
Lefrancois A., et al. //
12th Symp. (Intern.) on Detonation, 2002, 432-439
Temperature and pressure measurements comparison of the aluminized
emulsion explosives detonation front and products expansion
Nitram “a” explosive (based on AN
emulsion) without aluminum →
4179 К
French producer calculation is
2170 ÷ 2500 К
about two times lower !
according our methodology
T = 2200 ÷ 2300 K at 0.7-0,8
μs behind detonation front
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Conclusions
• The alternative view on the structure of the spectral
radiance signal recorded at detonation of an emulsion
explosive with embedded glass microballoons
• The location of the point to estimate the detonation
temperature is defined by the comparison of pressure,
particle velocity and temperature profiles behind the
detonation front
• Our experimental results are in qualitative and
quantitative accordance with independent calculations
• In the range of detonation pressures from 1 to 11 GPa
the detonation temperature of EMX is 1840 ÷ 2260 K
and has non-monotonous behavior on pressure.
• Temperature maximum is about at 6 GPa
Acknowledgments
The work was supported by
1. the Russian Foundation for Basic Research (project 1208-00092-а),
2. the Presidium of the Russian Academy of Science
(project 2.9),
3. the President of the Russian Federation for State
Support of Leading Scientific Schools (grant NSh2695.2014.1).
THANKS YOU FOR ATTENTION
Appendix
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Detonation temperature measurement of
heterogeneous explosives / Problems
Optical method based on the radiance of shocked/reacted
matter  hi-time resolution
Transparent window technique / low shock impedance
material is needed for EMX’s
Interpretation: short reaction time  luminosity maximum to
temperature estimation / longer reaction time (?)
Mismatch of acoustic impedances of window material and
explosive investigated  complexity of result’s analysis /
EOS of detonation products, black/grey/non-equilibrium
body model, effect of physical inclusions
High “hot spots” temperature / Low “matrix” temperature 
very large dynamic range of technique used, high
sensitivity
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Planck’ distribution
3,5
E
630 nm
660 nm
3
T hs
2,5
Two wave lengths
2
3000 K
630 (20) nm x 45 times
660 (120) nm x 38 times
2000 K
1,5
visible range
1
Td
0,5
0
0,2
0,7
l, μm
T630 - T660 ≈ 30-50 K
1,2
Wide dynamic range of
pyrometer is needed to
register and “hot spots”, and
detonation temperatures
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Shocked mono-layer luminosity
model of “hot spots” layer
Explosively driven duralumin plate
5-10 mm
2.4 – 5.1 km/s
20 GPa
~ 18º
Matrix
epoxy, water
GMBs
~ 60 μm
9 GPa
Optical fiber
Ø0.2 mm, ~ 10 m
mask
Ø6 mm
filter
to FMT
Ths ~ 1.5-2Tmatrix
Dt = 0.2 – 0.6 ms
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