Dayu Ding, Morimasa Higaki, Yozo Ooki and
Tadao Yoshida
Ashikaga Institute of Technology, 268-1 Omae-cho, Ashikaga-shi, Tochigi
326-8558, Japan
Abstract: The burning time of
stationary and flying fireworks stars was measured, the trajectories
of flying stars were observed and the results were analyzed in this
work. It was found that the difference in burning time between the
stationary and flying burning stars was dependent on the kind of
star. Modeling of flying star ballistics was applied to the trajectory
of stars with shorter burning times and was found valid for this
case.
Keywords: fireworks, burning
time, exterior ballistics, modeling
Temperature Measurements within the Luminous
Region of a Burning Ba(NO3)2/Al Mixture
P. J. Disimile, R. Prasad and N. Toy UC-FEST, Department of Aerospace
Engineering, University of Cincinnati, Cincinnati, OH 45221, USA
Abstract: Knowledge of the local
temperature field associated with a pyrotechnic event has numerous
implications, especially in the field of safety and survivability.
These implications involve the development of sensors that are capable
of detecting pyrotechnic events and that are used in part to eliminate
or reduce a fire hazard. However, in order to be able to predict
a possible fire scenario from a pyrotechnic event the temperature
distributions and the thermal heat transfer are prerequisites. This
experimental study discusses the temperature measurement methodology
required to evaluate the transient temperatures associated with
a small, commercially available, pyrotechnic device. Furthermore,
the temperature distribution close to the surface of two devices,
one commercial, the other fabricated, has been obtained, and shows
that the temperature distribution away from the event is not uniform.
Keywords: temperature distribution,
thermocouples, pyrotechnic facility
Ballistics of an Iron Bar Shot from a
Mortar
Morimasa Higaki, Dayu Ding, Yuuzo Ooki
and Tadao Yoshida Ashikaga Institute of Technology,
268-1, Omae-cho, Ashikaga-shi, Tochigi-ken 326-8558, Japan
Abstract: An accidental explosion
in 1848 in the USA became a trigger for the development of neuroscience.
An accidental explosion of Black Powder took place in a borehole
for blasting and the expelled iron bar penetrated the head of a
young man. He was injured but survived for 12 years. The authors
were asked to calculate the speed, impact pressure or energy of
the explosion by the producer of a TV program. At the time we were
carrying out similar experiments using a mortar and firework stars,
and so a model experiment was performed. Here we report of the results.
Keywords: Black Powder, ballistics,
iron bar, shot energy efficiency
Ballistics
of a No. 3 Spherical Shell with Illuminant
M. Higaki, D. Ding, Y. Ooki,
M. Higaki and T. Yoshida
Ashikaga Institute of Technology, 268-1, Omae-cho, Ashikaga-shi, Tochigi-ken
326-8558, Japan
Abstract: Shot experiments were
carried out using a No. 3 spherical shell with an illuminant. The
three dimensional trajectory of the flying shell was obtained by
tracing the shell with two high-speed video cameras in different
orientations and by analyzing the recorded video picture. The 3DSTAR1
computer code was developed for calculating the three dimensional
trajectory of a flying shell with high accuracy. The optimal drag
coefficient, wind speed and wind direction were estimated using
the 3DSTAR1 code by fitting the calculated trajectory to the experimental
one for a No. 3 shell.
Keywords: ballistics, no. 3
shell, trajectory
Effect
of Particle Size on the Mechanical Sensitivity and Thermal Stability
Aspects of Pyrotechnic Flash Compositions
S. P. Sivapirakasam, M. Surianarayanan,
F. Chandrasekaran and G. Swaminathan
Cell for Industrial Safety & Risk Analysis, Chemical Engineering
Department, Central Leather Research Institute, (Council of Scientific
& Industrial Research), Adyar, Chennai , 600 020, India
Abstract: The mechanical and
thermal sensitivity of pyrotechnic flash compositions consisting
of mixtures of potassium nitrate (KNO3), sulphur (S)
and aluminum (Al) with varying particle sizes of KNO3
and Al indicated that, irrespective of the composition of the cracker
mixture, all the compositions were found to be thermally and mechanically
sensitive. Although the impact sensitivity results reflected the
change in the surface area of the particle sizes, the changes were
within a narrow range of limiting impact energy (LIE) (7.5–9.1
J). Further it was difficult to pinpoint a particular sieve fraction
as sensitive since the response to explosion depended not only on
the flash composition and the particle size but also on the density
and the compactness of the chemicals.
DSC studies on the effect of the Al particle size showed that
a decrease in the Al particle size led to a second exothermic activity.
This behavior should be viewed with caution when considering safety
aspects.
Interrelation
between Impact, Friction and Thermal Energy in a Pyrotechnic Flash
Reaction
S. P. Sivapirakasam and M. Surianarayanan
Cell for Industrial Safety & Risk Analysis, Chemical Engineering
Department, Central Leather Research Institute, (Council of Scientific
& Industrial Research), Adyar, Chennai, 600 020, India.
Abstract: Firework chemical
mixtures are sensitive to thermal and mechanical stimuli and lead
to many explosive incidents. Experimentally determined thermal and
mechanical (impact and friction) sensitivity data of a flash composition
mixture are subjected to statistical and graphical analysis in order
to understand the mechanism of triggering accidents. The interrelationship
study reveals that irrespective of the nature of stimuli, explosion
is the final event and occurs due to a thermal mechanism. This study
shows that under severe impact thermal stimuli can occur. If the
thermal stimuli are equal to or greater than the activation energy
of the composition then ignition of the flash composition will occur.
Thermal
Characterization and Kinetic Modeling of a Pyrotechnic Flash Composition
under Adiabatic Conditions
S. P. Sivapirakasam, M. Surianarayanan
and R. Vijayaraghavan
Cell for Industrial Safety and Risk Analysis, Central Leather Research
Institute Chennai, 600 020, India
Abstract: A pyrotechnic flash
composition consisting of 53% KNO3, 30% Al and 17% S
is subjected to Accelerating Rate Calorimetry (ARC) studies. The
onset point for thermal explosion is 191 ºC resulting in the
generation of a considerable quantity of gaseous products. The mixture
is vulnerable to thermal hazards. There is good agreement between
the predicted and experimental self-heat rates determined using
adiabatic thermo kinetics.
Review by Christopher Pearce
of Fireworks – Principles and Practice, 4th
Edition by Rev R Lancaster MBE
Selected Papers from the 2nd
Workshop on Pyrotechnic Combustion Mechanisms:
The Combustion
Products of Novel High-Nitrogen Energetic Materials
David E. Chavez, Michael A. Hiskey, My
Hang Huynh, Darren L. Naud, Steven F. Son and Bryce C. Tappan Los Alamos National Laboratory, High Explosives
Science and Technology, DX-2 MS C 920, Los Alamos, NM 87545, USA
Abstract: High-nitrogen energetic
materials based on the tetrazine and tetrazole ring systems have shown
unique and unpredictable combustion behavior. Unlike traditional energetic
compounds, such as 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine
(RDX), which derive their energy by the oxidation of the carbon and
hydrogen skeletal atoms by the oxygen carrying nitro group, high-nitrogen
materials typically have large positive heats of formation as their
source of energy. This difference in the energy source may partly
explain why the combustion chemistries of some high-nitrogen materials
are unusual.
Using the precursor 3,6-bis-(3,5-dimethylpyrazol-1-yl)-s-tetrazine
(BDT), several useful energetic compounds based on the s-tetrazine
system have been synthesized and studied. A number of these tetrazine
based materials have shown to exhibit burn rates with low sensitivity
to pressure, namely 3,6-bis(1H-1,2,3,4-tetrazol-5-ylamino)-s-tetrazine
(BTATz), 3,6-bis-nitroguanyl-1,2,4,5-tetrazine (NQ2Tz),
the corresponding bis-triaminoguanidinium salt (TAG2NQ2Tz)
and the N-oxides of 3,3´-azobis(6-amino-1,2,4,5-tetrazine) (DAATO3.5).
A fifth compound of high nitrogen make-up, triaminoguanidinium azotetrazolate
(TAGzT, is not prepared from BDT, but it also burns at exceptional
rates with low pressure sensitivity.
The tetrazole-based materials, bis-(1(2)H-tetrazol-5-yl)-amine
(BTA) and 5,5´-bis-1H-tetrazole (BT), are useful high-nitrogen energetic
ligands for the preparation of metal complexes. While BTA, BT and
their salts have been previously shown as possible energetic fuels
for low-smoke pyrotechnic applications, some recent combustion experiments
with the metal complexes of BT and BTA have proved to be even more
noteworthy. These metal ion complexes have sufficient internal energy
that they can burn under an inert atmosphere to produce the free
metal, usually in the form of high-surface area foams or nano-sized
particles. This highly unusual, reductive combustion chemistry may
lead to efficient and controlled production of metal nanofoams.
The heat of formation (ΔHf) of 3,6-diazido-1,2,4,5-tetrazine
(DiAT), a highly energetic and sensitive energetic material (most
notably to friction, spark and impact), was calculated to be approximately
+1100 kJ mol−1, or +92 kJ mol-atom−1,
using an additive method. Depending on the heating rate, DiAT can
undergo pyrolytic decomposition to produce either carbon nanospheres
or carbon nitride nanopolygons. With slow heating, leaf-like or
rope-like forms of carbon nitride were the predominant products.
With faster heating, carbon spheres with diameters on the order
of 10 to 100 nm were produced. Such nanomaterials are of interest
to the scientific community for a wide number of industrial applications.
Laser-Initiated
Reactions of Energetic/Thermitic Composites
Jared C. Gump and Suhithi M. Peiris
Indian Head Division, Naval Surface Warfare Center, 101 Strauss Avenue,
Indian Head, MD 20640, USA
Abstract: Researchers are attempting
to prepare smaller (nano-scale) metal particles, and nano-scale
thermitic (metal–metal-oxide) composites. When added to energetic
compositions, these nano-materials could burn during or close behind
the shock front produced by an explosive material. Therefore, investigation
of their combustion kinetics is important, especially when the investigation
technique requires only very small quantities of material that is
initially prepared. This study uses time-resolved emission spectroscopy
to measure reaction kinetics and mechanisms of micrograms of material
initiated by a laser pulse. Results from nano-scale aluminum and
the thermite-type compositions of Al + Fe2O3,
Al + MoO3, and Al + B2O3 are presented
here.
Reprint
Information: Number of pages = 6. Price for this reprint is
the minimum charge of $5.00.
New Approaches to Model Pyrotechnic Reactions
Stefan Kelzenberg, Norbert Eisenreich and
Volker Weiser Fraunhofer Institut
für Chemische Technologie, Joseph-von-Fraunhofer-Str. 7, D-76327,
Pfinztal, Germany
Abstract: In most cases pyrotechnic
mixtures are constituted from granular components. A theoretical
study of such a granular system describes the temperature and concentration
evolution in the energetic material by using hot spots as source
terms for temperature and particles. The progress of the reaction
is mainly influenced by particle properties which are size, melting
and evaporation, gasification and surface reactions. In a first
step the influence of the particle size ratio between fuel and oxidizer
particles is investigated.
Keywords: hot-spot model, combustion,
ignition, pyrotechnics, Green’s method Reprint
Information: Number of pages = 8. Price for this reprint is
the minimum charge of $5.00.
Please send comments and suggested corrections to: B. Kosanke,
Publisher, Journal of Pyrotechnics, Inc.
1775 Blair Road Whitewater, CO 81527 USA
Phone/FAX +970-245-0692
You Can Help Keep Fireworks Legal
Did you know that efforts are underway in the United States at both State
and Federal levels to ban consumer fireworks and rocketry forever? You
can help turn the tide by joining the Fireworks Alliance.
It's free, and we need your voice today!