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Wyświetlanie 1-8 z 8
Tytuł:
Use of a Hot-Spot Model to Describe the Influence of Particle Size and Distance on Combustion in a Cloud
Autorzy:
Kelzenberg, S.
Knapp, S.
Weiser, V.
Powiązania:
https://bibliotekanauki.pl/articles/358445.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
combustion
particles
hot-spot-model
Opis:
The combustion of particles in a cloud can be very different from single particle combustion. In addition to the size of the particles, the number density of particles or the mean distance between the particles plays an important role. Experiments show that if the distance between the particles in a cloud is large enough, particles burn in a similar manner to single particles. However below a certain distance, particles form a common flame front. In a parametric study, a hot-spot model is used to simulate the two burning regimes and to find the critical parameters for the transition between them. The results are discussed with reference to the combustion of metalized, gelled and solid propellants and dust explosions.
Źródło:
Central European Journal of Energetic Materials; 2013, 10, 1; 69-85
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of the Mechanical and Thermal Properties, and Impact Sensitivity of Pressed HMX-based PBX
Autorzy:
Li, Yuxiang
Wu, Peng
Hua, Cheng
Wang, Jun
Huang, Bing
Chen, Jin
Qiao, Zhiqiang
Yang, Guangcheng
Powiązania:
https://bibliotekanauki.pl/articles/358006.pdf
Data publikacji:
2019
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
nanoexplosives
impact sensitivity
particle size
hot spot
Opis:
Submicron- and nano-explosives have attracted growing attention, while the mechanism of how particle size influences the impact sensitivity is not completely understood. In the present work, HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) based PBXs (plastic bonded explosives) of three particle size distributions (1-2 and 10-20 μm, and 100-300 nm) and two pressed densities (91%TMD and 79%TMD) were characterized and tested with a range of techniques to determine their mechanical and thermal properties and impact sensitivities. The results demonstrated that with decreased particle size, the mechanical strength as well as the thermal conductivity were dramatically improved, and the impact sensitivity was significant decreased. The structure of impacted samples suggested that the ignition mechanism is dependant on the particle size. Samples with higher density were more sensitive to impact, as the impact force acting on these samples was higher. The correlation between particle size and impact sensitivity is discussed in detail.
Źródło:
Central European Journal of Energetic Materials; 2019, 16, 2; 295-315
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Foci for Determining the Insensitivity Features of Nanometer RDX: Nanoscale Particle Size and Moderate Thermal Reactivity
Autorzy:
Wang, Y.
Song, X.
Song, D.
Zhang, J.
Song, K.
Powiązania:
https://bibliotekanauki.pl/articles/358576.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
nanometer RDX
sensitivities
reactivity
hot spots
kinetics
Opis:
In this paper, the reasons why nanometer RDX showed lower sensitivity than micro RDX is discussed. Herein we supposed two factors affect the sensitivity of nanometer RDX. Firstly, according detonation physics models, a nanometer particle size results in small hot spots and a high critical temperature. These features suggested high safety for nanometer RDX based on the hot spot theory. A further factor is the thermal reactivity of nanometer RDX, which considerably affects the safety of nanometer energetic materials. Employing the Kinetic Compensation Effect, we calculated the kinetic parameters of micro and nanometer RDX. The results indicated that there was no obvious distinction between the activation energies of micro and nanometer RDX, which implies almost the same reactivity of micro and nanometer RDX. Incorporating the results of small hot spots, high critical temperature, and the unchanged reactivity of micro and nanometer RDX, we concluded that nanometer RDX should exhibit low sensitivity as an intrinsic feature.
Źródło:
Central European Journal of Energetic Materials; 2015, 12, 4; 799-815
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Mechanism of Molecular Condensed EMs Transformation under the Effect of Shock and Detonation Waves
Autorzy:
Dremin, A. N.
Powiązania:
https://bibliotekanauki.pl/articles/358857.pdf
Data publikacji:
2008
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
detonation
decomposition regularities
homogeneous and hot spots mechanism
Opis:
Considerations based on available experimental data on regularities of molecular condensed EMs decomposition under the effect of shock waves of different intensities are presented. It follows from the considerations that there exist shock wave pressures p* typical for each charge (for TNT charges p* ~ 12 GPa) and the charges’ initial density ?0* (for TNT 0* ~ 1.40 g/cm3) such that at larger pressure and density EMs' decomposition proceeds according to the homogeneous mechanism (does not depend on the charge structure: initial density, size and structure of explosive particles, explosive state-liquid or solid, …) and at lower pressure and density – according to the hot spots mechanism (depends on the charge structure).
Źródło:
Central European Journal of Energetic Materials; 2008, 5, 1; 31-44
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and operation of a small scale set back force simulator and its use in investigation into composition B fillings subjected to hot gun scenarios
Autorzy:
Cartwright, M.
Delany, P.
Powiązania:
https://bibliotekanauki.pl/articles/358919.pdf
Data publikacji:
2009
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
set back simulation
composition B
hot gun defects
Opis:
Ammunition fired from large calibre gun chambers may experience accelerations in the regions of 150,000 m s-2 and as a result are subjected to considerable force during the process of set back. During firing some of the energy may be transferred to the filling and any defects present in the shell filling can lead to local hotspots which may result in premature ignition of the warhead. A potential source of defects is the application of excessive heat to the ammunition either by storage in a hot environment or accidentally by leaving the ammunition in a hot gun scenario in the chamber of the gun. A hot gun scenario can be defined as arising after 50 rounds or more have been fired in a four hour period. In this scenario the filling may easily exceed the qualification temperature with two possible accidents occurring. Cook-off of the filling can result in spontaneous firing of the round or, when correctly initiated, the round may premature in the gun barrel both of which may have catastrophic results. Currently there is no standard test to evaluate the behaviour of composition B (60% RDX: 40% TNT) filled ammunition subjected to a hot gun scenario. Because of its low melting point 80 °C the liquid TNT can separate from the RDX increasing its sensitivity and increasing the probability of an in bore premature when fired. This paper describes the design and operation of a small scale simulator for set back forces and its use to investigate the conditions under which composition B fillings, subjected to a hot gun scenario, could initiate. Samples of composition B were subjected to thermal treatments to mimic hot gun conditions and then subjected to simulated set back conditions and the level of impact energy required for initiation determined. This was compared with the level for untreated samples and a possible evaluation of current hot gun procedures undertaken. The indications are that the process can be cost effective in simulating set back induced premature ignitions.
Źródło:
Central European Journal of Energetic Materials; 2009, 6, 1; 103-117
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Analytic Investigation of "Hot-Spot" Formation in Compressible Energetic Materials
Autorzy:
Li, X.
Zhao, F.
Liu, J.
Powiązania:
https://bibliotekanauki.pl/articles/358425.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
analytic model
bulk compressibility
pore collapse
"hot-spot" formation
Opis:
In this paper, the formation of the shock-induced “hot-spot” in compressible energetic materials has been analyzed. By applying the compressible elastic-viscoplastic material model to a hollow sphere, and solving the governing equations with the initial and boundary conditions, this paper proposes an analytic pore collapse model that is able to simulate the viscoplastic deformation which determines the formation of a “hot-spot”. In this new model there are three mechanisms, of which instantaneous deformation and the subsequent quasi-static incompressible deformation dominate “hot-spot” formation, while quasi-static compressible deformation is of little effect. In comparison with the incompressible solution, this model demonstrates that the bulk compressibility has a great influence on “hot-spot” formation, as the degree of the “hot-spot” reaction is a positive quasi-linear function of Poisson’s ratio ν. An error in Kim’s original pore collapse model has also been discussed.
Źródło:
Central European Journal of Energetic Materials; 2017, 14, 4; 806-820
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detonation Characteristics of a NOx-Free Mining Explosive Based on Sensitised Mixtures of Low Concentration Hydrogen Peroxide and Fuel
Autorzy:
Araos, M.
Onederra, I.
Powiązania:
https://bibliotekanauki.pl/articles/358423.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
hydrogen peroxide
NOx free mining explosives
detonation
hot spots
Opis:
Mining explosives based on ammonium nitrate(V) are safe and effective, however, the risk of NOx fume production during blasting is still present. In 2013, a project to eliminate NOx fumes from blasting began and hydrogen peroxide was chosen to replace ammonium nitrate(V) as the oxidiser. Previous work in this area demonstrated that hydrogen peroxide/fuel-based mixtures were able to detonate, provided that they are initiated under a situation of high confinement and also using hydrogen peroxide at relatively high concentrations. In contrast, a comprehensive study was conducted to determine the detonation properties of hydrogen peroxide/fuel-based mixtures that used hydrogen peroxide at lower concentrations (below 50 wt.%), detonated in unconfined conditions and used void sensitisation to achieve an efficient detonation reaction. This article presents the results of the influence of the density, water content, critical diameter and type of void sensitisation on the velocity of detonation (VOD) of hydrogen peroxide/ fuel-based explosive mixtures. The results indicate that the mixtures can achieve a different VOD which depends on the size of the sensitising voids and more importantly, the mixtures behave as non-ideal explosive, similarly to ammonium nitrate-based explosives, but with the advantage of being a NOx-free explosive.
Źródło:
Central European Journal of Energetic Materials; 2017, 14, 4; 759-774
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analitical criteria of homogeneous and heterogeneous detonation of liquid energetic materials
Autorzy:
Kaim, S.
Powiązania:
https://bibliotekanauki.pl/articles/92588.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
mechanism detonation initiation
hot spots
nanopores
emission atoms and molecules
shock dissociation molecules
Opis:
Statistical theory of liquids is used to investigate mechanism of detonation initiation on fronts of flat shock waves in homogeneous liquid and in liquid containing spherical nanopores. We calculated thermodynamic parameters of liquid methane sufficient for shock dissociation of molecules at a front of a shock wave. Calculations of the average single-particle force potential show that at high pressures and temperatures atoms and molecules get emitted from the surface into a nanopore with hyper-thermal speeds. Implosion of spherically symmetric stream of molecules may lead to destruction of the molecules at impact. We explained existence of top and bottom bounds for pressure during detonation initiation in heterogeneous energetic materials. In terms of pair interaction potentials and correlation functions there are formulated criteria for boundary values of thermodynamic parameters which are required for initiation of homogeneous and heterogeneous detonations based on the "hot spot"’ mechanism.
Źródło:
Materiały Wysokoenergetyczne; 2013, T. 5; 5-13
2083-0165
Pojawia się w:
Materiały Wysokoenergetyczne
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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