摘要:

AbstractThermo‐analytical techniques such as DSC, TGDTG have been used to study the ternary mixtures of KNO3, S and charcoal/carbon black. S exists in two forms, one is called free sulphur on the surface of grains, while the other is termed adsorbed or trapped S. The first form of S, is removed between 175°C to 300°C while the second form is removed around 375°C. The ratio of two forms is altered by the grain and nature of carbon. Carbon black, as compared to charcoal, produces more energy from the oxidation of carbon. The effect of heating rate and the way the sample is placed, is also obse

ISSN:0721-3115    

DOI:10.1002/prep.19920170102

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

Abstract3,3‐Bis(azidomethyl)oxetane (BAMO) is a typical energetic azide polymer containing two N3, bonds in the molecular structure. Since BAMO is a solidified polymer at room temperature, a liquid BAMO copolymer with tetrahydrofuran (THF) was synthesized in order to gain energetic binders for solid propellants. Various types of experiments were carried out to elucidate the decomposition and combustion processes of BAMO polymer, BAMO/THF copolymer, and crosslinked BAMO/THF copolymer. The heat produced by the decomposition is caused by the bond breakage of ‐N3to produce N2, gas. The burning rate characteristics of crosslinked BAMO/THF copolymer depend largely on the mole fraction ratio of BAMO and

ISSN:0721-3115    

DOI:10.1002/prep.19920170103

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractThe degradation of the nitrate oxidant was followed in the course of the aging process of tracer pyrotechnic mix containing 22.0 % Mg, 46.0 % Sr(NO3)2, 22.0 % KCIO4, 9.0 % Al‐Mg alloy and 4.0 % organic binder. The accelerated aging was conducted under the conditions of the increased humidity (98.5 %, 85.0 %, 78.5 %) at the increased temperature (75 °C). Nitrate content as a function of aging time was calculated by substracting nitrite nitrogen from total nitrogen content determined by Devarda's alloy reduction method. The degradation products of the nitrate (nitrite and carbonate) were determined by UV/VlS (Griess reaction) and IR spectroscopy, respectively. Nitrate proved to have a great instability in the presence of the metal, the extent of its conversion to nitrite and carbonate being rather great in comparision to the previously studied alkali metal nitrates in the presence of Mg as well. The loss of the nitrate and the formation of the nitrite and carbonate are governed by the same kinetic laws as fuel degradation to the hydroxide. The rate of the metal oxidation to the hydroxide was faster than the rate of the nitrate degradation process. The failure of the mix is connected to the rather small content of the nitrite (0.4 %) while the texture was significantly destroy

ISSN:0721-3115    

DOI:10.1002/prep.19920170104

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractIn a combustion chamber equipped with windows, boron and boron alloy slurries were burnt. The fraction of the solids in these mixtures was 25%. For the quantitive analysis of the reaction products, three spectrometer systems were used: an optical multichannel analyzer for the range 0.2 μm to 0.9 μm, an acusto‐optical tunable IR‐filter for the range 1.2 μm ‐ 2.4 μm, and rotating IR‐filters covering the range from 2.5 μm to 14.5 μm. The determination of the gas‐phase temperature of the exhaust plume was obtained by evaluation of the OH rotation bands. The particle temperature was measured with a fast two‐color pyrometer. During the burning process of boron with an average particle size of 2 μm, only a weak background radiation was detected. Mg and AlB2, produced a greater amount of particles in the exhaust due to their particle size of about 50 μm.The spectra of the exhaust plume show typical bands for the particular metals and the combustion products of the JET Al fuel. Particle size distribution, surface characteristics, and temperature are important parameters for the ignition and combustion of solids. Also, the flow field inside the combustion chamber influences the burning behaviour of the solid particles. Therefore the slurries were injected against the main flow direction to prod

ISSN:0721-3115    

DOI:10.1002/prep.19920170105

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractRelationship was found between activation energies E of low‐temperature non‐autocatalyzed thermolysis of the nitric acid esters, on the one hand and their oxygen balances OB100, on the other. By this relationship, molecular‐structural dependence is evidenced of values E, at the same time existence is signalized of the direct relationship between the values E and the impact sensitivity of nitroe

ISSN:0721-3115    

DOI:10.1002/prep.19920170106

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractPredicting interface position of solid‐liquid phase change is important for the filling of explosives in the shell. The cooling process of casting charge is discussed analytically and experimentally. The basic equations describing this process are derived from a modified and extended equivalent heat capacity model. Numerical calculations are then performed to determine the solidification front distributions and temperature distributions. The experiments are performed using TNT as the phase change material. Comparison between practical experiments and computer simulation has shown that there is a good agreement. By using computer calculations, a better knowledge of important parameters for the casting process can be easily obtaine

ISSN:0721-3115    

DOI:10.1002/prep.19920170107

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractDuring jet formation and elongation, the shaped charge linear material is subject to forces which vary extremely in both magnitude and direction. As a result, the direction in which the slip planes are formed in the material, changes so as to comply with the force direction and strength. By following the direction of the slip planes from the beginning of liner motion until the jet breaks up, it is possible to suggest a description of the internal changes occurring in the material during liner collapse, jet formation, and jet elongation. The mechanism obtained by this study may account for the slight systematical deviation by a jet from the original shaped charge axis of symmetry, such as has been measured very accurately using the orthogonal synchro‐streak technique (OSST) developed by Held. The mechanism may also explain some jet details observed in OSST photographs and flash radiographs. The modeled mechanism identifies the possibility that some basic differences may exist between the break‐up process occurring in expanding rings and shells and the break‐up process occurring in shaped charge

ISSN:0721-3115    

DOI:10.1002/prep.19920170108

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractThe glass transition temperature of pure nitrocellulose is determined by torsional braid analysis. The reproducibility and reliability of the measured results are discussed.

ISSN:0721-3115    

DOI:10.1002/prep.19920170109

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractVersatile neutral polymeric bonding agents (NBPA's) have been developed for energetic propellants in which polar HMX particles are dispersed in a polar binder matrix containing highly polar plasticizers (TMETN, NG, etc.). Using a semi‐empirical approach through adjustment of solubility parameters and molecular weight, neutral acrylonitrile interpolymers were synthesized which mix uniformly with the submix and still have a high affinity for the HMX particles when they are added. Addition of about 0.2 % w/w of NPBA to HMX‐filled PEG binders increases the strength by a factor of as high as five compared to samples with no NPBA, and also eliminates the sudden decrease in modulus (knee) which occurs at relatively low elongation. The degree of filler reinforcement achieved by our NPBA's in energetic propellants is far superior to that achieved by adding nitrocellulose or any other previously proposed bonding agents, and similar to the effect of precoating the HMX particles with polyurea she

ISSN:0721-3115    

DOI:10.1002/prep.19920170110

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractA simple model capable of reproducing all of the experimental results known for the MRL 38 mm diameter shaped charge is described. The basis of this model is the original analytical work of F'ugh, Eichelberger and Rostoker and the more recent work of Hirsch, and of Carleone, Jameson and Chou. The three phenomenological constants required by the model are found by fitting to data from the BRL 105 mm diameter unconfined shaped charge. The model is then used to calculate the jet velocity gradient and the collapse angle versus time for the MRL standard charge. Good agreement has been found with recent experimental results.

ISSN:0721-3115    

DOI:10.1002/prep.19920170111

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY