摘要:

AbstractThe combustion process of pyrotechnics was studied in order to obtain informations of the rate control parameters of burning rate. The pyrotechnics tested was made of Mg (magnesium) and TF (polyfluoroethylene). The burning rate measurements revealed that the burning rate of the Mg/TF propellants (pellet in shape) increases with increasing the weight fraction (ξ) of Mg in the range of ξ>0.33. Though the adiabatic flame temperature is the maximum at ξ = 0.33, the burning rate increases with decreasing the flame temperature. The total burning surface area of the Mg particles mixed with in the unit mass of propellant plays an important role on the oxidation process in the gas phase just above the propellant burning surface. The heat flux feedback from the gas phase to the propellant burning surface increases with increasing ξ. Therefore, the burning rate increases as ξ incre

ISSN:0721-3115    

DOI:10.1002/prep.19870120502

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractHypergolic or self ignition delays of unsymmetrical dimethylhydrazine (UDMH) and several amine fuels, mixed with three fuming nitric acid oxidizers, have been determined, at room temperature, in a highly sensitive “Cup Test” apparatus. Ignition delay (ID) variations have been studied with respect to the chemical structure of fuel, oxidizer composition, and oxidizer‐to‐fuel (O/F) ratio. Probable preignition reactions and structure‐hypergolicity correlations have been suggested.Some non‐hypergolic hydrocarbons and petroleum fractions have been hypergolized by addition of UDMH, and ID variations have been studied with respect to UDMH‐content in fuel and catalytic additives (ammonium metavanadate, ammonium dichromate, and cuprous oxide) in the red fuming nitric acid oxidizer (RFNA). Increment in UDMH‐content improves the hypergolicity of fuels towards RFNA. For example, kerosene + UDMH 60:40 blend ignites with RFNA with a remarkably low ID of 6 ms. However, the catalytic effect of the additive in RFNA varies widely with the fuel‐

ISSN:0721-3115    

DOI:10.1002/prep.19870120503

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractThe problem of end effects influencing the ejection angles of fragments near the ends of cylindrical warheads is approached semi‐empirically. A correction term is added to the Taylor angle, based on the accepted concept that the reduced fragment velocities near the ends of a warhead are due to release waves in the detonation gas. Acceptable agreement between experiment and prediction is found for available experimental data. The results indicate that the accelerative drag due to the axially‐outward component of the release‐wave gas flow over the fragments dominates the divergence of the fragments for prefragmented casings, the axial pressure drop playing a minor part, while the reverse seems to be true for the divergence of fragments from solid ca

ISSN:0721-3115    

DOI:10.1002/prep.19870120504

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractA new high performance liquid chromatography (HPLC) method has been developed for the quantitative analysis of diphenylamine and itsN‐nitroso‐ andC‐nitro derivatives found in single‐base gun propellants. Of the potential derivatives, only 2‐ and 4‐nitrodiphenylamine, 2,2′‐, 2,4′‐ and 4,4′‐dinitrodiphenylamine, 2,2′4‐ and 2,4,4′‐trinitrodiphenylamine. 2,2′4′4′‐tetranitrodiphenylamine,N‐nitrosodiphenylamine and 4‐nitro‐N‐nitrosodiphenylamine were found in major amounts. Minor derivatives noted were: 2,4‐dinitrodiphenylamine, 2‐nitro‐N‐nitrosodiphenylamine, 2,4′‐ and 4,4′‐dinitro‐N‐nitrosodiphenylamine. Other derivatives were looked for but not found. This HPLC method can be used to quantify all the major derivatives in a single chromatogram and importantly, can be used even in the presence of propellant additives dinitrotoluene, di(ethylhexyl) phthalate and dibutyl phthalate. This procedure provides the most effective analysis of stabilizer in single‐base propellants yet published. We have used this method to study the derivatisation of diphenyla

ISSN:0721-3115    

DOI:10.1002/prep.19870120505

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractAfin d'améliorer les délais de réponse et la productivité, une méthode d'analyse autre que la méthode Dewarda était recherchée pour doser I'azote nitrique des nitrocelluloses, avec des succès divers mais sans obtenir la précision demandée. Les auteurs ont étudié I'influence des paramètres régissant le dosage par potentiometrie de l'azote nitrique par le sulfate ferreux, tels que la température, la stabilité des réactifs, les concentrations, I'agitation. Cette étude a permis de concevoir un prototype de dosage entitrèment automatisé, permettant d'obtenir un temps de réponse de l'ordre de 20 minutes et une précision comparable à celle de la méthode Dewarda. Elle s'applique à la nitrocellulose. aux esters nitriqu

ISSN:0721-3115    

DOI:10.1002/prep.19870120506

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractThe results of experiments on the initiation of covered, but unconfined high explosive charges with shaped charge jets from Chick and Hatt, which have been diagnosed by the flash X‐ray technique, as well as the author's own experiments in which the build‐up distances and the run‐up times have been recorded by means of a rotating‐mirror camera in the framing and streak modes, are analyzed and explained in detail in this paper. Build‐up distances and run‐up times versus the residual jet velocity, or versus the dynamic pressure, are in fairly good agreement, despite the somewhat different shaped charges and acceptor charges that have been used in the two approaches.The greater initiability of an acceptor charge behind a barrier, but with an air gap between, is attributed less to a precursor shock that desensitizes the high explosive charge which is in contact with a barrier, but rather to the higher velocity of the free shaped charge jet and, particularly, to the area loading on a high explosive charge with an air g

ISSN:0721-3115    

DOI:10.1002/prep.19870120507

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractA modification of the Mot fragmentation formula, accounting for a maximum fragment size, is suggested. Twelve experimental data sets are used to test the goodness of fit of the original and the modified formula. Generally, the modified formula is found to give a better representation of the experimental data, and particularly, the overestimation of the number of very large fragments is avoided.

ISSN:0721-3115    

DOI:10.1002/prep.19870120508

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

ISSN:0721-3115    

DOI:10.1002/prep.19870120509

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

ISSN:0721-3115    

DOI:10.1002/prep.19870120501

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY