ISSN:0721-3115    

DOI:10.1002/prep.19870120302

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractSolid rocket propellants containing nitramine are considerably superior to doublebase propellants, both as regards their performance and mechanical properties. The pressure exponent of non‐modified nitramine propellants is n ≥ 0.9. The possibility of changing the burning rate or, respectively, the pressure exponent has, however, only been realisable to a restricted extent up till now in propellants with an increased nitramine content. In the following propellant system containing nitramine, the effects of ammonium perchlorate on burning behaviour are studied:ammonium perchlorate (AP)hexogen (RDX)nitroglycerin (NG), or trimethylolethane trinitrate (TMETN)polyurethane binder (PU)AP concentrations already as great as 10% produce considerable changes in the burning behaviour of the propellants described above. It is possible to reduce the pressure exponent by the addition of ammonium perchlorate from n ≥ 0.9 to n ≤ 0.65. The burning rates may also be influenced with AP concentrations ≤ 20% and by varying the AP particle size by the factor of 2. All the propellants prepared were easily castable and showed exceptionally good viscoelastic properties (strain at break εR>200%) in the temperature range between −40 °C to + 50 °C. The thermal chemical stability is not influenced negatively in any way by the combination of nitric acid esters and ammoni

ISSN:0721-3115    

DOI:10.1002/prep.19870120303

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractAn optical system is described for measuring the burning rate of solid propellant strands. It consists of a bomb equipped with quartz windows, an objective, a photo diode array and a data acquisition and processing unit. A Simultaneous observation of the burning in possible by other optical and spectroscopic methods.The system is tested by recording the pressure dependence of the burning rates of typical propellants. The results are compared to those obtained by the standard Crawford method. The advantages of the optical system are due to the easier handling in sample preparation and the assessment of a distribution of the burning rate.

ISSN:0721-3115    

DOI:10.1002/prep.19870120304

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractThermal and mechanical stability of rocket and gun propellants are very important properties with regard to safety during storage and handling and to the interior ballistics behavior during combustion.However, our knowledge of how these properties are connected is poor. In order to better understand the aging behavior of double base propellants, the following properties were measured between 60 °C and 90 °C: the depletion of the stabilizers, the degradation of the molecular weights of nitrocellulose and the decrease of the mechanical properties (tensile strength and strain at break).The evaluation of the kinetic parameters of the different aging processes mentioned has shown that stabilizer depletion, molecular weight degradation of nitrocellulose and decrease of mechanical properties must be closely connecte

ISSN:0721-3115    

DOI:10.1002/prep.19870120305

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractBoron particle combustion is retarded by initial presence of an oxide coating. In current boron ignition models, oxygen is assumed to desolve in the oxide and diffuse to the B/B2O3interface for reaction. One method to observe the reaction of boron with its surrounding atmosphere is the time resolved emission spectroscopy we applied in the range of 0.2 m̈m to 5.5 m̈m for different burning processes.In one experiment boron powder was burned in oxygen atmosphere initiated by an efficient pyrotechnic device. The energy transfer by the hot gases led to a glowing phase of the boron particles which then changed to a high temperature combustion and ended in a further glowing phase. The two glowing phases emitted continuous emission spectra, while the burning phase emitted the bands of BO and BO2.Another experimental setup was used to feed boron particles in a hot oxidizing atmosphere provided by a propane/air flame which flew into a combustion chamber. Herein the reaction of boron was recorded with high speed cinematography and time resolved emission spectroscopy. The flame contained a small amount of background radiation and we could identify emitted bands of BO, BO2, HBO2, CO and CO

ISSN:0721-3115    

DOI:10.1002/prep.19870120306

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractIn the environmental qualification of chemical energetics, influences from the environment occurring in production, logistics and applications are simulated. The attempt was thus made to demonstrate or, respectively, to estimate the manipulation safety, functional behaviour and life time of energetic materials. It is here the usual method to intensify simulated environmental influences for the purpose of accelerating tests. In this paper the example of mechanical load simulation is used to demonstrate how knowledge of the behaviour of the material is necessary for an ingenious modelling and a rational increasing of test levels. Apart from the microscopic and macroscopic point of view, especially the so called “micromorphological” observation level is well suited to this purp

ISSN:0721-3115    

DOI:10.1002/prep.19870120307

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractThe initiation behavior of TNT/RDX 35/65 high explosive charges under the impact of the jet from a 44 mm diameter shaped charge with 7.8 mm/m̈s jet tip velocity, which has previously perforated a 100 mm thick barrier is reported. In these tests,the high explosive charge under test was divided into different sections by transverse air gaps, with the first section being in contact with the barrier, orthe 100 mm thick barrier was sub‐divided in such a way that one part of it was in contact with the high explosive charge under test, orvarious air gaps, ranging from 0.5 mm to 450 mm, were made between the acceptor charge and the barri

ISSN:0721-3115    

DOI:10.1002/prep.19870120308

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractIn the uniaxial tensile test forces, longitutional and transversal elongation must be measured simultaneously. Recently(1)we presented a non intrusive method to measure both elongations in one experiment. To get more information about the material behaviour beyond the yield stress we modified this test equipment. Now we obtain the strain distribution along the whole sample.

ISSN:0721-3115    

DOI:10.1002/prep.19870120309

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractIt is shown that there exists a dominant solution of the Boltzmann equation for an artificial model gas in terms of a relation for the diffusion flux differing from the regular formulation of Fick's first law. Its mathematical structure corresponds to the Cattaneo‐formulation based on heuristics of the Fourier heat flux vector. This dominant solution allows a realistic estimation of a diffusion relaxation time and serves as the basis for valuable information concerning two actual problems of hypersonic gas dynamics: first, a useful relation for the calculation of collision integrals for diffusion coefficients, especially at high temperatures; second, a new type of a chemical reaction equation, which is particularly relevant in very fast relaxation processes encountered in the chemistry of fuel

ISSN:0721-3115    

DOI:10.1002/prep.19870120310

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

ISSN:0721-3115    

DOI:10.1002/prep.19870120301

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY