摘要:

AbstractThe computation of complex combustions is made classically by using an iterative Newton‐Raphson method, applied to the resolution of a system of equations under constraint by the method of Lagrange multipliers. In many mineral combustions, there are products of reaction that present the same formula but belong to different phases (solids, liquids or gaseous). In these cases, the classic method ends frequently in singular matrix. Indeed, combustion equations can present in these cases, several equal or very close solutions, which induce a numerical fork phenomenon (“stiff” problems) and a chaotic algorithm behaviour. The method presented uses a Monte‐Carlo random algorithm: the Method of Random mass Statements. It presents the advantage of converging in numerically stiff cases. It furthermore provides results equal to the classic method for non‐stiff

ISSN:0721-3115    

DOI:10.1002/prep.19970220602

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractThe1H and13C chemical shifts of methylene groups in nitric acid are reported for seven products and intermediates involved in the formation of 1,3,5‐trinitro‐1,3,5‐triazacyclohexane (RDX) from the nitrolysis of hexamethylenetetramine (HA). Based on the results, the1H and13C chemical shift ranges of the methylene groups in different kinds of methylenenitramines from the nitrolysis liquors of HA were disc

ISSN:0721-3115    

DOI:10.1002/prep.19970220603

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractNHN is a thermally and hydrolytically stable solid, easily prepared from available raw materials. Its preparation liquor can be used repeatedly, which means no waste‐water pollution in industrial manufacture. NHN is not sensitive to impact, friction, or electrostatic charge, but is more sensitive to flame. It is demonstrated that NHN is suitable as a replacement for lead azide as an intermediate charge in commercial detonator

ISSN:0721-3115    

DOI:10.1002/prep.19970220604

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractHigh performance liquid chromatography (HPLC) is used in a large extent for environmental analysis. In this field many components have to be determined at the same time, but it is difficult to find the optimum separation conditions. Therefore, retention times of explosives and propellant components were determined at different solvent compositions of methanol/water and different temperatures on a column with an octadecyl phase. From the data constants were calculated for solvent and temperature dependence. With the determined data different column conditions were simulated by computer and the separation was optimized. The optimal separation was verified experimentally and compared with the calculated values. The deviation from calculated and experimental retention times lies as a rule below 2% and has a maximum of approximately 3.3%. Thus, separation of substance mixtures can be optimized by determination of column constants for temperature and solvent dependence.

ISSN:0721-3115    

DOI:10.1002/prep.19970220605

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractIn the paper theoretical modeling of flamespreading through granular propellant charge during base ignition is given. The theoretical model includes the balance equations for the gas and solid phase, as well as necessary constitutive laws. The stable convergent numerical procedure for solution of the system of equations is developed. This procedure is included in computational program FSPC (Flame‐spreading through Propellant Charge). The program FSPC enables investigations of influence of ignition material, physical and chemical characteristics of propellant and propellant charge loading density on the flamespreading process. The experimental investigations by an especially designed apparatus are performed. The verification of the theoretical‐numerical access through the comparison with the experimental data (pressure vs. time and locations, flamespreading velocity, propellant grains displacements) is carried out. The entire access makes possible more successful solutions of many interior ballistics probl

ISSN:0721-3115    

DOI:10.1002/prep.19970220606

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractDinitrobitriazoles were obtained from aminotriazoles by diazotation, coupling with methazonic acid and subsequent cyclization. They proved to be highly energetic materials. The chemical, physical and explosive properties have been investigated.

ISSN:0721-3115    

DOI:10.1002/prep.19970220607

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractUnderwater explosion properties of an aluminized explosive, DXD‐03, were numerically modeled by two burn techniques; a programmed‐burn technique and a rate equation calibrated from two‐dimensional steady‐state detonation experiments based on the detonation shock dynamics. The modeling by using the programmed‐burn technique did not reproduce experimental data well; 12% to 34% error in peak pressure and 20% error in bubble period. The modeling by using the rate equation reproduced the experimental observations very well. Although there was some difference in peak pressure, the shock profile agreed very well with experimental observation. The calculated bubble period agreed with the experimental data within 1%. This result demonstrates that the underwater explosion properties for aluminized explosives can be calculated only when the slow energy release of aluminium is modeled

ISSN:0721-3115    

DOI:10.1002/prep.19970220608

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractA slightly divergent flow detonation model has been used to model previously published charge diameter data for nitroguanidine. The kinetic form at low density is shown to be of the hot spot/grain burning type. At higher densities the kinetics become progressively thermal explosion in form. The kinetics are discussed in terms of the pressure dependent rate law used in the model and models of hot spot formation in powder explosives. The particular crystal size and form of nitroguanidine used shows characteristics which suggest it to be of the type described by Price as Group 2 at low density but to show a change to Group 1 type behaviour at higher density. The analysis suggests reasons for this and for the observation that an alternative crystal size and form appears to show only Group 1 characteristics.

ISSN:0721-3115    

DOI:10.1002/prep.19970220609

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractAn experimental device using a laser diode is described. The laser diode is coupled with a 100 μm diameter optical fiber. Lasering times are about one ms and the energy of the pulse ranges from 0.5 mJ to 5 mJ. Output power provided by optical fiber is about 0.5 W and the wavelength of radiation is 820 nm. Before each shot the pulse energy is measured by means of a joule meter. It allows a very accurate determination of the amount of energy transferred to the solid explosive. A small reactor containing about 40 mg of explosive is used. It allows to initiate combustion with a direct contact between the output of an optical fiber and the solid explosive. Three pyrotechnic compounds were tested and tests have shown that it is possible to ignite Zr/KClO4and Zr/PbCrO4mixtures. Experimental results are discussed and compared with numerical simulations presented in Part I

ISSN:0721-3115    

DOI:10.1002/prep.19970220610

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY

摘要:

AbstractThe impact of a shaped charge jet, created by a stationary charge onto a moving target, creates an elongated cut on the target face. The length of the cut, together with additional data about the charge and target configuration, enables the calculation of the jet tail velocity. It was found that this velocity increases with the stand‐off distance between the charge and the target. A possible cause for this acceleration is that the jet material is under tension due to the velocity gradient along it and the stress throughout it equals the dynamic flow stress of the material. This stress pulls on the jet material towards the center of gravity and tends to reduce the velocity gradient, i.e. decelerate the tip and accelerate the tail. 1D simulations show that this mechanism results in a constant acceleration of the tail, and that the acceleration depends on the flow stress of the jet material, hence on its temperature. Based on the experimental evidence and on the simulations, it is postulated that in addition to the velocity gradient along the jet, there are temperature and strength gradients along it, as wel

ISSN:0721-3115    

DOI:10.1002/prep.19970220611

出版商:WILEY‐VCH Verlag GmbH    

年代:1997

数据来源: WILEY