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Author:
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ISBN:
Category :
Languages : en
Pages : 70
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Book Description
Increasing the nitramine content of solid rocket propellants increases the overall performance of the system as well as the sensitivity to Shock to Detonation Transition (SDT) and Deflagration to Detonation Transition (DDT). This report deals primarily with the analysis and numerical modeling of a combined SDT/DDT event. The results show that in some instances a zone of burning granulated propellant, confined and adjacent to a zone of cast propellant, can provide a rapid enough pressure-rise rate to shock initiate the cast material. This type of detonation hazard scenario is a real possibility in any high-energy rocket motor environment. The modeling study also indicates areas where important assumptions need to be further researched. These include: (a) relations for dynamic (transient) collapse of the voids or pores; (b) relations for setting the volume percent of hot spots based on initial porosity; (c) the evaluation and expression for the chemical rate of decomposition of the reactive, shocked material; and (d) the assessment of two-phase mixture equilibrium. The predicted run-to detonation distance as a function of porosity for HMX explosive compares favorably with limited shock initiation experiments. There is no data available to check whether the predictions of ramp-wave compressions (where rise times exceed several microseconds) presented here are valid.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 70
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Book Description
Increasing the nitramine content of solid rocket propellants increases the overall performance of the system as well as the sensitivity to Shock to Detonation Transition (SDT) and Deflagration to Detonation Transition (DDT). This report deals primarily with the analysis and numerical modeling of a combined SDT/DDT event. The results show that in some instances a zone of burning granulated propellant, confined and adjacent to a zone of cast propellant, can provide a rapid enough pressure-rise rate to shock initiate the cast material. This type of detonation hazard scenario is a real possibility in any high-energy rocket motor environment. The modeling study also indicates areas where important assumptions need to be further researched. These include: (a) relations for dynamic (transient) collapse of the voids or pores; (b) relations for setting the volume percent of hot spots based on initial porosity; (c) the evaluation and expression for the chemical rate of decomposition of the reactive, shocked material; and (d) the assessment of two-phase mixture equilibrium. The predicted run-to detonation distance as a function of porosity for HMX explosive compares favorably with limited shock initiation experiments. There is no data available to check whether the predictions of ramp-wave compressions (where rise times exceed several microseconds) presented here are valid.
Author:
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ISBN:
Category : Aeronautics
Languages : en
Pages : 1460
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Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Author: C. A. Cudak
Publisher:
ISBN:
Category :
Languages : en
Pages : 9
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Book Description
Increasing the nitramine content of solid rocket propellants increases the overall performance of the system as well as the sensitivity to detonation by shock initiation. In some instances a confined zone of granulated propellant adjacent to a zone of cast propellant can provide a rapid enough pressure-rise rate to shock initiate the cast material. If the cast propellant is porous, the detonation will initiate at some location ahead of the granulated bed/cast material interface. The work presented here is an effort to numerically model this Deflagration to Shock to Detonation Transition (DSDT) event. Results will be presented showing the detonation build up for propellant beds with various initial configurations and boundary conditions. (Author).
Author: Weiqiang Pang
Publisher: John Wiley & Sons
ISBN: 3527835334
Category : Science
Languages : en
Pages : 1005
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Book Description
Provides an up-to-date account of innovative energetic materials and their potential applications in space propulsion and high explosives Most explosives and propellants currently use a small number of ingredients, such as TNT and nitrocellulose. In comparison to conventional materials, nano- and micro-scale energetic materials exhibit superior burning characteristics and much higher energy densities and explosive yields. Nano and Micro-scale Energetic Materials: Propellants and Explosives provides a timely overview of innovative nano-scale energetic materials (nEMs) and microscale energetic materials (μEMs) technology. Covering nEMs and μEMs ingredients as well as formulations, this comprehensive volume examines the preparation, characterization, ignition, combustion, and performance of energetic materials in various applications of propellants and explosives. Twenty-two chapters explore metal-based pyrotechnic nanocomposites, solid and hybrid rocket propulsion, solid fuels for in-space and power, the sensitivity and mechanical properties of explosives, new energetic materials, and more. Explores novel energetic materials and their potential for use in propellants and explosives Summarizes the most recent advances of leading research groups currently active in twelve countries Discusses how new environmentally friendly, high-combustion energetic materials can best be used in different applications Explains the fundamentals of energetic materials, including similarities and differences between composite propellants and explosives Nano and Micro-scale Energetic Materials: Propellants and Explosives is an important resource for materials scientists, explosives specialists, pyrotechnicians, environmental chemists, polymer chemists, physical chemists, aerospace physicians, and aerospace engineers working in both academia and industry.
Author:
Publisher:
ISBN:
Category : Government reports announcements & index
Languages : en
Pages : 1336
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Book Description
Author: James Richard Stewart
Publisher:
ISBN:
Category :
Languages : en
Pages : 280
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Book Description
Author:
Publisher:
ISBN:
Category : Mechanics, Applied
Languages : en
Pages : 1028
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Book Description
Author:
Publisher:
ISBN:
Category : Detonation
Languages : en
Pages : 892
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Book Description
Papers presented in this publication cover special problems in the field of energetic materials, particularly detonation phenomena in solids and liquids. General subject areas include shock-to-detonation transition, time resolved chemistry, initiation modeling, deflagration-to-detonation transition, equation of state and equation of state and performance, composites and emulsions, and composites and emulsions/underwater explosives, reaction zone, detonation wave propagation, hot spots, detonation products, chemistry and compositions, and special initiation.
Author:
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 772
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Book Description
Author: Herman W. Krier
Publisher:
ISBN:
Category :
Languages : en
Pages : 30
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Book Description
This annual report represents the summary of work done on the modeling of processes leading from deflagration to detonation in porous or granular high energy propellants. Particular attention is paid to the analysis of shock development from compression waves forming ahead of confined burning in the original material. It is summarized that if the shock is sufficiently strong, it will lead to shock to detonation transition (SDT). During the development of the shock wave, the porous material may collapse into a solid plug of void free propellant because the speed at which the wave propagates increases as the material is compressed. The modeling effort presented indicates how two-phase unsteady combustion processes in granular material can couple to the solid mechanics of shock formation and eventually to a steady-state detonation. (Author).
