期刊,International journal of energetic materials and chemical propulsion 2024年23卷4期_国家学术搜索

SHORT OVERVIEW AND HIGHLIGHTS OF THE HISTORY OF THE GERMAN GEL PROPULSION RESEARCH AND TECHNOLOGY DEVELOPMENT ACTIVITIES

Helmut K. CiezkiKarl Wieland NaumannJürgen HürttlenMaxim Kurilov...

1-28页

查看更多>>摘要：Gel mono- and bipropellants (i.e., gelled fuels and/or gelled oxidizers) are interesting candidates for advanced low-hazard rocket or ramjet propulsion systems and gas dynamic systems. Gel propellants combine major advantages of solid propulsion systems and liquid propulsion systems, such as easy and simple storage and handling characteristics (solid systems) and excellent throttleability (liquid systems). This article gives a short overview of the themes and the obtained results about the work conducted in Germany within the last two and a half decades, whereas a focus is set on the progress achieved in the last years.

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SHORT OVERVIEW AND HIGHLIGHTS OF THE HISTORY OF THE GERMAN GEL PROPULSION RESEARCH AND TECHNOLOGY DEVELOPMENT ACTIVITIES

Helmut K. CiezkiKarl Wieland NaumannJürgen HürttlenMaxim Kurilov...

1-28页

查看更多>>摘要：Gel mono- and bipropellants (i.e., gelled fuels and/or gelled oxidizers) are interesting candidates for advanced low-hazard rocket or ramjet propulsion systems and gas dynamic systems. Gel propellants combine major advantages of solid propulsion systems and liquid propulsion systems, such as easy and simple storage and handling characteristics (solid systems) and excellent throttleability (liquid systems). This article gives a short overview of the themes and the obtained results about the work conducted in Germany within the last two and a half decades, whereas a focus is set on the progress achieved in the last years.

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NETL
NSTL

EFFECTS OF FLUORINATED AND NON-FLUORINATED ADDITIVES ON BURNING RATES OF BORON-TEFLON BLENDS FOR SOLID ROCKET PROPULSION

Patrick CatonAdam WilsonRonald WarzohaCraig Whitaker...

29-45页

查看更多>>摘要：Boron is considered a promising metal fuel for energetic propellants due to its high energy density, but in practice, boron experiences slow combustion kinetics. Fluorinated additives can improve boron combustion. The objective of this study was to determine how different fluorinated additives would affect the burn rate of a boron-based fuel in a high-pressure inert environment. Boron powder was sintered with polytetrafluoroethylene (PTFE) powder to create test pellets with variable fluorine:boron mass ratios. Three different purities of boron powders were tested, along with three different fluoropolymer additives and 14 other additives, which varied in molecular morphology and fluorination. The base boron-PTFE test pellets with no additives have a maximum burning rate at fluorine:boron mass ratio of ~ 3.5, which remains the same even with additives at 20 wt%. A commercial fluoropolymer, Aquivion, showed significant burn rate enhancement at 20 wt% but not at 5 wt%. At this lower loading level, materials that tend to enhance thermal conductivity (graphene, nanotubes) show some burn rate enhancement, even without fluorination. However, very significant burn rate enhancement is shown by a fluorinated carbon nanotube, likely due to the reduced bond dissociation energy of fluorine when attached to a nanotube. The data suggest this method of fluorination can have an important effect on enhancing boron combustion, and even small additives with readily available fluorine could significantly improve boron combustion rates for solid propellant applications.

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NETL
NSTL

EFFECTS OF FLUORINATED AND NON-FLUORINATED ADDITIVES ON BURNING RATES OF BORON-TEFLON BLENDS FOR SOLID ROCKET PROPULSION

Patrick CatonAdam WilsonRonald WarzohaCraig Whitaker...

29-45页

查看更多>>摘要：Boron is considered a promising metal fuel for energetic propellants due to its high energy density, but in practice, boron experiences slow combustion kinetics. Fluorinated additives can improve boron combustion. The objective of this study was to determine how different fluorinated additives would affect the burn rate of a boron-based fuel in a high-pressure inert environment. Boron powder was sintered with polytetrafluoroethylene (PTFE) powder to create test pellets with variable fluorine:boron mass ratios. Three different purities of boron powders were tested, along with three different fluoropolymer additives and 14 other additives, which varied in molecular morphology and fluorination. The base boron-PTFE test pellets with no additives have a maximum burning rate at fluorine:boron mass ratio of ~ 3.5, which remains the same even with additives at 20 wt%. A commercial fluoropolymer, Aquivion, showed significant burn rate enhancement at 20 wt% but not at 5 wt%. At this lower loading level, materials that tend to enhance thermal conductivity (graphene, nanotubes) show some burn rate enhancement, even without fluorination. However, very significant burn rate enhancement is shown by a fluorinated carbon nanotube, likely due to the reduced bond dissociation energy of fluorine when attached to a nanotube. The data suggest this method of fluorination can have an important effect on enhancing boron combustion, and even small additives with readily available fluorine could significantly improve boron combustion rates for solid propellant applications.

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NETL
NSTL

EFFECT OF HMX CONTENT ON THERMAL SAFETY CHARACTERISTICS OF MODIFIED DOUBLE-BASE PROPELLANTS

Lin-Wei ZuoWan-Li ChengChun-Ling LvMeng-Hui Liu...

47-60页

查看更多>>摘要：In order to explore the thermal safety characteristics of modified double-base propellants, differential scanning calorimetry (DSC) was used to study the thermal decomposition of modified double-base propellants with high melting explosive (HMX) content of 0%, 21%, and 40%, respectively. The thermal decomposition temperatures at the heating rates of 2, 5,10, and 20°C·min -1 were obtained. The apparent activation energy, pre-exponential factor, reaction rate, Gibbs free energy, activation enthalpy, and activation entropy were calculated by thermal reaction kinetics analysis. The response characteristics of modified double-base propellants with different HMX contents were obtained through slow cook-off, 5 s explosion point, and methyl violet chemical stability tests to characterize the thermal safety of propellants. The insensitivity of modified double-base propellant containing HMX was further studied by flame sensitivity and mechanical sensitivity tests. The results showed that when HMX content was 21%, the apparent activation energy was the highest, the slow cook-off response was the lowest, the 5 s explosion point response temperature was the highest, the methyl violet test paper had the longest discoloration time, and the flame sensitivity and mechanical sensitivity were the lowest; With the increase of HMX content, the first decomposition peak temperature of DSC moves backward, and the apparent activation energy decreases. The slow cook-off response temperature of the double-base propellant moves to the high-temperature direction, and the response level increases accordingly. When the HMX content is 40% or more, the response level is explosive, which cannot pass the slow cook-off test. After HMX component is added into the sample, its 5 s explosion point temperature moves to high temperature, and the trend of rise is obvious. The discoloration time of methyl violet test paper is prolonged, and the thermal stability of modified double-base propellant is improved; The flame sensitivity and the mechanical sensitivity decreased, which was helpful to improve the low vulnerability of the formula.

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NETL
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EFFECT OF HMX CONTENT ON THERMAL SAFETY CHARACTERISTICS OF MODIFIED DOUBLE-BASE PROPELLANTS

Lin-Wei ZuoWan-Li ChengChun-Ling LvMeng-Hui Liu...

47-60页

查看更多>>摘要：In order to explore the thermal safety characteristics of modified double-base propellants, differential scanning calorimetry (DSC) was used to study the thermal decomposition of modified double-base propellants with high melting explosive (HMX) content of 0%, 21%, and 40%, respectively. The thermal decomposition temperatures at the heating rates of 2, 5,10, and 20°C·min -1 were obtained. The apparent activation energy, pre-exponential factor, reaction rate, Gibbs free energy, activation enthalpy, and activation entropy were calculated by thermal reaction kinetics analysis. The response characteristics of modified double-base propellants with different HMX contents were obtained through slow cook-off, 5 s explosion point, and methyl violet chemical stability tests to characterize the thermal safety of propellants. The insensitivity of modified double-base propellant containing HMX was further studied by flame sensitivity and mechanical sensitivity tests. The results showed that when HMX content was 21%, the apparent activation energy was the highest, the slow cook-off response was the lowest, the 5 s explosion point response temperature was the highest, the methyl violet test paper had the longest discoloration time, and the flame sensitivity and mechanical sensitivity were the lowest; With the increase of HMX content, the first decomposition peak temperature of DSC moves backward, and the apparent activation energy decreases. The slow cook-off response temperature of the double-base propellant moves to the high-temperature direction, and the response level increases accordingly. When the HMX content is 40% or more, the response level is explosive, which cannot pass the slow cook-off test. After HMX component is added into the sample, its 5 s explosion point temperature moves to high temperature, and the trend of rise is obvious. The discoloration time of methyl violet test paper is prolonged, and the thermal stability of modified double-base propellant is improved; The flame sensitivity and the mechanical sensitivity decreased, which was helpful to improve the low vulnerability of the formula.

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EFFECT OF MAGNESIUM ON IGNITION AND COMBUSTION OF BORON-LOADED GELLED JET A-1 FUEL

R. MadhumithaP. PrabhudevaSrinibas Karmakar

61-74页

查看更多>>摘要：Boron (B) is a desirable fuel for explosives and propellants due to its high-energy density. However, the combustion of B particles is difficult because its native oxide layers serve as inhibitors and cover the particles. This oxide layer makes the combustion process more difficult. However, using B as an additive in gelled fuel has significant potential use in ramjets. The present study used magnesium (Mg) with B-loaded gel-based fuel as a burning promotor. Different combustion parameters were evaluated for four different fuel compositions. The present investigation employed a droplet combustion setup and high-speed imaging technique to examine the impact of Mg on B particles in gel fuel. The influences of Mg addition on the droplet combustion flame, B ignition delay time, boron oxide (BO 2 ) intensity, and post-combustion particles were studied. The addition of Mg significantly influenced B in reducing the ignition delay time, where the reduction was almost 70.58% at higher Mg loadings (GBMg30). The combustion of B-based samples resulted in the emission of BO 2 , which was characterized by a greenish appearance. The findings were corroborated by spectroscopic analysis. The analysis of the burning events was conducted utilizing a combination of color and high-speed camera techniques in conjunction with a 546 nm BO 2 filter. Post-combustion particles were analyzed with the help of scanning electron microscopy images and thermogravimetric analysis.

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EFFECT OF MAGNESIUM ON IGNITION AND COMBUSTION OF BORON-LOADED GELLED JET A-1 FUEL

R. MadhumithaP. PrabhudevaSrinibas Karmakar

61-74页

查看更多>>摘要：Boron (B) is a desirable fuel for explosives and propellants due to its high-energy density. However, the combustion of B particles is difficult because its native oxide layers serve as inhibitors and cover the particles. This oxide layer makes the combustion process more difficult. However, using B as an additive in gelled fuel has significant potential use in ramjets. The present study used magnesium (Mg) with B-loaded gel-based fuel as a burning promotor. Different combustion parameters were evaluated for four different fuel compositions. The present investigation employed a droplet combustion setup and high-speed imaging technique to examine the impact of Mg on B particles in gel fuel. The influences of Mg addition on the droplet combustion flame, B ignition delay time, boron oxide (BO 2 ) intensity, and post-combustion particles were studied. The addition of Mg significantly influenced B in reducing the ignition delay time, where the reduction was almost 70.58% at higher Mg loadings (GBMg30). The combustion of B-based samples resulted in the emission of BO 2 , which was characterized by a greenish appearance. The findings were corroborated by spectroscopic analysis. The analysis of the burning events was conducted utilizing a combination of color and high-speed camera techniques in conjunction with a 546 nm BO 2 filter. Post-combustion particles were analyzed with the help of scanning electron microscopy images and thermogravimetric analysis.

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NETL
NSTL

UNRAVELLING THE ROLE OF ENERGETIC POLYBENZOXAZINES IN MODERN REACTIVE STRUCTURE MATERIALS

Mehdi Derradji

75-85页

查看更多>>摘要：The development of polymers suitable to be used as reactive structure materials has been seen as a long path with major obstacles. This was due to the lack of monomers and polymers combining both the structural rigidity along with appropriate energetic performances. Hopefully, a new era is starting to emerge thanks to the dedicated work of several talented researchers around the world. The energetic polybenzoxazines discussed in this article provide a good substitute to the polyoxetanes in the field of reactive structure materials and can effectively and safely combine high thermomechanical properties and sufficient detonation properties. Therefore, this work not only unravels to enormous potential of the polybenzoxazines in the energetic field, but also effectively reviews all the previous efforts aiming at developing reactive structure materials with high glass transition temperatures. This also seeks to consolidate the existing research findings in this area, with the goal of emphasizing the potential of these materials and their significance in the future development of energetic materials.

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NETL
NSTL

UNRAVELLING THE ROLE OF ENERGETIC POLYBENZOXAZINES IN MODERN REACTIVE STRUCTURE MATERIALS

Mehdi Derradji

75-85页

查看更多>>摘要：The development of polymers suitable to be used as reactive structure materials has been seen as a long path with major obstacles. This was due to the lack of monomers and polymers combining both the structural rigidity along with appropriate energetic performances. Hopefully, a new era is starting to emerge thanks to the dedicated work of several talented researchers around the world. The energetic polybenzoxazines discussed in this article provide a good substitute to the polyoxetanes in the field of reactive structure materials and can effectively and safely combine high thermomechanical properties and sufficient detonation properties. Therefore, this work not only unravels to enormous potential of the polybenzoxazines in the energetic field, but also effectively reviews all the previous efforts aiming at developing reactive structure materials with high glass transition temperatures. This also seeks to consolidate the existing research findings in this area, with the goal of emphasizing the potential of these materials and their significance in the future development of energetic materials.

原文链接:

NETL
NSTL