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1.
Combustion wave temperature profiles are determined for two low calorific value propellants (Q
c = 2189 and 2518 kJ/kg). It is shown that the structure and parameters of the combustion wave differ significantly from those
for previously studied propellants of medium (propellant N) and high (propellant NB) calorific values. At a relatively short
distance from the burning surface, the temperature is significantly (180–270 K) higher than the calculated value due to fact
the combustion products contain carbon black from the decomposition of heat-resistant dibutyl dinitrotoluene and dibutyl phthalate.
Then, part of carbon black reacts endothermically with CO2 and H2O, leading to a decrease in temperature, which for the first sample is nevertheless 100–140 K higher than the thermodynamic
value. For the investigated propellants, the activation energy of the leading reaction is the same as for the previously studied
propellants, suggesting a common decomposition kinetics of the condensed phase regardless of the propellant composition. However,
a uniform dependence of the burning rate on surface temperature is not observed. For low calorific value propellants, the
surface temperatures are close to those for propellant N although their burning rate is significantly (2–2.2 times) lower.
The causes of this fact are considered. 相似文献
2.
Volker Weiser Norbert Eisenreich Sascha Poller Stefan Kelzenberg Roger Lo Harry Adirim 《Propellants, Explosives, Pyrotechnics》2002,27(3):150-155
Cryogenic Solid Propellant (CSP)‐technology is a new approach to develop more powerful rocket motors. CSPs include the advantages of classical solid propellants to save weight as well as those of a high energy content and safety of modern liquid propellants. The charges consist of liquid and/or gaseous fuels and oxidizers, both frozen. Two main versions of CSP‐technology can be realised: 1. Mono‐CSPs show the burning behavior of solid propellants. Experiments with mono‐CSPs have been carried out under inert pressure conditions in a window bomb. Mono‐CSPs have a stable burning behavior with a constant regression rate which follows the Vieille's law under varying pressure conditions. 2. The advantage of high safety is obtained by assembling oxidizer and fuel in sandwich configurations. The grain geometry governs the burning behavior. Such systems can be externally controlled, e.g. by the heat from a gas generator or they can work self‐sustained. A Rod‐in‐Matrix burner shows self‐sustained combustion in an inert pressure atmosphere with overall burning rates in a similar range as solid rocket propellants which obey also a Vieille‐like pressure law. Disc stack burners have also been investigated, the combustion of which is strongly dependent on the disc thickness. For a short time Mach's nodes have been observed in the exhaust plume of a disc stack burner. Currently, the temperature ranges are limited to the boiling temperature of liquid nitrogen. Therefore, liquid oxidizers like H2O2 have been used. However, for the first time a propellant strand of polymer rods embedded in solid oxygen was prepared and burnt. The experiments with CSPs end in the combustion of a small rocket motor showing no serious technical obstacles. Simplified models based on the heat flow equation can simulate the burning characteristics of the frozen energetic materials including phase transitions. 相似文献
3.
Martin Schiemann Peter Fischer Viktor Scherer Günter Schmid Dan Taroata 《化学工程与技术》2014,37(9):1600-1605
Combustion examinations on the single‐grain level were carried out in order to get further fundamental insight into the ignition and combustion of lithium particles. Combustion of solid lithium particles in a defined size fraction was analyzed in a laminar‐flow reactor. The exhaust gases of a methane‐air flame provided the reactants O2, CO2, N2, and H2O for the lithium conversion. Two different atmospheres at various temperatures were investigated. A high‐speed camera system measured size and radiation intensity of burning particles. The results indicate that two different combustion phenomena occurred in lithium combustion. The first was identified as a homogeneously enveloping flame around the lithium particle and the second as a reaction zone next to the particle surface. 相似文献
4.
E. N. Volkov A. A. Paletsky O. P. Korobeinichev 《Combustion, Explosion, and Shock Waves》2008,44(1):43-54
The chemical structure of an RDX flame at a pressure of 1 atm was studied using probing molecular beam mass spectrometry.
The flame was found to contain RDX vapor, and its concentration profile was measured in a narrow zone adjacent to the burning
surface. In addition to RDX vapor, ten more species were identified (H2, H2O, HCN, N2, CO, CH2O, NO, N2O, CO2 and NO2), and their concentration profiles were measured. Two main chemical-reaction zones were found in the RDX flame. In the first,
narrow, zone 0.15 mm wide adjacent to the burning surface, decomposition of RDX vapor and the reaction of NO2, N2O, and CH2O with the formation of HCN and NO occur. In the second, wide, zone 0.85 mm wide, HCN is oxidized by NO to form the final
combustion products. The composition of the final combustion products was analyzed from an energetic point of view. The measured
composition of the products near the burning surface was used to determine the global reaction of RDX gasification at a pressure
of 1 atm. Values of heat release in the condensed-phase calculated by the global gasification reaction and by the equation
of heat balance on the burning surface (using data of microthermocouple measurements) were analyzed and compared.
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Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 1, pp. 49–62, January–February, 2008. 相似文献
5.
Yoshio Oyumi Kiyotaka Inokami Kazuhiro Yamazaki Koki Matsumoto 《Propellants, Explosives, Pyrotechnics》1993,18(2):62-68
Thermal decomposition of BAMO [bis(azidomethyl)oxetane/tetrahydrofuran copolymer]/HMX composite propellants was studied by isothermal TGA (thermogravimetric analysis) and DSC (differential scanning calorimetry) in helium atmosphere, which was showing overall two steps first-order kinetics. The effects of cross-link ratio on the accelerated aging of the BAMO/HMX propellants were also measured with infrared spectroscopy and gas chromatography. The accelerated aging was conducted at 347 K for several weeks. BAMO/HMX propellants for a very low cross-link ratio made the cavity between HMX and BAMO binder by N2, CO2, and H2O evolutions during accelerated aging. An exotherm, generated by the decomposition of azide binder, initiated and accelerated the thermal decomposition of HMX. The burning rate of BAMO/HMX propellant was larger than those of BAMO binder and HMX, respectively. However, the propellant could not maintain the combustion at low pressure, at which its burning rate was equal to that of BAMO binder. 相似文献
6.
A. A. Paletsky E. N. Volkov O. P. Korobeinichev 《Combustion, Explosion, and Shock Waves》2008,44(6):639-654
The chemical structure of HMX flame during combustion in air at a pressure of 1 atm was calculated using molecular beam mass
spectrometric sampling. HMX vapor was recorded for the first time near the burning surface. A total of 11 species were identified
in the HMX flame (H2, H2O, HCN, N2, CO, CH2O, NO, N2O, CO2, NO2, and HMX vapor), and their concentration profiles were measured. The HMX combustion was unstable. The species concentration
profiles exhibit periodic pulsations related to variation in the HMX burning rate. The HMX flame structure at various distances
to the burning surface was determined using the average value of the burning rate. Two main zones of chemical reactions in
the flame were found. In the first zone ≈0.8 mm wide adjacent to the burning surface, HMX vapor decomposes and NO2, N2O, and CH2O react with each other to form HCN and NO. In the second zone ≈0.8–1.5 mm wide, HCN was oxidized by nitric oxide to form
the final combustion products. The composition of the final combustion products was analyzed. The global reaction of HMX gasification
at a pressure of 1 atm was established. Heat release values in the condensed phase calculated by the global gasification reaction
and by the equation of heat balance on the burning surface (using literature data from microthermocouple measurements) were
analyzed and compared.
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Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 6, pp. 26–43, November–December, 2008. 相似文献
7.
This work focuses on solid energetic materials designed to produce high‐pressure gas for pressurizing or inflating devices. In small gas generators sodium azide is often used. Unfortunately, this chemical exhibits drawbacks concerning toxicity and yield of gas. Other classical gas‐generating agents are double base propellants. However, they deliver toxic and reactive gases and their combustion temperatures are high. In previous work a series of alternative gas‐generating compositions have been proposed, fuelled with double base propellants, azodicarbonamide, nitroguanidine or guanidine nitrate and oxidized with potassium nitrate or potassium perchlorate. They were theoretically and experimentally evaluated on a series of combustion properties, such as ignition delay, burning rate, vivacity, specific energy, etc. The purpose of this paper is to experimentally examine the gas production of the previously proposed compositions. The yield of gas is determined through static pressure measurements after a closed vessel test, while the composition of the combustion gases is investigated through gas analysis. The addition of an oxidizer causes a significant drop in the yield of gas, but avoids the formation of hazardous gases, such as H2 and CO, in most of the studied cases. The only exception is the mixture of a double base propellant with potassium nitrate: potassium nitrate does not fully react with the double base propellant and therefore the formation of CO and H2 is not prevented. 相似文献
8.
E. N. Volkov A. A. Paletsky A. G. Tereshchenko O. P. Korobeinichev 《Combustion, Explosion, and Shock Waves》2006,42(6):663-671
A study was performed of the chemical and thermal structure of flames of model composite propellants based on cyclic nitramines
(RDX and HMX) and an active binder (glycidyl azide polymer) at a pressure of 1 MPa. Propellant burning rates were measured.
The chemical structure of the flame was studied using molecular-beam mass spectrometry, which previously has not been employed
at high pressures. Eleven species (H2, H2O, HCN, N2, CO, CH2O, NO, N2O, CO2, NO2, and nitramine vapor) were identified, and their concentration profiles, including the composition near the burning surface
were measured. Two chemical-reaction zones were observed. It was shown that flames of nitramine/glycidyl azide polymer propellants
are dominated by the same reactions as in flames of pure nitramines.
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Translated from Fizika Goreniya i Vzryva, Vol. 42, No. 6, pp. 48–57, November–December, 2006. 相似文献
9.
DavidE.G. Jones QueenieS.M. Kwok Marie Vachon Christopher Badeen William Ridley 《Propellants, Explosives, Pyrotechnics》2005,30(2):140-147
Ammonium dinitramide (ADN), NH4N(NO2)2 is being considered as one of the potential new energetic oxidizers for composite propellants. In this study, ADN crystals, prills and two ADN‐based propellants having different relative amounts of ingredients were characterized. The concentration of the crystals and the prills samples was determined using ion chromatography. The thermal behavior of the crystals, prills and propellants was studied using DSC, simultaneous TG‐DTA‐FTIR‐MS, ARC (accelerating rate calorimeter), HFC (heat flux calorimeter) and INC (isothermal nanocalorimeter). Decomposition of ADN was observed from all of the samples at temperatures above the melting point of ADN (~ 92 °C). Formation of N2O, NO2, H2O, CO2, CO, N2 and NO was detected during the ADN decomposition. The thermal stability of the ADN samples at temperatures below the melting point of ADN was studied. Early solid decomposition of ADN, which generates N2O and H2O, was observed at 60 °C. Electrostatic discharge (ESD) and impact sensitivity of the ADN samples were determined. The crystals and prills are sensitive to impact, while the two propellants are relatively less ESD and impact sensitive. 相似文献
10.
Bo Jin Rufang Peng Fengqi Zhao Jianhua Yi Siyu Xu Sengbo Wang Shijin Chu 《Propellants, Explosives, Pyrotechnics》2014,39(6):874-880
The effect of N‐methyl‐2‐(3‐nitrophenyl)pyrrolidino[3′,4′:1,2]fullerene (mNPF) on the decomposition characteristics of hexogen (RDX) was investigated using differential scanning calorimetry (DSC). The results show that mNPF can accelerate the decomposition of RDX, the peak temperature (Tp) of the exothermal decomposition is reduced by 6.4 K, and the corresponding apparent activation energy (Ea) is decreased by 8.7 kJ mol−1. N‐methyl‐2‐(3‐nitrophenyl)pyrrolidino[3′,4′:1,2]fullerene (mNPF), carbon black (CB), and C60 were used as combustion catalysts to improve the combustion performance of a composite modified double‐base propellant containing RDX (RDX‐CMDB). The burning rate experimental results show that mNPF has a stronger catalytic effect than C60 and CB. The magnitude of the effect of the three carbon substances on the enhancement of the burning rate is as follows: mNPF>C60>CB. The catalytic effects of different contents of mNPF on the burning rates of RDX‐CMDB propellants were also studied, and the results show that the burning rates of RDX‐CMDB propellants are improved with increasing mNPF content. The plateau burning rate of a RDX‐CMDB propellant can be increased to 19.6 mm s−1 when 1.0 % mNPF is added, and the corresponding plateau combustion region occurs at 8–22 MPa. 相似文献
11.
《Propellants, Explosives, Pyrotechnics》2017,42(11):1252-1260
A nanocomposite microsphere consisting of solid paraffin, nano‐TiO2, nano‐BN, zeolitic imidazolate framework‐67 particles and polymethyl methacrylate was prepared and applied as a functional additive for high energy propellants (with about 23 wt % RDX) to reduce the barrel erosion and improve its combustion performance as well. High energy propellants modified with the nanocomposite were manufactured by a solvent extrusion technique. According to the scanning electron microscope and differential scanning calorimetry results, there exists a good compatibility between the nanocomposite and propellant matrix. The energy and combustion performance as well as erosion of the modified propellants were studied by a closed bomb test and an erosion tube device, respectively. Results showed that compared with the unmodified propellant, both the erosion and energy performance of modified high energy propellant gradually decreased with the increase of nanocomposites contents. When the content of nanocomposites was 5.1 %, the erosion mass of the modified propellant reduced to 37.0 % while the propellant force only decreased 5.7 %, indicating that the nanocomposite has enormous ability to improve gun erosion resistance while barely affect energy performance of propellant. Furthermore, the closed bomb burning curves of the samples showed that addition of nanocomposites to propellant matrix could prolong the combustion time, efficiently inhibit the initial generation rate of combustion gas, and further achieve the progressive burning of the propellants. 相似文献
12.
The combustion wave structure and thermal decomposition process of azide polymer were studied to determine the parameters which control the burning rate. The azide polymer studied was glycidyl azide polymer (GAP) which contains energetic – N3 groups. GAP was cured with hexamethylene diisocyanate (HMDI) and crosslinked with trimethylolpropane (TMP) to formulate GAP propellant. From the experiments, it was found that the burning rate of GAP propellant is significantly high even though the adiabatic flame temperature of GAP propellant is lower than that of conventional solid propellants. The energy released at the burning surface of GAP propellant is caused by the scission of N N2 bond which produces gaseous N2. The heat flux transferred back from the gas phase to the burning surface is very small compared with the heat generated at the burning surface. The activation energy of the decomposition of the burning surface of GAP propellant, Es, is determined to be 87 kJ/mol. The burning rate is represented by r = 9.16 × 103 exp(–Es/RTs) where r (m/s) is burning rate, Ts (K) is the burning surface temperature, and R is the universal gas constant. The observed high temperature sensitivity of burning rate is correlated to the relationship of (∂Ts/∂T0)p = 0.481 at 5 MPa, where T0 is the initial propellant temperature. 相似文献
13.
John F. Moxnes Tomas L. Jensen Eimund Smestad Erik Unneberg Ove Dullum 《Propellants, Explosives, Pyrotechnics》2013,38(2):255-260
Environmental and health considerations have encouraged the development of ammunition with substitutes for lead and other heavy metals. In general, the emission products from munitions containing nitro‐based propellants are highly complex mixtures of gases, vapors, and solid particles. The major combustion products are H2O, CO, CO2, H2, and N2. In addition, compounds including hydrogen cyanide (HCN), ammonia (NH3), methane (CH4), nitrogen oxides, benzene, acrylonitrile, toluene, furan, aromatic amines, benzopyrene, and various polycyclic aromatic hydrocarbons are detected in minor concentrations. Many of the identified chemical species have severe toxicological properties, and some of the compounds do even have mutagenic effects. Gun smoke emission is a concern because its exposure to humans may be substantial during military and civilian police training, as respiratory protection equipment is not routinely worn. In this work we study the compositions of some of the main decomposition products, experimentally as well as theoretically. The concept of frozen equilibrium at around 1500–2000 K appears to apply for CO, CO2, and H2. However, the trace species in the combustion mixtures appear theoretically to be present in negligible concentrations. Our measured results are many orders of magnitude higher than theoretical results in open space. We forecast that future development of gun powder will focus on reducing the amount of toxic trace species. 相似文献
14.
Emissions of N2O, NH3 and NOx from fuel combustion, industrial processes and the agricultural sectors in China 总被引:4,自引:0,他引:4
Based on the methodology and default data recommended by IPCC, N2O, NH3 and NOx emissions from fuel combustion, industrial processes, field burning of agricultural residues and fertilization were estimated. Agricultural fertilization is the important contributor of N2O emission to the atmosphere. Fuel combustion, fertilizer application and animal waste were the important sources of NH3 and NOx emissions. Estimates of NH3 and NOx emissions from animal wastes were much lower when Chinese measured nitrogen excrement data were used rather than IPCC default values. The uncertainties in the estimates of N2O, NH3and NOx emissions were also analyzed in this paper. 相似文献
15.
MohammadHossein Keshavarz HamidReza Pouretedal 《Propellants, Explosives, Pyrotechnics》2005,30(2):105-108
A simplified method is shown, based on a semi‐empirical procedure, to estimate the detonation velocities of CHNO explosives at various loading densities. It is assumed that the product composition consists almost of CO, CO2, H2O and N2 for oxygen‐rich explosives. In addition solid carbon and H2 are also counted for an oxygen‐lean explosive. The approximate detonation temperature, as a second needed parameter, can be calculated from the total heat capacity of the detonation products and the heat of formation of the explosive by PM3 procedure. The detonation velocities of some well‐known CHNO explosives, calculated by the simple procedure, fit well with measured detonation velocities and the results from the well‐established BKW‐EOS computer code. 相似文献
16.
In order to tailor the surface properties of propellants to meet the requirements of progressive burning and anti‐erosion performance of propellant for high loading density tank guns, the surface migration and enrichment effects of fluorinated TiO2 nanocomposite additives with low surface energy toward the air/solid interface of propellants were investigated. Fluorinated TiO2 nanocomposites were prepared by emulsion polymerization and characterized by FT‐IR spectroscopy, TEM, and TGA to obtain the information of chemical groups, morphology, and thermal stability. The propellant samples containing the fluorinated TiO2 nanocomposite additives were manufactured by an extrusion process. The migration effect of the fluorinated TiO2 nanocomposite additives was observed by SEM and X‐ray energy dispersive analysis. The influence factors on the migration and enrichment properties of fluorinated TiO2 nanocomposite additives in propellants were discussed. The results showed that there exists a gradient distribution of fluorine element in the additive modified propellants, indicating a significant surface enrichment of fluorinated groups inside the propellants. The composition of propellants and the chain structure of fluoropolymer also have a significant influence on the migration and enrichment properties of fluorinated TiO2 nanocomposite additives in propellants. This study can bring forward the research of smart construction of slowing burning and anti‐wear layers in the propellants. 相似文献
17.
3,3-Bis(azidomethyl)oxetane (BAMO) is a typical energetic azide polymer containing two N3, bonds in the molecular structure. Since BAMO is a solidified polymer at room temperature, a liquid BAMO copolymer with tetrahydrofuran (THF) was synthesized in order to gain energetic binders for solid propellants. Various types of experiments were carried out to elucidate the decomposition and combustion processes of BAMO polymer, BAMO/THF copolymer, and crosslinked BAMO/THF copolymer. The heat produced by the decomposition is caused by the bond breakage of -N3 to produce N2, gas. The burning rate characteristics of crosslinked BAMO/THF copolymer depend largely on the mole fraction ratio of BAMO and THF. 相似文献
18.
Jianfei Xi Jianzhong Liu Yang Wang Daolun Liang Heping Li Junhu Zhou 《Propellants, Explosives, Pyrotechnics》2014,39(6):844-851
Boron is an attractive fuel for propellants and explosives because of its high energy density. However, its combustion is inhibited by the oxide layer that covers the particles. The use of oxalic acid as an additive was shown to promote boron oxidation. In this study, the thermodynamic model FactSage 6.2 and a laser ignition facility were used to investigate the effect of oxalic acid on the burning characteristics of boron particles. The results of the thermodynamic analyses show that oxalic acid can reduce B2O3(l) production during boron combustion. This enables removal of the the oxide film and promotes the burning of boron. However, only at high temperatures (>1500 K) H2O(g) (produced from H2C2O4) can react with B2O3 and remove the oxide film. The evolution of boron combustion flame takes place in three stages: ignition, stable combustion, and extinction; the bright yellow color in the flame indicates boron ignition, the bright white color indicates boron combustion, and the bright green color is interpreted as BO2 emission. Addition of oxalic acid into boron powders can significantly promote boron ignition and combustion. The ignition delay time of the resulting mixture is reduced by 42.4 %, the combustion intensity is raised by 16.7 %, and the combustion efficiency of boron is increased by 21.5 percentage points. The mechanism of action of oxalic acid on enhancing the combustion of boron was studied by scanning electron microscopy. 相似文献
19.
Jing Su Sanjiu Ying Zhenggang Xiao Fuming Xu 《Propellants, Explosives, Pyrotechnics》2013,38(4):533-540
Micro‐porous propellants containing titanium powder were obtained by supercritical CO2 (SC CO2) foaming technique. The morphologies of the micro‐porous propellants were characterized by scanning electron microscopy (SEM) and energy‐dispersive X‐ray spectroscopy (EDS) measurement. The burning rate, the impetus, and the heat of explosion of the micro‐porous propellants were measured by the closed vessel test and the calorimetric bomb test. The results show that the porosity increased with increasing titanium powder content; compared with Benite, the burning rate was substantially improved, and the maximum values of the impetus and the isochoric heat of explosion increased by 51.4 % and 6.5 %, respectively. The Ti‐containing micro‐porous propellants with rapid burning rate and better energetic properties described in this paper may have the potential to replace Benite as igniter material in a flame igniter of a gun propellant charge. 相似文献
20.
Liming Zhang Lin Zhang Yan Li Bingping Liu Junde Wang 《Propellants, Explosives, Pyrotechnics》2006,31(5):410-414
With a time resolution of 0.125 s and a spectral resolution of 4 cm−1, emission spectra of the combustion process of a solid propellant were recorded by highly time‐resolved passive FTIR. Some gaseous combustion products, such as H2O, CO, CO2, NO and HCl, were distinguished by the characteristic emission band of each molecule. The equation for flame temperature calculation based on the diatomic molecule emission fine structure theory was improved through judicious utilization of the spectral running number ‘m’ which makes the temperature measurement simpler and faster. Some combustion information of the solid propellant had been given including the characteristic spectral profile, the distribution of the absolute spectral energy, the distribution of the combustion flame temperature, and the concentration distributions of HCl and NO versus burning time. The results will provide theoretical and experimental bases for improving the formula and raising combustion efficiency of solid propellant, and developing the design of rocket motor, infrared guidance and antiguidance systems. 相似文献