共查询到20条相似文献，搜索用时 15 毫秒
1.
Makoto Kohga 《Propellants, Explosives, Pyrotechnics》2011,36(1):57-64
The burning rate of AP/HTPB composite propellant increases with increasing AP content and with decreasing AP size. In addition, the burning rate can be enhanced with the addition of Fe2O3. The burning characteristics and thermal decomposition behavior of AP/HTPB composite propellant using coarse and fine AP particles with and without Fe2O3 at various AP contents were investigated to obtain an exhaustive set of data. As the AP content decreased, the burning rate decreased and the propellants containing less than a certain AP content self‐quenched or did not ignite. The self‐quenched combustion began at both lower and higher pressures. The lower limit of AP content to burn the propellant with coarse AP was lower than that with fine AP. The lower limit of AP content to burn was decreased by the addition of Fe2O3. The thermal decomposition behavior of propellants prepared with 20–80 % AP was investigated. The decrease in the peak temperature of the exothermic decomposition suggested an increased burning rate. However, a quantitative relationship between the thermochemical behavior and the burning characteristics, such as the burning rate and the lower limit of AP content to burn, could not be determined. 相似文献
2.
Makoto Kohga 《Propellants, Explosives, Pyrotechnics》2008,33(4):249-254
Bubble contamination in an ammonium perchlorate (AP)‐based composite propellant has a positive effect on the burning rate. However, the quantitative effect of the bubble contamination on the burning rate has never been revealed. In order to clarify the relationship between the increase in the burning rate and the void fraction of the propellant, propellants were prepared with fine porous AP particles (PoAP) or fine hollow AP particles (HoAPs), and their burning rate characteristics were investigated. The voids inside AP particles have the effect of increasing the burning rate. The increase in the burning rate is enhanced linearly as the void fraction increases. The effect of the void fraction on the burning rate for a propellant containing PoAP is not identical with that for a propellant containing HoAP. It was found that the effect of the void fraction on the burning rate could be estimated by the void fraction when the bubble contamination is uniform in size and shape. 相似文献
3.
Ammonium nitrate (AN)‐based composite propellants have attracted a considerable amount of attention because of the clean burning nature of AN as an oxidizer. However, such propellants have several disadvantages such as poor ignition and a low burning rate. In this study, the burning characteristics of AN‐based propellants supplemented with Fe2O3 as a burning catalyst were investigated. The addition of Fe2O3 is known to improve the ignitability at low pressure. Fe2O3 addition also increases the burning rate, while the pressure exponent generally decreases. The increasing ratio (R) of the burning rate of the AN/Fe2O3 propellant to that of the corresponding AN propellant vs. the amount of Fe2O3 added (ξ) depends on the burning pressure and AN content. R decreases at threshold value of ξ. The most effective value of ξ for increasing the burning rate was found to be 4 % for the propellant at 80 % AN, and the value generally decreased with decreasing AN content. According to thermal decomposition kinetics, Fe2O3 accelerates the reactions of AN and binder decomposition gases in the condensed‐ and/or gas‐phase reaction zones. The burning characteristics of the AN‐based propellant were improved by combining catalysts with differing catalytic mechanisms instead of supplementing the propellant with a single catalyst owing to the multiplicative effect of the former. 相似文献
4.
Ammonium nitrate (AN)‐based composite propellants have several major problems, namely, a low burning rate, poor ignitability, low energy, and high hygroscopicity. The addition of a burning catalyst proved to be effective in improving the burning characteristics of AN‐based propellants. In this study, the burning characteristics of AN‐based propellants supplemented with MnO2 as a burning catalyst were investigated. The addition of MnO2 is known to improve the ignitability at low pressure. The most effective amount of MnO2 added (ξ) for increasing the burning rate is found to be 4 %. The increasing ratio with ξ is virtually independent of the burning pressure and the AN content. However, the pressure exponent unfortunately increased by addition of MnO2. The apparent activation energy of the thermal decomposition for AN and the propellant is decreased by addition of MnO2. From thermal decomposition kinetics it was found that MnO2 could accelerate the thermal decomposition reaction of AN in the condensed phase, and therefore, the burning characteristics of the AN‐based propellant are improved. 相似文献
5.
Alexander A. Gromov Alexey V. Sergienko Elena M. Popenko Konstantin V. Slyusarsky Kirill B. Larionov Ella L. Dzidziguri Anton Y. Nalivaiko 《Propellants, Explosives, Pyrotechnics》2020,45(5):730-740
Aluminum powders were comprehensively described as the prospective ingredients of the modern propellants. The paper also studied the influence of micro- and nanopowders of metals (μ-Me and n-Me) and metal oxides (μ-MeO and n-MeO) on the burning process of modern aluminized propellant with HMX, CL-20, AP, and active binder. The following metal additives were used: Al, B, Zn, Ni, Co, and Mo. The effect of the following oxides CoO, V2O5, MnO2, and Fe2O3 was studied together with LiF. The combustion tests of modified propellant compositions were carried out in the Vielle bomb in a pressure range 2–10 MPa. n-Me addition resulted in an increase in the burning rate by 10 % for n-B, by 30–40 % for n-Ni and n-Mo in the studied pressure range. The introduction of n-Cu caused a burning rate to increase fivefold. n-Zn additive resulted in increasing of the propellant burning rate by 130 % and 260 % at 4 and 10 MPa, respectively. It was probably caused by the catalytic activity of those metals in the gaseous phase. The effect of complex additive was observed to be insignificant for additives with μ-Co3O4, μ-V2O5, μ-Fe2O3 and n-Fe2O3. The burning rate of propellant with n-CuO additive value was higher by a factor of 4 in comparison with the basic formulation in the studied pressure range. 相似文献
6.
Shuang Xu Ai-Min Pang Yue Wang Xin-Zhou Pan Shang-Wen Li Hai-Tao Li Jie Kong 《Propellants, Explosives, Pyrotechnics》2022,47(1):e202000327
Ammonium perchlorate (AP) is the most widely used oxidant in composite propellants. Propellants based on AP usually have a high burning rate, but in some applications, it is necessary to have a slower burning rate. The functional additives, which can reduce the burning rate of propellants, were named coolants, burning rate suppressants (BRSs), burning rate depressants, or burning rate inhibitors. This paper introduced different types of BRSs, such as amide-based compounds, cyclic azines, quaternary ammonium salts, metal salts, etc., their mechanism and development in AP-based composite propellants. For organic amines, the burning rate trend is as follows: biuret<melamine<oxamide<urea<base. Cyclic azines are special organic amines which form large, thermally stable cyclic azines in addition to common low-molecular-weight gases NH3, CO2, HCN, and N2O when heated. With the smallest addition but the highest effect, quaternary ammonium salts will not reduce the specific impulse of the propellant, nor do they interfere with cure reaction or adversely affect the physical properties of the cured propellant. Metal salts reduce the burning rate by forming more stable substances than HClO4 with AP. The mechanism of BRSs is complicated, but all of them can be explained based on AP deflagration. At last, the development trend of efficient BRSs was discussed, the preparation of liquid BRSs and the combination of AP bonding agents with BRSs were both first proposed, which worth further research in the future. 相似文献
7.
Gurdip Singh Inder Pal Singh Kapoor Shalini Dubey 《Propellants, Explosives, Pyrotechnics》2011,36(4):367-372
Mixed transition metal oxides (MTMO) nanoparticles of 3rd‐series (NiCo2O4, CuCo2O4, and ZnCo2O4) were prepared by a co‐precipitation method. These were characterized by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The particle size was found to be in the order of 53.0, 43.4, and 21.2 nm, respectively. The thermolysis of ammonium perchlorate (AP), AP‐HTPB (hydroxyterminated polybutadiene) composite solid propellants (CSPs), and HTPB was found to be catalyzed with MTMOs and the burning rate of CSPs was also enhanced. TG and ignition delay study demonstrated that the higher temperature decomposition (HTD) of AP is catalyzed enormously by these catalysts and CuCo2O4 is the best candidate. 相似文献
8.
Tai‐Kang Liu 《Propellants, Explosives, Pyrotechnics》2011,36(2):131-139
This study acquired, classified, and analyzed more than 3500 repeated‐measured steady state strand burner burning rate data from our quality control data bank as well as from open literature. The large size of consistent data from our resource were employed for the construction of a model that correlates burning rate standard deviations with average burning rates for both within‐batch lots and among‐batch lots. An increase in standard deviations with burning rates was observed for both correlations. Both correlations exhibit an R2‐statistic larger than 0.82 within burning rate range of 3.4–38.6 mm s−1, and both correlations provide predictions in good agreements with some good quality published data. These two correlations may serve as feasible burning rate standard deviation tolerance reference when conducting composite propellants production quality control or burning rate data reproducibility checkup. Moreover, the confidence limits of parameters from the derived within‐batch correlation equation allow assessing the maximum pressure‐exponent uncertainties within selected burning rate range, thus provide insightful considerations to pressure‐exponent tolerance assignment for propellants under development or production. 相似文献
9.
Xiaode Guo Fengsheng Li Hongchang Song Guanpeng Liu Lingrui Kong Miaomiao Li Weifan Chen 《Propellants, Explosives, Pyrotechnics》2008,33(4):255-260
The novel grain‐binding high burning rate propellant (NGHP) is prepared via a solventless extrusion process of binder and spherical propellant grains. Compared with the traditional grain‐binding porous propellants, NGHP is compact and has no interior micropores. During the combustion of NGHP, there appear honeycomb‐like burning layers, which increase the burning surface and the burning rate of the propellant. The combustion of NGHP is a limited convective combustion process and apt to achieve stable state. The larger the difference between the burning rate of the binder and that of the spherical granular propellants exists, the higher burning rate NGHP has. The smaller the mass ratio of the binder to the spherical granular propellants is, the higher the burning rate of NGHP is. It shows that the addition of 3 wt.‐% composite catalyst (the mixture of lead/copper complex and copper/chrome oxides at a mass ratio of 1 : 1) into NGHP can enhance the burning rate from 48.78 mm⋅s−1 in the absence of catalyst to 56.66 mm⋅s−1 at P=9.81 MPa and decrease the pressure exponent from 0.686 to 0.576 in the pressure range from 9.81 to 19.62 MPa. 相似文献
10.
In this study, the hardening reaction speed of a rocket motor liner based on the Aging of a curing system comprised of a hardener and hardening catalyst was investigated. With the increasing Aging time of the curing system, the liner viscosity build-up was accelerated. The raw material having the biggest impact on the hardening reaction of the curing system's liner was triphenylbismuth (TPB). Stirring isophorone diisocyanate and TPB form an activated complex, and the activated complex facilitates the urethane reaction. If TPB is ligand bound with isocyanate, it forms a TPB-isocyanate complex. This is a type of TPB's oxide, and the formation of the activated complex is visible through changes in its color. In addition, lining hardening time can be adjusted by the Aging period of the curing system through used in this study, and the adhesive strength with the liner and propellant can be improved. 相似文献
11.
Richard Turcotte Phillip&#x;D. Lightfoot Christopher&#x;M. Badeen Marie Vachon David&#x;E.&#x;G. Jones Sek&#x;Kwan Chan 《Propellants, Explosives, Pyrotechnics》2005,30(2):118-126
It is well known that water‐based commercial explosives locally ignited in closed vessels do not undergo self‐sustained combustion when the pressure is lower than some threshold value. The latter is usually referred to as the Minimum Burning Pressure (MBP) of the explosive and is now being used by some manufacturers as a basis of safety for many associated manufacture, transport, and handling processes. In the present work, both an apparatus based on hot‐wire ignition and an associated methodology were developed to measure the MBP of water‐based explosives. Typical results for various emulsion and water‐gel explosives are also reported and discussed. It is also shown that the technique could be used to characterize very insensitive explosive substances normally used as explosive precursors. 相似文献
12.
Harmeet Singh Darshana Singh Dhanraj Chimurkar Jayesh Upadhyay Amit Kumar Arvind Kumar Shrikant Pande Priyesh More 《Propellants, Explosives, Pyrotechnics》2020,45(4):647-656
For enhanced range, higher payload capacities and for miniaturized propulsion systems, today's strategic and tactical weapon system designers demand for higher density and specific impulse of the propellant. In order to enhance the density impulse of HTPB/DOA/RDX/AP/Al based composite propellant, studies have been carried to replace conventional HTPB/DOA binder system with hydroxyl terminated block copolymer of polybutadiene and ϵ-caprolactone with NG as plasticizer. Total eight numbers of compositions were formulated with varying content of RDX. Both binder systems were compared in propellant compositions by evaluating various physical, thermal and ballistic properties. Various rocket performance parameters of each formulation were theoretically predicted by NASA CEC-71 program and burning rate was measured in pressure ranges of 3-7 and 7-11 MPa by the acoustic emission technique. In addition, density, viscosity build up, calorimetric values, thermal decomposition and sensitivity parameters of each composition were also assessed and compared. In an outcome, it was concluded that HTBCP25/NG based propellant compositions enhance the density by 4.4–5 % and calorimetric values by 12–15 % as compared to HTPB/DOA based compositions. Strand burning rate data show enhancement of burning rate by 40–70 % at 7 MPa pressure in HTBCP25/NG based compositions. Impact and friction sensitivity data also revealed their utility in propellant compositions for future applications. 相似文献
13.
Nadir Yilmaz Burl Donaldson Walter Gill William Erikson 《Propellants, Explosives, Pyrotechnics》2008,33(2):109-117
Strand burner pressure–time data are analyzed to determine if the propellant burning rate can be extracted. This approach is based on strand burner pressure–time history that is related to the temperature change due to exothermic reaction heating of chamber gases and gas addition to the chamber by propellant combustion products. In support of this method, chemical equilibrium calculations were made to project product composition, internal energy, and other needed properties. A mathematical model was formulated and solved numerically and the calculated burning rates were compared with the experimental wire‐break time results provided simultaneously and with the propellant manufacturer's results, when available. The comparisons reveal that the approach has merit and that more accurate pressure determination coupled with additional thermochemical information and strand burner gas temperature measurements has the potential to make this approach a viable technique and one that can be applied in conjunction with other burning rate measurements. The proposed method is similar to a well‐developed technique which is commonly applied to ballistic powders but with adjustments for the differences in geometry, pressure, and time of event. 相似文献
14.
A simplified mechanism of the plasma effect on the combustion on different types of propellants is presented. The model provides a semi‐quantitative prediction of the burning rate enhancement that should be expected for a given propellant composition and structure. Depending on the propellant structure and composition, one expects a burning rate enhancement either to disappear or to survive a certain time after the plasma injection has been turned off. In order to estimate the internal front propagation rate, we have built a simplified model of the RDX ignition inside the matrix. A cubic lattice topology has been assumed and the ignition front extends from one layer to its nearest neighbor. The propagation rate was found to be dependent on the lattice constant, the particle size, the thermo‐chemical properties of the RDX particles and the matrix background. 相似文献
15.
Richard Turcotte Sandra Goldthorp Christopher&#x;M. Badeen Hongtu Feng Sek&#x;Kwan Chan 《Propellants, Explosives, Pyrotechnics》2010,35(3):233-239
It has been well established that sustained combustion in ammonium nitrate water‐based emulsions (AWEs) can only occur if the ambient pressure is held above some threshold value, usually referred to as the ‘minimum burning pressure’ (MBP). For the commercial explosives industry, a good knowledge of the MBP for particular AWE formulations is essential to estimate safe operating pressures for the associated manufacturing and handling processes. In these processes, AWE products are most often pumped in closed systems and at elevated temperature. While previous studies have established that the MBP can depend critically on major ingredients, its dependence on physical characteristics such as temperature and viscosity had never been investigated. Moreover, the consequences of alterations in measurement methodologies on the resulting measured MBP values had not been studied. 相似文献
16.
Satyanarayanan&#x;R. Chakravarthy Jeffrey&#x;M. Freeman Edward&#x;W. Price Robert&#x;K. Sigman 《Propellants, Explosives, Pyrotechnics》2004,29(4):220-230
This paper reports a series of experiments involving ammonium dinitramide (ADN), a new energetic oxidizer of potential use in composite solid propellants. The experiments include (a) self‐deflagration of pressed pellets of ADN; (b) combustion of sandwiches with ADN laminae on both sides of a binder lamina that is either “pure” or filled with particulate oxidizer and other additives; and, (c) combustion of propellants with a bimodal oxidizer size distribution, wherein, combustion of coarse ADN and fine AP (ammonium perchlorate) and vice versa were used, in addition to mixtures of coarse ADN and AP, fine ADN and AP, and all‐ADN or all‐AP formulations. 相似文献
17.
Richard Turcotte Sandra Goldthorp Christopher&#x;M. Badeen Sek&#x;Kwan Chan 《Propellants, Explosives, Pyrotechnics》2008,33(6):472-481
Emulsions based on ammonium nitrate (AN) and water locally ignited by a heat source do not undergo sustained combustion when the pressure is lower than some threshold value usually called the Minimum Burning Pressure (MBP). This concept is now being used by some manufacturers as a basis of safety. However, before a technique to reliably measure MBP values can be designed, one must have a better understanding of the ignition mechanism. Clearly, this is required to avoid under ignitions which could lead to the erroneous interpretation of failures to ignite as failures to propagate. In the present work, facilities to prepare and characterize emulsions were implemented at the Canadian Explosives Research Laboratory. A calibrated hot‐wire ignition system operated in a high‐pressure vessel was also built. The system was used to study the ignition characteristics of five emulsion formulations as a function of pressure and ignition source current. It was found that these mixtures exhibit complicated pre‐ignition stages and that the appearance of endotherms when the pressure is lowered below some threshold value correlates with the MBP. Thermal conductivity measurements using this hot‐wire system are also reported. 相似文献
18.
Sungjun Park Sunghan Choi Kyungmin Kim Woonjae Kim Jungho Park 《Propellants, Explosives, Pyrotechnics》2020,45(9):1376-1381
In this study, ammonium perchlorates (APs) with two or more different particle sizes were mixed to optimize the viscosity of the propellant slurry and the burn rate of the resulting solid composite propellants at various mixing ratios. First, to investigate the characteristics of bimodal AP, APs with 200 and 6 μm particles were used. The experimental results showed that the viscosity of the propellant mixture was excellent when the AP-200 content, i. e., the AP with 200 μm particles, ranged from 55 to 70 wt%, and the burn rate increased with the increasing AP-6 content. To investigate the characteristics of trimodal AP, three types of APs with 400, 200, and 6 μm particles were used. The findings revealed that the mixing ratio of the three types of APs most favorable to the rheological properties was approximately 1 : 1 : 1. In addition, although adjusting the ratio between large and small particles was desirable for changing the burn rate, varying the ratio between AP-400 and AP-200 did not significantly change the burn rate. Adjusting the AP-6 ratio effectively changed the burn rate. The method of adjusting the AP contents, i. e., the solid contents of propellant, can effectively alter the viscosity and burn rate of propellant. When the total AP content was reduced, the burn rate decreased, but the overall propellant performance degraded. However, the performance parameters of the propellant, such as its density and specific impulse, could be improved by adding solid fuels, such as aluminum. 相似文献
19.
《Propellants, Explosives, Pyrotechnics》2017,42(6):665-670
Although a polytetrahydrofuran (PTHF) blend with added glycerin as a crosslinking modifier is an effective binder for improving the performance of a propellant, a burning catalyst is required for the combustion of the ammonium nitrate (AN)/PTHF/glycerin propellant. MnO2 and Fe2O3 are useful burning catalysts for AN‐based propellants. The thermal decomposition behaviors of the AN/PTHF/glycerin propellant supplemented with MnO2 and Fe2O3 catalysts, and the catalytic effect of these catalysts on the burning characteristics was investigated in this study. The thermal decomposition behaviors of these propellants depended on the kind of catalyst used. The propellants containing MnO2 burned above 4 MPa, while those containing Fe2O3 burned above 0.5 MPa. The burning rate increased in the order, (AN/PTHF/Fe2O3)<(AN/PTHF/MnO2)<(AN/PTHF/MnO2/Fe2O3). The improvement in the ignitability and burning rate was dependent on the kind of catalyst used. The burning characteristics of the AN/PTHF/glycerin propellants were improved by the combined effect of multiple catalysts with differing catalytic mechanisms, as compared to the propellant supplemented with any single catalyst. 相似文献
20.
Robert Kellogg Saul Lapidus Trevor Hedman Joseph Kalman 《Propellants, Explosives, Pyrotechnics》2020,45(3):480-485
Ammonium perchlorate is commonly used as an oxidizer in solid rocket propellant. Having a knowledge of its thermal expansion properties is essential for its application in different environments. Knowledge of thermal expansion properties is also useful for the prediction of propellant mechanical properties and response of propellant slow cook off applications. X-ray diffraction analysis was performed on ammonium perchlorate at temperatures ranging from 260 K to 500 K. From there, Bragg peaks were indexed by fitting theoretical values of 2θ to the 2θ values of peaks obtained from the experiment. The Miller indices along with the 2θ values were then used to solve for the lattice parameters at each temperature. The lattice parameters, in nanometers, range from 0.9201 to 0.9373, 0.5805 to 0.5865, and 0.7439 to 0.7535 for a, b, and c, respectively. The measurement of the lattice parameter expansion leads to the determination of the temperature dependent thermal expansion coefficients within the temperature range. The lattice parameter values also lead to the determination of strain and stress on the ammonium perchlorate crystal. Direct measurement of the strain within the crystal lattice provides a more accurate measurement method over traditional optical-based techniques. 相似文献