共查询到20条相似文献,搜索用时 78 毫秒
1.
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
2.
Ting Liu Xin Chen Huixiang Xu Aijun Han Mingquan Ye Gongpei Pan 《Propellants, Explosives, Pyrotechnics》2015,40(6):873-879
Boron particles have several major burning problems, such as incomplete combustion, poor ignitability, and a complex burning process in solid propellants. It is documented that the low ignitability and combustion efficiency of boron are caused by the oxidation of its surface. In order to improve the combustion efficiency of boron particles, a precipitation method was employed to prepare nanometer‐sized NiO and coat it on boron particles. The morphology and coating results of the B/NiO nanocomposite thermite were characterized using different approaches such as SEM, X‐ray Diffraction (XRD), and EDS. The results indicated that the boron particles were well distributed and coated completely by nanocomposite NiO. The B/NiO nanocomposite thermite reaction process was tested by TG‐DTA. The results showed that the reaction temperature of B/NiO particles is about 30 °C lower than that of boron particles. The B/NiO thermite and boron powder were added to Mg/PTFE propellant to be measured for their respective combustion performance. The results showed that the burning rate of the B/NiO‐Mg/PTFE propellant increased by 22.8–25.2 %, mass burning rate by 26.7–30.8 %, and combustion temperature increased by 8–56 °C compared to the B‐Mg/PTFE propellant. The above results indicate that NiO coating of boron particles has a significant effect on the combustion behavior and increases the combustion performance of the propellant compared with uncoated particles. 相似文献
3.
《Propellants, Explosives, Pyrotechnics》2017,42(6):649-658
The incorporation of nano‐scaled cyclotrimethylene trinitramine (nRDX) in nitrocellulose (NC)‐based propellants poses processing problems when following conventional methods. Hence, a new preparation method containing a pre‐dispersion process was developed, by which 30 mass % RDX (290 nm) was incorporated in the propellant. Meanwhile, the corresponding 290 nm, 12.85 μm and 97.76 μm RDX‐based propellants were prepared for comparison using a conventional method. The morphology, structure, ballistic and mechanical properties of the prepared propellants were characterized by scanning electron microscopy (SEM), density analyzer, closed vessel (CV), uniaxial tensile tester and impact tester. The results indicate that the nRDX particles were uniformly dispersed in the NC/NG/TEGDN matrix using the novel method, while agglomerated and recrystallized into large particles with the conventional method. The propellant density increased with decreasing RDX particle size. In particular, the 290 nm RDX‐based propellant exhibited a higher burning rate and lower average pressure exponent (α =0.958) compared to the 12.85 μm RDX‐based propellant (α =1.043). The tensile strength, elongation at break and impact strength of the RDX‐based propellant at −40 °C, 20 °C and 50 °C were dramatically improved by using 290 nm RDX with the novel method. 相似文献
4.
《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
5.
Avi Birk Miguel Del Guercio Amy Kinkennon Douglas E. Kooker Pamela Kaste 《Propellants, Explosives, Pyrotechnics》2000,25(3):133-142
Enhanced burning of plasma‐ignited propellants has been deduced in recent years from closed bomb pressure traces. The question remains, however, whether the enhanced burning is inherent or possibly the result of propellant grain fracture. To find out, interrupted and non‐interrupted burning tests were conducted with cylindrical perforated grains of JA2 and M30 in a closed bomb with a loading density of approximately 0.2 g/cm3. Both, conventional black powder and plasma igniters were used, and a few tests were carried out with the propellants cooled to −20 °C. The plasma igniter was an ablating capillary, and the electrical energy density was about 0.7 kJ/g of propellant. The diameters of the collected grains yielded the actual burn distance at the time of the interrupted burning. The experimental pressure traces and the conventional burn rate coefficients of the propellants were used to calculate the theoretical depth burned assuming no plasma‐induced burn rate modifications. From overlapping pressure traces at several interrupted pressures, and from comparison to the calculated versus measured burn distances, it was found that there is burn rate enhancement during the plasma pulse–but not much once the pulse has ended. In contrast to the JA2 burn rates, both ambient and cold M30 burn rates, deduced from the non‐interrupted tests using the BRLCB code, were enhanced even after the plasma turn‐off, thus contradicting the interrupted‐tests results. However, vivacity analysis of the non‐interrupted tests indicated that the M30 grains exhibited increased surface area (possible fragmentation) because of the plasma interaction–an effect that would cause erroneous results from the BRLCB. Indeed, simulation of the non‐interrupted M30 tests using the XNOVAKTC code, and assuming partial fragmentation of the propellant charge, yielded vivacities that mimicked the experimental ones. 相似文献
6.
The effects of porous structure on the burning characteristics of foamed NC‐based (nitrocellulose‐based) gun propellants were investigated by closed vessel and quenched combustion experiments. The foamed NC‐based TEGDN (triethylene glycol dinitrate) gun propellants with different porous structures were prepared by adjusting the process parameters in the foaming process. SEM (scanning electron microscopy) was used to observe the morphologies of foamed TEGDN propellants, and the densities of the foamed propellants were also measured to evaluate the porosities of foamed propellants. The experimental results showed that the burning characteristics of the novel foamed propellants are totally different from combustion characteristics of parallel‐layer. Further investigations revealed that the burning characteristics of the foamed NC‐based propellants largely depend on the porous structure, larger pores and higher porosity would lead to higher burning rate of the foamed TEGDN propellants. 相似文献
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8.
Hai‐Tao Huang Mei‐Shuai Zou Xiao‐Yan Guo Rong‐Jie Yang Peng Zhang 《Propellants, Explosives, Pyrotechnics》2012,37(4):407-412
A high‐pressure combustor and a metal/steam reactor were used to simulate the two‐stage combustion of a fuel‐rich propellant used for water ramjet engines. The solid combustion products from the two stages were collected and characterized by scanning electron microscopy (SEM) and X‐ray diffraction (XRD). In addition, the thermal properties of the solid products of the primary combustion were characterized by differential thermal analysis (DTA) and simultaneous thermogravimetry (TG). The burning rates at different pressures were measured and the secondary combustion process in hot steam was monitored by high‐speed cinematography. The results showed that the propellant has a good combustion performance and a high burning rate. After primary combustion, the solid product mainly contained magnesium, magnesia, magnesium chloride, and carbon. During the secondary combustion, the ignition temperature was approximately 720 °C, and two burning stages were observed. The rest of magnesium hasn’t completely reacted with hot steam until the temperature reached a value higher than 800 °C for 30 min. 相似文献
9.
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
10.
通过配方调节与工艺控制得到3种不同结构的泡沫发射药,讨论了泡孔结构形成的影响因素;采用密闭爆发器实验和恒压燃速测试实验研究了不同结构泡沫发射药的燃烧性能。结果表明,控制气体生成速率、添加RDX颗粒、调节NC含氮量和发泡时间能够有效控制泡沫发射药的泡孔结构;皮芯结构泡沫发射药具有渐增燃烧特性,发泡区的动态活度可达不发泡皮层的2.4倍以上;独立泡孔结构的泡沫发射药在100MPa下燃速可达未发泡样品的30倍;非独立孔隙结构的泡沫发射药不同方向上的燃速差异显著,密度为1.37g/cm~3的样品100MPa下轴向燃速最高可达3.860m/s。 相似文献
11.
为了研究粒径为50nm的纳米镍粉(nano-Ni)对含Al改性双基(Al-CMDB)推进剂、含六硝基六氮杂异伍兹烷(CL-20)改性双基(CL-20-CMDB)推进剂燃烧性能的影响,通过吸收-压延的方法制备了推进剂样品,用靶线法测试了推进剂的燃速,并计算了压强指数。通过电镜扫描、火焰照片、燃烧波、熄火表面形貌及元素分析和DSC分析了纳米镍粉对Al-CMDB推进剂燃烧性能影响的原因。结果表明,在Al-CMDB推进剂中加入nano-Ni可大幅度提高推进剂燃速,降低推进剂的压强指数;当加入质量分数0.7%的nano-Ni时推进剂10MPa的燃速达到35.59mm/s,8~20MPa压强指数从0.43降低至0.17,15~20MPa出现麦撒效应。在CL-20-CMDB推进剂中加入质量分数0.5%的nano-Ni能明显提高推进剂的中低压(4~10MPa)燃速,8~20MPa压强指数约为0.01,15~20MPa出现麦撒效应。 相似文献
12.
A study is conducted to determine the effect of acoustic field on the thermal conductivity of composite propellants based on poly- butadiene and polyurethane binders. The thermal conductivity of the propellant is determined by a specially designed equipment. The thermal conductivity measurements are made in steady state conditions and in an acoustic field of constant amplitude at various frequencies ranging from 1 kHz to 6 kHz and at different temperatures ranging from 30°C to 50°C. The results indicate that the thermal conductivities of the composite propellants increase when they are subjected to an acoustic field. The data obtained are presented in the paper. Since the burning behaviour of solid propellants is influenced also by its thermal conductivity, the present work may be of direct relevance in improving upon some of the existing burning rate and combustion models. 相似文献
13.
Yu‐Zhu Pan Yong‐Gang Yu Yan‐Huang Zhou Xin Lu 《Propellants, Explosives, Pyrotechnics》2012,37(4):439-444
A new device for measuring the linear burning rate of liquid propellants at high pressures is reported. High‐pressure environments were generated by the combustion of solid propellants. The coated propellants, which burn progressively, were introduced to maintain the approximate constant‐pressure environments. By use of ion probe transducers, measurements were made of the spread velocity of the flame surface, i.e. the apparent linear burning rate of the HAN‐based liquid propellant LP1846 (HAN =hydroxylammonium nitrate) was measured quantitatively at pressures from 6 to 28 MPa. The results show that it follows the exponential burning rate law. The burning rate coefficient and exponent were fitted by least‐squares methods. Based on the experiment, a simplified model of the linear burning rate of HAN‐based liquid propellants at high pressures was developed. The numerical simulation is found to be in good agreement with the experimental data. 相似文献
14.
Andreas Koleczko Walter Ehrhardt Stefan Kelzenberg Norbert Eisenreich 《Propellants, Explosives, Pyrotechnics》2001,26(2):75-83
Electro‐thermal‐chemical (ETC) initiation and combustion offers the possibility to increase the performance of guns substantially as new propellant formulations and high loading densities (HLD) can be safely ignited and burnt in an augmented way. This paper reports investigations of burning phenomena in the low pressure region for JA2 and the effects of plasma interaction on ignition and study its influence on the burning rate. The comparison of transparent and opaque versions of the propellant is of special interest. Electrically produced plasma can strongly influence the ignition and combustion of solid propellants. Predominantly, plasma arcs influence strongly the burning of propellants by its radiation. The high intensity of the radiation initiates burning with short time delays in the µs‐range and high conversion during exposure also in the case of a stable burning. Radiation can penetrate into the propellant interior and partially fragment at absorbing structures which could be artificially introduced or be inherently present as in the case of a JA2 propellant. Simplified approaches based on the heat flow equation and radiation absorption can explain these effects at least on a qualitative scale. Dynamic effects are understood by more sophisticated models. 相似文献
15.
Jiang Zhi Li Shu‐Fen Zhao Feng‐Qi Liu Zi‐Ru Yin Cui‐Mei Luo Yang Li Shang‐Wen 《Propellants, Explosives, Pyrotechnics》2006,31(2):139-147
A comparison of various experimental results for combustionrelated properties evaluation, including burning rates, deflagration heat, flame structures and thermal decomposition properties, of AP/RDX/Al/HTPB composite propellants containing nano metal powders is presented. The thermal behavior of n‐Al (nano grain size aluminum) and g‐Al (general grain size aluminum i.e., 10 μm) heated in air was also investigated by thermogravimetry. The burning rates results indicate that the usage of bimodal aluminum distribution with the ratio around 4 : 1 of n‐Al to g‐Al or the addition of 2% nano nickel powders (n‐Ni) will improve the burning behavior of the propellant, while the usage of grading aluminum powders with the ratio 1 : 1 of n‐Al to g‐Al will impair the combustion of the propellant. Results show that n‐Al and n‐Ni both have a lower heating capacity, lower ignition threshold and shorter combustion time than g‐Al. In addition n‐Al is inclined to burn in single particle form. And the thermal analysis results show that n‐Ni can catalyze the thermal decomposition of AP in the propellant. The results also confirm the high reactivity of n‐Al, which will lead to a lower reaction temperature and rather higher degree of reaction ratio as compared with g‐Al in air. All these factors will influence the combustion of propellants. 相似文献
16.
为了研究DAGQ发射药在膛内的燃烧性能,以经典内弹道理论为基础,建立了发射药膛内燃烧测试系统和处理方法,通过密闭爆发器燃烧试验和微波干涉法发射药膛内动态燃烧性能试验,研究了DAGQ发射药的静动态燃烧规律及不同温度下的动态燃烧特性。结果表明,所建立的试验系统和处理方法,能够很好地获得弹丸在膛内的运动过程。DAGQ发射药的静动态燃速都存在转折现象,静态燃速在转折点前压力指数大于1,转折点后压力指数都远小于1,动态燃速压力指数基本都小于1。在膛内燃烧过程中,由于高速气流对发射药的燃面冲刷,使得膛内的动态燃速要大于密闭爆发器内的静态燃速,并且随着膛内压力的增大,燃速相差越来越大。 相似文献
17.
David A. Reese Steven F. Son Lori J. Groven 《Propellants, Explosives, Pyrotechnics》2014,39(5):684-688
Composite propellants based on the solid nitrate ester 2,3‐hydroxymethyl‐2,3‐dinitro‐1,4‐butanediol tetranitrate (SMX) were theoretically and experimentally examined and compared to formulations based on ammonium perchlorate (AP). Thermochemical equilibrium calculations show that aluminized SMX‐based formulations can achieve theoretical sea level specific impulse values upwards of 260 s. Both ignition sensitivity (tested via drop weight impact, electrostatic discharge, and BAM friction) and physical properties (hardness and thermal properties) are comparable to those of the AP‐based formulations. However, the SMX‐based formulation could be detonated using a high explosive donor charge in contact with the propellant. Differential scanning calorimetry of the SMX‐based propellant indicated an exotherm onset of 140 °C, which corresponds to the known decomposition temperature of SMX. The propellant has a high burning rate of 1.57 cm s−1 at 6.89 MPa, with a pressure exponent of 0.85. This high pressure sensitivity might be addressed using various energetic and/or stabilizing additives. With good performance and high density, SMX‐based composite propellants may offer a promising perchlorate‐free alternative to existing AP‐based formulations. 相似文献
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19.
含FOX-7发射药的燃烧性能 总被引:1,自引:0,他引:1
采用常规密闭爆发器研究了含FOX-7硝胺发射药的燃速、压强指数和压强变化率。结果表明,随着样品中FOX-7含量的增加,发射药的点火延滞时间增加,燃速系数减小,燃速降低;其压强变化率的最大值及增长速率均降低。当燃烧压强小于150MPa时,FOX-7含量对发射药的压强指数没有影响,FOX-7改善发射药压强指数的能力不明显;随着燃烧压强的增加,含FOX-7发射药的压强指数降低,尤其当燃烧压强大于200MPa时,发射药的燃速压强指数显著降低。随着发射药中FOX-7含量的增加,其压强指数及燃速系数均降低,有利于发射药的稳定燃烧。 相似文献