GAP/ADN/nano–Al膏体推进剂的能量特性与激光点火特性

采用最小自由能原理方法计算了GAP(聚叠氮缩水甘油醚)/ADN(二硝酰胺铵)/nano–Al推进剂的能量特性,制备了一系列ADN质量分数为8%~38%的GAP/ADN/nano–Al膏体推进剂,采用CO2激光点火的方法研究了4种配方在不同激光功率密度作用下的激光点火特性。结果表明:GAP/ADN/nano–Al膏体推进剂的标准理论比冲(Isp)、特征速度(C*)、燃烧温度(Tc)均随ADN含量增加而依次增大,爆热(Qv)则主要随铝粉含量的增加而增大;GAP/ADN/nano–Al膏体推进剂的点火延迟时间和点火能量总体上随着激光功率密度增加呈现减小的趋势;配方中ADN含量较高时,GAP/ADN/nano–Al膏体推进剂具有较好的激光点火特性。     

含1,1–二氨基–2,2–二硝基乙烯推进剂的能量特性参数计算研究

利用国军标方法及CAD系统软件,在标准条件(pc∶p0=70∶1)下,计算了含1,1-二氨基-2,2-二硝基乙烯(FOX-7)的各类推进剂的能量特性参数,分析了氧化剂(AP、RDX、CL-20)及黏合剂(HTPB、PET、GAP、PBAMO)等成分对FOX-7推进剂能量特性的影响。结果表明,将AP加入HTPB/FOX-7推进剂配方中取代FOX-7可有效改善氧条件,有利于推进剂能量的提高。在黏合剂含量较低(质量分数<8%)的推进剂体系中,使用惰性黏合剂有利于提高推进剂的能量;而在黏合剂含量较高(质量分数>10%)的推进剂体系中,使用含能黏合剂提高推进剂能量的幅度优于惰性黏合剂,且GAP优于PBAMO。用FOX-7取代NEPE推进剂中的AP,推进剂最大理论比冲可达2 567 N.s/kg。由GAP/FOX-7/RDX组成的无烟推进剂,在很宽的范围内都可以达到2 400 N.s/kg以上的理论比冲值。     

二硝基胍在固体推进剂中的能量性能分析

为考察新型含能化合物二硝基胍(DNGu)对固体推进剂能量性能的影响,采用能星5.0版程序,模拟计算了DNGu替换CMDB(复合改性双基)、HTPB(端羟基聚丁二烯)推进剂中的AP(高氯酸铵),替换NEPE(硝酸酯增塑剂聚醚)、GAP(聚叠氮缩水甘油醚)推进剂中的主氧化剂AP和次级氧化剂HMX(环四亚甲基四硝胺)后体系的能量效果。结果显示:DNGu单质推进剂平衡流比冲比ADN(二硝酰胺铵)、AP要高得多;DNGu对4种推进剂配方体系能量贡献均优于AP,如果设计合适的配方体系,DNGu对CMDB推进剂能量贡献超越ADN;DNGu作为GAP推进剂中主氧化剂时,能量水平高于AP,作为次级氧化剂时,能量水平低于HMX;DNGu作为NEPE推进剂主氧化剂时,理论比冲存在最大值,替换HMX作为次级氧化剂时,理论比冲降低。     

P(BAMO-r-AMMO)在推进剂中的应用

以3,3′-双叠氮甲基环氧丁烷-3-叠氮甲基-3′-甲基环氧丁烷无规共聚物(P(BAMO-r-AMMO))为高分子预聚物,通过能量计算优化配方组成,制备了固含量为80%的P(BAMO-r-AMMO)基热固性复合推进剂。采用最小自由能法对3种配方进行了能量计算,用表界面张力仪、氧弹式量热仪、差示扫描量热仪(DSC)和静态拉伸试验测定了样品的密度、爆热、玻璃化转变温度(Tg)和力学性能。结果表明,该复合推进剂在10MPa压强下的标准理论比冲可达275.43s,密度为1.7924g/cm3,爆热达6 124kJ/kg,Tg为-50.80℃,拉伸强度为1.24MPa,断裂伸长率为21%,高于相同配方下端羟基聚丁二烯(HTPB)基和聚叠氮缩水甘油醚(GAP)基热固性复合推进剂,较HTPB基和GAP基热固性复合推进剂有更优良的综合性能。     

无机氧化剂二硝酰基胺铵在固体推进剂中的能量性能分析

为考察新型含能无机氧化剂二硝酰基胺铵(ADNA)对固体推进剂能量性能的贡献水平,采用编制的能量计算星程序5.0版,模拟计算了ADNA、ADN(二硝酰胺铵)及AP(高氯酸铵)对CMDB(复合改性双基)、HTPB(端羟基聚丁二烯)、NEPE(硝酸酯增塑聚醚)、GAP(聚叠氮缩水甘油醚)推进剂的能量贡献水平。结果表明:ADNA取代CMDB、HTPB、GAP、NEPE推进剂中的AP,都使体系标准理论比冲增加,羽流红外辐射性能降低;ADNA对推进剂的能量贡献要优于ADN,如果设计合适的HTPB、GAP配方体系,ADNA的能量贡献超越RDX。     

含3,5-二硝氨基-1,2,4-三唑肼盐推进剂的能量特性计算

为评价新型高氮化合物3,5-二硝氨基-1,2,4-三唑肼盐(HDNAT)作为固体推进剂组分的应用潜力,采用NASA-CEA软件,在标准条件下(pc∶p0=70∶1),计算了含HDNAT的丁羟推进剂(HTPB)、聚叠氮缩水甘油醚(GAP)推进剂和改性双基推进剂(CMDB)的能量特性。绘制了HTPB/Al/AP/HDNAT推进剂(金属Al的最大质量分数为20%)的标准理论比冲Isp、特征速度C*、燃烧温度Tc、燃气平均相对分子质量Mw的等性能三角图。结果表明,HDNAT单元推进剂的比冲为2 533.0N·s/kg;在HTPB推进剂中,当HDNAT质量分数为50%时,Isp最大为2 658.0N·s/kg,较基础配方提高了326.6N·s/kg;在GAP推进剂中,当HDNAT质量分数为30%时,Isp最大为2 529.0N·s/kg,较基础配方提高了252.7N·s/kg;在CMDB推进剂中,当HDNAT质量分数为27%时,Isp最大为2 593.1N·s/kg,较基础配方提高了57.3N·s/kg。     

Zr/Al基高能固体推进剂的能量特性分析

为探究锆粉含量对高能推进剂能量特性的影响规律,利用热力学计算软件CEA分析了不同锆含量的Zr/Al基NEPE推进剂和Zr/Al基叠氮高能推进剂的能量特性;通过计算这两种推进剂的燃烧温度、密度、比冲和密度比冲等能量特性参数,得到了锆含量对推进剂能量特性参数的影响规律,并将结果与ZrH_2/Al基高能推进剂进行对比分析。结果表明,随着Zr含量增加,NEPE推进剂的燃烧温度和比冲均呈下降趋势,密度比冲持续上升,但考虑推进剂的能量特性和高燃温条件下的不稳定燃烧,认为在推进剂中添加质量分数3%～5%的Zr粉较适中;随着Zr含量增加,叠氮高能推进剂的燃烧温度和比冲呈现先增后减的趋势,且分别在Zr粉质量分数为6%和3%左右达到最大值,推进剂密度比冲持续上升。ZrH_2/Al基推进剂的能量性能低于Zr/Al基推进剂的。     

含ADN推进剂的能量特性及综合性能

为研究含二硝酰胺铵(ADN)推进剂的能量、安全、贮存及燃烧性能,根据最小自由能原理计算了含ADN推进剂的能量特性参数,采用密闭爆发器及靶线法测试其爆热及燃速,并对其吸湿性及感度进行了研究。结果表明,含ADN/Al/HMX、ADN/Al/CL-20、ADN/AlH3/HMX和ADN/AlH3/CL-20推进剂的标准理论比冲分别为2 675~2 685、2 677~2 686、2 801~2 810和2 803~2 812N·s·kg-1,采用硝酸酯增塑的惰性聚醚黏合剂体系可制备出固化正常、结构致密的含ADN推进剂。随着推进剂配方中ADN含量的增加,推进剂的爆热、吸湿性、燃速和压强指数增大,摩擦感度和撞击撞击提高,密度略有降低。     

叠氮聚合物燃烧机理

论文研究了叠氮聚合物的燃烧波结构和热解过程以确定控制燃速的参数。研究的叠氮聚合物是带有含能的—N_3 官能团的缩水甘油基叠氮聚合物(GAP)。GAP 经过亚己基二异氰酸酯(HMDI)处理和与三羟甲基丙烷(TMP)交联后形成 GAP 推进剂。从实验中发现,尽管 GAP 推进剂的绝热火焰温度低于一般固体推进剂,但其燃速明显的高。GAP 推进剂燃烧面释放的能量是由产生氮气的 N—N_2 键的断裂引起的。从气相传递回燃烧面的热流量与燃烧面产生的热量比较起来是很小的。GAP 推进剂燃烧面的分解活化能 E_s 为87kJ/mol,燃速用Υ=9.16×10~3 exp(-E_s/RT_s)表示,其中Υ(m/s)为燃烧速度,T_s(K)为燃烧面的温度,R 为摩尔气体常数。在5 MPa 压力下观察到燃速高的温度敏感性与关系式((?)T_s/(?)To)_p=0.481有关,T_o 为推进剂初温。     

ADN及其固体推进剂燃烧特性的研究进展

系统介绍了二硝酰胺铵(ADN)燃烧的最新研究动态,综述了国内外近年来报道的ADN燃烧时发生的物理化学变化、ADN燃烧机理、催化剂/ADN混合物燃烧性能以及ADN基固体推进剂燃烧特性的最新研究进展。首先指出了ADN的燃烧主要受凝聚相反应控制,ADN燃烧波结构包括固相层、泡沫层(包括固-气和液-气)和气相层;其次,总结了ADN基固体推进剂燃烧特性的研究现状,对现有研究中存在的局限性进行了分析;最后,指出继续开发适用于ADN基固体推进剂的新型燃烧催化剂是今后研究的重点方向之一。另外,随着非异氰酸酯固化体系在ADN基固体推进剂中的应用,需进一步加深ADN基固体推进剂燃烧性能的研究,尤其是三唑环的引入对ADN热分解及推进剂中其他组分热分解的影响。     

Mechanical Properties of Smokeless Composite Rocket Propellants Based on Prilled Ammonium Dinitramide

Ammonium dinitramide (ADN) is a high performance solid oxidizer of interest for use in high impulse and smokeless composite rocket propellant formulations. While rocket propellants based on ADN may be both efficient, clean burning, and environmentally benign, ADN suffers from several notable disadvantages such as pronounced hygroscopicity, significant impact and friction sensitivity, moderate thermal instability, and numerous compatibility issues. Prilled ADN is now a commercially available and convenient product that addresses some of these disadvantages by lowering the specific surface area and thereby improving handling, processing, and stability. In this work, we report the preparation, friction and impact sensitivity and mechanical properties of several smokeless propellant formulations based on prilled ADN and isocyanate cured and plasticized glycidyl azide polymer (GAP) or polycaprolactone‐polyether. We found such propellants to have very poor mechanical properties in unmodified form and to display somewhat unreliable curing. However, by incorporation of octogen (HMX) and a neutral polymeric bonding agent (NPBA), the mechanical properties of such smokeless formulations were significantly improved. Impact and friction sensitivities of these propellants compare satisfactorily with conventional propellants based on ammonium perchlorate (AP) and inert binder systems.     

二硝酰胺铵在火炸药中的应用

综述了新一代氧化剂二硝酰胺铵盐(ADN)在固体推进剂、炸药及发射药中的应用研究进展,认为ADN是替代推进剂中过氯酸铵氧化剂的最佳侯选物。提出了优化工艺、降低成本、改进ADN稳定化和球形化技术以及ADN应用方面的建议。     

新型绿色液体推进剂研究进展

对近年来国内外出现的新型绿色（无毒、对环境友好）液体推进剂进行了评述。硝酸羟铵基单组元推进剂具有冰点低、密度比冲高、安全无毒的特点,适用于小卫星和上面级,催化分解技术还有待深入研究;二硝酰胺铵基单组元推进剂比冲高于硝酸羟胺基单元推进剂,发动机脉冲工作能力可与无水肼发动机相媲美,但目前发动机预热温度和燃烧室温度都过高;高浓度过氧化氢／醇基推进剂比冲为常规推进剂比冲的93％,密度比冲为102％;过氧化氢／叠氮胺类不但密度比冲高,而且可实现自燃;一氧化二氮基双组元推进剂在微推进系统中有广泛的应用前景;原子推进剂以其优良的比冲性能将给航天运载器带来革命性的飞跃,但对低温技术提出了挑战。     

基于聚三唑固化体系的ADN推进剂研究进展

综述了国内外聚三唑固化体系及基于其的二硝酰胺铵(ADN)推进剂应用研究情况,分析了聚三唑固化体系的优缺点,指出了基于聚三唑固化体系的ADN推进剂的应用研究方向.认为聚三唑固化体系具有反应条件温和、对水分不敏感、毒性低等优点,以及玻璃化转变温度偏高、力学性能偏低等缺点.在空间推进、洁净绿色推进以及低特征信号推进剂领域,基...     

Combustion of ammonium dinitramide based solid propellant with PBT as energetic binders

Focusing on a new kind of solid propellants, which takes the ammonium dinitramide (ADN) as the high-energetic oxidant, and 3,3-bis(azidomethyl)oxetane and tetrahydrofuran copolymers (PBT) as the high-energetic fuel binder, the burning rates and the theoretical performance of the propellant were measured under different ADN contents, ADN sizes and pressures. The burning rates increased from 7.9 mm/s to 117.4 mm/s and 49.1 mm/s to 74.2 mm/s when the pressure increased from 0.1 MPa to 10 MPa and from 12 MPa to 20 MPa separately, with a singularity in the pressure dependence of the burning rate at around 10 MPa. In terms of the effect of the ADN content, under the experiment pressures from 0.5 MPa to 5.0 MPa, the burning rates of the propellant were promoted by the increase of the oxidizer loading in a range of 50 wt% to 75 wt%, with a transition from a kinetically-controlled reaction to a diffusion-controlled one. Within the condition scope of this study, no obvious effect of the ADN sizes on the propellant combustion properties was observed. This could be attributed to the solid-liquid mixed multiphase layer and the binder which served as a heat sink for the smaller ADN particles.     

Aging of ADN Rocket Propellant Formulations with Desmophen®‐Based Elastomer Binder

Desmophen® binder‐based rocket propellant formulations containing ammonium dinitramide (ADN) and different fuel filler types (Al, HMX) were manufactured and investigated. Desmophen® D2220 is a polyesterpolyol. Polyesters are seen as a binder possibility, because of the relatively low temperature of the glass transition region compared to polyether‐based prepolymers such as GAP. The analogous formulations with AP instead of ADN were also included for comparison. The aging was followed by SEM, DSC, and DMA measurements. The accelerated aging program was developed on the principle of thermal equivalent load and the generalized van’t Hoff rule with a scaling factor equal to F=2.9. The aging was performed in air (RH<10 %) at temperature values between 65 and 85 °C and aging times adjusted to a thermal equivalent load of 15 years at 25 °C. DMA measurements of the aged ADN/Desmophen®‐based propellants identified changes in the loss factor curve. In contrast to HTPB‐Al‐AP rocket propellant formulations, the loss factor curve of the ADN formulations with Desmophen®‐based elastomer binder shows only one main apparent peak. The loss factor curves were modeled with exponentially modified Gaussian functions, which have revealed the presence of a second hidden peak. It was found that the aging could be characterized by the time‐temperature dependence of the areas of the hidden peak. The area increased with aging, which is explained by scissioning of the polymer in the shell around the ADN particles. By this process the strength is reduced, which was recognized by the decrease in storage shear modulus.     

Microencapsulation of ADN with HTPB-based membrane in the presence of the bonding agents Tepan or Tepanol**

Ammonium dinitramide (ADN) has appeared as a promising oxidizer for green propellants and thereby a potential substitute for ammonium perchlorate, largely in use in composite propellants for tactical and strategic long-range missiles. The novelty lies in replacing ammonium perchlorate with a chlorine-free oxidizer less harmful to the health and environment. However, ADN is hygroscopic and can potentially react with other chemical components, which could be overcome by microencapsulating the particles. The simple coacervation method was tested herein to microencapsulate ADN with a membrane made of hydroxyl-terminated polybutadiene as pre-polymer and methylene diphenyl diisocyanate as the curing agent. The effect of polyamine bonding agents on the capsule formation was tested by adding 0.5 or 2 % of Tepan or Tepanol, whose efficacy to bond to ADN was confirmed by detecting ammonia release through infrared spectroscopy. The capsule membrane was examined by optical and scanning electron microscopy. The dissolution time and rate were the parameters adopted to quantify permeability in a straight dissolution test in water, which demonstrated that 0.5 % Tepanol can provide the most effective protection. The infrared spectroscopy indicated that 60 °C temperature for prolonged periods, normally experienced by propellants, does not chemically affect the capsules’ membrane but can turn it lumpy. In conclusion, these polyamine bonding agents can assist the capsule formation over ADN particles using the simple coacervation method, however, their functionality on mechanical properties of propellants needs to be substantiated in forthcoming works as well as the effect of the concentration of bonding agents on propellant formulations.