铝粉粒径对改性双基推进剂燃烧性能的影响

研究了3~10MPa、10~18MPa压力下,铝粉粒径对改性双基推进剂燃速和压强指数的影响。结果表明,随着铝粉粒度的增加,推进剂的燃速增加压强指数降低,3~10MPa下,压强指数从0.92降至0.51;在10~18MPa下,压强指数从0.74降至0.13。当铝粉粒度为24μm时,在10~18MPa含铝推进剂出现了平台燃烧。     

HTPB/AP/Al复合推进剂燃速降速剂研究

通过测定5．1MPa压强下HTPB／AP／Al复合推进剂药条静态燃速和BSF075mm、BSF0165mm标准发动机实验,研究了（NH4）2C2O4,LiF,CaCO3,SrCO3及季铵盐等燃速调节剂对推进剂燃烧性能、能量性能等的影响。结果表明,季铵盐降速效率最高,季铵盐与碳酸盐组合使用可使固体质量分数为87％的推进剂在5．1MPa压强下的静态燃速降至3mm／s左右。BSFΦ75mm发动机测试表明,含季铵盐与碳酸盐组合降速剂的推进剂配方在3．45～12．17MPa压强范围内的压强指数为0．2,达到了平台推进剂水平,密度比冲较相近燃速的含草酸铵推进剂高2．8％,且内弹道曲线更稳定。     

丁羟推进剂高压燃速及其调控方法研究进展

从丁羟推进剂的燃烧波结构出发,分析了高低压下推进剂燃烧火焰结构和燃面结构的变化,并借助燃速表达式阐明气固两相的传热传质是影响燃速的重要因素。综述了HTPB、AP粒径分布、RDX和HMX粒径等对丁羟推进剂高压燃速的影响,总结了金属氧化物、二茂铁及其衍生物、纳米催化剂、碳材料及其复合物、复合燃速调节剂在燃烧性能调控方面的研究进展,并分析了高压下丁羟推进剂发生燃速突增的可能原因。最后指出今后应加强以下几方面研究：(1)研究配方对丁羟推进剂高压燃烧性能的影响,阐明燃速拐点压强的变化规律;(2)研究压强对丁羟推进剂中各个组分燃烧特性以及组分之间相互作用的影响;(3)开发新型燃速调节剂,实现对丁羟推进剂高压燃烧性能的有效调控。     

AP和铝粉对AP-CMDB推进剂燃烧性能的影响

通过测定推进剂不同压强下的燃速和压强指数,研究了高氯酸铵(AP)和铝粉的粒度及含量对AP-CMDB推进剂燃烧性能的影响.结果表明,减小AP粒度和增大铝粉粒度均能有效提高AP-CDMB推进剂的燃速,推进剂在10～20 MPa压强范围内的燃速压强指数随AP和铝粉粒度的减小而明显增大;铝粉的质量分数低于14%时,调节不同比例的AP和铝粉含量对AP-CMDB推进剂的燃烧性能影响不明显,铝粉的质量分数高于14%时,由于铝粉燃烧不完全导致推进剂的燃速降低.     

低铝含量HTPB固体推进剂的燃烧特性

为研究低铝含量推进剂的燃烧特性，以铝粉质量分数5%的低铝含量HTPB推进剂为对象，以铝粉质量分数12%～18%的HTPB推进剂为参比，通过水下声发射、BSFΦ75及BSFΦ165标准试验发动机等测试方法研究了低铝含量推进剂的燃烧性能和能量性能。结果表明，同一固含量条件下，低铝含量推进剂燃速较高，压强指数没有明显变化；铝粉粒度越细，低铝含量推进剂燃速和燃速压强指数越大；经BSFΦ75发动机内弹道p(压力)—t(时间)曲线验证，8～10MPa内低铝含量推进剂燃烧稳定；经BSFΦ165发动机试车验证，7MPa下，低燃速低铝含量推进剂实际比冲2387N·s/kg,比冲效率达到97.3%,高燃速低铝含量推进剂实际比冲2465N·s/kg,比冲效率达到98.6%。低铝含量推进剂燃烧效率高，相近燃速下低铝含量推进剂与常规铝含量推进剂能量在同一水平。     

RDX-CMDB推进剂燃速温度敏感系数的实验研究

为了揭示RDX-CMDB推进剂中各常见组分对其燃速温度敏感系数的影响规律,制备了一系列含RDX、铝粉及燃烧催化剂的CMDB推进剂样品。采用氮气靶线法测得其在2~14MPa下的燃速温度敏感系数(σp)。讨论了RDX含量、铝粉、燃烧催化剂对RDX-CMDB推进剂燃速温度敏感系数的影响。结果表明,提高工作压强、增加RDX含量、添加燃烧催化剂均有助于降低RDX-CMDB推进剂在一定初始条件下的燃速温度敏感系数。配方中引入铝粉后可降低中低压下RDX-CMDB推进剂的燃速温度敏感系数,且燃速温度敏感系数几乎不随压强变化而变化。选用含邻苯二甲酸铅和没食子酸铋锆作燃烧催化剂,均可在2~10MPa下降低RDX-CMDB推进剂的燃速压强指数,同时降低燃速温度敏感系数。     

含LLM-105无烟CMDB推进剂的燃烧性能

采用燃速-靶线法研究了2,6-二氨基-3,5-二硝基吡嗪-1-氧化物(LLM-105)的含量和粒度、不同复合燃烧催化剂(A-Pb/A-Cu/CB、B-Pb/B-Cu/CB、C-Pb/C-Cu/CB)及辅助增塑剂(三醋酸甘油酯(TA)、邻苯二甲酸二乙酯(DEP))对含LLM-105无烟复合改性双基(CMDB)推进剂燃烧性能的影响。结果表明,随着LLM-105含量的增加,不同压强下推进剂的燃速均有明显降低,添加质量分数25%的LLM-105可使10MPa下推进剂的燃速下降达53.3%;粗颗粒LLM-105降低推进剂燃速的效果优于细颗粒,用粗颗粒LLM-105替代等量细颗粒LLM-105,可使不同压强下推进剂的燃速降低,10MPa下推进剂的燃速降低1.5mm/s;添加C-Pb/C-Cu/CB催化剂,推进剂在6~18MPa下的压强指数由0.43降至0.25。用TA替代DEP,可降低推进剂的燃速及压强指数。     

金属粉对NC/TMETN/FOX-7低敏感改性双基推进剂燃烧性能的影响

采用燃速-靶线法研究了铝粉(Al)、镁铝合金粉(Mg-Al)和硼粉(B)以及铝粉含量、粒度等对NC/TMETN/FOX-7改性双基推进剂燃烧性能(燃速和压强指数)的影响;采用单幅放大彩色摄影法研究了其火焰结构。结果表明,推进剂配方中添加金属粉可提高NC/TMETN/FOX-7改性双基推进剂的燃速,金属粉使推进剂燃速的增大幅度由大到小依次为:Al-MgAlB;随着Al粉(粒径12.5μm)质量分数由0增至10%,NC/TMETN/FOX-7推进剂的燃速先增大后减小,当铝粉质量分数为5%时推进剂燃速最高,达到21.19mm/s;NC/TMETN/FOX-7改性双基推进剂的燃速随着铝粉粒度的增大而增大,铝粉粒径由12.5μm增至45μm时,10MPa下推进剂的燃速由21.19mm/s增至24.47mm/s,8～14MPa的压强指数降至0.20以下;NC/TMETN/FOX-7推进剂的火焰结构与NC/NG基推进剂相似,由预热区、亚表面及表面区、暗区和火焰区组成,各区之间的界限不明显。     

低铝粉含量的HMX/HTPB推进剂研究

对低铝粉含量的HMX/HTPB推进剂进行了配方研究。为获得少烟、高密度、高模量、高燃速、低压强指数的优良的综合性能,配方调试以铝粉质量分数<10%,用HMX替代部分AP来达到少烟目的;以HTPB/TDI/MAPO/STR黏合剂体系来获取高模量;通过AP级配调节,燃速催化剂的选择等方法,使推进剂具有不挥发物质量分数≥88.5%、20℃下密度≥1.78 g/cm3、σm≥3.1 MPa,燃速≥40 mm/s的良好性能,并具有药浆初始黏度低,流动、流平性好的优点。HTPB/AP/Al/HMX四组元推进剂经BSFΦ127标准发动机地面试车,内弹道p–t曲线在压强30 MPa以下,燃烧稳定;推进剂燃烧未急升导致压强异常现象。研制成的药柱经发动机地面试验可知混合比冲高达2 456.7 N·s/kg。     

CuO/CNTs的制备及其对双基推进剂燃烧的催化作用

以醋酸铜和碳纳米管为原料,在常压和100℃下,用溶胶浸渍法制备出CuO/CNTs复合纳米催化剂,采用XRD、TEM等对CuO/CNTs进行了表征,并考察了其对双基推进剂燃烧的催化作用。结果表明,纳米CuO以8～10nm的椭球形粒子和长度50nm、宽度5nm的棒状粒子两种形态附着在碳纳米管表面。CuO/CNTs复合纳米催化剂可显著改善双基推进剂的燃烧性能,使其燃速大幅提高,压强指数降低。在6MPa、质量分数为2.5%时,该催化剂使推进剂的燃速从5.20mm/s提高到11.77mm/s,提高了115%;在16～22MPa出现平台燃烧,在该压强范围内的压强指数从0.617降低至0.238。     

Influence of Particle Size on the Combustion of CL‐20/HTPB Propellants

The effect of nitramine particle size on the combustion behavior of inert binder based propellants has been extensively studied for RDX and HMX, but not CL‐20. Although materials such as RDX and HMX are useful for particular combustion applications, CL‐20 has a greater potential to improve the oxygen balance and energy density of a propellant. The current work investigates the effect of CL‐20 particle size on the combustion of CL‐20/HTPB propellants down to submicrometer sizes. An influence of particle size on the burning rate and combustion mechanism is reported. The 30 micrometer formulation burning rate data showed evidence of convective burning specifically at higher pressures, but the pressure dependence was comparable to neat CL‐20 at pressures below 8 MPa. A change in the combustion mechanism of the submicrometer formulation as a function of pressure was determined to be a result of the interaction of the propellant flame and the combustion residue. Data suggested that at low pressures diffusion in terms of active cooling was dominant for the submicrometer formulation. Higher pressure data for both the submicrometer and 3 micrometer formulations suggest the degree of active cooling is decreased as the burning rate pressure exponent is near 0.5 for both propellants. The indirect evidence for the presence of a melt layer for CL‐20 propellants is discussed.     

Burning Rate – Pressure Relationship of NG‐PE‐PCP‐based High Energy Propellants

Nitramines are known to produce lower burning rates and higher pressure exponent (η) values. Studies on the burning rate and combustion behavior of advanced high‐energy NG/PE‐PCP/HMX/AP/Al based solid propellant processed by slurry cast route were carried out using varying percentages of HMX and AP. It was observed that propellant compositions containing only AP and Al loaded (total solids 75 %) in NG plasticized PE‐PCP binder produce comparatively lower pressure exponent (η) values similar to AP‐Al filled HTPB based composite propellants. However, energetic propellants containing high level of nitramine (40–60 %) produce high pressure exponent (0.8–0.9) values in the same pressure range. Incorporation of fine particle size AP (ca. 6 μm) and change in its concentration in the propellant composition reduces η value marginally and influences the burning rate. However, such compositions have higher friction sensitivity.     

铝/有机氟化物复合物对含铝HTPB推进剂燃烧性能的影响

为研究有机氟化物(OF)对含铝HTPB固体推进剂燃烧性能的影响,采用球磨法制备了纳米和微米铝/有机氟化物复合物(nmAl/OF和μmAl/OF),将其作为复合添加剂替代微米铝粉加入HTPB推进剂中,并考察其对推进剂燃烧性能的影响。采用SEM、TEM、粒度分析等对nmAl/OF和μmAl/OF复合物及推进剂凝聚相燃烧产物进行了表征。结果表明,nmAl/OF和μmAl/OF复合物有不同的结合状态;添加OF、nmAl/OF和μmAl/OF后,推进剂的爆热值下降约2%;添加nmAl/OF的推进剂配方燃速最低,在3MPa时仅为6.28mm/s,添加OF和μmAl/OF体系的推进剂燃速压强指数相比于原配方降低约20%;添加nmAl/OF的推进剂配方凝聚相燃烧产物粒度(D_(50))比原配方降低约47%。     

纳米镍粉对Al-CMDB和CL-20-CMDB推进剂燃烧性能的影响

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。     

有机铋铜复盐对DNTF/HMX-CMDB推进剂燃烧性能的影响

研究了有机铋铜复盐(Gal-BiCu)与炭黑、不同芳香族铜盐(Cu1和Cu2)及金属燃烧功能助剂(NB)复配对DNTF/HMX-CMDB推进剂燃烧性能的影响。分析了Gal-BiCu与其他催化剂复配后影响DNTF/HMX-CMDB推进剂燃烧行为的原因。结果表明,Gal-BiCu能有效调节DNTF/HMX-CMDB推进剂的燃烧性能,提高推进剂燃速,显著降低压强指数;当Gal-BiCu与炭黑、Cu1、NB复合时,催化性能更佳;NB质量分数为0.5%时,推进剂在8~20MPa较宽区间内出现平台燃烧,压强指数n≤0.2;8~15MPa区间内压强指数降至0.11。     

含FOX-7发射药的燃烧性能

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。     

Combustion Behavior and Thermochemical Properties of RDX-Based Solid Propellants

The combustion behavior and thermochemical properties of two types of RDX-based composite propellants, XM39 and M43, are studied and compared in order to investigate the effect introduced by an energetic ingredient in the M43 propellant formulation. Due to the enhanced rate of heat release on the burning surface caused by the energetic material of M43 propellants, the burning rate of M43 propellants is found to be higher than that of XM39 propellants. The presence of the energetic material in the M43 propellant formulation also increases the burning surface temperature and thermal diffusivity of M43 propellants; it does not, however, introduce any observed changes in the flame structure and the heat feedback from the gas phase to the condensed phase. Based upon SEM pictures, burning-surface structures of the recovered XM39 and M43 propellant samples are found to be significantly different, indicating the strong effect of the energetic material on the surface reaction. A set of important thermochemical properties of XM39 and M43 propellants is deduced from the experimental data.     

Combustion Characteristics of a Novel Grain‐Binding High Burning Rate Propellant

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.     

Energetic Solid Fuels for Ducted Rockets (II)

The combustion characteristics of variable-flow ducted rockets were evaluated in order to obtain optimum design parameters of the gas generators. The energetic solid fuels used for the gas generators were glycidyl azide polymer (GAP) with burning rate catalysts. The burning rate of GAP based energetic fuels was much higher than that of composite and double-base based fuel-rich propellants. The pressure exponent of the burning rate was high enough to obtain a wide range of variable-flow rat. Two types of combustion test were conducted: a semi-free jet and a direct connect flow. The pressure-time response in the primary combustor obtained by the use of a throttable nozzle was evaluated.     

含N,N-二硝基哌嗪无烟改性双基推进剂的燃烧性能

以CMDB推进剂为基础,用N,N-二硝基哌嗪(DNP)替代推进剂中的RDX,研究了DNP含量、燃烧稳定剂(CaCO3、TiO2、MgO及Al2O3)、燃烧催化剂(铅盐、铅盐/铜盐、铅盐/铜盐/炭黑)对DNP-CMDB推进剂燃烧性能的影响。结果表明,DNP可明显降低无烟CMDB推进剂的燃速,当DNP完全替代RDX时,在18MPa压强下推进剂的燃速降低约68%;铅盐/铜盐/炭黑燃烧催化剂复配体系能够有效降低DNP-CMDB推进剂的燃速压强指数,使其出现平台燃烧效应。