关于交联改性双基推进剂力学性能的几个问题

引言为适应壳体粘结装药的大型固体火箭发动机对推进剂力学性能的要求,近几年来,改性双基推进剂已发展到新的阶段,出现了交联改性双基推进剂。美国已把这种新型推进剂—XLDB推进剂应用于三叉戟C—4导弹上。近几年来,我们也进行了这种新型推进剂的研制,根据弹性体交联改性双基推进剂应具备的结构条件和两种聚合物共混改性的原理,选择了聚酯—HDI预聚物作为硝化棉的交联剂,已初步研制出弹性体的交联改性双基推进剂。本文仅就交联改性双基推进剂力学性能研究中的几个问题叙述如下。     

关于交联改性双基推进剂力学性能的几个问题

为适应壳体粘结装药的大型固体火箭发动机对推进剂力学性能的要求,近几年来,改性双基推进剂已发展到新的阶段,出现了交联改性双基推进剂。美国已把这种新型推进剂—XLDB推进剂应用于三叉乾C—4导弹上。近几年来,我们也进行了这种新型推进剂的研制,根据弹性体交联改性双基推进剂应具备的结构条件和两种聚合物共混改性的原理,选择了聚酯—HDI预聚物作为硝化棉的交联剂,已初步研制出弹性体的交联改性双基推进剂。本文仅就交联改性双基推进剂力学性能研究中的几个问题叙述如下。     

近几年来国外固体火箭推进剂发展动向(一)

本文综合了国外1975年以来公开发表的文献中就固体推进系统的发展;高能固体推进剂的发展;均质双基推进剂的发展;改性双基推进剂的发展;复合固体推进剂的发展;高燃速固体推进剂的发展;无烟固体推进剂的发展;关于安定性、相容性和贮存性能的研究;包复层和粘结技术;分析测试技术;应用和基础理论研究等方面作了简要评述。     

含CL-20、DNTF和FOX-12的CMDB推进剂的热分解

用PDSC研究了添加CL-20（或DNTF或FOX-12）的改性双基推进剂的热分解行为.发现PDSC曲线中CL-20、DNTF推进剂有两个放热峰,第一个为双基黏结剂的分解峰,第二个为CL-20或DNTF的分解峰.FOX-12改性双基推进剂只有一个分解峰,表明FOX-12和双基黏结剂（NC、NG等组分）一起分解.     

高能固体推进剂用粘合剂的研究进展

较为系统的从双基推进剂、复合固体推进剂、改性双基推进剂和NEPE推进剂等方面综述了其所用粘合剂的种类及其研究发展概况。介绍了当今新型含能粘合剂的类别和发展状况,并根据目前推进剂的发展要求,指出其粘合剂的发展趋势是含能化的热塑性弹性体。     

基于一维气相稳态反应流的燃速预估软件研究

在一维气相稳态反应流模型的基础上,总结了适用于双基推进剂、改性双基推进剂、复合固体推进剂燃速预估的修正因子,拓宽了燃烧理论模型的适用范围.采用Visual C++和Microsoft Access为开发工具,完成了基于组分化学键结构参数的固体推进剂燃速预估软件(SPRS)编制.该软件基于Windows XP系统,界面友好,使用方便,具有数据更新和信息查询功能.用户不仅能根据推进剂的化学组成(配方)和给定压强计算燃速、压力指数等参数,还可根据给定的燃速和压力指数等调整推进剂配方组成,对缩短固体推进剂研制周期和节约研制成本具有重要意义.     

改性双基推进剂的安定性和危险性

安定性和危险性是决定固体推进剂是否有使用价直的关键性能。因此特别引人注目。固体推进剂的安定性和危险性所包含的内容很多。其中最重要的是爆轰危险性和使用寿命。本文从现有国外资料报道出发,对改性双基推进剂(CMDB),特别是含奥托金(或黑索今)的改性双基推进剂(HMX-CMDB)的爆轰危险性和使用寿命进行探讨。同时与复合推进剂作些相对比较。     

改性双基推进剂的安定性和危险性

安定性和危险性是决定固体推进剂是否有使用价值的关键性能。因此特别引人注目。固体推进剂的安定性和危险性所包含的内容很多。其中最重要的是爆轰危险性和使用寿命。本文从现有国外资斟报道出发,对改性双基推进剂(CMDB),特别是含奥托金(或黑索今)的改性双基推进剂(HMX-CMDB)的爆轰危险性和使用寿命进行探讨。同时与复合推进剂作些相对比较。     

溶解度参数与改性双基推进剂的晶析问题

本文从理论上阐述了化合物的溶解度参数与改性双基推进剂晶析问题的关系。利用Small的基团克分子吸引常数及本文反算出的若干基团克分子吸引常数,计算了大量推进剂中常用化合物的溶解度参数值。并结合这些化合物在改性双基推进剂中使用时出现的晶析情况,提出了一个为防止晶析而选用推进剂组分的准则。利用此准则也可预估一个化合物在改性双基推进剂中是否会出现晶析现象。     

溶解度参数与改性双基推进剂的晶析问题

本文从理论上阐述了化合物的溶解度参数与改性双基推进剂晶析问题的关系。利用 Small 的基团克分子吸引常数及本文反算出的若干基团克分子吸引常数,计算了大量推进剂中常用化合物的溶解度参数值。并结合这些化合物在改性双基推进剂中使用时出现的晶析情况,提出了一个为防止晶析而选用推进剂组分的准则。利用此准则也可预估一个化合物在改性双基推进剂中是否会出现晶析现象。     

Rheology of HTPB Propellant: Development of generalized correlation and evaluation of pot life

Composite solid propellants based on hydroxy-terminated polybutadiene (HTPB) have become the workhorse propellants in the present-day solid rocket motors world-wide. Because of the high solid loading, the rheological behavior of such propellants is quite complex. The effect of solid loading, oxidizer particle size and aluminium content has been studied and reported. Similarly, the effect of temperature and mixer kinematics and mixing cycle time have also been studied and reported. In the present paper a generalized correlation has been developed for shear stress-shear rate based on the rheological parameters like yield stress, consistency index and pseudoplasticity index which are in turn functions of solid volume fraction, cure time, t, and temperature, and has a correlation coefficient of 0.94 with the experimental values. Also a commonly used term in propellant industries, pot life, has been defined and evaluated for the HTPB propellant system.     

Rheology of HTPB propellant. I. Effect of solid loading,oxidizer particle size,and aluminum content

Composite solid propellants based on hydroxyl-terminated polybutadiene (HTPB) have become the workhorse propellants in the present-day solid rocket motors. The other major ingredients of a composite propellant are the crystalline oxidizer and metallic fuel. As the solid loading of such propellants is as high as 86–90%, their rheological behavior is very complex. The propellant slurry needs to have reasonably low viscosity and a long pot life for better casting and, hence, for a defect-free rocket motor. The primary factors affecting the solid propellant viscosity are solid content, particle size, shape, and distribution. The present study concerns the variations of solid loading from 80 to 89% at constant aluminum cotent, variation of aluminium from 0 to 22% at constant solid loading, and the coarse-to-fine ratio of the oxidizer. The plots of yield stress, consistency index, pseudoplasticity index, and thixotropic index at different time intervals are drawn for all these parametric changes. Based on these rheological studies, the optimum ratio of oxidizer coarse-to-fine ratio, aluminum content, and level of solid loading have been determined.     

固体推进剂同向双螺杆元件混合性能模拟

首先设计了4种固体推进剂用螺杆元件,并进行了固体推进剂药浆的流变性能测试,通过使用Polyflow软件对4种螺杆元件的流场进行数值模拟。对各螺杆元件流场的剪切速率、加权平均剪切应力、平均回流系数、累积停留时间分布等表征螺杆元件混合性能以及流场特性的指标进行分析,对比4种螺杆元件的分散和分布混合性能,并建立了螺杆元件混合性能的评价体系。结果表明,KB元件和S型元件对药浆有较好的综合混合性能,有利于固体推进剂的混合。     

炭黑粒度对CMDB推进剂燃烧性能的影响

用燃速测试、扫描电子显微镜(SEM)和光电子能谱仪(EDS)研究了炭黑粒度对复合改性双基(CMDB)推进剂燃烧性能和熄火表面的影响.结果表明,将炭黑与铅、铜盐催化剂复配使用能够大幅度提高CMDB推进剂的燃速并降低压强指数,且炭黑粒度越小效果越显著,这可能与炭黑对铅、铜盐凝聚的阻滞作用有关.     

Reducing Agglomeration of Ammonium Perchlorate Using Activated Charcoal

Ammonium perchlorate is the most widely employed oxidizer for composite solid propellants. When exposed to atmosphere, it absorbs moisture and agglomerates. It is usually vacuum dried in order to avoid this agglomeration. When ammonium perchlorate that has been exposed to atmosphere for a certain period of time, is used in making a composite solid propellant, the burning rate is different because of the change in particle size distribution due to its agglomeration. This change in burning rate will change the thrust‐time profile from that of what it is designed for. As one goes to a finer ammonium perchlorate particle size this problem becomes more evident. Experimental studies aimed at reducing the agglomeration of ammonium perchlorate by coating it with activated charcoal. Ammonium perchlorate coated with 1 % activated charcoal showed almost no agglomeration, even when the particle size of ammonium perchlorate is approx. 1 μm. The burning rates also remained unchanged when ammonium perchlorate coated with 1 % activated charcoal was employed in propellant composition, after it has been exposed to the atmosphere for a period of 1 h.     

GAP高能推进剂工艺性能调节

分析了聚叠氮缩水甘油醚(GAP)高能推进剂工艺性能不佳的原因,提出了调节其工艺性能的技术途径,研究了氧化剂粒度级配、浇注温度、混合工艺、不同相对分子质量黏合剂组合使用、提高力学性能添加剂、固化催化剂和工艺助剂等对GAP高能推进剂工艺性能的影响,通过合理配置混合工艺、组合使用工艺助剂TE和力学性能添加剂TD,可有效改善GAP高能推进剂的工艺性能。     

New Propellant Component,Part I. Study of 4,6‐Dinitroamino‐1,3,5‐Triazine‐2(1 H)‐One (DNAM)

This paper reports a study of the synthesis and characterization of 4,6‐dinitroamino‐1,3,5‐triazine‐2(1 H)‐one (DNAM) carried out under the perspective of looking for new ingredients in propellant formulations. Emphasis is given to the characterization of DNAM. The following attributes were identified: low sensitivity to impact and friction, thermal stability over a wide temperature range, energetic nature, high density, and interesting particle size distribution. In Part 2 a preliminary evaluation of DNAM capabilities in a propellant formulation will be presented.     

Accumulation of nano-aluminium during combustion of composite solid propellant mixtures

Nano-aluminium particles are produced using the electric wire explosion process in an inert atmosphere at our institute. This paper reports the characterization of nanoaluminium particles in combination with other solid propellant ingredients for their thermal and combustion behaviour. High-heating-rate hot-stage microscopic experiments are performed with different mixtures of propellant ingredients. The effects of addition of nano-aluminium versus micron-sized aluminium in the middle lamina of sandwiches are analyzed for burning rates and by means of scanning electron microscope and transmission electron microscope micrographs of quench-collected aluminium agglomerates. Nano-aluminized sandwiches with thinner middle lamina show slightly higher burning rates than micron-sized aluminized ones. The quenched surface of nano-aluminized sandwiches shows relatively smaller aluminium agglomerates than with micron-sized aluminium. The resultant particle sizes of nano-aluminium agglomerates is in the range of 1–5 μm, which indicates a higher rate of agglomeration than with micro-aluminium, but these sizes are small relative to the agglomerates of the latter. This is also confirmed by quench-collected agglomerates of nano-aluminium emerging from the burning surface of a composite propellant.     

Burning Behavior of Composite Solid Propellant containing porous ammonium perchlorate

A pilot scale fluidized bed process was developed for preparing porous ammonium perchlorate (PAP) in various particle sizes. The oxidizer, ammonium perchlorate (AP), of composite solid propellant was partially replaced by PAP which was obtained by the fluidization process. The burning rate of propellants containing PAP was found to increase as compared with that of propellants without PAP. In the present study, the effects of percentage content and particle size of PAP incorporated in propellant compositions, on the burning rate were investigated. The results showed that the burning rate increases with increasing of PAP content and with decreasing of PAP particle size for trimodal oxidizer propellants.     

Al2O3在发动机燃烧室中尺寸分布的实验研究

采用压力可控式 T形燃烧室及实时脉冲微粒取样系统 ,结合微粒粒度分析技术 ,分析了在无铝双基推进剂中原始添加剂 Al2 O3在燃烧过程中随燃烧室压强变化的粒度及粒度分布的变化情况 ,结果发现 :燃气微粒呈单峰分布 ,燃烧室压强升高 ,趋于使推进剂燃烧产物微粒之间发生凝聚 ,但是燃气微粒与 Al2 O3原始粒径基本相符 ,未发生明显的凝聚现象