报废固体推进剂的降感技术

为了清理火箭发动机内报废的推进剂,采用萃取法对含能组分进行降感处理,研究了萃取剂质量浓度对萃取效果及含能组分溶解度的影响,最后对萃取液中含能组分采用蒸馏方法进行回收。结果表明,从报废复合固体推进剂中萃取出AP后,推进剂的撞击感度、摩擦感度降低60%,推进剂本体发生裂解、失强,有利于发动机内报废推进剂的安全销毁,优选出最优萃取剂为T J-3,AP组分的回收利用使推进剂中大量氧化剂得以回收,有利于环保。     

Energetic Opportunities of Solid Composite Propellants Containing Some Hypothetic Furazano-[3,4-d]-pyridazine-based Derivatives

Six furazano-[3,4-d]-pyridazine-based derivatives as main compounds in solid composite propellants have been investigated. It was shown that the use of some furazano-[3,4-d]-pyridazine-based derivatives as main compounds in solid composite propellants can considerably increase ballistic parameters compared with HMX if the compounds under consideration contain difluoramine groups. And the use of the compounds under consideration may be successful only in the presence of an active binder and 10%-30% of AP or ADN as additional oxidizers.     

Burning Rate Evaluation of Composite Solid Propellants. A simplified approach

One of the principal parameters associated with a solid propellant is its linear burning rate. Many attempts have been made in the past to determine theoretically the burning rates of solid propellants by the use of appropriate combustion models. The object of the present paper is to propose a simplified theory of burning rate suitable for composite solid propellants. While the paper follows basically the scheme suggested for this purpose by Beckstead, Derr and Price using multiple flamelets, certain simplifying assumptions have been introduced with a view to make the model easier to operate. An attempt is also made in the paper to extend it to the case of aluminized solid propellants as well on the basis of a specific hypothesis regarding the role of aluminium. The relevant transcendental equations of combustion were solved on a digital computer. The burning rates and related characteristics were evaluated by this technique for two specific ammonium perchlorate-based solid propellants, one aluminized and the other non-aluminized, and the results obtained agree reasonably with the reported experimental trends.     

Energetic Abilities of Solid Composite Propellants Based on 3,4,5-Trinitropyrazole and Ammonium Dinitramide

The investigation aims at the expansion of the basis of formulations of solid composite propellants by introducing new compositions with lower sensitivity to mechanic impact and improved thermal stability.The formulations based on trinitropyrazole(TNP)contains a binder(a hydrocarbon or active one),aluminum and inorganic oxidizer ADN.The results show that a binary formulation TNP+active binder(18%-19%)(volume fraction)with no metal is well designed which would achieve high specific impulse(at Pc∶Pa=40∶1)of 248s,high density of 1.80g/cm3 and combustion temperature Tcabout 3 450K.In terms of energy,metal-free compositions with TNP lose a bit to those with HMX,only if HMX fraction in formulation is higher than 45%-50%.     

A Stochastic Pocket Model for Aluminum Agglomeration in Solid Propellants

A new model is derived to estimate the size and fraction of aluminum agglomerates at the surface of a burning propellant. The basic idea relies on well‐known pocket models in which aluminum is supposed to aggregate and melt within pocket volumes imposed by largest oxidizer particles. The proposed model essentially relaxes simple assumptions of previous pocket models on propellant structure by accounting for an actual microstructure obtained by packing. The use of statistical tools from stochastic geometry enables to determine a statistical pocket size volume and hence agglomerate diameter and agglomeration fraction. Application to several AP/Al propellants gives encouraging results that are shown to be superior to former pocket models.     

Estimation of Aluminium in HTPB Based Composite Solid Propellants by hydrogen evolution method

Hydrogen gas evolution method has been applied to determine the percentage of aluminium (Al) in hydroxy-terminated polybutadiene (HTPB) based composite solid propellants premix/pastes. The determination is not effected by the presence of Zn, Fe, Cu or small amounts of silicon but magnesium has been found to interfere in the analysis. The results are obtained with remarkable accuracy and reproducibility.     

Determination of Primary Amine Content in Bonding Agent Used in Composite Solid Propellants

The primary amine content in tetraethylenepentamine (TEPA) and TEPAN, a bonding agent used in composite solid propellants, was determined by near infrared (NIR) spectroscopy and the results were compared to those obtained by potentiometry. The band at 4930 cm⁻¹, which showed to be influenced only by primary amine groups, was chosen as the analytical band. The calibration curves based on isopropylamine (IPA) and isopropylamine/dibutylamine (IPA/DBA) mixtures proved to be suitable for determining the NH₂ content of TEPA or of samples containing mixtures of NH and NH₂ groups. It was found that TEPA contains 26.4 % of NH₂ and 25.7 % of NH, and that TEPAN contains 0.5 % of NH₂, confirming the low content of primary amine of this bonding agent. The lowest amine equivalent of TEPA is 31.1±0.3 g/eq, as determined by potentiometry, was found because this technique measures the total hydrogen content, including primary and secondary amines. The literature value of 62.6 g/eq for TEPA ACROS obtained by potentiometry in a non aqueous medium and related to the first inflection of the primary amine, validates the value obtained by NIR in this work for a similar type of amine. The equivalent weight obtained by NIR spectroscopy (62.7 g/eq) allowed to calculate the molar mass of TEPA of 195.6 g mol⁻¹, which is close to the typical value of 200 g mol⁻¹.     

固体火箭推进剂快速洗井器设计原理

根据固体火箭推进剂释放能量高、燃气量大的特点 ,设计出一种新型、高效、快速水井洗井器 ,并从洗井原理、洗井效率、固体火箭推进剂性能等方面对其可行性进行了详细分析和经济评估。采用该洗井器可减少洗井设备、简化现场操作、减少辅助工作量、缩短施工时间 ,提高洗井综合效益。该洗井器在煤田、油田钻井工艺方面也有一定的使用价值。     

相稳定硝酸铵表面改性及在推进剂中的应用

为增加相稳定硝酸铵(PSAN)表面与黏合剂体系的界面粘接,选择能与PSAN发生氢键作用的KH792硅烷偶联剂包覆PSAN,并用扫描电镜、X射线光电子能谱等表征改性效果.结果表明,改性PSAN表面包覆形貌变化很大,包覆膜较完整,与NG和DEGDN的接触角分别下降56%和63%, 吸湿性下降约15%.研究了改性PSAN对BAMO-THF/PSAN推进剂工艺和力学性能的影响,发现抗拉强度提高约65%,脱湿比下降约20%,工艺性能也有所改善.     

Performance Optimization of Metallized Solid Propellants

The object of this paper is to present a method for determining, for a typical metallized solid propellant system, the optimum combination of the reactants so as to arrive at a composition which can yield the maximum specific impulse. A direct approach of this kind for optimization of propellants does not appear to have been attempted so far. The optimization is sought to be carried out by expressing the theoretical specific impulse of the propellant under frozen flow conditions as a function of the different variables involved and maximizing the same, subject to the usual linear and non-linear constraints of mass balance, mass action, pressure balance, energy conservation and entropy conservation. The gradient projection technique due to Rosen has been adopted for carrying out this optimization. The method was programmed on the IBM 360/Model 44 Computer in FORTRAN IV language and the results of the computations for a typical metallized solid propellant system are presented in the paper. The investigations reveal that the gradient projection technique can be a useful computational device for determining the optimum composition and the corresponding performance parameters of propellant systems containing a large number of reactants and products with or without condensed phases.     

Determining the Shelflife of Solid Propellants

While stored at various temperatures between 65°C and 90°C, several double base propellants with the Same composition differing only in the stabilizer, were aged artificially to the onset of autocatalytic decomposition. A correlation between the temperature and the storage period has been established for the results obtained at the respective temperatures. Moreover, studies were carried out on the chromatographic analysis of stabilizer reaction products of the type occurring in particular in propellants with diphenylamine, 2-nitrodiphenylamine, acardite I, acardite 11, and ethylcentralite as a result of storage at elevated temperatures due to reactions with the decomposition products of nitric acid esters. It has been shown that continuing aging of the propellant gives rise to stabilizer reaction products which are quite characteristic of the respective aging condition. These reaction products may be used as a criterion for different stages of aging within the shelflife of solid propellants.     

Advances in PolyNIMMO Composite Gun Propellants

Efforts to develop very high energy tank gun propellants based on traditional double or triple base propellant technology have often failed to deliver the low vulnerability required in Insensitive Munitions. One strand of the United Kingdom's formulation research programme has focused on the alternative technology of composite propellants. A range of composite LOVA propellants based on the energetic binder polyNIMMO in combination with various fillers and plasticisers has been examined. Assessment of their vulnerability in the UK Small Scale Shaped Charge Attack test has shown correlations linked both to the choice of filler and to the volume percentage of filler present. Through a fuller understanding of the factors involved it has been shown to be possible to formulate propellants with an impetus of up to 1300 kJ/kg which still show a low response to shaped charge attack. This and previous studies have also identified the effect of grain geometry and web size on vulnerability. Since these parameters are dictated by ballistic considerations a thorough understanding of the ballistic behaviour of this new class of materials is particularly important. Vulnerability and ballistic considerations are presented and discussed.     

Thermal Decomposition of RDX Composite Propellants

The thermal decomposition characteristics of RDX, binders, and RDX composite propellants were studied using thermal analytical techniques. Three kinds of binders were tested to elucidate the role of binder on the burning rate of the propellants. There were no apparent correlations between the thermal decomposition rates of binders and the burning rates of propellants, whereas there was a correlation between the decomposition temperature and the burning rate of the propellants. It is found that the major factor which controls the burning rate is the initial thermal-decomposition stage of the binders. Thus, the burning rate of nitramine composite propellants appeared to be largely dependent on the physical and chemical properties of binder.     

Burning of Nano-Aluminized Composite Rocket Propellants

Several aluminum nanopowders were examined and compared with the final goal to evaluate their application in solid rocket propulsion. A detailed investigation of pre-burning properties by the Brunauer-Emmet-Teller method, electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy was carried out. Ballistic properties and the combustion mechanism of several aluminized propellant formulations were investigated. In particular, aggregation and agglomeration of metal particles at and near the burning surface were analyzed by high-speed high-resolution color digital video recordings. All tested nano-powders are of Russian production; their physical characterization was carried out at the Istituto Donegani (Novara, Italy); ballistic studies were performed at the Solid Propulsion Laboratory (Milano, Italy) using laboratory and, for comparison, industrial composite propellants based on ammonium perchlorate as an oxidizer. Results obtained under a fair variety of operating conditions typical of rocket propulsion indicate, for increasing nano-Al mass fraction or decreasing nano-Al size, larger steady burning rates with essentially the same pressure sensitivity. While aggregation and agglomeration phenomena still occur, their significance may be reduced by using nano-Al instead of micro-Al. __________ Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 6, pp. 80–94, November–December, 2005.     

Nitramine Solid Rocket Propellants with Reduced Signature

Solid rocket propellants containing nitramine are considerably superior to doublebase propellants, both as regards their performance and mechanical properties. The pressure exponent of non-modified nitramine propellants is n ≥ 0.9. The possibility of changing the burning rate or, respectively, the pressure exponent has, however, only been realisable to a restricted extent up till now in propellants with an increased nitramine content. In the following propellant system containing nitramine, the effects of ammonium perchlorate on burning behaviour are studied:

• ammonium perchlorate (AP)
• hexogen (RDX)
• nitroglycerin (NG), or trimethylolethane trinitrate (TMETN)
• polyurethane binder (PU)

AP concentrations already as great as 10% produce considerable changes in the burning behaviour of the propellants described above. It is possible to reduce the pressure exponent by the addition of ammonium perchlorate from n ≥ 0.9 to n ≤ 0.65. The burning rates may also be influenced with AP concentrations ≤ 20% and by varying the AP particle size by the factor of 2. All the propellants prepared were easily castable and showed exceptionally good viscoelastic properties (strain at break ε_R > 200%) in the temperature range between −40 °C to + 50 °C. The thermal chemical stability is not influenced negatively in any way by the combination of nitric acid esters and ammonium perchlorate.     

新技术在固体推进剂中的应用

简要介绍了其他领域的一些新技术在固体推进剂制备过程中的应用前景,这些新技术主要应用于原材料处理、推进剂制备、推进剂性能模拟仿真与表征等方面.新技术的应用有利于提高行业整体技术水平,为开发高性能的固体推进剂提供技术支撑.     

固体推进剂危险源的定量评估方法

在火炸药、弹药企业重大事故隐患定量评估方法(BZA-1)的基础上,依据固体推进剂在不同生产工艺过程中各项感度值不同的特点,提出了固体推进剂危险源的定量评估法.利用综合感度值代替传统感度均值,采用无量纲化处理、等级参数处理等方法可以更加真实地反映固体推进剂在不同生产工艺过程中的综合危险度.     

Some Aspects of Time-Temperature Superposition Principle Applied for Predicting Mechanical Properties of Solid Rocket Propellants

Optimal test conditions for determining the mechanical properties of rocket propellants (temperatures and strain rates ranges) for delivering master curves were investigated. From master curves it is possible to predict the modulus, maximum stress and maximum strain in vide intervals of temperatures and strain rates, and especially the existing conditions during the ignition of rocket motor. Using the control experiments, at high strain rates, the good agreement between the results obtained from master curves was shown. The obtained results for composite rocket propellants (with carboxy-terminated polybutadiene, CTPB, as a binder), point out the drastic decreasing of maximum strain at high strain rates and low temperatures.     

Effect of Pre‐strain Aging on the Damage Properties of Composite Solid Propellants based on a Constitutive Equation

Accelerated aging tests under pre‐strain were conducted on HTPB‐based composite solid propellant with the goal of investigating the effect of pre‐strain aging on its damage properties. A statistical damage constitutive model based on continuum damage theory and statistical strength theory was established. The aging damage coefficient, making aging process of propellant equivalent to a form of damage, was introduced to correct the damage variable. Experimental results show that theoretical model has good agreement with experimental results and can accurately describe the mechanical behavior of propellant during pre‐strain aging. Further analysis indicated that the damage effects caused by pre‐strain can be identified from the equation of the aging damage coefficient. Aging time influences both tensile strength and shape characteristics of the stress‐strain curve of propellant in the damage stage, while pre‐strain only decreased the tensile strength. The strain damage threshold value decreased linearly over the aging period and with increasing pre‐strain level during the aging process.     

Short-Action Solid Rocket Motors with Double-Base Propellants

Due to various reasons double-base solid propellants have been replaced increasingly by composite propellants in the past years. However, the ALARM rocket motor of the Bayern-Chemie GmbH is one exception. Applications ideal for double-base propellants are short-action rocket motors with burning times ranging from some milliseconds up to approximately 200 ms. Various rocket motors of this type were developed at Dynamit Nobel GmbH for different kinds of application. Based on multiple-tube grains improved designs and manufacturing methods have been developed to enable cost-effective solutions even at low production rates. This includes also simplified test procedures to supervise the propellant fabrication.