催化剂对浇铸RDX-CMDB推进剂燃烧性能影响的研究

针对浇铸中能无烟ＲＤＸ－ＣＭＤＢ推进剂配方，进行了催化剂对燃烧性能影响的研究。对几种不同催化剂进行研究之后，选择了Ｃｔ－３催化剂。研究结果表明，在推进剂中加入适量的Ｃｔ－３，在１５ＭＰａ压力下，推进剂的燃速由基础配方的１９．６０ｍｍ／ｓ提高到２６￣２７ｍｍ／ｓ，１３￣２０ＭＰａ下压力指数０．９以上降低到０．２左右。     

NGu对含RDX硝胺发射药燃烧性能的影响

为从微观的角度研究NGu对含RDX的硝胺发射药燃速压力指数改变的影响,采用改进的小型点火燃烧模拟装置,在35MPa左右对几种发射药进行低压中止燃烧实验.通过SEM电镜观察发射药在低压下燃烧的表面状况.结果表明,在硝胺发射药的燃烧过程中,NGu在燃烧表面形成较厚的熔融层,抑制了RDX的爆燃;RDX的爆燃与燃烧表面熔融层之间的"均衡状态"影响发射药燃速压力指数的变化,当RDX与NGu质量比小于1时,燃速压力指数明显降低;当RDX和NGu同时存在时,发射药的燃烧表面有针状晶体生成.     

Multiscale Simulation on the Influence of Dimethyl Hydantoin on Mechanical Properties of GAP/RDX Propellants

The influence of dimethyl hydantoin (DMH) on the mechanical properties of GAP/RDX propellant was studied by molecular dynamics (MD) and dissipative particle dynamics (DPD) simulation. The results showed that the binding energies (E_binding) between GAP and different surfaces of RDX were in the order of (010)>(001)>(100). Compared to GAP/RDX, GAP grafted with DMH (GAP‐DMH) exhibits higher binding energies with RDX, and the sequence of E_binding turns to (001)>(010)>(100). Radial distribution simulations demonstrated that GAP‐DMH is more close to the surfaces of RDX, increasing the van der Waals energies between GAP‐DMH and RDX. The stress and strain of GAP‐DMH/RDX excel those of GAP/RDX. DPD simulations showed that GAP‐DMH was able to restrain the agglomeration of RDX, to improve the dispersibility and to enlarge the contact surface with RDX, which also increased the mechanical properties of GAP/RDX propellant.     

Combustion Effects of Nitrofulleropyrrolidine on RDX‐CMDB Propellants

The effect of N‐methyl‐2‐(3‐nitrophenyl)pyrrolidino[3′,4′:1,2]fullerene (mNPF) on the decomposition characteristics of hexogen (RDX) was investigated using differential scanning calorimetry (DSC). The results show that mNPF can accelerate the decomposition of RDX, the peak temperature (T_p) of the exothermal decomposition is reduced by 6.4 K, and the corresponding apparent activation energy (E_a) is decreased by 8.7 kJ mol⁻¹. N‐methyl‐2‐(3‐nitrophenyl)pyrrolidino[3′,4′:1,2]fullerene (mNPF), carbon black (CB), and C₆₀ were used as combustion catalysts to improve the combustion performance of a composite modified double‐base propellant containing RDX (RDX‐CMDB). The burning rate experimental results show that mNPF has a stronger catalytic effect than C₆₀ and CB. The magnitude of the effect of the three carbon substances on the enhancement of the burning rate is as follows: mNPF>C₆₀>CB. The catalytic effects of different contents of mNPF on the burning rates of RDX‐CMDB propellants were also studied, and the results show that the burning rates of RDX‐CMDB propellants are improved with increasing mNPF content. The plateau burning rate of a RDX‐CMDB propellant can be increased to 19.6 mm s⁻¹ when 1.0 % mNPF is added, and the corresponding plateau combustion region occurs at 8–22 MPa.     

固体推进剂燃烧波结构研究

设计了一套分析燃烧波结构的数值计算方法,可以利用热偶数据有效地分析均质推进剂固相反应的细节,为了解固体推进剂机理提拱了一种重要的手段;提出了均质推进剂也没有明显的固气界面的观点,因而也无表面温度可言;设计了固相反应热计算模型,提出了固相反应机理的观点,并指出压力不同固相反应机理基本相同,但固相放热程度不同;提出Π型热偶不宜测量非均质推进剂燃烧波结构的观点。     

A Novel Class of Nitrogen‐rich Explosives Containing High Oxygen Balance to Use as High Performance Oxidizers in Solid Propellants

In this study, density functional theory (DFT) calculations and the best available reliable predictive methods are used to assess performance, thermodynamics, physical and sensitivity of several high nitrogen content energetic tetrazole derivatives. Detonation pressure and velocity of these compounds are greater than 470 GPa and 10.2 km/s, respectively. Furthermore, suitable methods are used to study the condensed phase heat of formation, Gibbs free energy of formation, heat of sublimation, heat of combustion, melting point, enthalpy of fusion, entropy of fusion, specific impulse, Gurney velocity, strength, deflagration temperature, impact sensitivity and shock sensitivity of the novel compounds. The predicted results of the new compounds are compared with the calculated and experimental values of N,N‐bis(1H‐tetrazol‐5‐yl)amine (HTBA), dihydroxylammonium 5,5′‐bistetrazole‐1,1′‐diolate (TKX‐50) and 1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine (HMX) as high performance energetic compounds.     

硝化棉球形药粒度级配对推进剂燃烧性能的影响初探

通过对硝化棉球形药进行粒度级配,发现以某种级配方式进行粒度级配后制成推进剂可提高低压段（７～１５ＭＰａ）推进剂的燃速,从而有利于降低ＲＤＸ－ＣＭＤＢ推进剂的燃速压强指数。     

Influence of an Electric Field on the Burning Behavior of Solid Fuels and Propellants

An experimental study on the effects of an applied external electric field on the combustion behavior of solid fuels and solid propellants has been conducted. In an opposed flow burning configuration, application of an electric field was shown to extinguish a paraffin fuel and gaseous oxygen flame over a broad range of operating conditions. When subjected to the electric field, burning paraffin fuel strands were found to extinguish at various axial locations relative to the exit of the oxidizer gas jet. Extinguishment location was found to be a function of field strength as well as electrode surface area, while changes in polarity did not significantly alter the results. In addition, the combustion behaviors of two composite solid rocket propellants were studied while subjected to an external electric field. Both propellants were based on HTPB/AP combinations, with one propellant containing aluminum and the other being non‐aluminized. Application of an electric field to the composite solid rocket propellant strands demonstrated decreases in propellant burning rate under all operating conditions for both propellants including changes in polarity. The flame structure of the aluminized propellant was examined closely as the luminosity, flame length, and flame width varied significantly with field strength and burning location of the strand relative to the electrodes.     

RDX对含硼富燃料推进剂一次燃烧产物组分影响的计算研究

为了研究黑索今(RDX)对含硼富燃料推进剂一次燃烧产物组分的影响,用吉布斯最小自由能法计算了5种推进剂配方的一次燃烧产物组分,并通过测试燃烧产物中的总硼含量对热力学计算结果进行了验证。结果表明,采用最小自由能法计算含硼富燃料推进剂的一次燃烧产物组分,其结果准确、可靠;当含硼富燃料推进剂中RDX含量增加时,一次燃烧产物中B_4C和B_2O_3含量减少、C和BN含量增加,且一次燃烧温度也升高;提高一次燃烧压强可提高硼的氧化率、降低B_4C的生成量,有效提高一次燃烧温度,因此提高一次燃烧压强有助于提高含硼富燃料推进剂的二次燃烧效率。     

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.     

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.     

GAP对高能硝胺发射药力学性能及燃烧性能的影响

为改进高能硝胺发射药的力学性能,制备了含缩水甘油叠氮聚醚(GAP)的单孔管状硝胺发射药,用材料试验机测试其冲击和压缩性能,通过扫描电镜观察其内部形貌,用密闭爆发器分析了其燃烧性能。结果表明,GAP可改善高能硝胺发射药的力学性能,加入质量分数1.5%GAP时,高能硝胺发射药的低温抗冲强度由基础配方的4.51kJ/m2提高到5.58kJ/m2,GAP的加入使固体填料与黏结剂体系界面间的黏接强度提高,脱湿现象减少;随着GAP含量的增加,管状发射药的压强指数(n)相比基础配方增加,爆温(Tv)及火药力(f)逐渐降低,GAP质量分数为3.5%时,与基础配方相比,f、Tv分别降低1.41%、3.69%,n增加0.51%。     

RDX表面能及其分量的测定

采用Washburn薄层毛细渗透技术测定了RDX粉体的接触角和表面能及其色散、极化、电子受供体分量.选用非极性的二碘甲烷和1-溴萘作为测定RDX表面能色散分量的探针液体,极性的乙二醇和甲酰胺作为测定RDX表面能极性分量和酸、碱分量的探针液体.通过测定不同探针液体的渗透曲线,发现基于不同探针液体分子的接触角获得的RDX粉体的表面能成分彼此一致,RDX的总表面能(40.20 mJ · m-2)与理论计算结果(40.60 mJ · m-2)基本一致.测得的色散分量为23.71 mJ · m-2,极性分量为16.49 mJ · m-2,电子受体分量为1.149 mJ · m-2,电子供体分量为51.87 mJ · m-2.结果表明,在RDX的表面能中,色散分量占主要部分,而且在极性分量中电子供体碱性分量明显大于电子受体酸性分量.     

叠氮推进剂的感度和能量特性研究

对叠氮推进剂的感度和能量特性进行了理论计算,得到了采用硝化甘油/低感度硝酸酯混合体系来降低冲击感度和摩擦感度的有效方法,以及高能量叠氮缩水甘油醚(GAP)推进剂各主要组分含量。增塑剂为硝化甘油/丁三醇三硝酸酯(NG/BTTN),增塑比为2.0,Al粉、高氯酸铵(AP)和奥克托今(HMX)质量分数分别为18%、30%和22%。     

内弹道稳定剂对中高燃速RDX-CMDB推进剂燃烧性能的影响

以一种中高燃速改性双基推进剂配方为基础配方,添加不同粒度的Al_2O_3及不同品种的内弹道稳定剂,研究了6~20MPa下推进剂燃速和燃速压强指数的变化规律,并对其燃烧机理进行了分析。结果表明,添加Al_2O_3后推进剂的燃速降低,且随着压强的升高,燃速降低的幅度减小;不同品种的内弹道稳定剂对燃速及燃速压强指数降低和提高的幅度不同,TiO2提高了推进剂高压段的燃速,MgO几乎不影响推进剂燃速,而Al_2O_3、ZrO_2均降低了推进剂的燃速。添加不同粒度的Al_2O_3后,均使燃烧表面的催化剂含量(浓度)降低,改变了催化剂的催化效率,从而导致添加芳香铅A催化剂的推进剂中Al_2O_3粒径分别为10μm和2.5μm时,燃速相应降低0.25mm/s和1.25mm/s。不同品种的内弹道稳定剂对燃烧表面催化剂含量、分散均匀性、催化活性的影响不同,TiO_2、MgO的活性高于Al_2O_3和ZrO_2,从而表现出添加TiO_2、MgO的推进剂燃速高于添加Al_2O_3、ZrO_2的推进剂。     

Study on the Synthesis and Interfacial Interaction Performance of Novel Dodecylamine‐Based Bonding Agents Used for Composite Solid Propellants

An effective pathway was explored to design and select proper bonding agents that could effectively improve the interfacial interactions between bonding agents and solid particles, with three novel synthesized alkyl bonding agents, dodecylamine‐N,N‐di‐2‐hydroxypropyl‐acetate (DIHPA), dodecylamine‐N,N‐di‐2‐hydroxypropyl‐hydroxy‐acetate (DIHPHA) and dodecylamine‐N,N‐di‐2‐hydroxypropyl‐cyano‐acetate (DIHPCA), as examples. Molecular dynamics simulation was applied to compare unit bond energies of these bonding agents with the [110] crystal face of ammonium perchlorate (AP) and the [120] crystal face of hexogen (RDX). The infrared test was used to characterize the interfacial interactions of these bonding agents with AP or RDX. XPS test was applied to calculate the adhesion percentage of the bonding agents on the surface of precoated AP or RDX particles. All of the above results indicated that these three bonding agents have strong interfacial interactions with AP or RDX in the order of DIHPCA>DIHPHA>DIHPA. The prepared three bonding agents were used in HTPB/AP/RDX/Al propellants, and their effects on tensile strength (σ), elongation under maximum tensile strength (ε_m), elongation at breaking point of the propellant (ε_b) and adhesion index (Φ) of the propellant were studied. The results show that the bonding agents improve the mechanical properties of the propellant in the order of DIHPCA>DIHPHA>DIHPA. The methods found from theoretical design, materials synthesis, and mechanistics studies up to practical application show effective guiding significance for choosing the proper bonding agent and improving the interfacial interactions between the solid particles and binder matrix.     

Response of TEGDN Propellants to Plasma Ignition with the Same Magnitude of Ignition Energy as Conventional Igniters in an Interrupted Burning Simulator

In order to consider the potential influence of ignition energy factors on the response of double base propellants plasticized with triethyleneglycol dinitrate (TEGDN propellants), the influence of different ignition methods at the same magnitude of ignition energy level on the response of TEGDN propellants was investigated in an interrupted burning simulator. Compared to conventional ignition methods, plasma ignition exhibits a significantly shorter ignition delay and lower ignition energy. There are stronger ablation and impact interactions of plasma flow with the surface of propellants. For TEGDN propellants coated with titanium dioxide, a greater amount of melted white layer is deposited on the surface of propellants. The content of copper on the surface of recovered plasma‐ignited samples observed by X‐ray Fluorescence (XRF) spectroscopy is much larger than that on the surface of recovered conventionally ignited samples, indicating more deposition of copper wire discharge on the surface of the samples. The test results will benefit the design of plasma generator and electrical parameters of pulse power to satisfy certain propellant compositions.     

Semi‐quantitative Study on the Inclusion in Cooling Crystallization of RDX Using Various Solvents

Inclusion entrapped inside the crystals prepared in the cooling crystallization of cyclotrimethylenetrinitramine (RDX) from solution was studied. Effect of supersaturation on the inclusion formation was also studied in crystallization using solvents. Solvents such as acetone (AC), cyclohexanone (CH), dimethylsulfoxide (DMSO), N‐methylpyrrolidone (NMP), γ‐butyrolactone (BL), and their mixtures with water were investigated. The quantitative amount of inclusions entrapped in the RDX crystallized in various solvents was related to the supersaturation. The inclusion fraction in the crystals was affected by the supersaturation and the solvent. In order to decrease the inclusion fraction, in the low supersaturation, AC and CH were recommended, while in high supersaturation, NMP and DMSO were desirable. Eventually the solvent effect on the inclusion was grasped by considering the supersaturation effect.     

HMX as an Impurity in RDX Particles: Effect on the Shock Sensitivity of Formulations Based on RDX

Two main kinds of heterogeneities are pointed out in RDX particles in using optical microscopy with matching refractive index and scanning electron microscopy. These are HMX impurities and solvent inclusions.