Combustion of HMX-CMDB Propellants (II)

The burning rate characteristics of HMX-CMDB propellants were examined as a function of HMX concentration. In the region of low HMX concentration, below about 50%, the burning rate decreases with increasing the HMX concentration. However, in the region of high HMX concentration, above about 50%, the burning rate increases with increasing the HMX concentration. When the measured results are extrapolated to the 100% HMX concentration, it is recognized that the burning rate approaches the burning rate of an HMX single crystal. The burning rate analysis indicates that the effect of the addition of HMX particles within double-base propellants on burning rate is determined by the reaction rates in the gas phase and in the condensed phase. The gas phase reaction rate in the fizz zone decreases monotonously as the HMX concentration increases. On the other hand, the heat of reaction at the burning surface increases as the HMX concentration increases. The experimental results indicate that the burning rate with low HMX concentration is mainly controlled by the gas phase reaction rate and the burning rate with high HMX concentration is mainly controlled by the condensed phase reaction rate.     

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。     

Combustion of Propellants with Ammonium Dinitramide

This paper reports a series of experiments involving ammonium dinitramide (ADN), a new energetic oxidizer of potential use in composite solid propellants. The experiments include (a) self‐deflagration of pressed pellets of ADN; (b) combustion of sandwiches with ADN laminae on both sides of a binder lamina that is either “pure” or filled with particulate oxidizer and other additives; and, (c) combustion of propellants with a bimodal oxidizer size distribution, wherein, combustion of coarse ADN and fine AP (ammonium perchlorate) and vice versa were used, in addition to mixtures of coarse ADN and AP, fine ADN and AP, and all‐ADN or all‐AP formulations.     

程序控制开裂棒状发射药的燃烧性能

应用密闭爆发器试验，对程序控制开裂棒状（ＰＳＳ）发射药的燃烧性能进行了研究。发现采用不同端封剂的ＰＳＳ发射药的燃烧性能有着明显的差异。研究结果表明，提高端封层的抗燃气冲击性能是研制ＰＳＳ发射药成功的关键之一。     

Experimental study of Double-Base Propellants Combustion Mechanisms

Experimental results about r_b(P) laws of double-base propellants are presented. The influence of many parameters (calorific potential, fabrication process, additives) is studied. With surface structure examination, we show that the first super-rate (P < 100 bar) is in relation with the presence of a carbon layer which increases chemical reactions. The second super-rate (200 bar < P < 400 bar), more physical than chemical, is in relation with the presence of globules (probably PbO) which increase the thermal conductivity near the propellant surface.     

Oscillating Combustion of Gun Propellants in the Closed Vessel. I. preliminary investigation

The oscillating combustion, which takes place in the closed vessel when certain colloidal gun propellants are fired has been investigated. The amplitude of the oscillation depended on the geometry and flame temperature of the propellant. For propellants having the same composition but different geometry, the amplitude of the oscillation varied inversely with the maximum pressure in the vessel. This was tentatively ascribed to vortex formation during combustion.     

Combustion Wave Structure of AP Composite Propellants

The combustion mechanism of ammonium perchlorate (AP) composite propellants were studied. The oxidizer-rich propellants tested were made with excess concentrations of AP particles. The pressure deflagration limit of propellant decreases with increasing the concentration of binder. The combustion wave consists of two reaction regions I and II: the region I is the zone of AP monopropellant flame and the region II is the zone of diffusion flame. The heat flux feedback from the gas phase to the burning surface increases as pressure increases, and the heat flux is responsible for the burning rate characteristics.     

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。     

钝感发射药燃烧稳定性研究

对3个主流药型的发射药,即单基药、双基药和硝胺药经两种钝感方法处理后的燃烧稳定性进行了分析和评价,总结了不同钝感方法对发射药燃烧稳定性的影响规律。结果表明,两种钝感处理方法使火药燃烧呈现明显的燃速渐增性,但同时也增大了火药燃烧的不稳定性,并使火药的燃速压力指数上升。     

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.     

适应高压强的HTPB推进剂的燃烧性能

为改善高压强下HTPB推进剂的燃烧特性,研究了碳酸盐复合调节剂、二茂铁衍生物G、高氮化合物M、纳米铝粉和纳米金属氧化物对HTPB推进剂燃烧性能的影响.结果表明,碳酸盐复合调节剂能够降低推进剂的燃速和压强指数;二茂铁衍生物G能够提高推进剂的燃速,同时将推进剂在8.60～17.12MPa下的压强指数降至0.27;高氮化合物也可降低推进剂的燃速和压强指数;将高氮化合物M与二茂铁衍生物G配合使用可将推进剂在8.63～16.48MPa下的压强指数降至0.24; 纳米铝粉和包覆的纳米金属氧化物可明显降低推进剂的燃速压强指数.     

两相燃烧大涡模拟研究进展(Ⅰ)喷雾燃烧大涡模拟(英文)

Spray combustion is widely used in power, transportation, chemical and metallurgical, iron and steel making, aeronautical and astronautical engineering. In recent years, large-eddy simulation (LES) becomes more and more attractive, because it can give the instantaneous flow and flame structures, and may give more accurate statistical results than the Reynolds averaged Navier-Stokes (RANS) modeling. In this paper, the present status of the studies on LES of spray combustion is reviewed, and the future research needs are discussed.     

Modeling of Ignition and Combustion of Boron-Containing Solid Propellants

Combustion, Explosion, and Shock Waves - This paper presents the results of an experimental study of the ignition and slagging characteristics for combustion of boron-containing solid propellants...     

Combustion of Energetic Fuel for Ducted Rockets (I)

Energetic solid fuels composed of modified GAP (glycidyl azide polymer) propellants were formulated in order to obtain optimized combustion characteristics for variable flow ducted rockets. Burning rate in a primary combustor and the combustion efficiency in a secondary combustor were studied and evaluated as a function of the mixture ration of fuel and air. The energetic fuels consisting of – N₃ groups in its chemical structure burned very rapidly even though the combustion temperature was low when compared with conventional solid propellants for rockets. The pressure exponent of the burning rate was optimized to gain wide range of mass generation rate. The combustion gases generated in the primary combustor burned very efficiently in a secondary combustor. The effective specific impulse of the ducted rockets was obtained to be about 780 s.     

Simulation of Agglomerate Dispersion in Combustion of Aluminized Solid Propellants

The paper deals with mathematical simulation of dispersion of agglomerates formed in combustion of aluminized solid propellants. A substantial effect of the separation conditions of agglomerating metal particles from the surface of the burning propellant on the size of agglomerates is demonstrated. A mathematical model of agglomerate formation is constructed for propellants whose typical feature is active burning of the metallic fuel in the surface layer. Satisfactory quality of simulation is validated by the agreement of experimental and numerical data.     

Studies of the Combustion of Solid Propellants at High Pressures

To determine burning velocities of solid propellants at high pressures, a new type of manometric bomb of 0.1 1 volume has been designed. Tightening is provided by a cartridge section from a 30 mm HS 831 steel case. 3 0 to 50 ms after the maximum, the pressure is automatically released by erosion of a 1 mm nozzle, this time lag being given by the electric igniter placed before the nozzle and by blocking it for a short time. The bomb has been applied to measure pressures p in a range up to 7000 bar as a function of loading density A for a double base propellant. The curve p(A) shows a change of slope at about 5000 bar for which explanation is still lacking.     

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.     

Combustion Mechanism of Double-Base Propellants with lead burning rate catalysts

On the basis of relevant experimental phenomena and results, which also include the results on the domain of non-propellant combustion, this paper has determined basic reactions caused by lead burning rate catalysts in the combustion process and their approximate reaction temperature. In the presence of carbonaceous matter on the burning surface the partial NO is reduced to N₂ through six reactions occurred on the carbonaceous matter instead of the reaction between NO and CO. As a result of changing the reducing path of a part of NO the burning rate rises through increasing the temperature gradient in the fizz zone at the burning surface. The reactions between PbO and C and between PbO and CO check the burning rate to rise through expending carbonaceous matter on the burning surface and causing char particles to “fly off” the burning surface. The super-rate, plateau and mesa effects are perfectly explained with these reactions and the fundamentals of heat transference. The production of the effects arises from the competing of two actions to increase burning rate and to check the burning rate enhancement of lead burning rate catalysts and the effect of the pressure on the burning rate. Because of the fact that the chance to form carbon nuclei and the time of the carbon deposit, the covering ratio of the carbonaceous matter on PbO particles, and the temperature increasing rate and the lagging temperature difference in C-PbO interfaces depend on the pressure, the ability by the reaction between PbO and C and between PbO and CO checking the burning rate to rise makes a great difference in different ranges of the pressure. In addition, according to the combustion mechanism advanced in the paper the effects of the physical and chemical properties of lead burning rate catalysts, especially their ability to absorb the ultraviolet light, on the rate-increased values and the pressure ranges of the plateau and the mesa regions have been expounded.     

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。     

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。