Solid Rocket Fuels Research Articles

Transient plasma enhanced combustion of solid rocket propellants

We demonstrate the use of nanosecond pulse transient plasma (NPTP) to improve the control (and acceleration) of the combustion of solid rocket propellants. Here, we fabricate end-burning propellant samples (i.e., grains) with a co-axial center wire electrode using hydroxyl terminated polybutadiene (HTPB), isodecyl pelargonate (IDP), modified diphenyl diisocyanate (MDI), and ammonium perchlorate (AP) as the fuel, plasticizer, curative, and oxidizer, respectively. High voltage (20 kV) nanosecond pulses (20 nsec) produce a streamer discharge that provides electronic throttling of the solid rocket propellant. These studies are carried out over a wide range of oxidizer mass fractions, including those considered insensitive munitions (IM). In addition, real time imaging is performed characterizing the plasma-formation, evolution of the ignition process, and plasma enhanced flame-fuel coupling. We believe the plasma-based mechanisms of enhancement are 3-fold: 1.) The plasma provides highly energetic electrons that drive new chemical reaction pathways via highly reactive atomic species such as H, O, and Cl, 2.) The plasma sputters chunks of the solid fuel material up into the flame where it is combusted, producing an agitated flame profile. 3.) The plasma provides increased turbulence and multi-scale mixing due to hydrodynamic effects (i.e., ionic winds), which further improves the combustion process. Having electronic control of the burn rate introduces the ability to “throttle” solid rocket motors and introduce new flight profile options beyond a pre-selected profile such as the typical boost-sustain profile. While we are unable to quantify the burn rate or thrust from these relatively simple observations, we observe clear evidence of the effect of the plasma on the combustion of these solid rocket fuels even at high oxidizer content.

Unraveling the ignition chemistry of singly levitated aluminum iodate hexahydrate (AIH) particles

The ignition chemistry of a newly synthesized oxidizing salt, aluminum iodate hexahydrate ([Al(H2O)6](IO3)3(HIO3)2; AIH), while acoustically levitated in the presence of molecular oxygen inside a controlled process chamber is reported. Exploiting temporally resolved ultraviolet–visible (UV–Vis) spectroscopy, a complex pool of reactive transients has been detected, namely- aluminum monoxide (AlO), atomic aluminum (Al), atomic iodine (I), iodine monoxide (IO), atomic oxygen (O), along with stable products such as molecular iodine (I2) and water (H2O). The plausible pathways for the ignition process have been proposed which reveal AIH as a potential additive in hydrocarbon-based and solid rocket fuels in the near future.

CHEMICAL STABILITY OF CELLULOSE NITRATES: REVIEW

The results of the analysis of literature data on updated methods for determining the chemical stability of cellulose nitrates are presented. The relevance of research is due to the need to control the operation and storage of a widespread component of solid rocket fuels and explosive compositions. The criterion for chemical resistance is the value of the decomposition rate or the time dependence of the degree of decomposition of the sample. It is shown that methods for assessing the chemical resistance of cellulose nitrates are based on determining the rate of its thermal decomposition, which is measured by a specific parameter accompanying decomposition. These parameters include weight loss, amount of gaseous decomposition products released, decomposition temperature or thermal effects. Studies are carried out at elevated temperatures and allow you to control the magnitude or rate of change in the parameter that accompanies thermal decomposition. The possibility of using modern analytical methods for evaluating chemical resistance is shown: differential scanning calorimetry, thermogravimetric analysis, chemiluminescent analysis, infrared spectroscopy, high-performance liquid and thin-layer chromatography, gas chromatography, electron paramagnetic resonance, mass spectrometry, X-ray diffraction analysis. The preference for methods of differential scanning calorimetry or differential thermal analysis is substantiated. The results of studies on improving the chemical resistance of cellulose nitrates and compositions based on it with the use of new stabilizers of the aniline series, stabilizers of natural origin with the advantage of the latter on the examples of curcumin and lignins are presented. Due to the insufficient stability of cellulose nitrates, stabilizers added to the formulation of explosive compositions lengthen the induction period of the decomposition of nitro compounds and do not allow the development of the autocatalytic decomposition stage. Methods for determining the chemical stability of cellulose nitrates obtained from alternative sources of raw materials are presented. For citation: Vdovina N.P., Korchagina А.А., Budaev I.А. Chemical stability of cellulose nitrates: Review. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2023. V. 66. N 5. P. 6-20. DOI: 10.6060/ivkkt.20236605.6725.

Exploring Theoretical Fundamentals of a Physical-Mathematical Model for Unsteady Combustion in Solid Rocket Fuel and Developing Methods for Unsteady Velocity Calculation

The article is dedicated to the theoretical study of the non-stationary Combustion Velocity of Solid Rocket Fuel (CVSRF). To calculate the Internal Ballistic Characteristics (IBC) of solid fuel missile engines, combustion velocity laws are used. These laws represent stationary relationships between the Combustion Velocity of Solid Rocket Fuel (CVSRF) and initial pressure and temperature. These relationships are experimentally determined under “stationary” conditions, i.e., by burning fuel samples in stationary conditions.

Innovative Methods of Terahertz Diagnostics in Selected Key Military and Security Applications

The article presents the main research directions of the project implemented by the consortium under the National Defence and Security Program: "Development of modern, breakthrough technologies for state security and defence", codename "SZAFIR". During the implementation of the project, the possibilities of using terahertz radiation will be examined for diagnostic tests of components crucial for defence and security, such as solid rocket fuels, aramid fibre-based composites (bulletproof vests, helmets, pyrotechnic suits), and polymer composites reinforced with glass and carbon fibres (aircraft elements). As a result of research, the interaction of tetheric radiation with materials of these components will be analysed, followed by the development of a methodology for determining their defects. This will result in creating innovative dedicated stations for non-destructive testing of these components. Neural network-based advanced signal processing and artificial intelligence algorithms will be used for automatic diagnostics of key components, improve the process of their control and therefore increase the safety of people and military equipment.

Ecological and toxicological assessment of hazard of contamination of water bodies by the γ-polyoxymethylene

Introduction. In the process of production, storage and application of the representative of new components of solid rocket fuels – γ-polyoxymethylene, its ingress into the water of reservoirs is not excluded, which determines the mandatory assessment of the danger of its single contamination of this ecosystem.
 Material and methods. As an object of research, γ-polyoxymethylene (γ-POM, polyformaldehyde, acetal copolymer) was used – a mixture of dimethyl esters of polyoxymethylene glycols – a fine amorphous white powder, CAS registration number 66455-31-0. The empirical formula is CH3O(CH2O)nCH3 at n = 100–300. It is practically insoluble in water.
 Results. It was found that the ecotoxicant content in water at a concentration of 50.0 mg/l led to a change in its transparency. The indicated concentration of γ-POM was determined as a threshold for organoleptic harmfulness.
 In the course of studying the effect of the toxicant on the general sanitary regime of reservoirs, in the absence of changes in the indicators of biochemical oxygen consumption, its negative impact on nitrification processes and saprophytic microflora was revealed. The threshold concentration of the substance according to the general sanitary indicator of harmfulness is 3.5 mg/l.
 In experiments on laboratory animals, it was noted that a single intragastric administration of the tested xenobiotic in the form of a suspension in a 2.5% solution of aqueous starch caused a significant decrease in heart rate and a change in a number of hematological parameters. The threshold of a single general toxic effect of γ-POM is 90.0 mg/kg.
 Limitations of the study. The revealed features of the behavior of γ-polyoxymethylene must be taken into account when it once pollutes the water of reservoirs (in case of an emergency). However, the data obtained are insufficient to substantiate the hygienic standard of the connection in the water of water bodies.
 Conclusion. The results of the performed experiments indicate that a single ingress of γ-polyoxymethylene into the water represents an ecological and toxicological hazard registered for all three basic signs of harmfulness, which is taken into account when justifying its maximum permissible concentration in the water of reservoirs.

COMBINED DATA AND DEEP LEARNING MODEL UNCERTAINTIES: AN APPLICATION TO THE MEASUREMENT OF SOLID FUEL REGRESSION RATE

In complex physical process characterization, such as the measurement of the regression rate for solid hybrid rocket fuels, where both the observation data and the model used have uncertainties originating from multiple sources, combining these in a systematic way for quantities of interest (QoI) remains a challenge. In this paper, we present a forward propagation uncertainty quantification (UQ) process to produce a probabilistic distribution for the observed regression rate r. We characterized two input data uncertainty sources from the experiment (the distortion from the camera <i>U</i><sub>c</sub> and the non-zero-angle fuel placement <i>U</i><sub>Y</sub>), the prediction and model form uncertainty from the deep neural network (<i>U</i><sub>m</sub>), as well as the variability from the manually segmented images used for training it (<i>U</i><sub>s</sub>). We conducted seven case studies on combinations of these uncertainty sources with the model form uncertainty. The main contribution of this paper is the investigation and inclusion of the experimental image data uncertainties involved, and how to include them in a workflow when the QoI is the result of multiple sequential processes.

INCREASING THE ENERGY OF alpha, omega - DIHYDROXYPOLIBUTADIENE (HTPB) USED IN SOLID HETEROGENEOUS ROCKET PROPELLANT

Solid heterogeneous rocket propellants (SHRP), which are very popular and widely used in the armaments industry (guided missile propulsion engines and long-range, short-range and medium-range anti-aircraft rockets) have inert binders that significantly affect the final performance parameters of propulsion charges. In this study, the popular HTPB binder was modified by introducing azide groups into the polymer chain during three different syntheses. Compounds with different content of explosive groups were obtained and tested for compatibility with the essential SHRP components: ammonium chlorate(VII) and dioctyl adipate. Then, preliminary application tests of the obtained HTPB derivative were carried out, showing the potential of the obtained energetic polymer and the possibility of its use as a binder in solid heterogeneous rocket fuels. HTPB, energetic binder, azide groups

Study of the state of laboratory animals after subchronic oral exposure to solid rocket fuels component

The toxic effect of poly[3,3-bis(azidomethyl)oxetane] of high molecular weight in subchronic oral intake of white mongrel rats was investigated. It has been found that in a one month experiment the compound at doses of 90,0 mg/kg, 30,0 mg/kg, and 10,0 mg/kg caused a change in the complex of physiological, behavioral, hematological, biochemical, immunological, and pathomorphological parameters in animals. At the same time, the cumulative properties of the toxicant were not registered.The deviations revealed were dose-dependent. Thus, during the entire period of intragastric administration of the substance, 15 significant changes were noted in the males of the first group, two of which went beyond the 2 sigma deviations in relations to the control values. The same ratio for the second experimental group was 10/1. The oral intake of the substance under investigation at minimum dose was accompanied by 5 violations in the homeostasis of the experimental animals, which did not go beyond the 2 sigma values in relations to the control values.Taking into account the insignificant number of changes detected and based on the current diagnostic criteria, the dose of 10,0 mg/kg has been accepted as a threshold of subacute general toxic effect for poly[3,3-bis(azidomethyl) oxetane] of high molecular weight.The obtained data was used when developing the maximum permissible concentration of the estimated component of solid rocket fuels in the water of water bodies.

Research on innovative high performance and low-cost solid rocket fuel

The fuel for space access rockets represents a significant investment for space programmes as the energy required to propel the vehicles beyond our gravitational sphere is immense. Dr Yasuhiro Morita, from the Japanese Aerospace Exploration Agency (JAXA), and his team have been developing new, high performance, low-cost solid rocket fuels that could revolutionise the industry. Morita's ground-breaking solid fuel relies on the addition of a thermoplastic resin, and the process he has developed can be modified to allow more efficient manufacturing with smaller scale facilities.

Catalytic Perchlorate Reduction Using Iron: Mechanistic Insights and Improved Catalyst Turnover

Perchlorate is a non-coordinating and kinetically inert anion commonly used in solid rocket fuels and explosives. Upon introduction to the environment, it is a pervasive groundwater pollutant that ...

Development of elementorganic chemistry in Belarus: historical flashback, modern status and perspectives (To the 100th anniversary of the birth of Yu. A. Ol’dekop)

The development of organometallic chemistry of metallocenes, in particular, the chemistry of organic derivatives of iron, manganese, titanium and niobium, is explained by their diverse catalytic activity with respect to polymerization reactions, isomerization and hydrogenation of olefins, cyclotrimerization of acetylene hydrocarbons, fixation of molecular nitrogen under mild conditions and many other processes, using these compounds as additives to fuels and high-temperature lubrication oils, vulcanization accelerators of rubbers constituting lacos and water-repellent impregnation, anti-knock agents, driers, fungicides, etc. Of particular interest are the synthetic methods and chemical transformations of titanocene and niobocene derivatives containing the metal-carbon σ -bond. Most of the titanium-c-derivatives have low thermal stability, and the niobocene derivatives are extremely sensitive to the action of air oxygen, which makes it difficult to study their chemical transformations. Carborane derivatives are used for the preparation of various types of polymers used in solid rocket fuels and as heat-resistant coatings. They are also used as agents in boroneutron capture therapy of oncological diseases. This review presents a brief historical flashback, the current state and further development of the work carried out in the laboratory of organoelement compounds, which began and was supervised by Yu. A. Ol’dekop, covering the period from 1971 to 2018. References include 80 references.

EXPERIMENTAL EVALUATION OF CHRONIC ORAL TOXICITY AND LONG-TERM EFFECTS OF SOLID ROCKET FUELS COMPONENT

The chronic oral toxicity and long-term effects of the basic lead-nickel salt of phthalic acid have been investigated by long-term oral ingestion of white outbred rats. The compound at doses of 1.0 mg/kg; 0.3 mg/kg and 0.1 mg/kg have changed the physiological, behavioral, hematological, biochemical, immunological parameters, as well as the relative weight of internal organs of animals in the six months experiments. The threshold of chronic oral toxicity of the substance is set at 0.1 mg / kg.The study of long-term effects revealed the absence of its mutagenic activity both at the gene (Ames test) and chromosomal (dominant lethal method) levels. In addition, the analyzed compound did not adversely affect the reproductive function of male rats. When entering the body of females during gestation, the toxicant did not reveal embryo-lethal and teratogenic properties.However, chronic administration of the compound into the body of non-pregnant animals at a dose of 1.0 mg/kg contributed to a significant decrease relative to the control of the mass and disk diameter of the placenta, which indirectly indicated the functional inferiority of the organ. Therefore, the considered level of the substance is defined as a threshold for gonadotoxic effect.The obtained data are taken into account in developing of hygienic standard of the estimated component of solid rocket fuels in water reservoirs.

Topology Optimization of Solid Rocket Fuel

This paper investigates possible improvements in the combustion properties of multicomponent solid propellants through the application of topology optimization methods to representative volume element (RVE) of HMX-aluminum fuel. Design objectives for the material include increased thermal conductivity and reduced amounts of induced strains under thermal loads. The targeted increases in thermal conductivity generate designs that increase burn propagation rates, whereas the reductions in structural compliance minimize relative displacements within the design cell. Novel domain-filter treatments are also developed to better control the boundary effects on the resulting designs. A family of wire-like solutions is found to provide optimal combustion and structural properties. Burn performance estimates showed 52 and 33% improvements in burn propagation speeds relative to previous designs at, respectively, 20 and 200 atm.

Anomalous Effect of Turbulence on the Combustion Rate of a High-Energy Solid Material

Study of the practice of using solid rocket fuels and explosives has determined the existence of an increase in the combustion rate due to turbulence. However, this rule is violated in the case of small-scale turbulence produced by the gasification zone of solid fuel. The incoming heat from the gas phase is partially consumed to maintain the chemical reaction of gasification and partially returns to the gas phase. If the return energy of turbulent motion is high, then the combustion rate decreases.

The synthesis of ultra-long cobalt chains and its outstanding catalytic performance on the thermal decomposition of ammonium perchlorate

A simple method without assisted of external magnetic field or surfactant soft templates was utilized to fabricate ultra-long cobalt chains. The formation mechanism was investigated by time dependent experiment, and it was considered that the link of adjacent spherical particles were through dipolar interaction. Due to the preferred orientation and shape anisotropy of the chain structure, the coercively (Hc) value was about 84.5 Oe and saturation magnetization value was up to 149 emu/g at room temperature. To develop its further practical application, the products with regard to accelerate the thermal decomposition of ammonium perchlorate revealed that it exhibited an outstanding performance of reducing the thermal decomposition temperature. This excellent performance has great practical significance on the development of solid rocket fuels. The mechanism of the excellent performance probably ascribed to the synergistic effect of cobalt and cobalt oxide was proposed.

Generation of Hydrodynamic Instability in the Gasification Zone of Solid Rocket Fuel

Generation of Hydrodynamic Instability in the Gasification Zone of Solid Rocket Fuel

Production of Industrial Explosive Substances on the Basis of the Powders and Solid Rocket Fuel Released from the Utilization of the Expired Ammunition

In many states of the former Soviet Union, Georgia in particular, there are many waste dumps at military bases where the ammunition is past its expiry date. Disposal in landfill, by incineration or explosion leads to environmental problems and requires considerable expenditure. The following report describes a research project where the goal is to recover explosives from military refuse dumps, which can further be processed into industrial explosives suitable for extraction of raw materials in open-cast mining.

Physicomathematical modeling of burning aluminum nanoparticles near the shock-wave end

INTRODUCTIONRecently, a number of publications have appearedin which various problems associated with the behavior of nanosize particles have been studied. Thesestudies included questions about chemical reactionsproceeding in mixtures of an oxidizer and nanosizemetal particles (see, e.g., [1, 2]). The particular interest in ignition and combustion of these particles iscaused by several reasons. Among them, there areproblems of increasing the combustion rate of solidrocket fuels with additions of aluminum nanoparticles. Particularly, in this case, the burning time is significantly reduced compared to particles of the regularsize, which we consider below to exceed one micron.Indeed, in [3], the data are given on the burning time

Degradation of space exposed surfaces by hypervelocity dust bombardment, and refractory materials for space

Abstract Dust particles with diameters below 100 μm represent an important part of the space environment. Objects like satellites or spacecrafts, are constantly bombarded with particles of cosmic velocities of 10 km/s and more. These hypervelocity impacts lead to evaporation of a large fraction of these particles and to the formation of craters on the material surfaces which exhibit diameters which are up to one order of magnitude larger than the impinging particles. This results in a remarkable materials degradation of space exposed surfaces which can considerably reduce the life time e.g. of semiconductor panels for the generation of energy, due to the cumulative effect of a multitude of such particles which hit a surface during a certain time. The particle population in space near to earth consists of two distinct groups: (a) Natural particles, micrometeorites: These particles are a natural part of the space environment and cannot be avoided. Most of them have so-called “chondritic” compositions and consist of Si, Al, Mg, Fe, Ca and O, an elemental makeup resembling the bulk composition of the original solar nebula from which our solar system and the planets formed 4.5 billion years ago. (b) Man made debris particles: These stem from various sources, e.g. exhausts from solid rocket fuels, paint chips, fragments from space crafts etc. These particles pose an increasing danger to space flight and their future production must be reduced by strict debris policies. The important question was now: What percentage of impact particles is man-made? Cosmic and man-made particles exhibit different chemical compositions. Hence, a micro-chemical analysis of particle impacts on satellite surfaces can be used to determine the particle ratio. For this purpose, the LDEF-experiment (Long Duration Exposure Facility) was launched by NASA in 1984 to study erosion phenomena on material surfaces (of more than 10,000 test samples) in a Low Earth Orbit (LEO)-environment. LDEF was retrieved only in 1990 because of the Challenger disaster which essentially delayed the retrieval up to the last moment before the experimental setup would have been destroyed upon entrance into the earth atmosphere. The demonstration of pronounced material degradation of space exposed materials logically leads to the question which materials are used in space technology. Plansee SE in Reutte/Tyrol has quite a tradition in the production of smaller rocket nozzles, e.g. satellite propulsion nozzles and general propulsion components made of Mo, W, Nb or Ta-based alloys. The W–Ag evaporation cooled alloy was among the earliest materials for rocket combustion chambers enduring ultra high temperatures due to partial evaporation of the silver which thereby cooled the chamber. Ni- and Fe-based ODS superalloys find application in durable TPS/hot structures of hypersonic vehicles, e.g. as honeycomb panels and fasteners of PM 1000/2000. These are PM-ferritic and nickel based oxide dispersion strengthened alloys. We have studied the significance of Yttrium depletion within the oxide scales of these alloys.