Solid Rocket Propellants Research Articles

Effects of Thermal Damage on Impact Response Characteristics of High-Energy Propellants.

Thermal damage due to microstructure changes will occur in propellants under thermal stimulation. It can significantly affect the sensitization, combustion, and other properties of the propellant, which, in turn, affects the impact safety of the solid propellant rocket engine. A new component which uniformly heats the sample was designed to conduct the Lagrange test and EFP impact test at different temperatures. The thermal decomposition and damage characteristics of the propellant during the heating process were quantitatively analyzed. Additionally, the effects of ambient temperature on impact initiation and detonation growth of the high-energy propellant were elucidated at a mesoscopic level. The results showed that the porosity of the specimen increased by 0.89% under the thermomechanical mechanism, which was mainly characterized by interfacial de-bonding between the AP and the binder. The increase in thermal damage changed the hot spot reaction rate and significantly affected the growth process of propellant impact initiation. A method was proposed to systematically calibrate the reaction rate model for the propellant at different temperatures. The theoretical model parameters of the high-energy propellant at two typical temperatures were calibrated in this way. The critical shell thicknesses computed using LS-DYNA, which, for 20 and 70 °C, were obtained as 15 and 20 mm, respectively.

A review on the effect of ageing on the ballistic properties of solid gun and rocket propellants

AbstractThis review covers the effect of ageing on solid gun and rocket propellants in terms of their ballistic properties. A brief overview of the types of methods, which can be used to determine such parameters, is provided and the literature is described in terms of broad motivation areas for the research. It has been demonstrated that understanding the effects and outputs of propellants, and how these might be affected by ageing, remains an important area of research in the field of energetic materials.

Solid rocket motor propellant health monitoring based on oxide-doped curved long-period fiber grating.

A kind of curved long-period fiber grating(CLPFG) engraved by CO2 laser based on oxide-doped fiber was designed to monitor the structural integrity of propellant. The mechanical damage characteristics of the propellant were analyzed. The sensor model is constructed and the refractive index modulation characteristics of the CLPFG are analyzed. The strain coupling characteristics and the strain transfer efficiency of the interface between the CLPFG and the propellant are clarified. Propellant modules with implanted CLPFG were fabricated. The novel grating sensor has been effectively coated and structurally packaged. Conducted experiments on strain and temperature of propellant modules. The large strain measurement of propellant from 0 με to 24000 με is realized. Solved the thorny problem of large strain measurement for propellants. In addition, the temperature discrimination measurement in the temperature range of 30 ℃ to 250 ℃ can be realized. Sensor exhibit extremely high stability characteristics and has good compatibility with propellants. The sensor implantation and extraction structure has been designed to improve the survival rate of the sensor inside the solid rocket motors (SRM). Sensors can accurately measure the mechanical and thermal state parameters of propellants, providing effective data support for the health management of SRM.

Investigation of thermomechanical properties of solid rocket propellant used in multi-barrel rocket systems

AbstractThe effectiveness of multi-barrel rocket systems on today’s battlefields is strongly dependent on the reliability of operation and, hence, proper action of all components, especially rockets and propellants. Therefore, the properties of the solid rocket propellants used in the rocket motors must be determined with an efficient and reliable tool providing repeatable results. The article presents the results of a thermomechanical analysis of solid double-base rocket propellant used in multi-barrel rocket systems. One of the recommended methods for testing solid rocket propellants is dynamic mechanical analysis. Mechanical properties such as the dynamic storage modulus $$(E^\prime )$$ ( E ′ ) , the dynamic loss modulus $$(E^{\prime \prime }),$$ ( E ″ ) , and the tangent tan$$(\delta )$$ ( δ ) of the phase shift angle $$(E^{\prime \prime }/E^\prime )$$ ( E ″ / E ′ ) were measured with the use of the TA Instruments DMA Q 800 device, in a temperature range of − 100 to $$+$$ + 100 $$^\circ $$ ∘ C with the use of different frequencies of applied force and heating rates. Special attention was devoted to determining the glass transition temperature following the STANAG 4540 standardization agreement, as well as the influence of testing parameters on the obtained experimental results. Dynamic mechanical analysis has proven to be an effective method for the evaluation of key properties influencing rocket motor behavior.

Research on the Jet Milling Process of Oxidizer for Solid Propellant

The particle size of the oxidizer used by the solid rocket propellant has a great impact on the combustion performance of the grain. In order to study the influence law of the oxidizer used for the jet milling, the jet milling process test system is constructed. The influence of the main process parameters on the average particle size was studied by single-factor test.The orthogonal test was designed, and the prediction model of the relationship between particle size and milling pressure, milling chamber material mass and classification wheel speed was established using multiple linear regression method, and the significance analysis and the prediction test were conducted.The results show that the particle size prediction model is significant, and the classification wheel speed affects the average particle size the most, followed by milling pressure and milling chamber material mass.The conclusion is that the deviation of the milling average particle size under the prediction model acquisition process parameters is between 1.79%∼5.88%, and the prediction model acquisition process parameters can be obtained to mill the AP with the average particle size requirements of different specifications.

Исследование газодинамики горения смесевого твердого топлива при колебаниях давления

The non-stationary burning rate of a solid rocket propellant under harmonic variations in pressure over the combustion surface is studied. The physical and mathematical model is based on the equations of heat transfer and oxidizer decomposition in the solid phase, and on the flow model for the reacting products of solid propellant gasification. Calculations are carried out for the unsteady burning rate of mixed solid propellants with harmonic pressure variations over the combustion surface. The dependence of the amplitude of the burning rate fluctuations on the frequency of the pressure variations are obtained. The amplitude of the burning rate varies non-monotonically with frequency. As the frequency increases, the amplitude first increases and then decreases. At a frequency of pressure variation with a semi-period greater than or equal to the characteristic time of relaxation for heat transfer in solid propellants, the instantaneous burning rate at the lowest point of the pressure curve is lower than the equilibrium value and is higher at the highest point. At high frequencies, the burning rate exceeds the corresponding equilibrium value at minimum pressure and is lower than the equilibrium value at maximum pressure.

Computational Determination of the Specific Impulse of Solid Rocket Propellant Compositions of closo-Dodecaborate ([B12H12]2‒) Salts with HTPB Binder and Ammonium Perchlorate as an Oxidizer

Computational Determination of the Specific Impulse of Solid Rocket Propellant Compositions of closo-Dodecaborate ([B12H12]2‒) Salts with HTPB Binder and Ammonium Perchlorate as an Oxidizer

THE NEW 1942 METHOD FOR PROPELLANT DESIGN AND LATER UPDATES

The brief research reviews the history of an innovative method in propellant technology. In 1942, the renowned US scientist Joseph Hirschfelder led a team that devised a simple calculative method for helping to design wartime solid propellants, whose gas, when burnt, served to drive projectiles in gun barrels. The method estimated the temperature of the gas for each propellant and other factors. Until then, these were estimated through a rigorous theoretical process. The simplified theoretical approach of the new method gave nearly the same temperatures and other important values, all with basic arithmetic. It was later refined by others, for better accuracy, and applied for designing solid rocket propellants, through a short theoretical adaptation.

Risk Assessment of Solid Propellant Rocket Motor using a Combination of HAZOP and FMEA Methods

The development of rockets in Indonesia has long been carried out by the National Aeronautics and Space Agency (LAPAN), which has now been integrated into the National Research and Innovation Agency (BRIN). The Research Centre for Rocket Technology, which is one of the centres within BRIN, has been developing solid propellant-based rockets with a various sizes and types. Solid-propellant rocket technology is commonly used because of their reliability, cost-effectiveness, and simple design. However, this technology is one of the high-risk technologies, whose failure can harm humans, damage the environment and cause huge losses to assets. As a high-risk technology, risk assessment activities must be carried out, starting from the design, manufacturing, testing and up to the launching stage. In this paper, we studied a risk assessment for general Solid-propellant Rocket Motor (SRM). SRM is basically a device that processes chemical energy in solid propellant into thrust (kinetic energy) in a container that functions as a pressure vessel. The risk assessment methods commonly used in this technology are the HAZOP or FMEA methods. The HAZOP is excellent in identifying failure modes systematically through identifying the deviation of physical process parameters but has difficulties in prioritizing the risk. The FMEA has effectiveness in understanding failure mechanisms and establishing necessary countermeasures, but for a product with a lot of components, the worksheet is also complex. By combining these two methods, integrating the superiority of each method, this research can identify modes, causes and effects of failure that may occur in SRM effective and accurately. In addition, this research also proposes corrective or preventive actions for each failure mode. As the objective of the risk assessment, results of the research can be used as input for the designers to improve their design and as inspection and surveillance objects for QC officers.

Ammonium Perchlorate-Based Energetic Molecular Perovskite DAP-4 Deposited on CNTs: Catalytic Decomposition Behavior, Mechanisms, and Kinetics

Energetic molecular perovskite with superior decomposition enthalpy and high oxidizing ability is the out coming potential oxidizer in advanced highly energetic systems. In this study, perovskite DAP-4 was fabricated by molecular assembly stagey; multi wall carbon nanotubes (MWCNTs) were employed as a potential catalyst for thermal decomposition of DAP-4. Encapsulation method was adopted to develop DAP-4@MWCNTs nanocomposite. MWCNTs experienced superior catalytic effect on DAP-4 decomposition. MWCNTs offered an increase in DAP-4 decomposition enthalpy by 37.5%, with decrease in its main decomposition temperature by 6 °C. Decomposition kinetics were investigated via isoconversional (model free) and model fitting including Kissinger, Kissinger–Akahira–Sunose (KAS), and integral isoconversional method of Ozawa, Flyn and Wall (FWO). DAP-4@MWCNTs demonstrated apparent activation energy of 135.3 ± 3.9 kJ/mol compared with 142.3 ± 4.15 kJ/mol for pure DAP-4 via KAS model. While DAP-4 demonstrated decomposition reaction of first order reaction model (F1); DAP-4@MWCNTs demonstrated decomposition reaction of third order model (F3). Moreover, a possible catalytic mechanism of MWCNTs via induced holes and electrons to enhance electron transfer ability. This work could promote the application of DAP-4 in the field of solid rocket propellant.

Investigation of the basic parameters for alternative solid rocket propellant engines for research and civilian use

Investigation of the basic parameters for new generation of alternative solid rocket propellant engines for research and civilian use was implemented. This was caused from needs for substitution of the widely used construction materials of the aircraft units based on polymers and of petroleum composites. Numerous fire tests, both static and flight, in a real working environment of a new generation of environmentally friendly solid rocket propellant engines that are completely degradable in the nature were carried out. The obtained results after burning of rocket fuel for internal engine ballistics and thermo-mechanical coupled characteristics of composite materials are presented.

ANALYSIS OF FOREIGN EXPERIENCE OF DUAL USE SOLID ROCKET MOTORS

In countries, such as the United States, China, India, France, Israel and many others, solid-propellant rocket engine technologies are used not only in military missiles, but also in launch vehicles of the rocket and space industry. Such an approach of dual application of technologies makes it possible to introduce and develop new innovative solutions to increase the degree of unification of related technologies. One of the most important factors influencing the efficiency of using solid propellant rocket engines in space programs is the cost of solid rocket propellants and propulsion system components. For this reason, a high degree of unification of solid fuel products for various purposes is aimed at ensuring a high utilization of the industry’s production capacities, which can significantly reduce prices for materials, fuel and the design of propulsion systems as a whole. The analysis confirmed that the creation of launch vehicles based on rocket engines of solid fuel for military missiles naturally leads to a reduction in the time and costs for the development of such products, a reduction in technical risks and an increase in the reliability of the technologies used.

Parametrical analysis of the strength of the nozzle of a solid fuel rocketer

The paper presents an approach to solving the problem of designing a solid propellant rocket engine nozzle using a design feature in the form of a carbon fiber insert. The design task is to select the optimal parameters of the plate thickness (plate shape) that provide the necessary strength and stability of the structure with a minimum weight. During the design process, a parametric analysis of a carbon fiber insert in the solid propellant rocket nozzle was carried out. By varying the thickness of the plate, an optimal design scheme is found that meets the given safety and stability factors. Parametric analysis of an insert plate made of CM includes modeling of the main weight and strength parameters: determination of the stress-strain state of the structure, values of natural frequencies, determination of the buckling margin, determination of the mass of the solid propellant rocket motor nozzle. Analysis of the bearing capacity of the solid propellant rocket motor nozzle with an insert plate made of CM was carried out using the finite element method using the SolidWorks Simulation software package. During the parametric analysis, two variants of the solid propellant rocket engine nozzle with and without an insert plate were considered. According to the results of the parametric analysis of the solid propellant rocket nozzle, its geometric dimensions were determined and the mass of the structure was minimized.

Aluminum particle agglomeration characteristics and suppression method during the combustion of aluminum‐based solid propellants: A review

AbstractAluminum is widely used in solid rocket propellants to improve the energy performance of the propellant. However, during propellant combustion, aluminum particles may agglomerate, resulting in slag deposition, incomplete combustion of metal particles, increased two‐phase flow losses, and reduced motor specific impulse. Therefore, it is of great scientific significance and engineering value to understand the agglomeration mechanism of aluminum particles and to explore the method of agglomeration suppression. Based on this, this paper firstly briefly introduced the agglomeration process of aluminum particles during propellant combustion. Subsequently, factors influencing the agglomeration of aluminium particles were analysed. The influencing factors can be roughly divided into two aspects: propellant‘s own formulation and external environment. Immediately afterwards, the existing agglomeration suppression methods were emphasized and summarized and analyzed. Presently, agglomeration suppression methods can be broadly classified into four categories, namely, conventional formulation optimization, use of aluminum nanoparticles, and modification of aluminum particles using fluorine‐containing compounds or alloy particles. Finally, several directions that need to be focused on in the future are proposed to address the problems in the study of aluminum particle agglomeration suppression methods.

Propulsion theoretical and experimental analysis of composite propellants motors

Rockets have revolutionized space technology and human space exploration. Most rockets and missiles are both propelled by rocket motors that use composite solid propellants. The ICT code and the NSAS CEA code are two programs that can be used to forecast theoretical propulsion parameters for composite solid rocket propellant. Rocket propellant performance is governed by a specific impulse factor, which is calculated theoretical and experiment. In this paper, the theoretical specific impulse for different composite solid propellant formulations at 70 bar combustion pressure and an adapted nozzle (optimum expansion) were calculated by the NASA-CEA code and the ICT code. Meanwhile, a static firing test was performed on a small scale test motor to experimentally determine the actual specific impulse. The objective is to verify theoretical calculations from two codes with experimental data, via the determination of the specific impulse deviation co-efficient.

New Insights into the Chemical Compatibility of Nitrochitosan with Potential Energetic Molecules

This study provides new insights into the compatibility of a promising energetic polysaccharide, called nitrochitosan (NCS), with energy-rich ammonium perchlorate (AP), ammonium nitrate (AN), and hydrazine 3-nitro-1,2,4-triazol-5-one (HNTO) molecules, in order to survey their application prospects in solid rocket propellants and explosives. For this purpose, differential scanning calorimetry (DSC) and thermogravimetric (TGA) analyses were carried out to accurately evaluate the chemical compatibility of NCS with the selected energetic molecules following the STANAG 4147 criterion. Fourier transform infrared spectroscopy (FTIR), as a non-thermal complementary technique, was also performed to further elucidate the eventual structural alterations occurring in the physical mixtures (NCS/AP, NCS/AN, and NCS/HNTO). Based on DSC results, the maximum exothermic peak temperature difference between NCS (Tpeak = 164.7 °C) and the as-prepared NCS/AP (Tpeak = 164.3 °C), NCS/AN (Tpeak = 204.3 °C), and NCS/HNTO (Tpeak = 197.0 °C) admixtures is found to be lower than 4 °C. Moreover, TGA experiments showed that the observed mass losses of the physical mixtures are lower than the sum of the weight losses of their respective individual compounds. Therefore, thermal results demonstrated the excellent chemical compatibility of NCS with the corresponding energetic molecules. In addition, FTIR measurements highlighted the absence of chemical interactions between NCS and the selected AP, AN, and HNTO. Therefore, a deep investigation into the characteristics of such energetic composites and their real-world applications will be among the main focuses of the postulated next stage of research.

Rapid optimization method of solid rocket motor propellant with structural strength

AbstractTo design a solid rocket motor with a high mass ratio, it is necessary to find out the parameters of the grain shape to meet the structural strength under volume loading fraction and initial burning areas conditions. A rapid optimization method for complex grain of solid rocket motors based on parametric modelling and GA‐BP is proposed. Through the sensitivity analysis of the geometric parameters related to the grain, the sensitive parameters are determined. 30 groups of parameters are determined by the mixed horizontal orthogonal test and the learning samples of the neural network are obtained by FEA. The artificial neural network is established based on the FEA results, and the accuracy of the network is verified by 10 groups of test data sampled by the LHS method. The comparison results show that the prediction error of the maximum Von Mises strain is 5.09 %, the prediction error of the volume loading fraction is 0.16 %, and the prediction error of the initial burning surface is 0.865 %. Based on this, the neural network prediction results are optimized as a function of fitness in GA, and the optimization results show that the maximum strain is reduced by 20.41 % while the constraints are satisfied.

Reliability Analysis of a Three-Engine Simultaneous Pouring Control System Based on Bayesian Networks Combined with FMEA and FTA

Pouring is an important process in the production of solid propellant rocket engines, and usually, the cost of a solid propellant rocket engine is extremely high. Therefore, pouring production with high reliability is very important. The pouring of three engines of solid propellant rocket engines simultaneously can greatly improve its production efficiency. However, it makes the system more complex and redundant. For a multi-state system, it is difficult to make an accurate evaluation of system reliability. Aiming at the redundancy of multiple engines and acousto-optic combined control in the three-engine simultaneously slurry pouring alarm control system with dissimilar redundant alarm units, a reliability analysis method is proposed based on the combination of Failure Mode Effect Analysis (FMEA) and Fault Tree Analysis (FTA). The control system is divided into several redundant states according to the alarm function, and then the Bayesian Networks method is used for reliability evaluation and calculation. Finally, the reliabilities of systems with dissimilar redundancy degrees are obtained. The tangible results of this research work are as follows: (1) The research results obtained by applying the FMEA method laid a foundation for the establishment of a fault trees model for analyzing the reliability of the control system using the FTA method, in addition, which can guide the maintenance and fault identification of the control system during engineering application. (2) The calculated value of the reliability of the control system is 0.999989, and the mean time between failures is MTBF is 5 × 104 by using the fault tree analysis method, which proves that the designed three-engine simultaneous pouring system is very reliable. (3) Based on the calculation and comparison of the Bayesian Networks of redundant three-engine pouring control systems, the circuit diagram of the improved control system is identified.

Вплив шорсткості поверхні камери енергетичної установки на низькочас-тотні автоколивання холодного робочого газу

Dynamic processes in the combustion chamber have a significant effect on the characteristics of the working processes of solid-propellant rocket engines (LPREs). Pressure jumps and a sharp increase in the local temperature of the combustion products in non-stationary engine operation modes can lead to overrating values of operating parameters and a failure of the LPRE combustion chamber structure. The dynamic processes in the LPRE combustion chamber develop in a complex interconnection of a large number of physical and chemical processes that occur in the gas-dynamic part of the working space of the engine chamber and often lead to self-oscillating modes of engine operation. This is evidenced by numerous data on LPRE fire tests. This paper presents the results of a numerical study of the effect of the LPRE chamber inner surface roughness on LPRE operating parameter low-frequency self-oscillations. The study was made using up-to-date computer simulation means and analysis. Low-frequency (up to 1,000 Hz) oscillations in an LPRE combustion chamber were studied for a power plant test chamber in cold operation with the use of two different approaches to numerical modeling of the dynamics of in-chamber processes: the development and study of a 3D model of the dynamic system of combustion chamber structure – combustion products using the finite element method and the development and study of an axisymmetric 2D model of engine chamber gas flow using the finite volume method. The study revealed a self-oscillatory flow regime caused by combustion product vorticity and acoustic feedback due to vortices colliding with the chamber components or the LPRE nozzle. It was shown that accounting for the wall roughness increased gas vorticity in the gas–solid dynamic interaction zone and the chamber gas oscillation amplitude (on the average, by a factor of 2.5 at a maximum wall roughness height of 56 ?m). The calculated gas flow pattern in the vorticity zones of the chamber and the low-frequency gas pressure oscillation parameters are in qualitative agreement with the experimental ones.

Synthesis and characterization of iron and ruthenium complexes with the hydrotris(3,5-dimethyl-pyrazolyl)borate ligand and application as burning rate catalysts for solid rocket motor propellant

In this work, we reported two complexes [Tp*FeCp*] (1) and [Tp*RuCp*] (2) obtained from the reaction of respective pentamethylcyclopentadienyl metal precursors and [hydrotris(3,5-dimethyl-pyrazolyl)borate] (Tp*). Both complexes were characterized by 1H and 13C NMR, elemental analysis, FT-IR, UV–vis, and cyclic voltammetry. The synthesized complexes [Tp*MCp*] and analogous compounds [(Cp*)2M] (with M = Fe and Ru) were tested as catalysts on the thermal decomposition of ammonium perchlorate by a differential scanning calorimetry (DSC) technique. Compound 2 caused a decrease ammonium perchlorate’s decomposition temperature displacing it to 326 °C compared to compound 1 and [(Cp*)2M] species. However, compound 2 presented the lowest energy released compared to the complexes here reported (408 J·g−1). In addition, the results obtained from the cyclic voltammetry characterization evidenced that the electrochemically active species of compounds 1 and 2 exhibit noteworthy oxidation peaks. These results suggest that compounds 1 and 2 here presented are suitable and competitive alternatives to be used as a modifier for composite solid propellants.