Propellant Components Research Articles

Influence of long-term stay of elements of capillary intake devices in liquid propellant components on their parameters

In this paper, we consider the results of a long-term study of the effect of prolonged stay (more than 30 years) of elements of capillary intake devices - mesh phase separators in the liquid propellant components (and under vapors) on the change in their working parameters (characteristics). In the process of research, the following types of work were carried out: extracting mesh phase separators from the propellant tanks of the missile stages to be detected after they were neutralized; analyzing the chemical composition of the substances located on the grids of mesh phase separators; determining the capillary holding capacity of the mesh, measuring the geometric dimensions of the mesh by the optical method; and performing metallographic studies of the mesh patterns. As a result, the authors determined the decrease in the capillary holding capacity of the screen of mesh phase separators for 31 years of their stay in the liquid propellant components and under their vapor. The analysis of the main factors was made that influenced the change in the design parameters of the capillary intake device: uniform corrosion damage and local changes in the microstructure of the structural material of the meshes, as well as a change in the value of the contact angle of the propellant with the mesh material.

A promising hydrogen peroxide adduct of ammonium cyclopentazolate as a green propellant component

A novel hydrogen peroxide adduct of ammonium cyclopentazolate was successfully synthesized and shows promising application potential as a green propellant component.

Increasing the burning rate through energetic compound tuning: Hybrids of the furazan and [1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine ring systems

Combustion behavior, flame structure, and thermal decomposition of hybrid compounds based on tetrazine, triazole and furazan rings have been described. It has been found that the introduction of [1,2,4]triazolo[4,3-b][1,2,4,5] tetrazine core into the molecules of energetic materials allows obtaining energetic hybrid compounds with combustion rates greater than those of common explosive HMX and RDX. These hybrids have good thermal stability, which depends on the substituent at the furazan ring, and not on the triazolotetrazine core. Combustion with thermocouple-aided studies has shown that all triazolotetrazine hybrids are nonvolatile and have high burning surface temperatures which cause their condensed-phase combustion mechanism. Based on the condensed-phase combustion model, the constants of the leading combustion reactions were determined. It turned out that the burning rates of nitrogen-rich compounds of this study are controlled by the decomposition kinetics at surface temperature. It is shown that the two-stage decomposition of substances leads to the appearance of two regions in the burning rate-pressure dependences that related to each other by the instability region. The incorporation of the triazolotetrazine moiety into an energetic compound is a promising way to design new propellant components with high burning rates and attractive performance.

Snow pollution by nitrogen-containing substances as a consequence of rocket launches from the Baikonur Cosmodrome

In this paper, we assessed snow pollution by nitrogen-containing substances including rocket propellants – UDMH (unsymmetrical dimethylhydrazine, (СН3)2NNH2) and NT (nitrogen tetroxide, N2O4) – and their transformation products (NDMA (nitrosodimethylamine, (CH3)2NNO), NO3−, NO2− and NH4+) within the falling regions (FRs) of the first and second stages of Proton-M rockets launched from the Baikonur Cosmodrome. At the first stage FR in Central Kazakhstan, snow with a pH range from 1.7 to 9.0 was contaminated by N-containing substances (maximal value in g/L): UDMH – 0.27, NDMA – 0.04, NO3− – 19, NH4+ – 0.04 and NO2− – 0.13. The first stage landing resulted in snow contamination by soil dust particles and N-containing substances at a rate of 13 g/m2 and 82 mg/m2/day, respectively. The maximal permissible addition (MPA) for UDMH, NDMA and NO3− to the 0–5 cm layer of soil was estimated at 0.06, 0.006 and 70.2 mg/m2, respectively. At the second stage FR in the NE Altai, substances released by space transportation were absent and the concentration of NO3− and NH4+ corresponded to the natural background level. The index of contamination (IC) was used for characterizing the degree of snow contamination by N-containing substances. A simulation model was developed for analysing the dependence of snow contamination by rocket propellant components on the weather parameters.

Improve the interfacial adhesion, corrosion resistance and combustion properties of aluminum powder by modification of nickel and dopamine

To improve the interface incompatibility, poor corrosion resistance, and limited combustion efficiency of aluminum powder for propellant applications. The surface of the naked aluminum was coated with a layer of dense nickel of about 100 nm by replacement method. A polydopamine film was then deposited by self-polymerization. The double-layer structure and chemical composition were investigated. The polydopamine content of composite particles was 2.3% by thermal analysis. And its heat release around 1050 °C reached 4137 J g−1, which was much higher than that of aluminum of 1644 J g−1. The surface energies was used to calculate the theoretical adhesion work of aluminum and composite particles to propellant binder. The adhesion work after modification was increased from 62.33 mN m−1 to 74.89 mN m−1. No matter in the weak acid/alkaline or neutral environment, the composite particles exhibited excellent stability at 50 °C. In addition, the combustion test revealed that the composite particles had higher combustion efficiency, smaller condensed phase product size, and stronger ignition ability. All the conclusions indicate after modification by nickel and dopamine, the comprehensive performance of aluminum is improved, and it may be used as an energy component in propellants or other energetic fields.

High-accuracy and high-performance WAAM propeller manufacture by cylindrical surface slicing method

The propeller is the important component of the power system in ships, the blades of which are spatial curved structures with continually changing sections. Wire arc additive manufacture (WAAM) is a novel technology and an effective method for manufacturing propellers. Currently, the planar slicing methods cannot form the high-accuracy propellers with complex spatial curves, a new cylindrical surface slicing method, based on the principles of conformal slicing, is applied to WAAM, the section for slicing being a cylindrical surface coaxial with the hub. Both cylindrical circumferential filling and cylindrical axial filling are used for filling the blades. In the manufacturing process, the hub is firstly formed by plane slicing and offset filling, then the blade is formed piece by piece by cylindrical slice and cylindrical axial filling and cylindrical circumferential filling alternately. A non-contact 3D measuring is conducted with a surface structure light 3D scanner after the completion of printing, and a 3D comparison is made with Geomagic qualify software. The dimensional error of the product is within ± 1.6 mm. The mechanical properties of WAAM propeller components are higher than the casting ones with the same composition.

Theoretical study on the mechanisms of the decomposition of nitrate esters and the stabilization of aromatic amines.

The nitrate esters are important components of double-base propellants. Aromatic amines are recommended as the stabilizers to delay the decomposition of nitrate esters and increase their storage time. The decomposition mechanisms of alkyl, alkoxy dinitrate, and poly-fluoride nitrate esters and the stabilizing effect of aromatic amines including new designed phenols are studied at the level of B3LYP/6-31G**. Alkyl and alkoxyl dinitrate esters are likely to be transformed by hydrogen abstraction, which is consistent with that of mononitrate and trinitrate esters. However, for poly-fluoride nitrate esters, NO2 catalyzed self-decomposition is preferred. In addition, comparing with mononitrate and trinitrate esters, the order of their stability is mononitrates > dinitrates > trinitrates. Poly-fluoride nitrate esters have a poorer stability than non-fluorinated nitrate esters. Comparing with parent nitrate esters, the stability of new designed poly-fluoride oxygen-containing nitrate esters is slightly improved. Aromatic amines including new designed phenols are effective stabilizers of nitrate esters, especially when introduced hydroxyl in the para position, can enhance the effects of stabilizers. The rate constants for the decomposition of nitrate esters and the bimolecular reaction between stabilizers and NO2 are calculated by using traditional transition state theory. Graphical abstractComparison between the reaction energy barrier of nitrate esters and stabilizers with NO2.

Simulation of thermal reaction mechanism between energetic components of hydroxyl-terminated polybutadiene propellant based on quantum chemical calculation

In this article, hybrid functional B3LYP method is used to construct the reactant structure of energetic components in propellant at the bhandhlyp/6-31g(d) level, and to calculate the closed-shell layer of the system. At the bhandhlyp/6-31g(d) level, the energy difference (activation energy) between the transition state and the reactant was calculated and the reaction mechanism between energetic components was analyzed. It is found that the O30 atom of RDX first breaks off from the nitro group and is easier to break away from RDX and interact with the vertex atom Al1 of the Al13 cluster. With the further separation of O30, it also acts with Al11 until it completely breaks away from N26 atom. The activation energy of this reaction is 56.448 × 103 J mol−1. The oxygen dioxide atom in ammonium perchlorate is more likely to interact with the Al11 atom of the Al13 cluster. With the reaction proceeding, the O22 atom will not completely separate from the Cl19 atom. The activation energy of the reaction is 27.830 × 103 J mol−1.

Thermochemical and Energy Characteristics of Alkoxy-NNO-Azoxy Derivatives of Pyrazole and Nitropyrazoles

The standard enthalpies of formation of the compounds 1-(2,2-bis(methoxy-NNO-azoxy)ethyl)pyrazole, 1-(2,2-bis(methoxy-NNO-azoxy)ethyl)-3-nitropyrazole, and 1-(2,2-bis(methoxy-NNO-azoxy)ethyl)-4-nitropyrazole were measured experimentally to be 273.6 ± 6.7, 231.0 ± 3.3, and 213.8 ± 7.9 kJ/mol, respectively. These enthalpy values were used to determine the contribution of the replacement of the H atoms at the N atoms in the heterocycles by CH2CH(N2O2Me)2 groups (151.9 kJ/mol). Calculations have shown that 1-(2,2-bis(methoxy-NNO-azoxy)ethyl derivatives of pyrazole, 3- and 4-nitropyrazole, 3,4-dinitropyrazole, and 3,4,5-trinitropyrazole and the bis-derivative of bis-furazano[3,4-b;3′,4′-e]piperazine are inferior to HMX as gasifying components of solid composite propellants in metal-free compositions with an active binder. Only the derivative of 3,4-dinitropyrazole, which added in a small amount together with ammonium Perchlorate to aluminum-free propellant compositions provides a specific impulse of 249 s.

Исследование особенностей развития рабочего процесса в камере сгорания кислород-керосинового жидкостного ракетного двигателя

The paper considers the specifics of gasification, mixing and burnout processes for propellant components in a combustion chamber featuring coaxial bicentrifugal injectors and operating in the liquid/liquid mode employing oxygen and the T-1 and T-6 kerosene types. Numerical simulation revealed that when using the T6 fuel, the structure of recirculation zones appearing in the leading region of the combustion chamber may provide more efficient oxygen and kerosene mixing and burnout as compared to a chamber running on the T-1 fuel

Energy Potential of Some Hypothetical Derivatives of Tetrazole as Components of Solid Composite Propellants

The energy potential of compositions based on a number of hypothetical tetrazole derivatives with a very high mass content of nitrogen (73-75%) have been studied by thermochemical calculations. Quantitative dependences of the energy parameters of solid composite propellants on the nature of the high-enthalpy polynitrogen oxidizer and the presence of metal in the composition have been determined.

Thermochemical and Energy Characteristics Di-, Tri-, and Tetraazide-Substituted Azines as Gas-Forming Components of Solid Propellants for Ramjet Engines

Thermochemical and Energy Characteristics Di-, Tri-, and Tetraazide-Substituted Azines as Gas-Forming Components of Solid Propellants for Ramjet Engines

Fault Diagnosis Method of Autonomous Underwater Vehicle Based on Deep Learning

In order to solve the questions that autonomous underwater vehicle(AUV) can’t accurately predict thrusters’ fault only depend on sensor’s information, which is caused by the effect of closed-loop control system, and shallow neural network can’t well fit the complex nonlinear system, this paper proposes a new method for the fault diagnosis of AUV’s thruster, based on Deep Neural Network(DNN) and Denoising Autoencoder(DAE).In this proposed method the difference between AUV’s theoretical state value and measured state value are used as input signal. Considering the disturbance of AUV’s working environment, when using DAE to pre-training the DNN, Gaussian noise was added in the input signal to simulate environment. The trained DNN network was finally used to detect the AUV’s fault propeller components. The results show that the proposed method is more effective, accurately and robust than other traditional methods.

Polynitromethyl derivatives of furazano[3,4-e]di([1,2,4]triazolo)-[4,3-a:3′,4′-c]pyrazine as components of solid composite propellants

The energetic potential of solid composite propellants (SCP) with furazano[3,4-e]di([1,2,4]- triazolo)[4,3-a:3′,4′-c]pyrazine including trinitromethyl (C(NO2)3), fluorodinitromethyl (CF(NO2)2), and (difluoroamino)dinitromethyl (C(NF2)(NO2)2) groups was estimated based on thermochemical calculations. It was shown that C(NO2)3 and C(NF2)(NO2)2 derivatives can constitute the basis of metal-free compositions of SCP with a specific impulse from 251 to 263 s, i.e., comparable or superior in efficiency to HMX-based propellants.

Silicone bridged iron metallocene butadiene composite solid propellant binder: aspects of thermal decomposition kinetics, pyrolysis and propellant burning rate

ABSTRACTPropellant binders are essential components of composite solid propellants (CSP’s) used in launch vehicles and missiles. Binders act as a fuel and contribute directly to the combustion in conjunction with oxidizer particles and metallic fuel apart from imparting structural integrity to the solid propellant grain .The performance of CSP’s are directly related to the burn rate of the propellant. The burn rates of the ammonium perchlorate (AP) propellants are generally moderated using various types of transition metal oxide (TMO) catalysts. However, TMO’s are associated with inherently large dispersions in propellant burn rates and compromise on energetics. One of the most suitable methods for achieving lower dispersion in burn rate is using binders wherein a burn rate catalyst is grafted to the polymer matrix. In the present paper, the thermal decomposition of ferrocene bound hydroxyl terminated polybutadiene (FC-Si-HTPB) grafted to butadiene backbone via hydrosilylation was investigated The thermal degradation mechanism, stability and its effectiveness as burn rate catalyst are the most important aspects for use in CSP’s. The mechanism of decomposition of the neat resin and in combination with AP has been elucidated using pyrolysis gas chromatography–mass spectrometric technique (GC-MS). FC-Si-HTPB exhibits single stage decomposition in the temperature range of 263–491°C. The decomposition of FC-Si-HTPB with AP oxidizer follows a two stage mechanism in the 195–490°C.The char residue was characterized using FTIR, Raman spectroscopy and FE-SEM analysis, which enables to vindicate the mechanism of reaction. The activation energy for the decomposition of HTPB is 283.6 kJ/mol, FC-Si-HTPB is 251.5 kJ/mol and for Fc-Si-HTPB-AP system is 67.1 kJ/mol. The major pyrolysis products of neat FC-Si-HTPB are ferrocenyl derivatives, silylated ferrocenyl derivatives and precursors emanating from polybutadiene backbone. The propellants based on the new binder exhibited an increase in burn rate with iron content and higher fine content. A comparison of propellant burn rate with conventional micron sized ferric oxide exhibited an improvement of 34%.Based on the thermal analysis studies, the thermal endurance of the system was computed to be FC-HTPB> HTPB> FC-HTPB-AP.

Energetic abilities of nitro derivatives of isomeric (pyrazol-3-yl)tetrazoles as components of solid composite propellants

Theoretical estimation of the efficiency factors of solid propellants whose components are CHNO compounds designed from various combinations of four structural motifs, namely pyrazole and tetrazole rings, nitro group, and trinitromethyl moiety, was performed. The positional isomerism was shown to have effect on the properties of the compounds and the energy characteristics of solid composite propellants (SCPs) on their basis. The use of these components in metal-free SCP compositions can allow one to achieve a specific impulse of 258–263 s, neither toxic HCl nor condensed products being produced upon their combustion, i.e., they are superior in energy and environmental indices to SCP formulations based on ammonium perchlorate.

DETONATION NANODIAMOND AS PROSPECTIVE COMPONENT OF COMPOSITE SOLID PROPELLANTS

In this articlethe the possibility of application of detonation nanodiamond (DND) as a prospective component of composite solid propellants (CSP) and additive approach to optimization of fuel compositions based on binary fuel compositions is considered. The introduction to the fuel composition of DND allows creating a metal-free CSP with increased energy-to-mass characteristics. Usage of the additive approach for calculations when creating new prospective compositions of CSP allows reducing significantly the volume of work to optimize the fuel compositions and to simplify the process of thermodynamic engineering.

Thermal Analysis of a Certain Type of High Energy Propellant

In order to study the thermal decomposition characteristics of four component HTPB propellants, the thermo gravimetric analysis (TG) experiment was carried out. The TG curves of propellants at different temperatures, and the TG curves of different components of propellants at the same temperature were obtained, and the kinetic parameters at different heating rates were calculated. In general, the heat of the solid propellant was found. Decomposition is a continuous process with thermal stability and thermal safety.

Diffusion Model of Combustion of Large Boron Particles

Owing to its high mass and volume heats of combustion, boron is a promising component of solid propellants for air-breathing engines. Its application is limited by difficulties of organizing high-efficiency combustion. Experimental investigations of combustion of individual boron particles demonstrate a large number of unique features, which are not typical for other materials: variable ignition temperature, two stages of combustion, and drastic reduction of the burning rate for particles with sizes of several micrometers or smaller. Models that cover the entire range of temperatures, concentrations, and particle sizes are physically non-obvious, can be hardly reproduced, and do not provide the accuracy needed for solving practical problems. In this paper, we propose a simple diffusion model of combustion, which ensures an adequate description of combustion of boron particles 34.5 and 44.2 μm in size at temperatures above 2240 K.

Catalytic effects of p-phenylene-bridged methylated binuclear ferrocenes on thermal decomposition of the main component of composite solid propellants

This contribution describes the catalytic activity of homobimetallic complexes derived from p-phenylene on the thermal decomposition of ammonium perchlorate (abbreviated as AP). The complexes, [CpFe-p-Ph-FeCp] (1), [Cp*Fe-p-Ph-FeCp*] (2), [CpFe-p-Ph’-FeCp] (3) and [Cp*Fe-p-Ph’-FeCp*] (4) (with p-Ph: p-Bis(3,4-dimethylcyclopentadienyl)benzene and p-Ph’: p-Bis(2,3,4,5-tetramethylcyclopentadienyl)benzene), were compared with the catalytic activity of the catocene (cat) complex previously reported. Furthermore, in order to clarify the mechanism of the bimetallic compounds, it was tested ferrocene (Fc), frequently used as burning rate (BR) catalyst on the thermal decomposition of AP. The synthetized compounds shown a shift on the peak temperature to lower values and an increase in the released heats during thermal decomposition of AP. The burning rate catalytic activity of the compounds on thermal decomposition of AP were examined by thermogravimetry and differential scanning calorimetry techniques. Theoretical calculations of these compounds were carried out to gain further understanding of these catalysts systems.