Detonation Velocity Research Articles

Discovery of high-energy nitro-azolo-pyridine compounds with high-throughput computation and machine learning

The nitro-azolo-pyridine compounds have planar molecular backbones with high nitrogen content, which are considered as a candidate system of insensitive high-energetic explosive (IHE). In this work, 30969 energetic molecules were generated based on 7 kinds of azolo-pyridine backbones; among them 2000 sample molecules were chosen to perform high-throughput calculations (HTC) of detonation velocity and pressure, then the machine learning (ML) models were constructed according to the computed molecular descriptors and detonation parameters; the detonation parameters for the other molecules besides the HTC samples were predicted by the ML models, and the molecular stability for the highest energy molecules were computed using quantum chemistry. Finally, 3 nitroazolo-pyridine compounds with high-energy and low-sensitivity were screened, and their synthetic accessibility were verified.

Pathological detonation in H[formula omitted]-Cl[formula omitted] mixtures: Uncertainty quantification and thermal non-equilibrium effects

Pathological detonations are detonations with a propagation velocity higher than the classical Chapman–Jouguet velocity and which depends on the wave structure. Such a behavior has been experimentally observed in low-pressure hydrogen-chlorine mixtures and important discrepancies were reported between the experimental and the theoretical velocities. Using the steady planar detonation model, along with a state-of-the-art chemical mechanism this work aims at investigating two aspects potentially responsible for these discrepancies: (i) the impacts of uncertainties in chemical kinetics mechanisms, and (ii) thermal non-equilibrium effects. The uncertainties in the rate constants of reactions R2: 2Cl+M=Cl2+M and R3: Cl2+H=HCl+Cl are found to be the dominant sources of uncertainty for the steady propagation velocity and the induction length of the pathological detonations. The multi-temperature, thermal non-equilibrium model is found to provide generally higher detonation velocity than the experimental value and the eigenvalue solutions obtained under thermal equilibrium. Nevertheless, for specific values of the initial vibrational temperature of HCl, the results can be closer to the experimental values. This latter aspect provides the motivation for future work that relies on more comprehensive thermal non-equilibrium modeling.

Thermodynamics and energy properties of the lowest eutectic mixture of TNBA/MTNP

In light of the challenges posed by the low density, diminished energy levels, and shrinkage holes in the loading arise of the current cast-cured explosive liquid vehicle, TNT, the investigation of low-melting eutectic materials as potential substitutes for TNT has emerged as a focal point of research. By employing the solvent-nonsolvent method, the lowest eutectic mixture of TNBA(2,4,6-trinitro-3-bromoanisole)/MTNP(1-methyl-3,4,5-trinitropyrazole) was synthesized, distinguished by a moderate melting point and markedly elevated energy levels as compared to TNT. Comprehensive SEM, EDS, IR, XRD, and XPS analyses were conducted on the lowest eutectic mixture, substantiating the absence of any chemical interaction between TNBA and MTNP and affirming their exceptional compatibility. Moreover, an exploration into the thermal decomposition behavior and mechanism of the lowest eutectic mixture was undertaken, its mechanical sensitivity was tested, and its detonation performance was evaluated by EXPLO-5 software. The thermal decomposition parameters of the lowest eutectic mixture closely paralleled those of the precursor materials, with the thermal decomposition kinetics model function being identified as the Jander function. The impact sensitivity of the lowest eutectic was 48.1 cm and the friction sensitivity was 12%. Furthermore, the density of the lowest eutectic mixture surpassed 1.8 g/cm3, and its detonation velocity approached 8000 m/s, markedly surpassing the explosive performance of TNT.

Comparative study on the equation of state of detonation products

The equation of state (EOS) for detonation products can predict explosive performance with basic information about density, enthalpy of formation, and elemental composition. However, to achieve higher prediction accuracy, it is necessary to select an appropriate EOS for the specific detonation parameters being calculated. To study the applicability of different equations of states for explosive products, five EOSs, Becker–Kistiakowsky–Wilson, Kihara–Hikita–Tanaka, Virial-Wu (VLW), Lennard-Jones–Devonshire (LJD), and Jacobs–Cowperthwaite–Zwisler (JCZ), were used to calculate the Hugoniot curve of nitrogen and the detonation performance of typical explosives. The calculation results show that all five EOSs can provide reasonably accurate predictions of the Hugoniot curve of nitrogen on the relative volume-pressure plane. Moreover, the EOSs can accurately predict the detonation velocity and pressure of explosives within a wide range of initial densities. When it comes to temperature calculations, LJD and JCZ demonstrate higher prediction accuracy. Additionally, the results indicate that VLW may not be suitable for calculating the overdriven detonation of explosives, particularly at higher pressures.

An empirical confinement model for ANFO explosive

AbstractAmmonium‐nitrate‐fuel‐oil (ANFO) explosive, one of the most used mining explosives, exhibits highly non‐ideal behaviour. The non‐ideality of the detonation is manifested in the strong dependence of the detonation velocity on the charge radius and existence and the characteristics of confinement. This can lead to the detonation velocities as low as one‐third of the ideal velocity. The literature reported experimental detonation velocities of cylindrical ANFO charges confined in different confiners (aluminium, copper, steel, polymethyl methacrylate, and polyvinyl chloride) are analysed in this paper. An empirical confinement model, which relates the detonation velocity to the charge radius and the mass of the confiner to the mass of explosive ratio per unit length, is proposed. The model predicts the detonation velocity of unconfined and confined ANFO charges with a mean average percentage error of 8.8 %.

Oil-in-water nanoemulsion adhesive system: Preparation by ultrasonic homogenization and its application in 3D direct writing composite energetic materials

Stable and low-particle size nanoemulsions were prepared using ultrasound homogenization. The conditions for preparing low-viscosity nanoemulsions were optimized using Response Surface Methodology (RSM) experimental design. The results showed that the addition of composite surfactants at 1%, an ultrasound amplitude of 35%, an ultrasound time of 4 min, and an ultrasound temperature of 20 °C yielded nanoemulsions with the best particle size and stability. The particle distribution was uniform, and the cold and heat stability were good. Compared with traditional emulsions, the low-viscosity nanoemulsion had better environmental stability, storage stability, and exhibited a phenomenon of self-reducing particle size at 40–55 °C, indicating that the emulsion had good performance under complex environmental conditions. The performance test of composite energetic materials using two types of emulsions as bonding systems showed that the low-viscosity nanoemulsion composite energetic material effectively reduced friction sensitivity, increased detonation velocity, and had better thermal stability and smaller propagation size. The results confirmed that the low-viscosity nanoemulsion perfectly met the requirements of bonding agents for composite energetic materials. This study provides a new approach for bonding agent systems of composite energetic materials and can serve as a new method to meet the special requirements of composite energetic materials.

Detonation Performance of Insensitive Nitrogen-Rich Nitroenamine Energetic Materials Predicted from First-Principles Reactive Molecular Dynamics Simulations.

Because of the excellent combination of high detonation and low sensitivity properties of the 1,1-diamino-2,2-dinitroethylene (FOX-7) energetic material (EM), it is useful to explore new energetic derivatives that start with the FOX-7 structure. However, most such derivatives are highly sensitive, making them unsuitable for EM applications. An exception is the new nitroenamine EM, 1,1-diamino-2-tetrazole-2-nitroethene (FOX-7-T) (synthesized by replacing a nitro group with a tetrazole ring), which exhibits good stability. Unfortunately, FOX-7-T shows an unexpected much lower detonation performance than FOX-7, despite its higher nitrogen content. To achieve an atomistic understanding of the insensitivity and detonation performance of FOX-7 and FOX-7-T, we carried out reactive molecular dynamics (RxMD) using the ReaxFF reactive force field and combined quantum mechanics MD (QM-MD). We found that the functional group plays a significant role in the initial decomposition reaction. For FOX-7, the initial decomposition involves only simple hydrogen transfer reactions at high temperature, whereas for FOX-7-T, the initial reaction begins at much lower temperature with a tetrazole ring breaking to form N2, followed by many subsequent reactions. Our first-principles-based simulations predicted that FOX-7-T has 34% lower CJ pressure, 15% lower detonation velocity, and 45% lower CJ temperature than FOX-7. This is partly because a larger portion of the FOX-7-T mass gets trapped into condensed phase carbon clusters at the CJ point, suppressing generation of gaseous CO2 and N2 final products, leading to reduced energy delivery. Our findings suggest that the oxygen balance is an important factor to be considered in the design of the next generation of high-nitrogen-containing EMs.

Theoretical exploration of the stabilities and detonation parameters of nitro-substituted 1H-benzotriazole.

The nitro group was introduced into the nitrogen heterocycle of 1H-benzotriazole to design a total of 31 derivatives. To estimate the thermal stability of these derivatives, the heat of formation (HOF) is calculated based on the isodesmic reaction. The bond dissociation energy (BDE) was also predicted based on the homolytic reaction to further evaluate the dynamic stability. To evaluate the possibility of utilizing as high energy density compounds (HEDCs), the detonation parameters including the detonation pressure (P), detonation velocity (D), and explosive heat (Q) are predicted by taking advantage of the Kamlet-Jacobs empirical equation. To measure the sensitivity to impact, both the characteristic height (H50) and free space in crystal (∆V) are considered in this paper. Based on our calculations, D-series and E are found to be the candidates for HEDCs. The Gaussian 09 software package was used in this paper. The B3PW91 hybrid function with the 6-311 + G(d,p) basis set was chosen to perform the structural optimization, frequency analysis, heat of formation, and bond dissociation energy. The detonation parameters were calculated following the Kamlet-Jacobs equation.

Stabilization of N6 and N8 anionic units and 2D polynitrogen layers in high-pressure scandium polynitrides

Nitrogen catenation under high pressure leads to the formation of polynitrogen compounds with potentially unique properties. The exploration of the entire spectrum of poly- and oligo-nitrogen moieties is still in its earliest stages. Here, we report on four novel scandium nitrides, Sc2N6, Sc2N8, ScN5, and Sc4N3, synthesized by direct reaction between yttrium and nitrogen at 78-125 GPa and 2500 K in laser-heated diamond anvil cells. High-pressure synchrotron single-crystal X-ray diffraction reveals that in the crystal structures of the nitrogen-rich Sc2N6, Sc2N8, and ScN5 phases nitrogen is catenated forming previously unknown N66− and N86− units and ∞2(N53−)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\!\\,}_{\\infty }{\\!\\,}^{2}({{{{{\\rm{N}}}}}}_{5}^{3-})$$\\end{document} anionic corrugated 2D-polynitrogen layers consisting of fused N12 rings. Density functional theory calculations, confirming the dynamical stability of the synthesized compounds, show that Sc2N6 and Sc2N8 possess an anion-driven metallicity, while ScN5 is an indirect semiconductor. Sc2N6, Sc2N8, and ScN5 solids are promising high-energy-density materials with calculated volumetric energy density, detonation velocity, and detonation pressure higher than those of TNT.

Bistriazolotriazole-tetramine: commendable energetic moiety and cation.

Various 7H,7'H-[6,6'-bi[1,2,4]triazolo[4,3-b][1,2,4]triazole]-3,3',7,7'-tetramine (A) based nitrogen-rich energetic salts were designed and their properties explored. All energetic salts possess relatively high nitrogen content (> 48%), positive heats of formation (> 429kJ/mol) and stability owing to a significant contribution from fused backbone. The cationic component shows a very high heat of formation (2516kJ/mol); therefore, it is highly suitable for enthalpy enhancement in new energetic salts. The cation was paired with the energetic anions nitrate (NO3-), perchlorate (ClO4-), dinitromethanide (CH(NO2)2-), trinitromethanide (C(NO2)3-), nitroamide (NHNO2-), and dinitroamide (N(NO2)2-) to improve oxygen balance and detonation performance. Designed salts show moderate detonation velocities (7.9-8.7 km/s) and pressures (23.8 - 33.1 GPa). The distribution of frontier molecular orbitals, molecular electrostatic surface potentials, QTAIM topological properties, and noncovalent interactions of designed salts were simulated to understand the electronic structures, charge distribution in molecules, hydrogen bonding, and other nonbond interactions. The predicted safety factor (SF) and impact sensitivity (H50) of designed salts suggest their insensitivity to mechanical stimuli. This work explored the 7H,7'H-[6,6'-bi[1,2,4]triazolo[4,3-b][1,2,4]triazole]-3,3',7,7'-tetramine as a suitable cationic component which could be promising and serve exemplarily in energetic materials. The optimization and energy calculations of all the designed compounds were carried out at the B3LYP/6-311 + + G(d,p) and M06-2X/def2-TZVPP levels, utilizing the Gaussian software package. The molecular surface electrostatic potential, quantum theory of atoms in molecules (QTAIM), reduced density gradient (RDG), and noncovalent interaction (NCI) analysis were performed by employing Multiwfn software. The EXPLO5 (v 7.01) thermochemical code and PILEM web application were used to predict the detonation properties.

Study on blast-induced vibration of single-hole cylindrical charge

It is essential to study the blast-induced vibration of cylindrical charge so as to reduce ground vibration level and protect the surrounding environment. In this paper, the Heelan model is used to study the generation and propagation mechanisms of blasting vibration induced by single-hole cylindrical charge. It shows that the superposition of vibration waves induced by explosives in different positions of the cylindrical charge causes the increase of peak particle velocity ( PPV) in the region along the propagation direction of detonation waves. The vector peak particle velocity ( VPPV) versus distance for different stemming lengths ( SL) indicates that the linear attenuation between the VPPV and the exponential of distance appears only over a certain distance. Hence, the traditional formula for PPV prediction is suitable just in the middle and far field, not in the near field. The influences of charge length, detonation velocity and initiation pattern on the blast vibration are also investigated. The generation of Mach waves is determined by the relationship of scale between velocity of detonation ( VoD), P-wave velocity, and S-wave velocity. Over a certain value, the charge length doesn’t affect maximum VPPV, but affects the range of VPPV with relatively large values. Moreover, the bottom and top detonator positions have similar consequences on vibration control in the far field as the influence of limited charge length on blast vibration can be ignored. The VPPV of the middle initiating is almost twice as much as the other two detonator positions in the far field. Thus, in practical blasting, the middle initiating needs to be avoided.

Experimental and Theoretical Investigation of External Electric-Field-Induced Crystallization of TKX-50 from Solution by Finite-Temperature String with Order Parameters as Collective Variables for Ionic Crystals.

External electric fields are an effective tool to induce phase transformations. The crystallization of ionic crystals from solution is a common phase transformation. However, understanding of mechanisms is poor at the molecular level. In this work, we carried out an experimental and theoretical investigation of the external electric-field-induced crystallization of TKX-50 from saturated formic acid solution by finite-temperature string (FTS) with order parameters (OPs) as collective variables for ionic crystals. The minimum-free-energy path was sketched by the string method in collective variables. The results show that the K-means clustering algorithm based on Euclidean distance and density weights can be used for enhanced sampling of the OPs in external electric-field-induced crystallization of ionic crystal from solution, which improves the conventional FTS. The crystallization from solution is a process of surface-mediated nucleation. The external electric field can accelerate the evolution of the string and decrease the difference in the potential of mean forces between the crystal and the transition state. Due to the significant change in OPs induced by the external electric field in nucleation, the crystalline quality was enhanced, which explains the experimental results that the external electric field enhanced the density, detonation velocity, and detonation pressure of TKX-50. This work provides an effective way to explore the crystallization of ionic crystals from solution at the molecular level, and it is useful for improving the properties of ionic crystal explosives by using external electric fields.

Modification of an N-Methyl Group toward a New Energetic Melt-Castable Material with a Good Energy-Stability Balance

AbstractThe energy and stability properties of energetic materials are often contradictory to each other (e.g., high energy vs low thermal stability). There is no doubt that it is still challenging to explore the effective balance between energetic performance and molecular stability, especially for melt-castable materials. In this study, we selected the 4-methoxy-3,5-dinitropyrazole framework and a stable nitro group to design a new energetic melt-castable compound, namely 4-methoxy-3,5-dinitro-1-(nitromethyl)-1H-pyrazole (MDNNMP). Compared with the N-methylation product DMDNP and the nitrato-substituted derivative MC-7, MDNNMP exhibits a better balanced performance, including good thermal stability (Td : 203.7 °C), detonation velocity (Dv : 8099 m s–1) and impact sensitivity (20 J). The favorable balanced performance of MDNNMP suggests that it is a suitable candidate as a high-performance melt-castable material. Additionally, compared with the nitratomethyl group, the nitromethyl group demonstrates superior advantages in performance regulation.

Effects of composition on the explosive properties of potassium chlorate and oils

Abstract Potassium chlorate has long been utilized as an excellent oxidizing agent in pyrotechnics and explosives. As mixtures of potassium chlorate and any type of combustible material can be explosive, there is a potential risk of misuse in homemade explosives. Unlike commercial explosives, homemade chlorate and oil mixtures do not have a constant composition, which limits their understanding. This study reports the effects of two types of oil (motor oil and cooking oil) and their ratios (ranging from 2.5% to 40.0% (w/w)) on the explosive properties of such mixtures. The impact sensitivity was highest at a motor oil ratio of 5%. The friction sensitivity increased with an increasing oil ratio, reaching a maximum at an oil ratio of around 22.5%, and was close to those of primary explosives. The motor oil mixtures exhibited higher sensitivity than the cooking oil mixtures at oil ratios of 25% or less. A 10% oil mixture, which was close to the ratio of oxygen balance equal to zero, detonated in weak confinement, such as a paper cylinder. The highest detonation velocities in a polypropylene tube were around 2300 and 2550 m/s at a 10% ratio of motor oil and cooking oil, respectively. The velocities of the metal case wall, measured by photonic Doppler velocimetry, reached about 1100 m/s near the end of acceleration. These results show that homemade chlorate and oil mixtures are capable of detonation and quite sensitive over a wide range of oil ratios, with sufficient power to cause damage in the vicinity.

Imploding Detonation Waves in Self-gravitating Ideal Gas

In the present paper, the propagation of strong spherical imploding detonation waves in a reacting ideal gas under the effect of self-gravitation of the non-homogeneous medium has been investigated, by the help of Chester-Chisnell-Whitham (CCW) theory. It is considered that detonation wave is initially Chapman-Jouguet. Initial taking the density distribution law as power decreasing with distance, the analytical expressions for the detonation velocity just behind the front along with other flow variables are derived. Neglecting the effect of overtaking disturbances the variation of non-dimensional detonation velocity, the pressure and density with the propagation distance have been calculated numerically. The effect of change in density parameter at different Alfven Mach number on the convergence of detonation front have been discussed through graphs in details. Finally, it is found that density parameter and Alfven Mach number of gas have a significant role on propagation of strong spherical detonation front in reacting ideal gas with gravitation effect on all the post-flow variables. The software MATLAB have been used for computation of the problem. Keywords: Self-gravitating gas, Strong detonation waves, CCW theory.

Comparative study on detonation parameters of ammonium dinitramide and ammonium perchlorate in composite explosives

ABSTRACT Ammonium dinitramide (ADN) has the advantages of chlorine free, low characteristic signal and high energy compared with ammonium perchlorate (AP), which is the most likely oxidant to replace ammonium perchlorate. Therefore, we conducted theoretical calculations to analyze the influence of oxidant content and RDX content on the detonation parameters of composite explosives. We compared the detonation parameters of ADN-based composite explosives with AP-based composite explosives, then verify the theoretical calculation analysis results through actual testing. The main research conclusions of this paper are as follows: (i) The detonation parameters of ADN based composite explosive are higher than those of AP-based composite explosive, in which the detonation velocity is about 3.3%~17.2% higher, the detonation heat is about 0.65% ~41.8% higher, and the explosion volume is about 1.6% ~11.6% higher; (ii) the average detonation velocity of the ADN-based explosives tested in practice is 20.4% and 3% higher than that of AP-based explosives respectively, which is basically consistent with the theoretical calculation results. However, the work capacity is lower than that of AP-based composite explosive.

Impact of Velocity of Detonation and Charge per Bank Cubic Meters on Flyrock Throw Prediction Using Support Vector Machine

One of the ambient effects of production blasting is flyrock. To effectively manage flyrock throw distance in mining, there is the necessity to successfully envisage blasting output without sacrificing the hazardous impact of flyrock which may result in fatality and operational shutdown. For flyrock throw distance prediction, velocity of detonation (VOD) and charge per bank cubic meter (CPBCM) are not usually included. This paper focuses on the use of support vector machine (SVM) regression to ascertain the impact of VOD and CPBCM on flyrock throw predictions. The machine learning models were linear support vector machine (LSVM), quadratic Gaussian support vector machine (QGSVM), fine Gaussian support vector machine (FGSVM), medium Gaussian support vector machine (MGSVM), and cubic Gaussian support vector machine (CGSVM). The outcome indicates that FGSVM was the most sensitive with a 4% improvement when VOD and CPBCM were included. As a result, the LSVM model provides a suitable AI competitive alternative tool for flyrock throw prediction in mining operations by incorporating VOD and CPBCM.

Thermal decomposition kinetics and compatibility of NH3OHN5

AbstractHydroxylammonium cyclo‐pentazolate (NH3OHN5), as one of the poly‐nitrogen compounds, has a broad prospect in the field of energetic materials, due to its high specific impulse, high detonation velocity, and the pollution‐free products. In this paper, the thermal decomposition behavior of NH3OHN5 was studied by differential scanning calorimetry (DSC) using four heating rates (2, 5, 8, 10 °C min−1). The apparent activation energy (EK,O=114.31 kJ mol−1), the pre‐exponential factor (AK=4.78×1011 s−1) and the critical temperature of the thermal explosion (Tb=108.08 °C) of NH3OHN5 were calculated by Kissinger and Ozawa method under non‐isothermal heating conditions. The compatibility of NH3OHN5 with 1,3,5‐trinitro‐1,3,5‐triazacyclohexane (RDX), 1,3,5,7‐tetranitro‐1,3,5,7‐tetraazacyclooctane (HMX), 2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaza‐isowurtzitane (CL‐20), ammonium perchlorate (AP), and hydroxy‐terminated polybutadiene (HTPB) were tested and judged based on a standard agreement (STANAG‐4147). The DSC results showed that NH3OHN5/HMX, NH3OHN5/RDX, NH3OHN5/CL‐20, NH3OHN5/AP and NH3OHN5/HTPB had good compatibility.

A density functional theory investigation of the substituent effect on acyclovir and guanine derivatives for applications on energetic materials

The main challenge in designing new energetic materials is to find a good balance between four seemingly incompatible requirements, namely, high-energy content, low sensitivity, low production costs and less-polluting content. Fused nitrogen heterocycles of imidazole and pyrimidine, such as acyclovir and guanine, may offer interesting features due to the combination of a coplanar framework and a large conjugate system, which contribute to a reduced sensitivity, and a number of energetic bonds that can be increased by the introduction of explosophore substituents. In this work, to evaluate the potential of acyclovir and guanine derivatives as energetic materials, density functional theory (DFT) calculations were carried out to investigate the influence of the type and position of the explosophore substituent groups –NO2, –NHNO2, –N3, –ONO2, –CN, −N=N−, and −N=N(O)− on the energetic properties and chemical reactivity of 91 acyclovir- and guanine-based molecules, including thirty one nitramines, three nitroheterocycles, seventeen azides, seventeen nitrate esters, seventeen nitriles, three azo and three azoxy compounds. Several molecular properties were computed, including the chemical reactivity, the heat of formation and the detonation velocities and pressures using semiempirical equations. Among the molecules with no bridge groups, we found that, except for cyano group, position 4 were the most stable for acyclovir derivatives, whereas, except for the azido group, position 2 and 5 provided the most stable compounds for guanine derivatives. Among the bridged derivatives, depending on the molecule and positions, the nitrate esters and the nitro derivatives were more stable. In comparison with the parent compounds, calculations showed that the heat of formation (HOF) increased the most with azido and cyano groups, the density increased substantially with nitrate esters, nitro and nitramino groups, and the detonation velocities and pressures increased the most with nitrate ester, nitro and nitramino groups. Although azo groups resulted in higher HOFs than azoxy groups, azoxy derivatives showed superior values in terms of density, heat of maximum detonation, detonation velocity and pressure. Four nitrate esters (GD134, GD245, AZOXYGD13 and AZOXYGD25) displayed higher values of detonation velocity and pressure than RDX. The designed nitramines are less sensitive to impact than RDX. Except for GD134 and GD245, all guanine-based nitrate esters, with no bridge linkages, are expected to be less sensitive to impact than TNT. Due to the combination of good performance and stability, the compounds GD25, GD13, GD45, GD34, and GD14 have considerable potential as energetic materials. Therefore, their synthesis and further investigation are recommended.

Effects of swirling inflow on the stability and combustion mode of rotating detonations

In this study, a novel approach for enhancing the stability of rotating detonation waves (RDWs) with the use of a swirling inflow strategy is presented. A series of numerical simulations are carried out by solving the two-dimensional reactive Navier–Stokes equations. The effects of the swirling angle on the stability of the RDWs and the combustion mode are analyzed. The results show that the formation of the burnt gas bumps is suppressed by the implementation of a swirling inflow. The swirling inflow also contributes to an increased homogeneity of the reactant within the fuel refill zone. As a result, a remarkable enhancement of the stability of the RDWs in terms of their oscillations in heights and inclined angles is achieved without an apparent compromise of the heights of the RDWs. The propagation speeds of the RDWs are controllable within a wide range approximately from 81% to 114% of the Chapman–Jouguet detonation speed by adjusting the swirling angle. Moreover, the oscillations in the instantaneous fuel consumption rates of both detonative and deflagrative combustion are dominated by the oscillation in the height of the RDW; hence, the swirling inflow reduces the oscillations in these two fuel consumption rates and subsequently the detonation fraction. Consequently, the smoothness of the performance output in terms of specific impulses can be significantly improved with a reduced standard deviation of oscillation up to 84% by the implementation of swirling inflows, and the averaged specific impulse only encounters a small deficit of no more than 7.4%.