In rock drilling and blasting,the misfire of electronic detonators will not only affect the rock fragmentation result but also bring serious potential safety hazards to engineering construction.An accurate and compreh...In rock drilling and blasting,the misfire of electronic detonators will not only affect the rock fragmentation result but also bring serious potential safety hazards to engineering construction.An accurate and comprehensive understanding of the failure mechanisms of electronic detonators subjected to impact loading is of great significance to the reliability design and field safety use of electronic detonators.The spatial distribution characteristics and failure modes of misfired electronic detonators under different application scenarios are statistically analysed.The results show that under high impact loads,electronic detonators will experience failure phenomena such as rupture of the fuse head,fracture of the bridge wire,falling off of the solder joint,chip module damage and insufficient initiation energy after deformation.The lack of impact resistance is the primary cause of misfire of electronic detonators.Combined with the underwater impact resistance test and the impact load test in the adjacent blasthole on site,the formulas of the impact failure probability of the electronic detonator under different stress‒strength distribution curves are deduced.The test and evaluation method of the impact resistance of electronic detonators based on stress‒strength interference theory is proposed.Furthermore,the impact failure model of electronic detonators considering the strength degradation effect under repeated random loads is established.On this basis,the failure mechanism of electronic detonators under different application environments,such as open-pit blasting and underground blasting,is revealed,which provides scientific theory and methods for the reliability analysis,design and type selection of electronic detonators in rock drilling and blasting.展开更多
Aiming to know the requirement of penetrating the munition semiconductor bridge detonator under the impact overload environment, the impact overload simulation device and the structural finite element software ANSYS/A...Aiming to know the requirement of penetrating the munition semiconductor bridge detonator under the impact overload environment, the impact overload simulation device and the structural finite element software ANSYS/AUTODYN are used to study the variation of the axial dimension, charge and the chip gap of the semiconductor bridge detonator under the impact overload environment. The typical semiconductor bridge detonator is affected by the acceleration, and the strain increases with the increase of the acceleration. The semiconductor bridge detonator shows axial compression, in which the size becomes smaller, and the structural deformation occurs at the output end of the semiconductor bridge detonator. The typical semiconductor bridge detonator is elastically deformed when the acceleration is less than 40 000 g. When the acceleration is more than40 000 g, the semiconductor bridge detonator housing is plastically deformed. The gap between the drug column and the chip is divided into three stages with the increase of the acceleration. Initially,with the increase of the acceleration, the gap rises rapidly until the acceleration reaches 43 000 g,and when the gap reaches the maximum, the gap decreases rapidly with the increase of the acceleration. When the acceleration reaches 57 000 g, the gap tends to be 0 μm in the initial state, and then the gap does not change with the acceleration to keep tending to 0 μm.展开更多
The laser-cladding technique for welding of bridge wires is reported for the first time.The essen- tial feature of this technique different from the cur- rent methods is the realization of mutual melting of workpieces...The laser-cladding technique for welding of bridge wires is reported for the first time.The essen- tial feature of this technique different from the cur- rent methods is the realization of mutual melting of workpieces.Thus the stability of products is im- proved in an order of magnitude.The main points of the technique and the microanalyses of the weld- ing spot and other features are given.The technique presented is a novel method of welding between tiny piece and workpiece of different sizes and proper- ties.展开更多
Through the failure mechanism analysi s and simulation test of a certain kind of detonator,this paper confirms the str ess level of the stepping stress acceleration life test of the detonator,and t hen e stablishes th...Through the failure mechanism analysi s and simulation test of a certain kind of detonator,this paper confirms the str ess level of the stepping stress acceleration life test of the detonator,and t hen e stablishes the data processing mathematical model and storage life forecasting m ethod.At last,according to the result of the stepping stress acceleration lif e test of the detonator,this paper forecasts the reliable storage life of the detonator under the normal stress level.展开更多
The NONEL high precision MS Delay Detonator (FDG-1detonator) is introduced. The main aspects about the FDG-1 detonator include the choice of structure, delay composition, control of the gas chamber, optimum charge and...The NONEL high precision MS Delay Detonator (FDG-1detonator) is introduced. The main aspects about the FDG-1 detonator include the choice of structure, delay composition, control of the gas chamber, optimum charge and density, suitable explosives per meter in the NONEL tube, base firing charge and the main specifications. The improvement of the characteristics of FDG-1 detonator has been tested systematically. The testing method is reliable and its precision can meet the demand for usage.展开更多
Electronic detonators are widely used because of their advantages in real-time supervision of the whole life cycle (Zang, 2022). Due to the high requirements of the time difference synchronization between the electron...Electronic detonators are widely used because of their advantages in real-time supervision of the whole life cycle (Zang, 2022). Due to the high requirements of the time difference synchronization between the electronic initiation system and the seismic wave recording system, the Electronic detonator has not been widely used for Seismic exploration (Yang, 2020). This paper expounds the systematic and scientific test method from the aspects of the comprehensive performance of electronic detonators for exploration, the compatibility between the electronic detonator initiation system and the geophysical blasting machine system, the constraints of the geophysical explosion-related collaborative Danling managment cloud platform, and the quality of data collected by electronic detonator blasting in wells., and based on the analysis of the test results, the problems that need to be improved in the application of electronic detonators and detonation systems in the large-scale production of geophysical prospecting industry are put forward. .展开更多
To elucidate the dispersion and explosion characteristics of multi-metal powder and liquid composite fuel formulations,high-energy metal powders(aluminum(Al),boron(B),and magnesium hydride(MgH_(2)))are incorporated in...To elucidate the dispersion and explosion characteristics of multi-metal powder and liquid composite fuel formulations,high-energy metal powders(aluminum(Al),boron(B),and magnesium hydride(MgH_(2)))are incorporated into a liquid fuel primarily composed of diethyl ether(DEE)and isopropyl nitrate(IPN).The explosion characteristics of different solid-liquid fuel-air-explosive(FAE)under unconfined conditions are investigated using a high-speed camera,infrared thermal imaging,and a pressure measurement system.Results demonstrate that high-energy metal powders significantly enhance detonation energy dissipation,with aluminum exhibiting the most pronounced effect.Fuel 5#(45.4 wt%DEE,9.2 wt%IPN,29.5 wt%Al,9.1 wt%B,6.8 wt%MgH_(2))exhibits superior explosion performance,achieving higher values of overpressure,impulse,and thermal radiation damage during the detonation stage compared to other fuels.However,Fuel 5#also displays faster decay rates,attributed to accelerated heat release rates induced by B and MgH_(2)powders.This study reveals that different metal powders in solid-liquid FAE exhibit distinct enhancements in explosion performance,providing critical insights for optimizing composite fuel design.展开更多
Excellent detonation performances and low sensitivity are prerequisites for the deployment of energetic materials.Exploring the underlying factors that affect impact sensitivity and detonation performances as well as ...Excellent detonation performances and low sensitivity are prerequisites for the deployment of energetic materials.Exploring the underlying factors that affect impact sensitivity and detonation performances as well as exploring how to obtain materials with desired properties remains a long-term challenge.Machine learning with its ability to solve complex tasks and perform robust data processing can reveal the relationship between performance and descriptive indicators,potentially accelerating the development process of energetic materials.In this background,impact sensitivity,detonation performances,and 28 physicochemical parameters for 222 energetic materials from density functional theory calculations and published literature were sorted out.Four machine learning algorithms were employed to predict various properties of energetic materials,including impact sensitivity,detonation velocity,detonation pressure,and Gurney energy.Analysis of Pearson coefficients and feature importance showed that the heat of explosion,oxygen balance,decomposition products,and HOMO energy levels have a strong correlation with the impact sensitivity of energetic materials.Oxygen balance,decomposition products,and density have a strong correlation with detonation performances.Utilizing impact sensitivity of 2,3,4-trinitrotoluene and the detonation performances of 2,4,6-trinitrobenzene-1,3,5-triamine as the benchmark,the analysis of feature importance rankings and statistical data revealed the optimal range of key features balancing impact sensitivity and detonation performances:oxygen balance values should be between-40%and-30%,density should range from 1.66 to 1.72 g/cm^(3),HOMO energy levels should be between-6.34 and-6.31 eV,and lipophilicity should be between-1.0 and 0.1,4.49 and 5.59.These findings not only offer important insights into the impact sensitivity and detonation performances of energetic materials,but also provide a theoretical guidance paradigm for the design and development of new energetic materials with optimal detonation performances and reduced sensitivity.展开更多
The selection of an appropriate basic detonation wave flow field is crucial for improving the performance and geometric design of standing detonation vehicles.This paper employs a detailed chemical reaction model and ...The selection of an appropriate basic detonation wave flow field is crucial for improving the performance and geometric design of standing detonation vehicles.This paper employs a detailed chemical reaction model and solves the unsteady axisymmetric Euler equation to study the characteristics of the Axisymmetric Inward Turning Curved Detonation Wave(AIT-CDW)flow field and the parameters affecting the stability of the wave system structure of AIT-CDW flow field.The numerical results demonstrate a radial compression effect in the AIT-CDW flow field.This effect causes the detonation wave to have a shorter initiation length than oblique detonation wave flow field and the detonation wave angle to gradually increase with the flow direction postdetonation.The AIT-CDW flow field is confined space,making it prone to normal detonation waves when the detonation wave reflects from the wall.This phenomenon is detrimental to the stability of the wave system structure in the flow field.It has been observed that increasing the center body radius and decreasing the fuel equivalent ratio can effectively reduce the height of the normal detonation wave or even eliminate it.Additionally,a well-designed generatrix shape of the center body can enhance airflow,reduce choked flow,and promote the stability of the wave structure in the flow field.展开更多
Rectangular explosive charges are usually used in military or civilian explosive transportation and storage.The effects of shape parameters and detonation positions on the peak overpressure and maximum impulse of blas...Rectangular explosive charges are usually used in military or civilian explosive transportation and storage.The effects of shape parameters and detonation positions on the peak overpressure and maximum impulse of blasts lack comprehensive investigation,which is significant for the design of blast-resistant structures.In this paper,the side-length ratio of the rectangle,orientation,and detonation position of the charge are chosen as controlling parameters to investigate their influence on blast loads in the scaled distances of the gauges ranging from 0.63 to 10.54 m/kg^(1/3) with well validated 3D numerical simulations.The results show that there is a large difference in the near-field spatial distribution of the blast load of the rectangular charge;if the blast load of the rectangular charge is simply evaluated with the spherical charge,the maximum peak overpressure(maximum impulse)will be underestimated by a factor of 7.46(4.84).This must be taken seriously by blast-resistant structure designers.With the increase in the scaled distance,when the critical scaled distance is greater than 6.32(7.38)m/kg^(1/3),the influence of the charge shape on the maximum peak overpressure(maximum impulse)of the spatial blast load can be ignored.In general,the impact of detonation of the charge at the end on the maximum peak overpressure is greater compared with central detonation,but for the impact of the maximum impulse,it is necessary to pay attention to the side-length ratio of the rectangular charge and the specific detonation position on the end face.Furthermore,the structural response of steel plates placed at different azimuths under the blast load of a rectangular charge is preliminarily analyzed,and the results show that the deformation and energy of the plates are consistent with the distribution of the blast load.These analysis results provide a reference for the explosion protection design in near-field air explosions.展开更多
To explore the design criteria for composite charges and reveal the intrinsic relationship between the detonation wave propagation in composite charges and the overall energy distribution of shock waves,this study ana...To explore the design criteria for composite charges and reveal the intrinsic relationship between the detonation wave propagation in composite charges and the overall energy distribution of shock waves,this study analyzes the propagation and interaction processes of detonation waves in composite charges with different structural dimensions and explosive combinations. It also investigates the spatial distribution characteristics of the resulting shock wave loads. Based on dimensional analysis theory, a theoretical analysis of the shock wave overpressure distribution in free air fields is conducted. Utilizing the derived dimensionless function relationships, the hydrocode AUTODYN is employed to investigate the effects of charge structure parameters and explosive combinations on the internal overdriven detonation phenomena and the distribution of shock wave loads. It is found that the overdriven detonation phenomenon in the inner layer of composite charges increases the strength of the axial detonation wave,thereby enhancing the intensity of the primary end wave formed upon refraction into the air, which affects the distribution characteristics of the shock wave overpressure. Research has shown that increasing the thickness ratio and detonation velocity ratio of composite charges is beneficial for exacerbating the phenomenon of overdriven detonation, improving the primary end wave intensity and axial overpressure. This gain effect gradually weakens with the propagation of shock waves. When overdriven detonation occurs inside the composite charge, the detonation pressure first increases and then decreases. The Mach reflection pressure of the composite charge with a larger aspect ratio is attenuated to a greater extent. In addition, as the aspect ratio of the composite charge increases, the shock wave energy gradually flows from the axial direction to the radial direction. Therefore, as the aspect ratio of the composite charge increases, the primary end wave intensity and axial overpressure gradually decrease.展开更多
Research on detonation has traditionally focused on forward solutions,with limited attention to inverse design methods,which has significantly hindered the development of detonation engines.In this paper,the Method of...Research on detonation has traditionally focused on forward solutions,with limited attention to inverse design methods,which has significantly hindered the development of detonation engines.In this paper,the Method of characteristics for Curved-Detonation(MOCD)is proposed to enable the inverse design of detonation waves.MOCD is based on the Method of Curved-shock Characteristics(MOCC)and integrates higher-order aerodynamic parameters from Curved Detonation Equations(CDE),allowing the calculation of the wedge angle given specific wave angle.The effectiveness of MOCD is validated using both oblique and curved detonation waves with single-step and detailed chemical reactions.Various applications demonstrate the ability to meet the inverse design requirements of detonation engines.For example,inverse design for given wave angles can optimize engine thrust and prevent Mach reflections.Additionally,inverse design schemes tailored to incoming flow conditions,such as varying Mach numbers and equivalence ratios,enhance the feasibility of detonation engines.Applying the method to given post-wave aerodynamic parameters enables more precise engine design,which is crucial for improving propulsion performance and effective thermal protection.In summary,the advantages of MOCD include not only performing a fast solution of the detonation flow field,but also allowing the inverse design of the detonation wave.展开更多
This study investigates the paradoxical detonation behavior of TKX-50,a nitrogen-rich energetic material,exhibiting higher detonation velocities but lower metal acceleration ability compared to HMX.Through experimenta...This study investigates the paradoxical detonation behavior of TKX-50,a nitrogen-rich energetic material,exhibiting higher detonation velocities but lower metal acceleration ability compared to HMX.Through experimental measurements and theoretical calculations,we propose a novel three-factor competition mechanism to explain this phenomenon.TKX-50-based PBX formulations achieved detonation velocities up to 9100 m/s,surpassing HMX-based counterparts.However,cylinder expansion tests revealed a 15%reduction in metal acceleration ability.Thermochemical measurements showed lower detonation heat for TKX-50(4900 J/g)versus HMX(5645 J/g).Our mechanism involves:(1)compositional effects prevailing at high pressures;(2)Energy release becoming essential as pressure drops;(3)Pressure-dependent product composition evolution functioning at low pressure.VLW code calculations unveiled a"crossover"in Hugoniot curves,lending support to this mechanism.This study furnishes a new framework for comprehending the performance of nitrogen-rich energetic materials,with significant implications for the design and optimization of future high-energy density materials.展开更多
In this study,we aimed to investigate the detonation wave characteristics of a gel propellant with high boron content.A steady-state detonation wave model of a boron-based gel propellant considering the latent heat of...In this study,we aimed to investigate the detonation wave characteristics of a gel propellant with high boron content.A steady-state detonation wave model of a boron-based gel propellant considering the latent heat of phase change was proposed.The detonation wave model was validated through a comparative analysis with shock tube experiments,which revealed that the maximum deviation in the calculated peak detonation pressure was 8%based on various initial pressures.Upon iterative calculations,the eigenvalue detonation velocity of the boron-based gel propellant under default working conditions was obtained as 1831.5 m/s.Subsequently,the refined model was used to study the structure and characteristics of the detonation wave flow field.The effects of incoming flow conditions,fuel parameters,and initial operating state on the detonation wave flow field of the propellant were investigated numerically.The findings revealed that stable and self-sustaining propagation of the detonation wave can be achieved only when its propagation velocity matches the eigenvalue detonation velocity.Note that an increase in initial temperature resulted in elevated gas phase temperature,density,detonation pressure,and particle phase temperature.An increase in boron content within the gel propellant increased the gas phase temperature but decreased the gas phase density and detonation pressure.At the Chapman-Jouguet(CJ)plane,the gas phase temperature and density,along with the particle phase temperature and detonation pressure,reached their peak values when the oxidizer reacted with the propellant in accordance with the stoichiometric ratio.展开更多
The distribution of exothermic reaction rates is jointly influenced by reduced activation energy and reaction rate constant.This study focuses on the effect of distribution of exothermic reaction rates on detonation w...The distribution of exothermic reaction rates is jointly influenced by reduced activation energy and reaction rate constant.This study focuses on the effect of distribution of exothermic reaction rates on detonation wave propagation instability,specifically under conditions where the length of the induction and exothermic reaction remains constant.It is found that the distribution variation of exothermic reaction rates significantly influences the detonation wave propagation characteristics.Specifically,under conditions of high activation energy,the exothermic reaction rate profile exhibits a smoother distribution but becomes more prone to perturbations.This heightened sensitivity,coupled with the augmented overdriven degree associated with pulsating detonation and cellular detonation wave propagation,further exacerbates the instability characteristics of detonation waves.Especially to the two-dimensional detonation waves with high activation energies,the distribution of exothermic reaction rates becomes more sensitive to these displacements,reinforcing the transverse shock wave and leading to a transformation of the wavefront and cellular structure towards more unstable configurations.This research delves into the intricate interactions between the distribution of exothermic reaction rates and detonation wave instability,aiming to provide an explanatory of detonation instability.展开更多
In order to find the optimal anions and cations for designing energetic salts with excellent detonation properties,the properties of 140 salts formed from the anions(A–G)of 3,3′-dinitroamino-4,4′-azoxyfurazan(DAAF)...In order to find the optimal anions and cations for designing energetic salts with excellent detonation properties,the properties of 140 salts formed from the anions(A–G)of 3,3′-dinitroamino-4,4′-azoxyfurazan(DAAF)derivatives substituted with the—NH_(2),—N_(3) or—NO_(2) group and the cations(1–20)of guanidine,triazole,or tetrazole derivatives were investigated by means of density-functional theory.The predicted densities,heats of formation,detonation velocities(D),and detonation pressures(P)of 140 salts were 11.72 to 2.06 g·cm ^(−3),570.2 to 2333.4 kJ·mol^(−1),8.29 to 10.02 km·s^(−1) and 30.16 to 47.57 GPa,respectively.Most of the salts had better detonation properties than the widely used hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX).Salts containing—NO_(2) group anions(C and F)have better detonation properties(D is 8.88 to 10.02 km·s^(−1) and P is 35.75 to 47.75 GPa)than other salts.Salts containing the cations NH_(4)^(+)(1),NH_(3)OH^(+)(2)and CH_(2)N_(4)NO_(2)^(+)(20)had good detonation properties(D is 9.38 to 10.02 km·s^(−1) and P is 40.72 to 47.75 GPa).Depending on the detonation properties,anions(C and F)and cations(1,2 and 20)are the recommended ions for the generation of energetic salts.展开更多
This study investigates the mixing enhancement mechanism and propagation characteristics of the detonation flow field of a Rotating Detonation Engine(RDE).Three-dimensional numerical simulations of a non-premixed ramj...This study investigates the mixing enhancement mechanism and propagation characteristics of the detonation flow field of a Rotating Detonation Engine(RDE).Three-dimensional numerical simulations of a non-premixed ramjet-based RDE fueled by gaseous ethylene are performed in OpenFOAM for configurations with 15,30,45,and 60 orifices at a flight Mach number of 4.The results show that fuels with a stripped distribution are primarily mixed via tangential diffusion in the cold flow field.The configuration with more orifices has a better upstream mixing efficiency,whereas its downstream mixing efficiency,which is limited by the depth of penetration,is difficult to improve further.Backward Pressure Perturbations(BPPs)opposite to the propagation direction of Rotating Detonation Waves(RDWs)are produced by the reflection of the upstream oblique shock wave with the incoming stream and the hot release of local reactions after RDWs,which significantly affects the propagation mode and mixing.The RDWs propagate in the stable single-wave mode in configurations with 45 or 60 orifices and in the multi-wave mode in configurations with 30 orifices,whereas they fail in configurations with 15 orifices.Compared with that in the cold flow field,deceleration of the main flow,pressurization,and tangential velocity perturbation caused by the RDW substantially enhance the mixing efficiency.Moreover,the tangential velocity perturbations of upstream oblique shock waves and BPPs reduce the unevenness of the fuel distribution for the next cycle.This study reveals the mixing enhancement mechanism of RDWs and can contribute to the design of the injection scheme of the RDE.展开更多
In this study, the three-dimensional non-premixed two-phase kerosene/air rotating detonation engines with different isolator configurations and throat area ratios are simulated by the Eulerian-Lagrangian method. The e...In this study, the three-dimensional non-premixed two-phase kerosene/air rotating detonation engines with different isolator configurations and throat area ratios are simulated by the Eulerian-Lagrangian method. The effects of the divergence, straight, and convergence isolators on the rotating detonation wave dynamics and the upstream oblique shock wave propagation mechanism are analyzed. The differences in the rotating detonation wave behaviors between ground and flight operations are clarified.The results indicate that the propagation regimes of the upstream oblique shock wave depend on the isolator configurations and operation conditions. With a divergence isolator, the airflow is accelerated throughout the isolator and divergence section, leading to a maximum Mach number(~1.8) before the normal shock. The total pressure loss reaches the largest, and the detonation pressure drops. The upstream oblique shock wave can be suppressed within the divergence section with the divergence isolator.However, for the straight and convergence isolators, the airflow in the isolator with a larger ψ_(1)(0.3 and0.4) can suffer from the disturbance of the upstream oblique shock wave. The critical incident angle is around 39° at ground operation conditions. The upstream oblique shock wave tends to be suppressed when the engine operates under flight operation conditions. The critical pressure ratio β_(cr0) is found to be able to help in distinguishing the propagation regimes of the upstream oblique shock wave. Slightly below or above the β_(cr0) can obtain different marginal propagation results. The high-speed airflow in the divergence section affects the fuel droplet penetration distance, which deteriorates the reactant mixing and the detonation area. Significant detonation velocity deficits are observed and the maximum velocity deficit reaches 26%. The results indicate the engine channel design should adopt different isolator configurations based on the purpose of total pressure loss or disturbance suppression. This study can provide useful guidance for the channel design of a more complete two-phase rotating detonation engine.展开更多
The incorporation of fluorine(F_(2)) into hydrogen-air(H_(2)/Air) mixtures presents a novel approach to enhancing the performance of rotating detonation engines(RDEs). This study systematically investigates the effect...The incorporation of fluorine(F_(2)) into hydrogen-air(H_(2)/Air) mixtures presents a novel approach to enhancing the performance of rotating detonation engines(RDEs). This study systematically investigates the effects of F_(2)concentration and inlet mass flow rate on rotating detonation wave(RDW) propagation using two-dimensional numerical simulations, providing the first comprehensive analysis of F_(2)as an oxidizing additive in regulating detonation performance, propagation stability, and heat release dynamics in RDEs. The results indicate that when F_(2)concentration is below 1%, the flow field primarily exhibits a stable single-wave propagation mode. As F_(2)concentration increases, RDW performance initially improves but then deteriorates, reaching its optimal state at 0.8% F_(2). When F_(2)concentration exceeds 1%, the coupled effects of F_(2)concentration and inlet mass flow rate induce a transition from single-wave to multi-wave propagation modes. While a higher inlet mass flow rate promotes increased wave numbers, it also intensifies wave-wave interactions. With further increases in F_(2)concentration, the enhanced heat release leads to intensified local deflagration, frequent hotspot formation, and wave collisions, ultimately degrading RDW performance and destabilizing the multi-wave flow field. Moreover, excessive HF formation is identified as a critical driver of enhanced deflagration, hotspot generation,and the disruption of multi-wave stability. These findings provide a theoretical foundation for integrating F_(2)additives into H_(2)/Air-based RDE systems.展开更多
基金supported by the Chongqing Youth Talent Support Program(Cstc2022ycjh-bgzxm0079)the Chinese National Natural Science Foundation(52379128,51979152)+2 种基金Science Fund for Distinguished Young Scholars of Hubei Proivnce(2023AFA048)Educational Commission of Hubei Province of China(T2020005)the Young Top-notch Talent Cultivation Program of Hubei Province.
文摘In rock drilling and blasting,the misfire of electronic detonators will not only affect the rock fragmentation result but also bring serious potential safety hazards to engineering construction.An accurate and comprehensive understanding of the failure mechanisms of electronic detonators subjected to impact loading is of great significance to the reliability design and field safety use of electronic detonators.The spatial distribution characteristics and failure modes of misfired electronic detonators under different application scenarios are statistically analysed.The results show that under high impact loads,electronic detonators will experience failure phenomena such as rupture of the fuse head,fracture of the bridge wire,falling off of the solder joint,chip module damage and insufficient initiation energy after deformation.The lack of impact resistance is the primary cause of misfire of electronic detonators.Combined with the underwater impact resistance test and the impact load test in the adjacent blasthole on site,the formulas of the impact failure probability of the electronic detonator under different stress‒strength distribution curves are deduced.The test and evaluation method of the impact resistance of electronic detonators based on stress‒strength interference theory is proposed.Furthermore,the impact failure model of electronic detonators considering the strength degradation effect under repeated random loads is established.On this basis,the failure mechanism of electronic detonators under different application environments,such as open-pit blasting and underground blasting,is revealed,which provides scientific theory and methods for the reliability analysis,design and type selection of electronic detonators in rock drilling and blasting.
文摘Aiming to know the requirement of penetrating the munition semiconductor bridge detonator under the impact overload environment, the impact overload simulation device and the structural finite element software ANSYS/AUTODYN are used to study the variation of the axial dimension, charge and the chip gap of the semiconductor bridge detonator under the impact overload environment. The typical semiconductor bridge detonator is affected by the acceleration, and the strain increases with the increase of the acceleration. The semiconductor bridge detonator shows axial compression, in which the size becomes smaller, and the structural deformation occurs at the output end of the semiconductor bridge detonator. The typical semiconductor bridge detonator is elastically deformed when the acceleration is less than 40 000 g. When the acceleration is more than40 000 g, the semiconductor bridge detonator housing is plastically deformed. The gap between the drug column and the chip is divided into three stages with the increase of the acceleration. Initially,with the increase of the acceleration, the gap rises rapidly until the acceleration reaches 43 000 g,and when the gap reaches the maximum, the gap decreases rapidly with the increase of the acceleration. When the acceleration reaches 57 000 g, the gap tends to be 0 μm in the initial state, and then the gap does not change with the acceleration to keep tending to 0 μm.
文摘The laser-cladding technique for welding of bridge wires is reported for the first time.The essen- tial feature of this technique different from the cur- rent methods is the realization of mutual melting of workpieces.Thus the stability of products is im- proved in an order of magnitude.The main points of the technique and the microanalyses of the weld- ing spot and other features are given.The technique presented is a novel method of welding between tiny piece and workpiece of different sizes and proper- ties.
文摘Through the failure mechanism analysi s and simulation test of a certain kind of detonator,this paper confirms the str ess level of the stepping stress acceleration life test of the detonator,and t hen e stablishes the data processing mathematical model and storage life forecasting m ethod.At last,according to the result of the stepping stress acceleration lif e test of the detonator,this paper forecasts the reliable storage life of the detonator under the normal stress level.
文摘The NONEL high precision MS Delay Detonator (FDG-1detonator) is introduced. The main aspects about the FDG-1 detonator include the choice of structure, delay composition, control of the gas chamber, optimum charge and density, suitable explosives per meter in the NONEL tube, base firing charge and the main specifications. The improvement of the characteristics of FDG-1 detonator has been tested systematically. The testing method is reliable and its precision can meet the demand for usage.
文摘Electronic detonators are widely used because of their advantages in real-time supervision of the whole life cycle (Zang, 2022). Due to the high requirements of the time difference synchronization between the electronic initiation system and the seismic wave recording system, the Electronic detonator has not been widely used for Seismic exploration (Yang, 2020). This paper expounds the systematic and scientific test method from the aspects of the comprehensive performance of electronic detonators for exploration, the compatibility between the electronic detonator initiation system and the geophysical blasting machine system, the constraints of the geophysical explosion-related collaborative Danling managment cloud platform, and the quality of data collected by electronic detonator blasting in wells., and based on the analysis of the test results, the problems that need to be improved in the application of electronic detonators and detonation systems in the large-scale production of geophysical prospecting industry are put forward. .
基金supported by the National Natural Science Foundation of China(Grant No.12402432)Natural Science Foundation of Jiangsu Province of China(Grant No.BK20230936)Graduate Education and Teaching Reform Project of Nanjing University of Science and Technology(Grant No.KT2024_C14)。
文摘To elucidate the dispersion and explosion characteristics of multi-metal powder and liquid composite fuel formulations,high-energy metal powders(aluminum(Al),boron(B),and magnesium hydride(MgH_(2)))are incorporated into a liquid fuel primarily composed of diethyl ether(DEE)and isopropyl nitrate(IPN).The explosion characteristics of different solid-liquid fuel-air-explosive(FAE)under unconfined conditions are investigated using a high-speed camera,infrared thermal imaging,and a pressure measurement system.Results demonstrate that high-energy metal powders significantly enhance detonation energy dissipation,with aluminum exhibiting the most pronounced effect.Fuel 5#(45.4 wt%DEE,9.2 wt%IPN,29.5 wt%Al,9.1 wt%B,6.8 wt%MgH_(2))exhibits superior explosion performance,achieving higher values of overpressure,impulse,and thermal radiation damage during the detonation stage compared to other fuels.However,Fuel 5#also displays faster decay rates,attributed to accelerated heat release rates induced by B and MgH_(2)powders.This study reveals that different metal powders in solid-liquid FAE exhibit distinct enhancements in explosion performance,providing critical insights for optimizing composite fuel design.
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.2682024GF019)。
文摘Excellent detonation performances and low sensitivity are prerequisites for the deployment of energetic materials.Exploring the underlying factors that affect impact sensitivity and detonation performances as well as exploring how to obtain materials with desired properties remains a long-term challenge.Machine learning with its ability to solve complex tasks and perform robust data processing can reveal the relationship between performance and descriptive indicators,potentially accelerating the development process of energetic materials.In this background,impact sensitivity,detonation performances,and 28 physicochemical parameters for 222 energetic materials from density functional theory calculations and published literature were sorted out.Four machine learning algorithms were employed to predict various properties of energetic materials,including impact sensitivity,detonation velocity,detonation pressure,and Gurney energy.Analysis of Pearson coefficients and feature importance showed that the heat of explosion,oxygen balance,decomposition products,and HOMO energy levels have a strong correlation with the impact sensitivity of energetic materials.Oxygen balance,decomposition products,and density have a strong correlation with detonation performances.Utilizing impact sensitivity of 2,3,4-trinitrotoluene and the detonation performances of 2,4,6-trinitrobenzene-1,3,5-triamine as the benchmark,the analysis of feature importance rankings and statistical data revealed the optimal range of key features balancing impact sensitivity and detonation performances:oxygen balance values should be between-40%and-30%,density should range from 1.66 to 1.72 g/cm^(3),HOMO energy levels should be between-6.34 and-6.31 eV,and lipophilicity should be between-1.0 and 0.1,4.49 and 5.59.These findings not only offer important insights into the impact sensitivity and detonation performances of energetic materials,but also provide a theoretical guidance paradigm for the design and development of new energetic materials with optimal detonation performances and reduced sensitivity.
基金supported by the National Natural Science Foundation of China(Nos.U20A2069,62376234 and 123B2037)the Advanced Aero-Power Innovation Workstation,China(No.HKCX2024-01-017)。
文摘The selection of an appropriate basic detonation wave flow field is crucial for improving the performance and geometric design of standing detonation vehicles.This paper employs a detailed chemical reaction model and solves the unsteady axisymmetric Euler equation to study the characteristics of the Axisymmetric Inward Turning Curved Detonation Wave(AIT-CDW)flow field and the parameters affecting the stability of the wave system structure of AIT-CDW flow field.The numerical results demonstrate a radial compression effect in the AIT-CDW flow field.This effect causes the detonation wave to have a shorter initiation length than oblique detonation wave flow field and the detonation wave angle to gradually increase with the flow direction postdetonation.The AIT-CDW flow field is confined space,making it prone to normal detonation waves when the detonation wave reflects from the wall.This phenomenon is detrimental to the stability of the wave system structure in the flow field.It has been observed that increasing the center body radius and decreasing the fuel equivalent ratio can effectively reduce the height of the normal detonation wave or even eliminate it.Additionally,a well-designed generatrix shape of the center body can enhance airflow,reduce choked flow,and promote the stability of the wave structure in the flow field.
基金supported by the National Science Foundation of China(Grant No.14102428)the Fundamental Research Funds for the Central Universities(Grant Nos.WK2090000019 and YD2480002002)the Open Research Fund of Anhui Province Key Laboratory of Green Building and Assembly Construction,Anhui Institute of Building Research&Design(Grant No.2021-JKYL-005).
文摘Rectangular explosive charges are usually used in military or civilian explosive transportation and storage.The effects of shape parameters and detonation positions on the peak overpressure and maximum impulse of blasts lack comprehensive investigation,which is significant for the design of blast-resistant structures.In this paper,the side-length ratio of the rectangle,orientation,and detonation position of the charge are chosen as controlling parameters to investigate their influence on blast loads in the scaled distances of the gauges ranging from 0.63 to 10.54 m/kg^(1/3) with well validated 3D numerical simulations.The results show that there is a large difference in the near-field spatial distribution of the blast load of the rectangular charge;if the blast load of the rectangular charge is simply evaluated with the spherical charge,the maximum peak overpressure(maximum impulse)will be underestimated by a factor of 7.46(4.84).This must be taken seriously by blast-resistant structure designers.With the increase in the scaled distance,when the critical scaled distance is greater than 6.32(7.38)m/kg^(1/3),the influence of the charge shape on the maximum peak overpressure(maximum impulse)of the spatial blast load can be ignored.In general,the impact of detonation of the charge at the end on the maximum peak overpressure is greater compared with central detonation,but for the impact of the maximum impulse,it is necessary to pay attention to the side-length ratio of the rectangular charge and the specific detonation position on the end face.Furthermore,the structural response of steel plates placed at different azimuths under the blast load of a rectangular charge is preliminarily analyzed,and the results show that the deformation and energy of the plates are consistent with the distribution of the blast load.These analysis results provide a reference for the explosion protection design in near-field air explosions.
基金funded by the National Natural Science Foundation of China(Grant No. 12302437)Jiangsu Provincial Natural Science Foundation (Grant No.SBK2023045424)。
文摘To explore the design criteria for composite charges and reveal the intrinsic relationship between the detonation wave propagation in composite charges and the overall energy distribution of shock waves,this study analyzes the propagation and interaction processes of detonation waves in composite charges with different structural dimensions and explosive combinations. It also investigates the spatial distribution characteristics of the resulting shock wave loads. Based on dimensional analysis theory, a theoretical analysis of the shock wave overpressure distribution in free air fields is conducted. Utilizing the derived dimensionless function relationships, the hydrocode AUTODYN is employed to investigate the effects of charge structure parameters and explosive combinations on the internal overdriven detonation phenomena and the distribution of shock wave loads. It is found that the overdriven detonation phenomenon in the inner layer of composite charges increases the strength of the axial detonation wave,thereby enhancing the intensity of the primary end wave formed upon refraction into the air, which affects the distribution characteristics of the shock wave overpressure. Research has shown that increasing the thickness ratio and detonation velocity ratio of composite charges is beneficial for exacerbating the phenomenon of overdriven detonation, improving the primary end wave intensity and axial overpressure. This gain effect gradually weakens with the propagation of shock waves. When overdriven detonation occurs inside the composite charge, the detonation pressure first increases and then decreases. The Mach reflection pressure of the composite charge with a larger aspect ratio is attenuated to a greater extent. In addition, as the aspect ratio of the composite charge increases, the shock wave energy gradually flows from the axial direction to the radial direction. Therefore, as the aspect ratio of the composite charge increases, the primary end wave intensity and axial overpressure gradually decrease.
基金the support of the National Natural Science Foundation of China,China(Nos.U20A2069,U21B6003,and 12302389)the Advanced Aero-Power Innovation Workstation,China(No.HKCX2024-01-017)。
文摘Research on detonation has traditionally focused on forward solutions,with limited attention to inverse design methods,which has significantly hindered the development of detonation engines.In this paper,the Method of characteristics for Curved-Detonation(MOCD)is proposed to enable the inverse design of detonation waves.MOCD is based on the Method of Curved-shock Characteristics(MOCC)and integrates higher-order aerodynamic parameters from Curved Detonation Equations(CDE),allowing the calculation of the wedge angle given specific wave angle.The effectiveness of MOCD is validated using both oblique and curved detonation waves with single-step and detailed chemical reactions.Various applications demonstrate the ability to meet the inverse design requirements of detonation engines.For example,inverse design for given wave angles can optimize engine thrust and prevent Mach reflections.Additionally,inverse design schemes tailored to incoming flow conditions,such as varying Mach numbers and equivalence ratios,enhance the feasibility of detonation engines.Applying the method to given post-wave aerodynamic parameters enables more precise engine design,which is crucial for improving propulsion performance and effective thermal protection.In summary,the advantages of MOCD include not only performing a fast solution of the detonation flow field,but also allowing the inverse design of the detonation wave.
基金support provided by the National Natural Science Foundation of China(Grant No.12102405)the Presidential Foundation of CAEP(Grant No.YZJJZQ2023008).
文摘This study investigates the paradoxical detonation behavior of TKX-50,a nitrogen-rich energetic material,exhibiting higher detonation velocities but lower metal acceleration ability compared to HMX.Through experimental measurements and theoretical calculations,we propose a novel three-factor competition mechanism to explain this phenomenon.TKX-50-based PBX formulations achieved detonation velocities up to 9100 m/s,surpassing HMX-based counterparts.However,cylinder expansion tests revealed a 15%reduction in metal acceleration ability.Thermochemical measurements showed lower detonation heat for TKX-50(4900 J/g)versus HMX(5645 J/g).Our mechanism involves:(1)compositional effects prevailing at high pressures;(2)Energy release becoming essential as pressure drops;(3)Pressure-dependent product composition evolution functioning at low pressure.VLW code calculations unveiled a"crossover"in Hugoniot curves,lending support to this mechanism.This study furnishes a new framework for comprehending the performance of nitrogen-rich energetic materials,with significant implications for the design and optimization of future high-energy density materials.
基金supported by the Science and Technology Innovation Program of Hunan Province(No.2022RC3045)the Hunan Provincial Natural Science Foundation of China(No.2023JJ30635)the National Natural Science Foundation of China(No.12302394).
文摘In this study,we aimed to investigate the detonation wave characteristics of a gel propellant with high boron content.A steady-state detonation wave model of a boron-based gel propellant considering the latent heat of phase change was proposed.The detonation wave model was validated through a comparative analysis with shock tube experiments,which revealed that the maximum deviation in the calculated peak detonation pressure was 8%based on various initial pressures.Upon iterative calculations,the eigenvalue detonation velocity of the boron-based gel propellant under default working conditions was obtained as 1831.5 m/s.Subsequently,the refined model was used to study the structure and characteristics of the detonation wave flow field.The effects of incoming flow conditions,fuel parameters,and initial operating state on the detonation wave flow field of the propellant were investigated numerically.The findings revealed that stable and self-sustaining propagation of the detonation wave can be achieved only when its propagation velocity matches the eigenvalue detonation velocity.Note that an increase in initial temperature resulted in elevated gas phase temperature,density,detonation pressure,and particle phase temperature.An increase in boron content within the gel propellant increased the gas phase temperature but decreased the gas phase density and detonation pressure.At the Chapman-Jouguet(CJ)plane,the gas phase temperature and density,along with the particle phase temperature and detonation pressure,reached their peak values when the oxidizer reacted with the propellant in accordance with the stoichiometric ratio.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFB3207000)National Natural Science Foundation of China(Grant No.12132017)Youth Cross Team CAS(Grant No.JCTD-2022-02)and Youth Innovation Promotion Association CAS(Grant No.2020019).
文摘The distribution of exothermic reaction rates is jointly influenced by reduced activation energy and reaction rate constant.This study focuses on the effect of distribution of exothermic reaction rates on detonation wave propagation instability,specifically under conditions where the length of the induction and exothermic reaction remains constant.It is found that the distribution variation of exothermic reaction rates significantly influences the detonation wave propagation characteristics.Specifically,under conditions of high activation energy,the exothermic reaction rate profile exhibits a smoother distribution but becomes more prone to perturbations.This heightened sensitivity,coupled with the augmented overdriven degree associated with pulsating detonation and cellular detonation wave propagation,further exacerbates the instability characteristics of detonation waves.Especially to the two-dimensional detonation waves with high activation energies,the distribution of exothermic reaction rates becomes more sensitive to these displacements,reinforcing the transverse shock wave and leading to a transformation of the wavefront and cellular structure towards more unstable configurations.This research delves into the intricate interactions between the distribution of exothermic reaction rates and detonation wave instability,aiming to provide an explanatory of detonation instability.
文摘In order to find the optimal anions and cations for designing energetic salts with excellent detonation properties,the properties of 140 salts formed from the anions(A–G)of 3,3′-dinitroamino-4,4′-azoxyfurazan(DAAF)derivatives substituted with the—NH_(2),—N_(3) or—NO_(2) group and the cations(1–20)of guanidine,triazole,or tetrazole derivatives were investigated by means of density-functional theory.The predicted densities,heats of formation,detonation velocities(D),and detonation pressures(P)of 140 salts were 11.72 to 2.06 g·cm ^(−3),570.2 to 2333.4 kJ·mol^(−1),8.29 to 10.02 km·s^(−1) and 30.16 to 47.57 GPa,respectively.Most of the salts had better detonation properties than the widely used hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX).Salts containing—NO_(2) group anions(C and F)have better detonation properties(D is 8.88 to 10.02 km·s^(−1) and P is 35.75 to 47.75 GPa)than other salts.Salts containing the cations NH_(4)^(+)(1),NH_(3)OH^(+)(2)and CH_(2)N_(4)NO_(2)^(+)(20)had good detonation properties(D is 9.38 to 10.02 km·s^(−1) and P is 40.72 to 47.75 GPa).Depending on the detonation properties,anions(C and F)and cations(1,2 and 20)are the recommended ions for the generation of energetic salts.
基金supported from support from the National Natural Science Foundation of China(Nos.12441204,12302451 and 1202491)the Postgraduate Scientific Research Innovation Project of Hunan Province,China(No.CX20210075)。
文摘This study investigates the mixing enhancement mechanism and propagation characteristics of the detonation flow field of a Rotating Detonation Engine(RDE).Three-dimensional numerical simulations of a non-premixed ramjet-based RDE fueled by gaseous ethylene are performed in OpenFOAM for configurations with 15,30,45,and 60 orifices at a flight Mach number of 4.The results show that fuels with a stripped distribution are primarily mixed via tangential diffusion in the cold flow field.The configuration with more orifices has a better upstream mixing efficiency,whereas its downstream mixing efficiency,which is limited by the depth of penetration,is difficult to improve further.Backward Pressure Perturbations(BPPs)opposite to the propagation direction of Rotating Detonation Waves(RDWs)are produced by the reflection of the upstream oblique shock wave with the incoming stream and the hot release of local reactions after RDWs,which significantly affects the propagation mode and mixing.The RDWs propagate in the stable single-wave mode in configurations with 45 or 60 orifices and in the multi-wave mode in configurations with 30 orifices,whereas they fail in configurations with 15 orifices.Compared with that in the cold flow field,deceleration of the main flow,pressurization,and tangential velocity perturbation caused by the RDW substantially enhance the mixing efficiency.Moreover,the tangential velocity perturbations of upstream oblique shock waves and BPPs reduce the unevenness of the fuel distribution for the next cycle.This study reveals the mixing enhancement mechanism of RDWs and can contribute to the design of the injection scheme of the RDE.
基金supported by the National Natural Science Foundation of China (Grant No. 12202204)the Natural Science Foundation of Jiangsu Province (Grant No. BK20220953)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Science and Technology Association's Young Talent Nurturing Program of Jiangsu Province (Grant No. JSTJ-2024-004)
文摘In this study, the three-dimensional non-premixed two-phase kerosene/air rotating detonation engines with different isolator configurations and throat area ratios are simulated by the Eulerian-Lagrangian method. The effects of the divergence, straight, and convergence isolators on the rotating detonation wave dynamics and the upstream oblique shock wave propagation mechanism are analyzed. The differences in the rotating detonation wave behaviors between ground and flight operations are clarified.The results indicate that the propagation regimes of the upstream oblique shock wave depend on the isolator configurations and operation conditions. With a divergence isolator, the airflow is accelerated throughout the isolator and divergence section, leading to a maximum Mach number(~1.8) before the normal shock. The total pressure loss reaches the largest, and the detonation pressure drops. The upstream oblique shock wave can be suppressed within the divergence section with the divergence isolator.However, for the straight and convergence isolators, the airflow in the isolator with a larger ψ_(1)(0.3 and0.4) can suffer from the disturbance of the upstream oblique shock wave. The critical incident angle is around 39° at ground operation conditions. The upstream oblique shock wave tends to be suppressed when the engine operates under flight operation conditions. The critical pressure ratio β_(cr0) is found to be able to help in distinguishing the propagation regimes of the upstream oblique shock wave. Slightly below or above the β_(cr0) can obtain different marginal propagation results. The high-speed airflow in the divergence section affects the fuel droplet penetration distance, which deteriorates the reactant mixing and the detonation area. Significant detonation velocity deficits are observed and the maximum velocity deficit reaches 26%. The results indicate the engine channel design should adopt different isolator configurations based on the purpose of total pressure loss or disturbance suppression. This study can provide useful guidance for the channel design of a more complete two-phase rotating detonation engine.
文摘The incorporation of fluorine(F_(2)) into hydrogen-air(H_(2)/Air) mixtures presents a novel approach to enhancing the performance of rotating detonation engines(RDEs). This study systematically investigates the effects of F_(2)concentration and inlet mass flow rate on rotating detonation wave(RDW) propagation using two-dimensional numerical simulations, providing the first comprehensive analysis of F_(2)as an oxidizing additive in regulating detonation performance, propagation stability, and heat release dynamics in RDEs. The results indicate that when F_(2)concentration is below 1%, the flow field primarily exhibits a stable single-wave propagation mode. As F_(2)concentration increases, RDW performance initially improves but then deteriorates, reaching its optimal state at 0.8% F_(2). When F_(2)concentration exceeds 1%, the coupled effects of F_(2)concentration and inlet mass flow rate induce a transition from single-wave to multi-wave propagation modes. While a higher inlet mass flow rate promotes increased wave numbers, it also intensifies wave-wave interactions. With further increases in F_(2)concentration, the enhanced heat release leads to intensified local deflagration, frequent hotspot formation, and wave collisions, ultimately degrading RDW performance and destabilizing the multi-wave flow field. Moreover, excessive HF formation is identified as a critical driver of enhanced deflagration, hotspot generation,and the disruption of multi-wave stability. These findings provide a theoretical foundation for integrating F_(2)additives into H_(2)/Air-based RDE systems.
