Abstract:In order to evaluate the output energy characteristics of the ignition cap， it was proposed to conduct the ignition cap firing test in an open burster container and use a high-speed mid-wave infrared thermal imager to capture the whole process of the ignition cap firing. Since it was difficult to measure the output flame temperature of ignition cap， the drop weight instrument was used to give the corresponding initial firing energy of ignition cap. At the same time， the infrared thermal imager was triggered to collect flame information. The experimental data and infrared images of ignition cap under three test conditions of normal（25 ℃）， heated（50 ℃） and frozen（-49 ℃） temperature were processed. The results show that the output flame maximum temperature can reach up to 1204 ℃， and the flame duration is about 3-4 ms. The whole process of the flame with time can be divided into four stages： firing， diffusion， forming and dissipation， and the temperature in the top and bottom area of flame is much higher than in other areas. Through calculation and software correction， the measurement error of this test is below 6.6%， which can prove the reliability of the method and provide a new way for evaluating the output energy characteristics of ignition cap.

Abstract:The lack of plenty of gas products during the combustion reaction of thermite is an important constraint on the development of high energy. To make up for the lack of gas production and improve the reactivity of nano-thermite， Al@KIO₄ and Al@NaIO₄ nano-thermites with core-shell structure were prepared by spray drying method. Scanning electron microscope， X-ray diffractometer， thermal analyzer， constant volume combustion chamber， hygroscopicity test and initiation power test were used to characterize the morphologies and structures， and also thermal properties， combustion performances， moisture-resistance performances and detonation performances. Results show that Al@KIO₄ and Al@NaIO₄ nano-thermites are seperatelly in high purities and with regular morphologies； the heat release are 1262.12 J∙g^-1 and 1414.7 J∙g^-1， respectively； the starting temperatures of the decomposition reactions are lower than the raw materials and accompanied with a large number of oxidizing gas products. The mass balances were reached on the 6th and 10th day， and the mass gains were about 0.64% and 0.65% in high humidity for the Al@KIO₄ and Al@NaIO₄ nano-thermites. Initiation power test showed that 96 mg samples charged into No.8 industrial detonator as primary explosive could completely detonate RDX， the perforation diameter of 5 mm thick lead plate showed that the initiation capacity of Al@KIO₄ and Al@NaIO₄ nano-thermites were comparable to LA. According to the perforation diameters， the order of initiating power is LA＞Al@NaIO₄＞Al@KIO₄＞LTNR.

Abstract:Metastable intermolecular composites （MICs） have the advantages of ultra-high reaction rate， high bulk energy density and micron critical reaction propagation size. They show broad application prospects in military fields such as micro energetic devices and rocket propellants. Nano Al/CuO energetic composite films are one of the research hotspots in the field of metastable intermolecular composites. They are prepared by vapor deposition， compatible with the micromachining process of energetic micro electro mechanical systems （MEMS）， and have great application prospects in integrated energetic devices. The preparation， thermal properties， combustion properties， reaction kinetics， the effect of transition layer on the properties of Nano Al/CuO energetic composite films， energetic devices （igniters） and their application technology are reviewed， and the development direction of Nano Al/CuO energetic composite films is prospected.

Abstract:To obtain the reaction characteristics of tetraethylammonium decahydrodecaborate （（C₂ H₅）₄N］₂B₁₀H₁₀，BHN-10） under explosion and shock， the reaction pathways and decomposition products of BHN-10 under shock were studied by electrically exploded plasma shock and explosive blast shock. Results show that the gaseous decomposition products of BHN-10 under electrically exploded plasma shock are organic combustible gases， such as carbon alkanes， alkenes， alkynes， and etc. BHN-10 has good stability under explosive blast shock. The shock wave of 25 GPa magnitude generated by explosive blast cannot promote the decomposition of BHN-10， while the explosion heat is a main factor leading to the reaction of BHN-10. The combustion of BHN-10 occurs under explosive blast shock after 8 ms， and the combustion appears from the central position， lasting for more than 200 ms. The mixture of HMX and BHN-10 has an accelerated diffusion speed of fireball under explosive blast shock， and its combustion time is equivalent to that of BHN-10.

Abstract:In order to determine the parameters of the JWL equation of state for unreacted explosives， a method to determine the JWL parameters by using the BP neural network-Genetic Algorithm （BP-GA Algorithm） and the shock Hugoniot was proposed. Firstly， BP neural network is trained to fit the nonlinear system composed of different JWL parameters， and then Genetic Algorithm is used to search the set of JWL parameters with the largest fitness value. The results show that the JWL parameters can be determined by the BP-GA Algorithm when the initial density， detonation velocity， Hugoniot parameters C₀ and S are known. The p-v curves of eight kinds of unreacted explosives determined by BP-GA Algorithm are consistent with those determined by test data， and the R² of eight p-v curves are not less than 0.9995， which proves the high accuracy of BP-GA algorithm.

Abstract:A 20 L explosion device was used to study the explosion characteristics of fuel-air explosive containing micro/nano-aluminum powder. Results indicated that when adding 5% and 10% nano-aluminum to micro-aluminum， the maximum pressure of mixed powder increased by 24.2% and 58.5%， respectively. The maximum rate of pressure rise increased by 80.6% and 103.4%. The nano-aluminum would not have any contribution to the explosion effect while its content was more than 10%. For the fuel with a solid/liquid ratio of 30/70， while the ignition energy increased from 11.83 J to 28 J， the explosion pressure consequently increased from 0.28 MPa to 0.52 MPa， meanwhile the explosion temperature increased from 834 ℃ to 1118 ℃，indicating that the explosion parameters of FAE could be improved by increasing the ignition energy. Increasing the content of micro/nano aluminum powders could effectively increase the explosion pressure and temperature of FAE.

Abstract:In order to study the energy output characteristics of three composite explosives containing Mg-based hydrogen storage materials， Ti-based hydrogen storage materials and ZrH₂ hydrogen storage materials respectively， a constant temperature detonation heat calorimeter and an underwater explosion system were used to study the detonation heat and underwater energy characteristics of the explosives. The results illustrated an order of the detonation heat in terms of a thermobaric formulation of RDX/hydrogen storage material/AP/others， which was Mg-based sample>Ti-based sample≫ZrH₂-based sample. Accordingly， the detonation heat for the three explosives were 7587.0606 kJ·kg^-1， 6416.4741 kJ·kg^-1 and 3950.6279 kJ·kg^-1. It was indicated that the detonation heat of the explosives containing hydrogen storage materials was positively correlated with the chemical potential of each hydrogen storage material. In underwater explosions， the explosion parameters including peak pressure， impulse， energy flow density and shock wave energy of the composite explosives presented a similar order， that the Mg-based sample was the best and the ZrH₂-based sample was the worst. Accordingly， the shock wave energy was 1.41 times， 1.26 times and 0.97 times of TNT equivalent for each formula. It was showed that hydrogen storage materials with much higher activity and potential energy could be beneficial for the shock wave in underwater explosion. The contribution to the energy released in underwater explosion of hydrogen storage materials was mainly in the form of bubble pulsation. The bubble energy of the composite explosives containing Mg-based， Ti-based and ZrH₂ hydrogen storage materials were 2.17 times， 1.78 times， and 0.86 times of TNT equivalent respectively， indicating that Mg-based hydrogen storage material had the best energy releasing performance in the secondary reaction， followed by Ti-based hydrogen storage material and ZrH₂was the worst The trends of the explosion parameters of the composite explosives in detonation heat test and underwater explosion test were consistent. The overall energy level of the explosives was in the order of Mg-based sample>Ti-based sample>ZrH₂-based sample. The explosive containing Mg-based hydrogen storage material had the largest energy in underwater explosion， reaching up to 2.02 times of TNT equivalent. The applicability of the ZrH₂ in thermobaric formulation was not strong for both of the energy tested in detonation heat and underwater explosion was lower than TNT.

Abstract:To study the energy output law of the suspended AlH₃ dust in explosion and release process， a modified 20 L ball explosion test system was used to study the explosion pressure and flame propagation law in closed and venting conditions alternately. The results showed that the lower explosion limit concentration of suspended AlH₃ in a closed system decreased from 40 g·m^-3 to 30 g·m^-3 comparing with aluminum powder， indicating that the hydrogen released by the burning AlH₃ accelerated the entire chemical reaction process. In addition， both the maximum explosion pressure and explosion pressure rise rate of AlH₃ dust explosion in a closed system were higher than that of the aluminum powder. The maximum explosion pressure rose from 1.02 MPa to 1.15 MPa， indicating that a combustible gas-dust composite system was formed due to the release of hydrogen to exacerbate the violence of the explosion energy release process. Under venting conditions， when the concentration of AlH₃ dust was 500 g·m^-3， the explosion pressure （p） and pressure rise rate （dp/dt） decreased the most， reaching 43% and 30% respectively， indicating explosion venting can effectively reduce explosion damage. Moreover， it was concluded that the length and speed of the explosion vent flame reached the peak values when the concentration of AlH₃ was 750 g·m^-3， meanwhile the probability and frequency of multiple flames presented a positive correlation with the concentration.

Abstract:How to improve the explosion energy and power ability of explosive by applying reactive metal particles effectively is the key problem for the design of metalized explosive. To explore the application of the micro-B/Al composite powder in enhance blast explosive （EBX） and thermobaric explosive （TBX）， three HMX-based explosives containing B/Al particles were designed and prepared. The energy output characteristics of the samples with a dimension Φ100 mm×105 mm was studied by air blast and underwater explosion tests， meanwhile the power abilities were evaluated by a Φ50 mm cylinder test. The effect of the content of micro-metal on energy output process and power ability of metalized explosives was discussed. Results show that in the air blast and underwater explosion tests， initiated by the detonation of HMX， the combustion of micro-Al can promote the afterburning effect of micro-Boron resulting in releasing a great amount of combustion heat to generate expansible products with high temperature and high pressure， finally increase the sustained duration of fireball and total energy in underwater explosion. In the cylinder test， there was not enough oxygen to react with micro-B before the cooper cylinder burst， accordingly the advantage of combustion energy of micro-boron in explosives containing B/Al could not present. However， after the cooper cylinder burst， the oxygen in the air can oxide B/Al composite powder to release a large amount of combustion heat， which can enhance the power ability of aftereffect.

Abstract:In order to study the influence of modification technology on the ignition and explosion characteristics of the composite hydrogen storage materials， the combustion heat of Al， MgH₂， Hydrogen storage material CM and hydrogen storage material CM-H coated with hydroxyl terminated polybutadiene （HTPB） was measured by an oxygen bomb calorimeter， and the mass change of the four samples within 48 h was test as well. Results show that CM-H has the highest combustion heat for 30.5633 MJ·kg^-1. Meanwhile its mass gained within 48 h in air is the least for 0.46%. Result show that the modification can effectively prevent the performance degradation of the materials so that they can maintain a high combustion heat. The minimum ignition energy， flame propagation characteristics and explosion pressure of the four samples were studied by an 1.2 L Hartmann tube， a high-speed camera and a 20 L ball explosion test device respectively. Results show that the minimum ignition energy of CM is 50-60 mJ， which was only a half of the critical ignition energy of aluminum powder （100-150 mJ）. It indicated that the addition of MgH₂ into metal materials can effectively reduce the ignition energy. The minimum ignition energy of CM-H dramatically increased to 700-750 mJ after coating. The test results of flame propagation speed， explosion pressure and explosion index presented the performance order of MgH₂ > CM > CM-H > Al. Results indicat that the modified composite hydrogen storage material has lower electric spark sensitivity， higher safety and better explosion performance.

Abstract:In order to explore the detonation law of α-AlH₃ in condensed phase explosive， the safety features of α-AlH₃ were characterized. The results indicated that α-AlH₃ had poor thermal stability due to its sensitivity to temperature and humidity. The operational condition for α-AlH₃ samples should not exceed 30 ℃ RT and 60% RH. HMX was selected as the main high explosive to develop a formulation containing α-AlH₃ with a self-designed technology namely direct method of step temperature control and cooling. The safety， detonation performance， work capacity and explosion reaction process of the explosive were studied. The molding powder had low mechanical sensitivity and good moldability. When the α-AlH₃ content exceeded 10%， the relative density of the grain decreased with increasing content of α-AlH₃. The characteristic detonation velocity of α-AlH₃ was 6078 m·s^-1. Compared with an HMX based explosive formulation containing aluminum， the counterpart with α-AlH₃ had an equivalent work capacity. But its work capacity was poor at the high and medium pressure stage of the detonation products. The hydrogen element in α-AlH₃ mainly existed in the form of hydrogen in the detonation products.

Abstract:To investigate the coupling effect and propagation law of shock wave for underwater array explosion with multiple charges. The shock wave parameters of group charge， two charges and four charges were measured by underwater explosion test. The influence of charge quantity and array distance on peak pressure， impulse and loading time of shock waves were analyzed and revealed the relationship beween array explosion shock wave parameters and distances. The results showed that the shock wave （symmetrical center line） can be superimposed in the focusing direction for two-charge explosion. The shock wave pressure intensity increased by 22.8%-55.4% in the scale distance of 2-6 m·kg^-1/3， and the gain increased gradually with the increase of propagation distance. For four-charge array explosion， the peak pressure of the shock wave in the focusing direction was close to that of group charge. For the same explosion points and layout of the array explosion， the impulse and shock wave loading time can be improved by increasing the array distance. The loading time of shock wave pressure increased with the increase of charge quantity and array distance. For two-charge and four-charge explosion， the peak pressure and impulse of multiple shock waves were still consistent with explosion similarity law， but the loading time of shock wave pressure was not.

Abstract:In order to precisely validate the parameters of detonation reaction rate model of explosives， a HMX/TATB based explosive PBX-1 was the research subject， and the mushroom test was conducted to study the corner-turning performance of explosives with various detonation propagation diameters. Then the mushroom test was simulated by LS-DYNA program with the three-term ignition and growth model calibrated by Lagrangian gauges measurements. The accuracy in calibrated parameters of the reaction rate model was validated by observing the growth and propagation of detonation waves and by comparing the corner-turning parameters. The comparison between experiments and numerical simulations shows that， the mushroom test can reflect the discrepancy of detonation growths of detonation waves in different directions. Finally， it was proved that the parameter validation of the reaction rate model of explosives is feasible by Mushroom test..

Abstract:Ammunitions might experience safety threats of high-temperature heating， high-speed fragment impact， and their combined effects in battlefield. In order to investigate the reaction phenomenon of insensitive explosive PBX-C04 under high-speed impact and the effects of high-temperature and booster charge on this reaction phenomenon， the insensitive explosive safety experiments under high-speed fragment impact were carried out， and the influences of high-temperature and insensitive booster charges（HNS） were considered. Based on the air overpressure， witness plate wreckage and chemical-physical analysis of remained explosives on the scene， the explosive reaction levels of PBX-C04 was assessed comprehensively， and the influences of high temperature and booster charge were studied. The results show that PBX-C04 at room temperature exhibits excellent safety characteristic under high-speed fragment impact， it merely reacted to burning when impacted by a fragment with velocity up to 1970 m·s^-1. When the booster charges of HNS was included， the reaction levels of PBX-C04 correspondingly deteriorated into deflagration. However， when heated to 200 ℃ before impact test， the high-speed impact safety of PBX-C04 equipped with booster charge deteriorated remarkably into detonation.

Abstract:To study the influence of RDX-based metallized explosive components on detonation process，the detonation reaction zone parameters of RDX-based metallized explosives were studied by the interface particle velocity history using photonic Doppler velocimetry （PDV）. Two kinds of RDX-based metallized explosives were granulated， one composition incorporates aluminum （RDX/AP/Al）， and the other incorporates hydrogen storage alloy （RDX/AP/Al/B/MgH₂）. The metallized explosives were initiated by detonation wave， and the detonation reaction zone parameters were analyzed and compared with those of phlegmatized RDX. The results show that the addition of AP/Al component reduced the CJ detonation pressure of phlegmatized RDX from 25.8 GPa to 20.1 GPa. In addition， the detonation reaction zone time （53.6 ns） and length （0.29 mm） of metallized explosives were both higher than those of phlegmatized RDX （24.3 ns， 0.15 mm）. The addition of B/MgH₂ further increased the detonation reaction time （58.0 ns） and length （0.30 mm） of the explosive. The addition of high-energy metal fuel reduced the output pressure of explosives， but increased the detonation reaction zone time and length of explosives.

Abstract:In order to improve the utilization rate of explosive energy and reduce the mass of welding explosive， it was proposed to use self-restrained explosive to carry out explosive welding research. T2/Q345 weldability window was obtained through theoretical calculations. T2 copper and Q345 steel were respectively used as the substrate and flyer layers， and honeycomb explosive of two layers was used as welding energy to carry out T2/Q345 explosion welding research. The results show that the T2/Q345 composite plate obtained by honeycomb explosive of two layers with self-restrained capability has good bonding performance. Compared with single-layer explosives with corresponding detonation velocities of 2505 m·s^-1 and 3512 m·s^-1， T2/Q345 explosive welding obtained by honeycomb explosive of two layers can save 54.4% and 31.4% explosive by weight， respectively. The honeycomb explosive improves the utilization rate of explosion energy converted into kinetic energy of flyer layer. In addition， with the increase of collision point distance， the interface of the T2/Q345 composite plate changes from flat to wavy.

Abstract:To study the thermal response of two new DNAN-based aluminized explosives RB-2X（DNAN/HMX/Al/binder） and RM-2X（DNAN/HMX/NTO/Al/binder）， small-scale cook-off experiments and simulations of RB-2X at a heating rate of 1.0 K·min^-1 and RB-2X at heating rates of 1.0 K·min^-1 and 0.5 K·min^-1 were conducted. The numerical simulation used multi-component grid cell calculation method and considered the air gap formed by cooling and contraction of fused cast explosive. The thermal response of explosives were analyzed. The comparisons of ignition time between simulation and experiment show that the ignition time deviation of RB-2X explosive is 1.13%， and the maximum deviation of RM-2X explosive is 5.63%. The influence of the air gap between the explosive and the inner wall of the bomb on ignition time was also analyzed. The results show that the delay time increases gradually with the increase of gap width， and when the air gap expands to 0.75 mm， the delay time is stable at 90 s， indicating that the air gap has a significant influence on the explosive ignition time. The thermal response of large-scale cook-off bomb with RM-2X explosive was predicted. The results show that the temperature at center point can be significantly reduced at ignition by increasing of ammunition size and heating rate. The state of DNAN changes from total melting to solid-liquid coexistence.

Abstract:To obtain the influence of submillimeter-sized gap or cushion on the behavior of flyer driven by the detonation of a triaminotrinitrobenzene（TATB）-based explosive， the precise detonation tests with submillimeter-sized gap or cushion were designed. The velocity histories of flyer driven by the triaminotrinitrobenzene（TATB）-based explosive and influenced by the submillimeter-sized gap or cushion were recorded by a laser interferometer （photon Doppler velocimeter）. The results show that the jump-up velocity of the flyer with the influence of submillimeter-sized cushion is lower than the case of flyer attached to explosive， but the final velocity is higher （around 20 m·s^-1 or 1% of the final velocity）. While the influence of submillimeter-sized gap is greater than that of submillimeter-sized cushion that， the final velocity is 50 m·s^-1 （2%） higher than the case of flyer attached to explosive. Simultaneously conducted numerical simulations show that both the point and line initiation conditions do affect the velocity history of the flyer， and the final velocity increases with the influence of submillimeter-sized gap and with either initiation condition. The theory analysis indicates that the introduction of submillimeter-sized gap between flyer and explosive results in weaker interaction between detonation products and flyer for the isentropic expansion of detonation products， and then leads to less entropy increasement of the system， higher energy for driving the flyer， and higher final velocity of the flyer. Additionally， different gap sizes result in different influences as the dominant mechanism varies.

Abstract:In order to study the influence of stoichiometric ratio and oxygen content of oxidant on detonation process of gelled gasoline/gas-phase oxidant， a three-dimensional two-phase detonation model of gelled gasoline and gas-phase oxidant was established， and the internal detonation process of pulse detonation engine was simulated numerically using conservation element and solving element method. The effect of stoichiometric ratio and oxygen content of oxidant on the formation time， formation distance， peak pressure and propagation velocity of detonation wave were analyzed. The numerical results indicated that when the stoichiometric ratio is lower than 1.15， the formation distance and time of detonation wave decrease with increasing of stoichiometric ratio， and the pressure peak and propagation velocity of detonation wave increase at the same time. When the stoichiometric ratio is of 1.15， the formation distance and time of detonation wave are 0.288 m and 278 μs， and the pressure peak and propagation velocity of detonation wave are 1.85 MPa and 1437 m·s^-1， respectively. The pressure peak and propagation velocity of detonation wave increase with increasing oxygen content of oxidant， and when the oxygen content increases from 23% to 48%， the pressure peak and propagation velocity of detonation wave increase from 1.85MPa， 1437 m·s^-1 to 2.85MPa， 1868 m·s^-1， respectively.