To enhance the combustion efficiency of boron, n-B/n-Ti/NC ternary spherical agglomerated particles were prepared by using swelling, adsorption, dissolution agglomeration, and prilling method.SEM and DSC were used to analyze the microscopic structural properties and thermal stability of the particles, and a laser ignition system was used to investigate their combustion characteristics.The results show that n-B and n-Ti can be adsorbed into the swelling NC capillary tubes, resulting in the formation of ternary spherical agglomerate particles with uniform distribution of elements, high density and high sphericity with n-Ti as a combustion improver and n-B as high-energy combustor.At the mass ratio of NC 17%, n-Ti 8% and n-B 75%, the agglomerated particle exhibits the shortest ignition delay time(3.42ms)and combustion time(8ms).The compatibility of n-B, n-Ti and NC is very good, and the agglomerated particles have excellent thermal stability.

Aiming at the mechanism, regularity characterization, influence factors and inhibition of ingredient migration in propellants, gun propellants and explosives, the ingredient migration theories which are mainly driven by concentration gradient and polarity action were introduced. The characterization methods of migration ingredients amount and migration ability based on advanced analytical techniques and migration kinetics were summarized. The effects of temperature, intermolecular interactions, crosslinking density, steric hindrance, structure, and other factors on ingredient migration were elaborated. The migration inhibition methods including chemical synthesis, material modification, and additive methods were discussed. The development directions of establishing rapid and non-destructive characterization methods of ingredient migration, improving migration models and synthesizing new ingredients with high anti-migration performance were proposed.Attached with 79 references.

From the perspectives of reducing the influence of external stimuli and optimizing the structural design of energetic materials, the desensitization mechanisms of single compound energetic materials under different desensitization strategies are reviewed, including buffering, lubrication, conduction, heat absorption and insulation, improving the quality of energetic crystals and enhancing the stability of energetic molecules. The comprehensive desensitization mechanisms of multi-dimensional desensitization strategies such as using multifunctional desensitization materials and coupling various desensitization means are analyzed. The development directions of desensitization of energetic materials in the future are put forward: to develop energetic materials with both high-energy and insensitive characteristics, to research the relationship between desensitization mechanism of energetic materials and operational environment, and to build up universal quantitative description models of sensitivity from the molecular scale, providing theoretical guidance and technical support for designing new high-energy insensitive energetic materials. 93 References were attached.

Aiming at the pyrolysis and combustion process of the near burning surface of the pasty propellant, the laser ignition combustion experiment of the pasty propellant were carried out. At the same time, the pyrolysis and combustion characteristics of the near burning surface region of the pasty propellant were studied based on the multiphase chemical reaction numerical solver developed by the research group and the 14-component and 14-primitive chemical reaction equation. The macroscopic structure of propellant combustion flame was obtained through experiments and the burning rate of the pasty propellant was measured under constant pressure conditions. The combustion flame structure and chemical reaction sequence of the pasty propellant under constant pressure conditions were analyzed by numerical calculations. The effects of different ambient pressure on the combustion process of the pasty propellant were calculated. The results show that the fitted burning rate curve was in good agreement with the experimental results. In the range of experimental pressure, the burning rate of propellant in the combustion chamber of pasty rocket engine could be predicted well. The decomposition of AP is the first reaction in the combustion of pasty propellant, and the higher ambient pressure limited the diffusion of primary combustion gases, but enhanced the thermal feedback effect on the pasty domain, which increased the burning rate of the pasty propellant.

In order to obtain the optimal casting process parameters of HTPB composite solid propellant, the constitutive model for the flow process of propellant slurry was established based on the rheological properties of HTPB propellant slurry adopting a combination of experimental and theoretical simulation methods. The casting process of HTPB composite propellant slurry was simulated by using the finite element software, and the reliability of the simulation results was verified through experiments. Moreover, the casting process of the propellant slurry was optimized and the optimal casting process parameters were obtained. The results show that HTPB propellant is a typical pseudoplastic fluid, and its viscosity decreases with increasing shear rate. The porosity and the casting time are 12.5% and 11.25%, respectively after comparison of experiment and simulation. Among them, temperature has the most significant impact on casting time, and vacuum degree has the most significant impact on porosity.

The working principles and recent technological advancements of high-speed photography, spectroscopic testing, laser interferometry, and terahertz Doppler wave measurement techniques were introduced. Also, the application of these techniques in the field of explosive detonation testing was discussed. Among them, high-speed photography and laser interferometry are widely used in the measurement of detonation velocity, pressure, and shock initiation. Spectroscopic testing is mainly applied to detonation temperature measurement and detonation product composition analysis, while terahertz Doppler wave measurement is employed for explosive detonation wave measurement. The advantages and disadvantages of optical-electronic testing techniques in detonation performance research and provided an outlook on the future development of detonation performance testing technologies were analyzed. It is concluded that strengthening the study of micro-scale testing technologies for explosives, expanding the application of current optical-electronic testing techniques, and integrating data processing with big data technologies are key areas for future research in explosive detonation performance. 128 References were attached.

In order to improve the safety performance of HMX, HMX/FOX-7 nano-cocrystals with different molar ratios were prepared by the ultra-low-temperature-assisted recrystallization method, where FOX-7 with low sensitivity was used as another component of the binary cocrystal. The morphology, structure, and thermal properties of the prepared HMX/FOX-7 cocrystals were characterized by SEM, XRD, FT-IR and DSC-TG, and their mechanical sensitivities were analyzed. The results show that the prepared HMX/FOX-7 crystals are mainly porous structure stacked with spherical particles, and their particle sizes are distributed primarily in the range of 0.1—0.5μm. During the formation of HMX/FOX-7 nano-cocrystals, the “low-temperature freezing” of the HMX/FOX-7 solution from liquid nitrogen and the formation of hydrogen bonding among HMX and FOX-7 have an significant influence on the formation of HMX/FOX-7 nano-cocrystals. The apparent thermal decomposition enthalpies of HMX/FOX-7 nanocrystals is significantly higher than that of the raw HMX and FOX-7, and increases with the increase of HMX content. The mechanical sensitivity of each HMX/FOX-7 nano-cocrystal is substantially reduced compared with that of the raw HMX. When the molar ratio of HMX and FOX-7 is 1:3, the prepared HMX/FOX-7 cocrystal has the lowest mechanical sensitivity, where the impact sensitivity is higher than 45J and the friction sensitivity is 288N.

The micro-reaction technology for the preparation of nitroaromatics, nitrate esters, nitroamines, and other energetic materials are overviewed. The existing preparation processes for these energetic materials by using micro-reaction technology are classified and described. The micro-reaction technology has the advantages of enhancing product yield and selectivity, improving mass and heat transfer efficiency, and reducing reaction time. The issues such as blockages in micro-reaction synthesis are also analyzed. Furthermore, this review explores the application of micro-reaction technology in the preparation of micro and nano energetic materials and composite energetic materials. The benefits of micro-reaction technology in controlling particle size and morphology and continuous preparation of energetic materials are emphasized. By summarizing the existing technical difficulties, it is pointed out that the combination of micro-reaction technology with numerical simulation, the optimal design of reaction and heat transfer structures, and the exploration of reaction mechanisms are the important research fields for the application of micro-reaction technology in the preparation of energetic materials. 80 References are attached.

By comparing the differences in the physical and chemical properties, such as the enthalpy of formation and phase transition temperatures of the fluorinated/oxidized products of metal fuels, the characteristics and potential application advantages of fluorination energy release reactions in energetic systems were summarized. The research progress of composite energetic systems based on fluorinated oxidizers, including typical types and characteristics of fluorinated oxidants, as well as their applications in pyrotechnics, propellants, mixed explosives, and aluminum thermites has been reviewed. The research and development direction of the application of fluorine-containing oxidizers in composite energetic systems was prospected. It is pointed out that the systematic computational chemistry research on composite energetic systems based on different fluorine sources should be conducted to understand the thermodynamic and kinetic mechanisms of fluorination reactions and their structure-activity relationships at the atomic/molecular level. Furthermore, research should also be intensified on the fluorine transfer mechanism in combustion reactions and the interfacial fluorine infiltration mechanism under pre-ignition conditions. Based on this, new typical fluorine-containing oxidizers suitable for different scenarios should be developed from the view point of nano architectonics and reaction pathway design. Attached with 137 references.

To study the explosiveness of biomass fuels, TG-DTG thermogravimetric analysis was used to analyze the combustion performance and kinetic parameters of several common biomass fuels(straw, sawdust, peanut shells)and their mixtures. The microstructures of these fuels were analyzed using scanning electron microscopy(SEM). Additionally, an elemental analysis of the wood powder and peanut shell powder mixture was carried out using an elemental analyzer. Based on the elemental composition, the amount of oxygen required for its oxidation reaction was calculated, and an explosion test was subsequently conducted. The results showed that the mixed fuel(wood powder and peanut shell powder in a 1:1 mass ratio)exhibited high stable combustion characteristics, flammability index, and overall combustion performance. The activation energy was moderate, and the surface appeared porous and rough, with more free surfaces and a larger specific surface area, which facilitated combustion. In an experiment,40g of this mixed fuel was loaded into a steel pipe with a diameter of 40mm, a length of 200mm, and a wall thickness of 1.5mm, and filled with 5MPa oxygen. The mixture was successfully detonated by a No.8 electronic detonator without producing toxic gases. The steel pipe was blasted into fragments of different sizes, with most fragments measuring less than 50mm. The research results indicate that biomass fuel can exhibit explosiveness under certain conditions.

Imidazolium 2,4,5-trinitroimidazole was synthesized by nitration of 2,4,5-trinitroimidazole(2,4,5-TII)in different mass fractions(20%, 50%, 65% and 98%)of nitric acid using micro-channel reaction technology, respectively. The structure was characterized by fourier transform infrared spectroscopy(FT-IR), nuclear magnetic resonance spectroscopy(NMR), elemental analysis(EA)and melting point testing. Results show that by using micro-channel nitration reaction technology, the optimal process conditions for preparing imidazolium 2,4,5-trinitroimidazole from 2,4,5-TII are as follows: the molar ratio of 2,4,5-TII and fuming nitric acid is 1:20, the reaction time is 6 min, the reaction temperature is 70～72℃, and the yield is 21.8%. Compared with the conventional tank reactor process, the micro-channel reaction process has the advantages of shorter reaction time, lower dosage of nitration reagent, slightly lower reaction temperature and slightly higher yield. However, it can not completely avoid the occurrence of side-reaction of oxidation.

To study the characteristic parameters during the plasticization process of propellants, plasticization-extrusion experiments were performed using a twin-screw extruder. The paper aimed to investigate the influence of different solvents, types of plasticizers, and plasticization time on the plasticization of single-base propellants. The Owens three-liquid method was employed to calculate the surface tension of nitrocellulose(NC)after plasticization with various solvents, including ethyl acetate(EAC), tetrahydrofuran(THF), acetone(ACE), and a 1:1 mixed solvent of alcohol and ACE. Further analysis was conducted to assess the impact of different plasticizers on surface tension. The results indicated that the highest surface tension of NC(43.07mN/m)was observed after 90 minutes of plasticization with the mixed alcohol and acetone solvent, which proved to be the most suitable in this study as it prevented sticking to the walls and screws. The surface tension of NC with varying nitrogen contents(12.14%, 12.80%, and 13.45%)was calculated over different plasticizing times using the contact angle method. For all nitrogen content levels, the maximum surface tension values were recorded at 90 minutes of plasticization. The tensile test revealed that at 90 minutes of plasticization, the single-base propellant with 12.80% NC exhibited a maximum tensile strength of 39.10MPa and an elongation at break of 16.9%, aligning empirical method for determining optimal plasticization. In addition, the maximum surface tension occurred earlier at 60 minutes as the plasticizer content increased for NC with nitrogen content of 12.14% and 12.80%; while the maximum surface tension still appeared at 90 minutes for 13.45% NC. The tensile strength and elongation at the break for each group displayed trends consistent with the change in surface tension. The surface tensions were influenced by the solvent, plasticizer, and plasticization time. The trends in surface tension aligned with the tensile properties, making surface tension a valuable preliminary indicator for assessing the plasticizing effect of propellants.

Ag/g-C₃N₄ photocatalyst was synthesized using self-made zinc nitrate-containing deep eutectic solvent(nitro-DES)as nitrating agent. Utilizing the Ag/g-C₃N₄ as photocatalyst, dinitroanisole(DNAN)was successfully synthesized from the nitration of anisole under a mild and non-acidic process. The photocatalyst Ag/g-C₃N₄ was characterized using X-ray powder diffraction(XRD), ultraviolet-visible diffuse reflectance spectroscopy(UV-vis DRS), infrared spectroscopy(IR), scanning electron microscopy(SEM), transmission electron microscopy(TEM)and energy-dispersive X-ray spectroscopy(EDX)analysis. The photocatalytic nitration mechanism of dinitroanisole(DNAN)was predicted. Results show that a low-melting, transparent and polar nitro-DES can be formed spontaneously, which is composed of zinc nitrate and choline chloride in equimolar proportions. It can be not only favored for the absorption and propagation of visible-light but also serve as a nitro source in the nitration reaction. The doping of noble metals is observed to remarkably improve the photocatalytic efficiency of C₃N₄. Using xenon lamp to simulate the sunlight irradiation, the conversion of anisole to DNAN is above 90% within a period of 3h at a temperature of 55℃. The inhibition experiments suggest that the mechanism of photo-driven nitration can be involved with the nitroxyl radicals.

In order to study the fracture properties and crack propagation mechanism of solid propellant, the theoretical research and common numerical simulation methods for fracture and crack propagation in solid propellants were introduced. It is pointed out that the extended finite element method(XFEM)and cohesive zone models(CZM)are the most common techniques for fracture simulation of solid propellants. The influencing factors of fracture properties of solid propellant were summarized, and the experimental studies on the interfacial dehumidification mechanism of solid propellants are reviewed. Compared to crack size and loading rate, temperature, ageing and confining pressure can change the crack propagation mechanism of solid propellants. Finally, the research on solid propellant fracture was prospected. It was considered that the research on dynamic fracture considering the influence factors of thermodynamic coupling, fracture performance in combustion environment, real-time microscopic observation of the whole process under dynamic loading and the update of numerical simulation methods will be the focus of the future research on solid propellant fracture and crack propagation with 73 references.

Aiming at the problems of nitration reaction such as intense exotherm, large volume online, and serious safety hazards during the synthesis of N-nitromethylamine(NMA), the precursor of linear nitramine energetic plasticizers(DNDAs), micro reaction technology was adopted to carry out the nitration of 1,3-dimethylurea using nitrate-sulfur mixed acid. Critical intermediate NMA was further synthesized through the hydrolysis reaction. The structure of synthesized NMA was characterized, and the reaction conditions of nitration were also optimized. The results show that micro-reaction technology can solve the problems of uncontrollability and high safety risk caused by large amounts of heat release and volume online of nitration reaction in the process of synthesizing NMA. The optimal nitration reaction temperature is 15℃, the optimal material mol ratio of nitric acid, sulfuric acid and 1,3-dimethylurea is 1:0.78:0.67, and the average residence time was 22.5s. The yields of NMA reached 90.7%, and the purity was 99.2%. This micro-reaction process has the advantages of high reaction temperature, high safety, fast reaction rate, and high product yield.

In order to study the dynamic mechanical properties of TiZrNbHf RHEA under dynamic impact, a flat plate impact experiment was carried out by using a 20mm caliber first-stage light gas gun, and the recovered samples were analyzed by scanning electron microscopy on their delamination mechanism from a microscopic perspective. The results show that the delamination strengths of TiZrNbHf RHEA ranges from 1.81 to 2.41GPa when the peak pressure of plastic wave pressure ranges from 0 to 20GPa. The delamination strength of TiZrNbHf RHEA is lower than that of 3d-HEA. The Hugoniot elastic limit ranges from 3.05GPa to 3.57GPa, increases with the increasing of impacting speed, and the reacceleration increases with the increasing of impacting speed. The Hugoniot equation of state obtained by the experiment shows a linear relationship. The state equation obtained by the cold energy mixing method is lower than the test data, but it can be used to predict the materials' properties over the experimental range. The metallographic analysis of the recovered samples shows that the SE and BSE image maps show that the holes are connected to form cracks, there are a large number of dimple and a small number of river-like patterns in the damage area, indicating that the damage mode is a mixed fracture mode dominated by ductile fracture.

To investigate the bubble pulsation and water jet characteristics under the gas-liquid-solid multiphase coupling effect of underwater explosions near the seabed, the Euler method was employed to establish a numerical model of underwater explosions near the seabed under different substrate/water depth conditions. The full physical process of underwater explosions near the seabed under muddy substrate conditions was simulated and compared with experimental results, which showed good agreement, verifying the effectiveness of the algorithm in solving the problem of underwater explosion bubbles near the seabed. Based on this, the influence of seabed substrate and water depth on the bubble morphology, radius, period, and water jet of underwater explosions near the seabed was discussed. The results show that under the premise that the bubbles can be split, the harder the substrate, the faster the bubbles split, and the deeper the water depth, the slower the bubbles split. The harder the substrate and the deeper the water depth, the smaller the maximum radius and period of the bubble, the larger the proportion of the bubble in the total bubble volume at the moment of splitting, and the smaller the peak velocity of the two water jets generated by splitting. During the evolution of the downward water jet, a reverse water jet will form. The harder the substrate, the greater the peak velocity of the reverse water jet. In all calculated cases, the depth parameter(H_ref)is in the range of 250—750, and the peak value of the reverse water jet velocity is positively correlated with the H_ref, and the H_ref is in the range of 750—1000, which is negatively correlated.

The influencing factors of fracture properties of solid propellant were summarized, and the research status of fracture properties and crack propagation of solid propellant was reviewed; The common numerical simulation methods for simulating propellant fracture and crack propagation were introduced; The research on solid propellant fracture was prospected. It was considered that the research on dynamic fracture considering the influence factors of thermodynamic coupling, fracture performance in combustion environment, real-time microscopic observation of the whole process under dynamic loading and the update of numerical simulation methods will be the focus of the future research on solid propellant fracture and crack propagation with 75 references.

To investigate the process optimizationof Cu-en/AP composite microspheres preparation via electrostatic spraying, and to reveal the effects of droplet properties and flow rate variations on the experimental results during the electrostatic spraying process, the prepared process parameters of Cu-en/AP composite microspheres by electrostatic spray method under the orthogonal experimental design simulated by ANSYS(Fluent). The influence of flow rate, solvent ratio, and solid mass on the experimental results is examined using a controlled variable method. The results indicate that under the conditions of a flow rate of 2.67×10^-3kg/s an acetone-to-deionized water ratio of 1.5:1.0, and a solid mass of 200mg, the theoretical particle size of the composite microspheres can reach e nanoscale. Droplet trajectories in the electric field remain stable without significant deviation. The simulation results show that particle diameter decreases with increasing flow rate, with the trend leveling off around a flow rate of 1×10^-3kg/s. As the solvent ratio increases(with higher acetone content), particle diameter initially decreases, reaching a minimum around a ratio of 1.5:1.0 before gradually increasing. Increasing the solid mass also reduces the particle diameter, with a linear increase in diameter observed at around 220mg. Cu-en/AP composite microspheres with nanoscale dimensions were confirmed under these conditions by the final SEM images.

To investigate the bubble pulsation and water jet characteristics under the gas-liquid-solid multiphase coupling effect of underwater explosions near the seabed, the Euler method was employed to establish a numerical model of underwater explosions near the seabed under different substrate/water depth conditions. The full physical process of underwater explosions near the seabed under muddy substrate conditions was simulated and compared with experimental results, which showed good agreement, verifying the effectiveness of the algorithm in solving the problem of underwater explosion bubbles near the seabed. Based on this, the influence of seabed substrate and water depth on the bubble morphology, radius, period, and water jet of underwater explosions near the seabed was discussed. The results show that under the premise that the bubbles can be split, the harder the substrate, the faster the bubbles split, and the deeper the water depth, the slower the bubbles split. The harder the substrate and the deeper the water depth, the smaller the maximum radius and period of the bubble, the larger the proportion of the bubble in the total bubble volume at the moment of splitting, and the smaller the peak velocity of the two water jets generated by splitting. During the evolution of the downward water jet, a reverse water jet will form. The harder the substrate, the greater the peak velocity of the reverse water jet. In all calculated cases, the depth parameter(H_ref)is in the range of 250—750, and the peak value of the reverse water jet velocity is positively correlated with the H_ref, and the H_ref is in the range of 750—1000, which is negatively correlated.

To study the effect of metal wires on the burning rate of solid rocket motor grain, six materials wires with superior thermal conductive and mechanical properties were selected and embedded into HTPB to conduct ignition tests. The relationship between the materials' burning rate enhancement ratio and tensile strength, and the effect of pressure on the burning rate enhancement ratio were analyzed, a transient analysis of the burning rate enhancement ratio based on heat transfer theory and burning surface back-calculation was conducted, and a comparative analysis on the impact of different materials property parameters on the burning rate enhancement ratio was carried out. The results indicate that the tensile strengths of the copper-silver and silver-nickel alloys are found to be 2.1 times and 3.6 times that of pure silver, the burning rate enhancement ratio at 94% and 43% of pure silver, respectively, the alloys have a more balanced performance combination of burning rate enhancement ratio and strength. When the average pressure increases from 3.8MPa to 9.1MPa, the max burning rate enhancement ratio of the silver-nickel alloy increases from 2.5 to 2.8. Under high pressure, the burning rate enhancement ratio increases from 0 to the maximum of 3.25, then decreases to 2.65 and stabilized, showing large fluctuations in the burning rate enhancement ratio. In contrast, under low pressure, there is hardly any rising or falling trend, leading to a more stable burning rate enhancement effect, which better match the theoretical analysis. The melting points and specific heat capacities of different materials are negatively correlated with the burning rate enhancement ratio, while the thermal conductivity shows a positive correlation.

The ignition energy and combustion characteristics of HTPE solid propellants were investigated by CO₂ laser ignition and combustion test system. The effects of pressure, atmosphere, initial temperature(-50—70℃)and burning rate regulator on the burning rate, flame morphology, combustion temperature and minimum ignition energy of HTPE solid propellants were analyzed. The results show that HTPE solid propellant has lower flame intensity, burning rate, and combustion temperature than hydroxyl-terminated polybutadiene(HTPB)solid propellant. The increase of temperature, pressure and oxygen content can increase the combustion intensity and decrease the minimum ignition energy of HTPE solid propellant. The minimum ignition energy of the three HTPE solid propellants(HTPE_0, HTPE_Ca, HTPE_Sr)is 0.738, 1.038 and 1.862J at -50℃, respectively. The low temperature initial environment can significantly increase the minimum ignition energy. The calcium carbonate and strontium carbonate can inhibit the burning rate of HTPE solid propellant.

In order to study the effect of arc-cone part of the liner on the performance of explosive shaped projectiles, numerical simulations by ANSYS/LS_DYNA was conducted to calculate concentrated charge model of the ratio of arc-cone angle to the slant height of the liner are 1/7, 2/6, 3/5, 4/4, 5/3, 6/2, 7/1, while controlling other variables to remain the same. A numerical model was established using the simulation software ANSYS/LS-DYNA, and simulations were performed to obtain the corresponding results. The numerical simulation results were then validated through experiments, analyzing parameters such as velocity, length, and compaction of explosion shaped projectiles formed with different arc-cone angle ratios. The results indicate that the velocity of the explosion shaped projectiles decreases gradually with increasing arc-cone angle ratio, stabilizing after the ratio of 3/5. The fracture time of the projectiles also decreases as the arc-cone ratio increases. For ratios between 3/5 and 5/3, the projectiles typically fractured into three parts, while those at the ratio of 6/2 fractured from the middle; the variations among ratios from 3/5 to 7/1 were not significant. By comprehensively comparing parameters such as speed, fracture time, and number of fracture parts, it was found that at the arc-cone ratio of 5/3, the projectile achieved a maximum speed of 2123m/s, with the least number of fractures(3 pieces)and a good level of compaction, resulting in superior overall flight performance and penetration capability. The experimental measurements of the projectile's speed showed a deviation of around 5% from the numerical simulation results, sufficiently validating the reliability of the research findings.

To investigate the bubble pulsation and water jet characteristics under the gas-liquid-solid multiphase coupling effect of underwater explosions near the seabed, the Euler method was employed to establish a numerical model of underwater explosions near the seabed under different substrate/water depth conditions. The full physical process of underwater explosions near the seabed under muddy substrate conditions was simulated and compared with experimental results, which showed good agreement, verifying the effectiveness of the algorithm in solving the problem of underwater explosion bubbles near the seabed. Based on this, the influence of seabed substrate and water depth on the bubble morphology, radius, period, and water jet of underwater explosions near the seabed was discussed. The results show that under the premise that the bubbles can be split, the harder the substrate, the faster the bubbles split, and the deeper the water depth, the slower the bubbles split. The harder the substrate and the deeper the water depth, the smaller the maximum radius and period of the bubble, the larger the proportion of the bubble in the total bubble volume at the moment of splitting, and the smaller the peak velocity of the two water jets generated by splitting. During the evolution of the downward water jet, a reverse water jet will form. The harder the substrate, the greater the peak velocity of the reverse water jet. In all calculated cases, the depth parameter(H_ref)is in the range of 250—750, and the peak value of the reverse water jet velocity is positively correlated with the H_ref, and the H_ref is in the range of 750—1000, which is negatively correlated.

In order to explore the thermal decomposition and combustion performances of zirconium powder(Zr)with high-energy oxidant composite, the thermal decomposition behavior, combustion heat and ignition combustion process of four kinds of energetic materials(EMs)of AP, CL-20, HMX, DAP-4 and Zr/EMs samples were compared and analyzed by using differential scanning calorimetry, automatic calorimetry and self-built combustion experimental system. Some combustion products were collected and characterized. The combustion mechanism of Zr/DAP-4 was analyzed. Results show that the thermal stability and combustion heat release of DAP-4 are better than that of the other three EMs samples. The addition of Zr leads to a higher combustion heat and a lower E_a value of the sample, the thermal decomposition temperature remains at 373.8℃, and the combustion performance is better than that of pure DAP-4. Compared with the thermal decomposition of Zr/CL-20 and Zr/HMX, Zr/DAP-4 has a higher initial decomposition temperature and peak temperature, a lower apparent activation energy E_a(138.7kJ/mol), and a higher combustion heat(17134J/g). The entire combustion time of Zr/DAP-4 composite is only 170ms, indicating a rapid and intense combustion reaction and its flame intensity is also superior to the other three samples. The combustion products of Zr/DAP-4 include solid products such as ZrO₂ and gas products such as H₂O and HCl. Zr/DAP-4 composite energetic material has higher energy characteristics and better combustion performances, which make it has great potential for application in the formulation design of propellants.

In response to the problem of defective ring fracture behavior under the effect of detonation superposition, theoretical analysis was conducted on the propagation process of detonation waves in charge containing waveform regulator. The range of waveform regulator thickness values was determined. Based on the designed warhead structure, numerical simulation validated by experiment was used to study the influence of skin parameter, waveform regulator parameters, rectangular notch parameters, and explosive types on the fracture behavior of defective ring under the detonation superposition effect. The result show that the waveform regulator can achieve multi-source synchronous detonation superposition and act on the ring. The ring can fracture simultaneously at the position of the detonation wave superimposed pressure(M position)and rectangular notches(D position). The increase of either the relative thickness of the skin, the relative depth of the notch, or the relative width of the notch will be unfavorable to the fracture of the M position, while the increase of either the detonation wave superimposed pressure, the relative spacing of the notch, or the curvature radius of the detonation wave acting on the D position will be conducive to the fracture of the M position. When the skin relative thickness is 0, the notch relative width is 0.015, the notch relative spacing is 0.45—0.88, the slot relative spacing is 0.39—0.77, the slot relative width is 0.1—0.167, the charge type is Comp B explosive or Octol explosive,and the notch is located on the outer wall of the ring, the ring can fracture at positions M and D with a large damage power at the same time.

To investigate the bubble pulsation and water jet characteristics under the gas-liquid-solid multiphase coupling effect of underwater explosions near the seabed, the Euler method was employed to establish a numerical model of underwater explosions near the seabed under different substrate/water depth conditions. The full physical process of underwater explosions near the seabed under muddy substrate conditions was simulated and compared with experimental results, which showed good agreement, verifying the effectiveness of the algorithm in solving the problem of underwater explosion bubbles near the seabed. Based on this, the influence of seabed substrate and water depth on the bubble morphology, radius, period, and water jet of underwater explosions near the seabed was discussed. The results show that under the premise that the bubbles can be split, the harder the substrate, the faster the bubbles split, and the deeper the water depth, the slower the bubbles split. The harder the substrate and the deeper the water depth, the smaller the maximum radius and period of the bubble, the larger the proportion of the bubble in the total bubble volume at the moment of splitting, and the smaller the peak velocity of the two water jets generated by splitting. During the evolution of the downward water jet, a reverse water jet will form. The harder the substrate, the greater the peak velocity of the reverse water jet. In all calculated cases, the depth parameter(H_ref)is in the range of 250—750, and the peak value of the reverse water jet velocity is positively correlated with the H_ref, and the H_ref is in the range of 750—1000, which is negatively correlated.

To investigate the bubble pulsation and water jet characteristics under the gas-liquid-solid multiphase coupling effect of underwater explosions near the seabed, the Euler method was employed to establish a numerical model of underwater explosions near the seabed under different substrate/water depth conditions. The full physical process of underwater explosions near the seabed under muddy substrate conditions was simulated and compared with experimental results, which showed good agreement, verifying the effectiveness of the algorithm in solving the problem of underwater explosion bubbles near the seabed. Based on this, the influence of seabed substrate and water depth on the bubble morphology, radius, period, and water jet of underwater explosions near the seabed was discussed. The results show that under the premise that the bubbles can be split, the harder the substrate, the faster the bubbles split, and the deeper the water depth, the slower the bubbles split. The harder the substrate and the deeper the water depth, the smaller the maximum radius and period of the bubble, the larger the proportion of the bubble in the total bubble volume at the moment of splitting, and the smaller the peak velocity of the two water jets generated by splitting. During the evolution of the downward water jet, a reverse water jet will form. The harder the substrate, the greater the peak velocity of the reverse water jet. In all calculated cases, the depth parameter(H_ref)is in the range of 250—750, and the peak value of the reverse water jet velocity is positively correlated with the H_ref, and the H_ref is in the range of 750—1000, which is negatively correlated.

Based on a simple droplet microfluidic technology to produce a single emulsion, the core-shell microspheres with 4-nitrobenzaldehyde(p-NBA)as nuclear layer and polystyrene(PS)as shell layer were prepared, combined with phase separation and crystallization solidification. The p-NBA was coated in one step as the analog of 3,4-dinitrotrifluorotoluene(DNTF). The microspheres with different structures and morphologies were obtained by adjusting the ratio of p-NBA, PS and the shaping agent ethyl cellulose(EC). The influence of above factors on the structures of core-shell microspheres was studied. Based on the double conditions of coating passivation effect and coating amount of high energy explosive DNTF, the optimal experimental conditions were obtained when using PS with large molecular weight(M_r=300000—350000): the mass ratio of EC and p-NBA is 1:10, and the mass fraction of PS is 8%. The results show that the addition of excipients can promote the crystallization of p-NBA and allow it to form spherical particles when the droplet phase is separated, then it can be completely coated. The larger the initial mass fraction of PS in the microdroplet, the thicker the shell layer and the higher the sphericity. However, the thicker the shell encapsulated with DNTF, the lower the detonation power.

To enhance the safety performance of energetic materials during production and utilization, microfluidics technology was employed to successfully and continuously fabricate high-energy impact-insensitive LLM-105/CL-20 composite materials using modified fluororubber as a binder. The microstructural morphology of the samples was observed using field emission scanning electron microscopy(SEM), while the structure and crystalline phase were analyzed through Fourier-transform infrared spectroscopy(FT-IR)and X-ray diffraction(XRD). The thermal decomposition behavior of the samples was assessed via differential scanning calorimetry(DSC), and the mechanical sensitivity of raw material CL-20 and composite particles was tested. The results show that under optimal conditions-where the solvent-to-nonsolvent flow rate ratio was set at 1:6, the binder mass fraction was 6%, and the total flow rate was 80mL/min-LLM-105 was effectively coated on the surface of CL-20, with particle size distribution ranging from 0.19 to 3.92μm. Characterization by FT-IR and XRD further confirmed the successful coating of LLM-105 on the surface of CL-20. The impact sensitivity of composite particles was increased from 10cm to 55cm(drop mass of 2kg), significantly enhancing their safety performance. The methodology of preparing LLM-105/CL-20 composite particles within microchannels demonstrated advantages in reducing sensitivity, showing that this method is easy to operate and suitable for continuous safe production.

In order to improve the safety performances of 3,4-dinitrofurazanfuroxan(DNTF), 2,6-diamino-3,5-dinitropyrazine-1-oxide(LLM-105)was used to combine with it by using the microfluidic technology, DNTF/LLM-105 composites with different mass ratios of 50:50, 60:40 and 70:30 were prepared. Scanning electron microscopy(SEM)was used to characterize the morphology and structure of prepared DNTF/LLM-105 composites, and the thermal decomposition were tested by DSC method. The mechanical sensitivities of the composites were tested. The results show that DNTF/LLM-105 composites are all in the prism-shaped structure, and the particle size are significantly smaller than that of raw DNTF, the thermal decomposition peak temperature of the composites are beyond 269.0, 262.6, and 255.4℃, which is 21.2, 27.6, 34.8℃ lower than that of DNTF, respectively. The mechanical sensitivity test shows that the characteristic drop height of the prepared DNTF/LLM-105 composites increased by(50±2),(45±2)and(45±2)cm, respectively, compared with raw materials of DNTF, and the characteristic drop height increased by(15±2),(10±2)and(10±2)cm, respectively, compared with raw materials of LLM-105. The critical load of friction sensitivity of the DNTF/LLM-105 composites are all higher than 360N. The results indicate that the microfluidic technology can be used to prepare the composites with small particle size and better sensitivity than the corresponding energetic material monomers.

In order to study the ignition response characteristics of HTPB propellant slurry with high burning rate under heat and low speed impact stimulation, two kinds of high burning rate propellant slurry(gas contents were 1.6% and 0.3%, respectively)and two kinds of high burning rate propellant(burning rates were 35mm/s and 5mm/s, respectively)were prepared. The experiments were carried out by self-made heating device, Separated Hopkinson Pressure Bar(SHPB)and drop hammer impact equipments. The ignition response characteristics of propellant and slurry under thermal and low-speed impacts were analyzed by means of synchronous thermal analysis infrared spectroscopy, micro-CT scanning and high-speed photography. The results show that the thermal ignition temperature of the propellant with high burning rate(241.6℃)is significantly lower than that of the slurry, and the thermal ignition temperature of the slurry presents a small positive correlation with gas content(thermal ignition temperature of the slurry with gas content of 1.6% and 0.3% are 261.3℃ and 255.7℃, respectively).The impact ignition threshold of the slurry with high burning rate is significantly affected by the gas content and restraint mode. In the SHPB impact test without radial constraint, the ignition threshold of the slurry is positively correlated with the gas content(ignition thresholds of the slurry with 1.6% and 0.3% gas content are 71J and 33J, respectively), indicating that the slurry with high gas content is not easy to be impacted and ignited. In the drop hammer test with radial constraints, the ignition threshold of slurry is negatively correlated with the gas content(the ignition threshold of slurry with gas content of 1.6% and 0.3% are 7J and 9J, respectively), indicating that when slurry with high gas content impacts, it is more likely to impact and ignite.

In order to explore the preparation method of spherical octogen(HMX), the preparation and properties of HMX in immiscible system were studied by three methods: dripping, undersurface drop formation, and microfluidic devices using dimethyl sulfoxide as solvent, polydimethylsiloxane/carbon tetrachloride(volume ratio 1:2)as non-solvent and nitrocellulose as binder. The morphology, crystal structure, thermal properties, friction sensitivity, and impact sensitivity of the HMX samples were characterized by scanning electron microscope, X-ray diffractometer, thermal analyzer, and sensitivity instrument. The results show that the spherical HMX with the particle sizes of about 1500μm, 950μm and 300μm can be prepared by dripping method, undersurface drop formation and microfluidic devices, repectively. Each crystal form of HMX prepared by the three methods is the same as that of raw material HMX, which is β crystal form. Compared with the raw material, the activation energy of HMX prepared by the dripping method is increased by 141.22kJ/mol. Moveover, the impact sensitivity is reduced by 2J, and the friction sensitivity is reduced from 120N to 240N. Compared with the raw materials, the activation energy of HMX prepared by undersurface drop formation and microfluidic devices increases by 5kJ/mol and 21kJ/mol, repectively. There is no significant change in impact sensitivity. And the friction sensitivity is reduced from the original 120N to 216N, which means that the structure of the microsphere has achieved a good desensitization effect.

1-Methyl-2,4,5-trinitroimidazole(MTNI)was synthesized by nitration of 1-methyl-2,4-dinitroimidazole(2,4-MDNI)with nitric-sulfuric mixed acid, and methylation of potassium 2,4,5-trinitroimidazole(2,4,5-TNIK)with dimethyl sulfate(DMS)using micro-channel reaction technology, respectively. The structure was characterized by fourier transform infrared spectroscopy(FT-IR), nuclear magnetic resonance spectroscopy(NMR), elemental analysis(EA)and melting point testing. The results show that by using micro-channel reaction process, the optimal conditions based on nitration of 2,4-MDNI are as follows: the molar ratio of 2,4-MDNI and fuming nitric acid is 2:3, the volume ratio of fuming nitric acid and fuming sulfuric acid is 1:2, the reaction time is 12min, the reaction temperature is 75℃, the yield and purity are 78.1% and 99.2%, respectively. The optimal conditions based on methylation of 2,4,5-TNIK are as follows: the molar ratio of 2,4,5-TNIK, DMS and K₂CO₃ is 1:2:2, the reaction time is 20min, the reaction temperature is 70℃, the yield and purity are 71.3% and 99.4%, respectively. Therefore, compared with the conventional tank reactor process, the micro-channel reaction process has the advantages of shorter reaction time, lower dosage of nitration reagent, slightly lower reaction temperature and slightly higher yield.

In order to study the chemical compatibility between the tracer markers and the water-gel explosives, the tracer markers(micron-sized particles of a rare earth element oxide)with 0, 1%, 3% and 5% mass fractions were added to the water-gel explosives. The microstructure, explosive properties and thermal decomposition characteristics of the water-gel explosives were studied by scanning electron microscope, chronometer method, lead column compression method and synchronous thermal analysis technology, and the water-gel explosives were detected by X-ray fluorescence spectrometer. The results show that, as the mass fraction of the tracer marker increases from 0 to 5%, the microstructure of water-gel explosives, detonation velocity and fierceness do not change significantly, and thermal stability is always good. The variation range of detonation velocity and fierceness is about 1.0% and less than 5.0%, respectively. Both TG and DTG curves are basically the same for the four samples, namely, there is no obvious change in the thermal decomposition process. When the conversion rate is less than 40%, the activation energy of the sample without tracer marker is smaller than that of the other three samples with tracer marker added. And the activation energy of the four samples is close to that of the other three samples when the conversion rate is increasing from 50% to 70%, especially when reaching 80%, which means that there is no obvious effect of tracer marker added on the stability of thermal decomposition of water-gel explosives. The peak of the X-ray spectrum is the most obvious under the excitation conditions of 0.1mA and 50kV for X-ray fluorescence spectrometer, and the water-gel explosives with a mass fraction of 0.05% tracer marker is added, which is of 597394CPS for count rate. The results indicate that the addition of a tracer marker with a mass fraction of 0.05% to hydrocolloid explosives can meet the requirements of tracer security inspection.

In order to improve the combustion performance and iodine content of high-energy bactericidal films, several Al/Ca(IO₃)₂/PVDF laminated films(3, 5, 7 and 9 layers)packaging 39% Al/Ca(IO₃)/(5% or 10%)PVDF thermite(5PVDF or 10PVDF)were designed and prepared. The influence of the thermite reactivity(5PVDF or 10PVDF)and its distribution structure(multilayers and thickness)on the reaction temperature, energy release, combustion performance and mechanism of the laminated films were studied by DSC-TG analysis, burning rate and flame temperature tests. Furthermore, the reaction temperature and mechanism between each component of the laminated film were determined. The results show that laminated films encapsulating 39% 5PVDF thermite exhibits 18%—35% higher burning rate than that of packaging 10PVDF thermite. Especially, the laminated films with 5 layers display the highest burning rates of 10.2cm/s and 8.6cm/s, respectively, which combines the effects of the thickness and low burning rate of the 30PVDF layer, the mass and heat transfer efficiency of the film-thermite layer at the interface. Moreover, the average flame temperature of the laminated films increase with the decrease of the thickness of the thermite. DSC-TG results indicate that the Al/Ca(IO₃)₂/PVDF-based laminated films exhibit the exothermic iodine release reaction zone of Al-Ca(IO₃)₂-PVDF at 330—410℃. The Ca(IO₃)₂/PVDF at a mass ratio of 1.55:1 exhibits an intense exothermic reaction at 320—350℃, while the AlF₃, CaF₂, CaO, etc are determined in combustion products, which both suggests the reaction path of Al-Ca(IO₃)₂-PVDF. The study preliminarily reveals the combustion law and mechanism of Al/Ca(IO₃)₂/PVDF-based laminated films sandwiching thermite, providing a new technological solution for sterilization of high-energy materials.

To explore the nucleation process of hexanitrohexaazaisowurtzitane(CL-20)/1-methyl-3,4,5-trinitropyrazole(MTNP)cocrystal,a comparative study was conducted on the solubility and metastable zone width(MSZW)of the CL-20/MTNP cocrystal and its co-formers in ethanol. And a modified Sangwal model was applied to further analyze their nucleation behaviors. The results show that the MSZW decreases with increasing saturation temperature(T_s)and decreasing cooling rate(q), and q has a more pronounced effect on the MSZW at higher q values. Furthermore, the interfacial energy(γ)and nucleation kinetic factor(A)of all three substances decrease with increasing T_s, which suggests that higher T_s is beneficial to nucleation. The CL-20/MTNP cocrystal exhibits the highest γ, critical nucleus radius(r_crit), and Gibbs free energy(ΔG_crit)along with the lowest A, resulting in the widest MSZW and the most challenging nucleation. In contrast, MTNP exhibits the lowest γ, r_crit, and ΔG_crit as well as the highest A, leading to the narrowest MSZW and the easiest nucleation. The case of CL-20 has fallen in between.

In order to reveal the composition-structure-sensitivity relationship of energetic crystalline materials, the influence of crystal characteristics, namely, the crystal structure, crystal morphology, multi-component crystal composition and composite structure, as well as test conditions and sample state on impact sensitivity, were systematically studied and summarized and the basic reasons were explored. The influence of crystal morphology, grain size, defects and aggregation structure on impact sensitivity is mainly of macroscopic or qualitative, where the limit of influence and quantitative relationship of crystal characteristics on impact sensitivity are unclear. The construction mechanism of cocrystallization, doping and coating of multicomponent composite crystals is unclear, and the qualitative and quantitative relationship between composition and structure and sensitivity is not established yet. The mechanism of the different crystal characteristics on impact sensitivity has not reached a unified understanding. On this basis, the strategies were proposed to reduce impact sensitivity from three aspects: crystal structure design, crystal particle morphology control, composite crystal design and preparation technology, which will provide a guidance and reference for the design and application of high-energy and low-sensitivity energetic materials. 128 References were attached.

To investigate the bubble pulsation and water jet characteristics under the gas-liquid-solid multiphase coupling effect of underwater explosions near the seabed, the Euler method was employed to establish a numerical model of underwater explosions near the seabed under different substrate/water depth conditions. The full physical process of underwater explosions near the seabed under muddy substrate conditions was simulated and compared with experimental results, which showed good agreement, verifying the effectiveness of the algorithm in solving the problem of underwater explosion bubbles near the seabed. Based on this, the influence of seabed substrate and water depth on the bubble morphology, radius, period, and water jet of underwater explosions near the seabed was discussed. The results show that under the premise that the bubbles can be split, the harder the substrate, the faster the bubbles split, and the deeper the water depth, the slower the bubbles split. The harder the substrate and the deeper the water depth, the smaller the maximum radius and period of the bubble, the larger the proportion of the bubble in the total bubble volume at the moment of splitting, and the smaller the peak velocity of the two water jets generated by splitting. During the evolution of the downward water jet, a reverse water jet will form. The harder the substrate, the greater the peak velocity of the reverse water jet. In all calculated cases, the depth parameter(H_ref)is in the range of 250—750, and the peak value of the reverse water jet velocity is positively correlated with the H_ref, and the H_ref is in the range of 750—1000, which is negatively correlated.