To enhance the analysis of experimental data in closed vessel tests, an iso-volumetric combustion model was established to numerically calculate the characteristics of pressure(p)—time(t). The fitting calculation was developed between the experimental test and the theoretical model, and the varying of burning rate could be solved for the high energy nitramine propellant. After that, different 7-perforated deterred high energy nitramine gun propellant samples were prepared, and the related equivalent parameters of iso-volumetric combustion model were fitted. It could quantitatively present the effects of deterring technology on the desensitizing layer, which referred to the decreasing of burning rate and the average thickness. The results show that, the static combustion characteristics of different gun propellant samples can be yielded by the iso-volumetric combustion model with the equivalent parameters. There are good agreements between the theoretical calculation and the experimental measurement. The equation of u=u₀+u_xpⁿ can conform to the relationship of burning rate(u)—pressure(p)for the high energy nitramine gun propellant. In the dry deterring technology, compared with the blank gun propellant, it can reach 72%—84% for the relative variation of equivalent burning rate of the deterring layer. Meanwhile, it locates in the level of O(10^-2)for the relative magnitude of average thickness between the deterring layer and the propellant web.

In order to study the effect of flow field characteristics on the breaking of solid propellant by cavitation water jet, HTPB propellant was taken as the research object, the numerical calculation of cavitation water jet at different nozzle expansion angles were carried out by using stress mixed eddy current model(SBES), and the influence mechanism of nozzle structure parameters on flow field characteristics were analyzed. The experimental study on HTPB propellant breaking by cavitation water jet were carried out, and the influence of flow field characteristics and breaking effect were discussed. The results show that the length of the potential flow core is affected by the expansion angle of the nozzle, which affects the velocity distribution on the target surface, and the propellant breaking depth is positively correlated with the velocity peak distribution on the target surface. The return jet at the nozzle outlet limits the development of cavitation towards the nozzle wall, thus affecting the cavitation intensity. The surface area of the breaking pit is positively correlated with the cavitation intensity, and is slightly smaller than the area covered by the cavitation cloud. The experimental results show that there is a great correlation between the flow field characteristics and the breaking results, which indicates that the flow field characteristics calculated by this method can be used to optimize and design the nozzle structure, improving the breaking efficiency of propellant. When the nozzle expansion angle is 60°, the cavitation water jet velocity and cavitation intensity have significant advantages. Combined with the analysis of breaking mass, breaking depth and breaking pit area, the breaking effect is the best at this time.

In order to improve the interfacial bonding strength between the thermal insulation layer and the liner layer of solid rocket propellant, the surface of thermal insulation layer was processed by a femtosecond laser, and the microstructures were processed on the surface of the thermal insulation layer by the etching effect of the femtosecond laser. The microstructuresurface of the thermal insulation layer was characterized by a confocal laser microscope after the processing. The contact angle with water of the thermal insulation layer surface before and after processing were measured by a contact angle tester. The tear-off tests were conducted by complex environment test system to characterize the interfacial bonding strength of the thermal insulation layer before and after processing. The results show that the microstructure of the thermal insulation layer surface after femtosecond laser processing is uniformly distributed, and the morphology is homogeneous. The microstructure surface after processed greatly improves the wettability of the thermal insulation layer surface, and the contact angle with water is reduced from 94.6° to 27.7°. Compared with the unprocessed thermal insulation layer, the tensile strength after femtosecond laser processing was increased by 218% from 1.31MPa to 4.16MPa. The surface wettability and bonding strength of the thermal insulation layer was improved.

In response to the issues of the change in hydroxylammonium nitrate(HAN)concentration due to water evaporation during the reaction process, which leads to alteration of the activity as well as the inability to perform real-time online qualitative and quantitative analysis of reactants and products, a high-pressure continuous-flow fixed-bed reactor was designed to investigate the catalytic decomposition of HAN aqueous solutions over various alumina-supported noble metal catalysts with the real-time online mass spectrometry. It is found that the conversion of hydroxylammonium ions(NH₃OH⁺)is always greater than that of nitrate ones(NO^-₃)at the same temperature. And Pt-based catalysts exhibites the best activity, where the conversion rates of NH₃OH⁺ and NO^-₃ reach 100% and 45% at 120℃, respectively. At low temperatures(<100℃), NH₃OH⁺ is mainly converted to N₂O and NH⁺₄ with the selectivity of about 60% and 40% at 80℃, respectively, while NO^-₃ reacts with NH⁺₄ to produce N₂O as the temperature increases. The reactor designed in this work could provide the reference for studying the structure-activity relationship of catalysts and reaction mechanism.

To obtain the evolution law of polymer bonded explosive(PBX)with high viscosity during the resonant acoustic mixing process, a high-efficiency resonant acoustic mixer, rotational rheometer, and differential scanning calorimeter were used to study the evolution law with mixing time of the morphologies, rheological properties, and safeties of NTO/HMX/Al based high-viscosity PBX in different process conditions. The results indicate that the material goes through four major stages during the resonant acoustic mixing: initial stage, spheronization stage, viscoelastic stage, and fluidization stage. As in the morphological evolution of high-viscosity PBX, the mode is determined by the container shape, while the difficulty is affected by the mixing temperature and acceleration. Additionally, altering the parameters to improve mixing efficiency can result in a quick decrease in the viscosity. In the spheronization stage, the temperature and electrostatic voltage of the material reach the peak. The thermal and mechanical safety of the material is relatively low, and the electrostatic safety decreases rapidly with the addition of the binder.

In order to accurately characterize the nonlinear mechanical behavior of polymer bonded explosive(PBX)during long-term creep loading and unloading process, the effectiveness of the classical models(power law model and Burgers model)from two kinds of traditional models in predicting creep unloading recovery performance was analyzed firstly by taking the PBX9502 explosive as an example. Based on the Boltzmann superposition principle, a nonlinear creep constitutive model dependent on loading history was proposed and extended to three-dimensional variable load form. Meanwhile,the stress update form and Jacobian matrix of the model were derived through discretizing it numerically. The nonlinear constitutive model was numerically implemented by compiling user-defined material subroutines, and the complete creep process and relaxation process of PBX were further simulated. The results show that two kinds of traditional viscoelastic-plastic models cannot predict the complete creep unloading recovery properties of PBX. However, the nonlinear creep constitutive model along with the numerical simulation method integrates the loading and unloading performance of PBX, and can describe a complete creep loading and unloading mechanical responses of PBX, which has potential in predicting the creep and relaxation properties of related materials under variable loads.

To improve the morphology and particle size distribution and realize the controlled preparation of FOX-7 crystals, the micro-reaction technology was used to prepare refined FOX-7 by a modular microreactor. The effects of the microstructure disc size, solvent type, and the flux ratio of solvent-nonsolvent on the morphology and size distribution of the refined FOX-7 crystals were investigated and the optimal process conditions were determined. Scanning electron microscope(SEM)and particle size analysis software were used to characterize the morphology and particle size of the refined FOX-7 crystals. The structure and properties were studied by X-ray crystal diffraction(XRD), differential scanning calorimetry(DSC), thermogravimetric analysis(TG), BAM impact susceptibility meter and friction susceptibility meter. Results show that the FOX-7 crystals with a median particle size of d₅₀=1.23μm and a narrower particle size distribution(d₁₀=0.48μm, d₉₀=2.14μm)are obtained under the following conditions: the size of microstructure discs is 60×105μm(number×width), the solvent is NMP, and the flux ratio of solvent-nonsolvent is 1:10. There is no change in crystalline shape between the refined FOX-7 and the raw FOX-7. The critical temperature of thermal explosion of refined FOX-7 is increased by 18℃ compared with that of raw FOX-7. The impact energy is increased from 27.5J to 35J, and the friction energy is increased from 192N to 324N, indicating that the refined FOX-7 crystals have better thermal stability and lower mechanical sensitivity.

The dihydrazinium salt of 1,3-bis(5-tetrazolyl)triazene was synthesized via a diazotization/neutralization reaction using 5-aminotetrazole(5-ATz)as the starting material. On this basis, an energetic coordination polymer, [Zn₂(ATz)₃(CN)]_n(ECP-1), was prepared hydrothermally using zinc perchlorate. The crystal structure of ECP-1 was elucidated by single-crystal X-ray diffraction, and the thermal stability was studied by DSC and TG. The mechanical sensitivities of ECP-1 was tested and its detonation velocity and detonation pressure was calculated. Its catalytic performance in promoting the thermal decomposition of ammonium perchlorate(AP)was evaluated by DSC. The results show that the ECP-1 reveals a trigonal system with space group R32 and a high crystal density of 2.231g/cm³. It exhibits excellent thermal stability with a peak decomposition temperature of 391℃. The impact sensitivity and friction sensitivity are more than 40J and 360N,respectively. The detonation velocity and detonation pressure are 7.53km/s and 28.20GPa. The addition of 20% ECP-1 lowers the decomposition temperature of AP to 325.6℃ and reduced the activation energy by 34.27kJ/mol. These results highlight the promising catalytic capabilities of ECP-1 for AP decomposition, which shows potential utility as an energetic combustion catalyst.

To study the influence of silicon(Si)on 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20), NC/CL-20 composite explosives and Si/NC/CL-20 composite explosives were prepared by the electrostatic spraying method. The morphology, structure and thermal decomposition properties of the samples were analyzed using scanning electron microscopy(SEM), X-ray energy spectroscopy(EDS), infrared spectroscopy(FT-IR), and simultaneous thermal analyzer(TG-DSC). Additionally, the combustion process of the samples was tested using a high-speed camera. The results show that the addition of nano-Si contributes to the formation of composite explosives with regular morphology and smaller particle size. The Si/NC/CL-20 composite explosive has better and more uniform sphericity, with an average particle size of 73.4nm, compared to the NC/CL-20 composite explosive. The Si/NC/CL-20 composite explosive which produced by the electrostatic spraying method, achieves physically uniform distribution of the components including NC, CL-20, Si. The addition of Si promotes the thermal decomposition of CL-20. In comparison to the NC/CL-20 composite explosive, the activation energy of the Si/NC/CL-20 composite explosive decreases by 16.78kJ/mol, and the self-accelerated decomposition temperature and the critical temperature of thermal explosion decreases by 3.12K and 2.61K, respectively. Furthermore, Si/NC/CL-20 composite explosive has shorter ignition delay time and faster combustion rate compared to the NC/CL-20 composite explosive, which shows that Si can improve the combustion performance of CL-20.

Based on the classification of three commonly used azide polymers including glycidyl azide polymer, poly(3,3'-diazidomethyl epoxybutane), and poly(3-azidomethyl-3'-methyl epoxybutane), the synthesis process and modification method of azide binders are reviewed, and the future development of azide adhesives are looked forward:(1)based on the improvement of polymerization method and synthesis process, as well as the design and optimization of component and structure(introducing fluorine elements and utilizing chiral chemistry)of polymers, improving the energy and mechanical properties of azide binders;(2)developing new self-healing or easily healable azide binders;(3)developing nano-size azide binders to make each component in nano-size, enabling practical specific impulse closer to the ideal state. 121 References were attached.

In order to further reduce the glass transition temperature(T_g)of HTPB propellants and expand their operational temperature range, the molecular structures and T_g values of high cis HTPB, anionic polymerized HTPB and type I HTPB were analyzed and compared. Propellants based on different HTPB were prepared, and their curing reaction kinetics, mechanical properties, energy performance, combustion performance, and feasibility of ignition at ultra-low temperatures were investigated. The results show that the molecular structures of HTPB has a significant influence on its T_g. The T_g of hydroxyl-terminated polybutadiene with a cis-1,4 structure accounting for 74% to 76% is approximately -101℃. Compared with type I HTPB propellants, propellants based on high cis HTPB has a lower curing reaction rate and a lower T_g. By using nonyl oleate plasticizer and optimizing the plasticization ratio, the T_g of HTPB propellant can reach -96.2℃. Compared with the propellant containing anionic polymerized HTPB and type I free-radical-polymerized HTPB as a binder, high-cis HTPB-based propellants have a lower elongation under the condition of comparable tensile strength. Verified by the BSFΦ118 engine tests and BSFΦ165 engine tests, the burning rate and energy performance of the high-cis HTPB propellant are at the same level as those of the type I HTPB propellant. High-cis HTPB-based propellants passed the -70℃ BSFΦ118 engine test, preliminary demonstrating the feasibility of high-cis HTPB propellants in ultra-low-temperature environments.

To evaluate the anti-high overload performance of HTPB propellant over a wide temperature range, based on one-dimensional elastic stress wave propagation and loading theory, the test system for high overload loading of propellant charge was developed, the theoretical design of overload amplitude and pulse width of propellant charge strip sample under the single pulse loading was realized. In addition, the waveform shaping technology was combined to achieve accurate control of high overload stress wave, and the high and low temperature control systems were coupled to realize the wide temperature range axial high overload test condition of propellant. A series of high-overload experiments with different loading pulse widths(100, 200, 300μs)of propellant samples at 12000g and 16000 g overload amplitude under high and low temperature(-50, -20, 0, 25 and 70℃)were investigated. Based on the genetic integral form viscoelastic constitutive model, the finite element analysis of the high overload test process was carried out. Combined with μCT test and finite element analysis, the variation of damage response characteristics of propellant samples with overload amplitude, pulse width, temperature under complex and high overload loading were studied. The results show that under high overload conditions, with the same overload amplitude and pulse width, the stress level increases as the temperature decreases; under the same overload amplitude and temperature conditions, the stress level increases as the pulse width increases. The stress distribution of the propellant samples at high and low temperatures show a relatively consistent pattern, with the maximum stress occurring near the end of the load climbing section and stress concentration at the bottom of the propellant grain. By taking the compressive strength varying with strain rate and temperature as the strength criterion and through the coupled analysis of the stress field, strain rate field and temperature, the structural integrity of the propellant column can be guaranteed under five different temperatures and three different pulse widths under 16000g overload. Meanwhile, the increase of temperature would inhibit the formation of damage characteristics, while the increase of pulse width under loading would promote the formation of damage characteristics.

An energetic binder based on hydroxyl-terminated polybutadiene(HTPB), doped with different ratios of nitrocellulose(NC)(10%, 20%, 30%, and 50%), was developed to study the effect of NC doping on the thermal decomposition behavior of a composite propellant(CP)comprising ammonium nitrate(AN)as an oxidizer and magnesium(Mg)as a fuel. Optimization of the propellant formulation was conducted using Chemical Equilibrium with Applications-National Aeronautics and Space Administration(CEA-NASA)software, which demonstrated an increase in specific impulse by 12.09s when the binder contained 50% NC. Fourier-transform infrared spectroscopy(FTIR)analysis confirmed the excellent compatibility between the components, and density measurements revealed an increase of 6.4% with a higher NC content. Morphological analysis using optical microscopy showed that NC doping improved the uniformity and compactness of the surface, reduced cavities, and achieved a more homogeneous particle distribution. Differential scanning calorimetry(DSC)analysis indicated a decrease in the decomposition temperature of the propellant as the NC content increased, while kinetic studies revealed a 48.68% reduction in the activation energy when 50% NC was incorporated into the binder. These findings suggest that the addition of NC enhances combustion efficiency and improves overall propellant performance. This study highlights the potential of the new HTPB-NC energetic binder as a promising approach for advancing solid propellant technology.

In order to solve the problem of reducing the damage area caused by the axial energy waste of conventional fuel air explosive, numerical simulation researches on the multiphase cloud near-field growth process of fuel air explosive were carried out. The influence mechanism of axial non equal diameter degree on the near-field growth characteristics of cloud was revealed at multiple scales. By incorporating the baroclinic effect induced by axial non equal diameter and the annular shear fragmentation of the fuel, a multiphase cloud near-field growth model of axial non equal diameter structured fuel air explosive was constructed. Based on this model, the cloud size and radial growth rate were quantitatively calculated. The results show that the axial non equal diameter structured induces a baroclinic effect on the fuel. With the increase of axial non equal diameter, the radial growth rate of multiphase clouds in the near-field stage decreases, and the axial growth rate increases. The particle size distribution along the radial direction demonstrates a gradient decay from the center outward during the near-field stage. As the axial non equal diameter degree of the device intensifies, the axial velocity component of the fuel increases, whereas the radial component decreases, leading to a morphological transition of the multiphase cloud from a “lantern shape” to an “umbrella shape”. The central cavity size of the multiphase cloud was reduced in the axial non equal diameter structure, and the continuity of the internal distribution of the cloud was strengthened. A maximum deviation of less than 6.5% between the predicted cloud size and experimental data validates the reliability of the multiphase cloud near-field growth model.

To investigate the effects of different machine oil-diesel ratios on the explosive properties of site-mixed emulsified explosives, the viscosity and particle size distribution of emulsion matrices with varying oil-diesel ratios by using digital viscometry, laser particle size analysis, and optical microscopy were examined, the internal phase structure of explosive samples was observed. The density of matrices and explosive specimens were measured through PVC tube simulations of borehole charging configurations. Detonation velocity and brisance were respectively determined by using a detonation velocity tester and lead cylinder compression method. The results reveal that as the oil-diesel ratio in explosive formulations increased from 0:5.5 to 5.5:0, the matrix viscosity rose from 1.5×10⁵mPa·s to 3.7×10⁵mPa·s. Concurrently, the sensitized bubble concentration increased while the bubble size decreased, demonstrating improved uniformity. The dispersed phase droplet size distribution narrowed significantly with distribution width decreased from 86.19μm to 6.33μm, the mean particle size reduced from 13.85μm to 2.78μm, and dispersion index declined from 6.23 to 2.27, indicating enhanced homogeneity. At 0.3% sensitizer content, the explosive density increased progressively from 0.95g/cm³ to 1.10g/cm³. Corresponding improvements in detonation performance were observed: the detonation velocity increased by 24.08% from 3155m/s to 3915m/s showing consistency with theoretical predictions from the B-W method, and the brisance increased by 34.48% from 9.05mm to 12.17mm.With increasing the sensitizer concentrations(0.3%,0.5%,0.7%), the bubble density increased and the explosive density reduced. Distinct performance trends emerged based on oil-diesel ratios: formulations with ratios ≤3:2.5 exhibited initial enhancement followed by decline in detonation parameters, while those with ratios ≥4:1.5 demonstrated progressive reduction in explosive performance characteristics.

In order to obtain the damage characteristics of the double-layer shell structure under the underwater explosion of the shelled charge, the damage test of the double-layer shell structure under the underwater explosion was carried out with a small explosive tank device, and the influence of the hollow medium at the back cavity of the inner plate, the filling medium between the inner and outer plates, the explosion position and distance and other factors on the damage characteristics of the double-layer shell were analyzed, and the damage mode of the double-layer shell structure under the underwater explosion of the shelled charge was obtained. The results show that under the contact explosion of the underwater shell charge, there are three kinds of damage modes: the overall plastic deformation of the double-layer shell, the tearing of the inner and outer plates in the shape of “mouth”, “grid” and “cross”, and the local bending or fracture deformation of the inner and outer plates and ribs. Under the same underwater contact explosion conditions, when the explosion position is at the intersection of the transverse and longitudinal ribs of the double-layer shell, the damage range caused to the inner and outer plates is larger, and the filling of the water medium between the double-layer shells greatly reduces the impact effect on the inner shell and improves the impact resistance of the inner plate of the double-layer shell.

In order to obtain the application properties of HMX containing RDX impurities, HMX/RDX composites doped with different RDX contents were prepared by solvent-non-solvent method using N,N-dimethylformamide and dimethyl sulfoxide as the mixed solvent. The morphology, structure, and thermal properties of the prepared HMX/RDX composites were characterized by SEM, XRD, FT-IR and DSC-TG, and their mechanical sensitivities were analyzed. The results show that the prepared RDX-doped HMX/RDX composites are of blocky and flat circular particles, where the particle sizes mainly distribute in the range of 0.5—3μm. The particle size of the composites decreases with the increase of the RDX-doped content, and the doping of RDX has no effect on the crystalline morphology and phase of HMX. The RDX-doped HMX/RDX composite only has one decomposition exothermic peak, which means the doping is uniform. Compared with pure HMX, the exothermic decomposition peak temperatures and apparent thermal decomposition enthalpies of RDX-doped composites decrease slightly with the increase of RDX content(less than 30%), while their mechanical sensitivity is decreased and their safety properties are improved. They can effectively replace pure HMX in some applications.

In order to make up for the small production capacity, poor stability of the production process and low production efficiency of m-dinitrobenzene(m-DNB)in the traditional kettle production process, m-DNB was synthesized based on a microchannel reactor using nitrobenzene(NB)as the raw material, ethylene dichloride as the solvent, and a mixture of fuming nitric and fuming sulfuric acids as the nitrifying agent. The effects of the molar ratio of mixed acids, molar ratio of nitric acid to NB, reaction temperature, and total flow rate of the material on the nitrification reaction were investigated, where the reaction kinetics was also studied. The results show that the optimal conditions for the reaction are 60mL/min for the total flow rate of the material, 1:4 for the molar ratio of nitric acid to sulfuric acid, 1:2 for the molar ratio of NB to nitric acid, and 40℃ for the reaction temperature, under which the yield of m-DNB is as high as 93.60%. The activation energy of the NB nitration reaction is 63.930kJ/mol, and the finger-forward factor is 1.115×10⁹ L/(mol·s). It indicates that the microchannel reactor has the advantages of high heat transfer and mass transfer efficiency, accurate control of the reaction process, and high safety.

A novel heat-resistant explosive, 2,6-bis(tetrazolylamino)-3,5-dinitro-4-pyridone-1,1'-dipotassium salt, was synthesized from 4-amino-2,6-dichloropyridine and 5-amino-1H-tetrazole by a three-step reaction of nitration, condensation, and oxidation in an overall yield of 41%. The target compound was characterized using nuclear magnetic resonance spectroscopy(¹H and¹³C), Fourier transform infrared spectroscopy and elemental analysis, and its structure was determined by single crystal X-ray diffraction. The thermal stability was investigated by differential scanning calorimetry(DSC)and thermogravimetry(TG)analyzer, the mechanical sensitivity was determined by BAM method, and the detonation properties were predicted by EXPLO5 software. The results show that the crystal of 4·5H₂O belongs to triclinic crystal system, Pī space group, with a crystal density of 1.782g/cm³(296K). The anionic ligand structure is nearly planar and exhibits face-to-face π-π stacking, which further forms a three-dimensional coordination polymer structure by coordinating with K⁺. Compound 4 has a measured density of 2.10g/cm³, a thermal decomposition temperature of 308.5℃, a detonation velocity of 7884m/s, a detonation pressure of 25.02GPa, an impact sensitivity of 20J, and a friction sensitivity of above 360N, indicating good heat resistance, low sensitivity and high energy.

The research progresses of machine learning in the field of energetic materials at home and abroad in recent years were reviewed. The applications of machine learning in the design and property prediction of energetic materials were summarized. In machine learning-driven energetic material design, the application of machine learning in molecular generation methods and auxiliary screening of energetic molecules was introduced. In the machine learning-driven prediction of the properties of energetic materials, the application of machine learning methods in the prediction of different properties of energetic materials, such as detonation performance and combustion performance, was introduced. Finally, the challenges facing the in-depth application of machine learning in the field of energetic materials were summarized, including the quantity and quality of energetic material-related datasets. The prospect for the application of machine learning in energetic materials was put forward, suggesting that the future development direction of energetic materials lies in establishing an automated experimental platform through the combination of machine learning and intelligent robots to achieve an the automated closed-loop optimization process of “design-prediction-optimization”. With 104 references attached.

To address the theoretical deviations caused by the CJ(Chapman-Jouguet)hypothesis in the calculation of detonation parameters, the LADM(Least Action Detonation Model)based on the principle of least action was adopted. In this model, the entropy principle is used to determine the endpoint of the detonation process, while the Hamilton principle is applied to describe the reaction zone of the detonation, thereby replacing the traditional CJ hypothesis. The model was used to calculate detonation velocity parameters for 29 types of typical gaseous, liquid, and solid elemental explosives, including metallic hydrogen and all-nitrogen compounds, as well as mixed explosives. The detonation heat values were measured with calorimetric bomb, and the adiabatic index closely matched theoretical values. The results show good agreement between calculated and experimental data, demonstrating strong universality of the method. This indicates that the proposed approach can effectively calculate detonation parameters of novel explosives, offering solid theoretical guidance and promising application prospects.

In order to accurately evaluate the reaction level of ammunition charge under the impact of high-speed fragments,with the help of an overloading setup,the photon Doppler velocimeter(PDV), high-speed photography, shock wave overpressure measurements, self-short-circuit electric probes, together with static explosion tests,were used to study the response levels of the HMX-based charge(PBX-8)under different impact conditions caused by high speed fragments. The results indicate that the qualitative evaluation of the non-reaction level and combustion level was mainly based on the remaining debris and the high-speed images of the reaction process.For the accurate evaluation of deflagration, explosion, and detonation levels,the quantitative values of reaction intensity were obtained from quantitative parameters such as shock wave overpressure, shell expansion velocity, and reaction time,etc. The quantification of the reaction intensity between the deflagration and explosion reaction levels exists a one order of magnitude difference. Moreover, the different impact positions of fragments on the charge can affect the final reaction intensity of the charge under the same impact velocity.

A numerical computational model of the hybrid rocket motors was established based on the heat transfer between gas and solid fuel, the effects of oxygen swirl intensity, oxygen mass flux and combustion chamber pressure on the combustion efficiency were studied using polyethylene as fuel and oxygen as oxidant. The results show that the flame is far from the burning surface and the gas reaction mainly occurs near the axis of high oxygen content when oxidizer is injected in rectilinear form, causing a significant amount of fuel residue in the rear combustion chamber cavity, which leads to a low combustion efficiency. A significant advantage in enhancing the gas mixing is exhibited as S > 0.2, and the combustion increases by 5.25% when S increases from 0.167 to 0.444. The combustion efficiency increases by 1.1% with the increase of 25kg/(m²·s)in the mass flux of O₂. Chamber pressure has little influence on the combustion efficiency and burning surface regression rate.

A numerical computational model of the hybrid rocket motors was established based on the heat transfer between gas and solid fuel, the effects of oxygen swirl intensity, oxygen mass flux and combustion chamber pressure on the combustion efficiency were studied using polyethylene as fuel and oxygen as oxidant. The results show that the flame is far from the burning surface and the gas reaction mainly occurs near the axis of high oxygen content when oxidizer is injected in rectilinear form, causing a significant amount of fuel residue in the rear combustion chamber cavity, which leads to a low combustion efficiency. A significant advantage in enhancing the gas mixing is exhibited as S > 0.2, and the combustion increases by 5.25% when S increases from 0.167 to 0.444. The combustion efficiency increases by 1.1% with the increase of 25kg/(m²·s)in the mass flux of O₂. Chamber pressure has little influence on the combustion efficiency and burning surface regression rate.

Thermoplastic composite solid propellant with solid content of 86.5% was prepared by resonance acoustic mixing(RAM)process by using ethylene ethyl acrylate copolymer based thermoplastic binder(EEA)as matrix, aluminum powder and ammonium perchlorate as energetic solid fillers. The rheological parameters of thermoplastic binder/propellant were measured by rheological method. The rheological properties of thermoplastic binder and thermoplastic propellant were studied systematically, including apparent viscosity, modulus, thixotropy, strain scan, frequency scan, temperature scan and time scan. The results show that the prepared propellant has good formability and flow property. The EEA-based thermoplastic propellants exhibit obvious thixotropy, and the apparent viscosity decreases with the increase in the shear rate, showing obvious pseudoplastic fluid characteristics. The viscoelastic properties of EEA-based thermoplastic propellants are frequency- and temperature-dependent, showing a second plateau at low frequency and solid-liquid transition at high temperature. Unlike thermoset propellants, the modulus and viscosity of thermoplastic propellants remain essentially constant over time.

To solve the problems associated with difficulty in reaction controlling, high reaction temperature, and low yield in the synthesis of isopropyl nitrate(IPN)by conventional process, a heart-shaped microchannel reactor was used to synthesize IPN by using isopropanol as raw material and dichloromethane as solvent, through the reaction of fuming nitric acid and acetic anhydride. The effects of factors such as the molar ratio of isopropanol, fuming nitric acid and acetic anhydride, the mass fraction of fuming nitric acid, total flow rate, and reaction temperature on the nitrification reaction were investigated. Results show that at the temperature of 10℃, total flow rate of 60mL/min, mass fraction of fuming nitric acid of 98%, molar ratio of isopropanol, fuming nitric acid and acetic anhydride of 1:1.2:0.9, and mass ratio of isopropanol and dichloro-methane of 1:1, the conversion rate can reach to 99.83%. A homogeneous kinetic model for the nitration reaction of IPN was established.The activation energy is 37.05kJ/mol by fitting, and the pre-exponential factor is 4.93×10⁴L/(mol·s).

In view of the technical challenges brought by the industrialization and engineering application of resonance acoustic mixing(RAM)technology, the current state of researches on application effect, efficiency, safety and influencing factors of RAM was summarized, and the development directions in the future are prospected. RAM technology can not only be applied to simple mixing to achieve uniform dispersion of material components, but also can be applied to chemical reaction, cocrystal, surface treatment and other aspects because of its advantage of efficient interface contact among mixed materials; In its applicable fields, RAM has obvious efficiency and scale-up advantages, and the maximum efficiency can even be improved by hundreds of times compared with the traditional process, and there is almost no scaling effect; moreover, because of its lower shear characteristics without paddle, compared with vertical kneaders, screws, mills and other high shear devices, the structural integrity of the material is better maintained, which is conducive to process the sensitive and hazardous materials. At present, research mainly focuses on the laboratory experiment and lacks unified mechanism cognition on some processing phenomena. In the future, further research should be carried out on the process mechanism, scale-up characteristics, and comprehensive efficiency, so as to accelerate the engineering application of RAM.100 References are attached.

In order to reduce the characteristic signal of solid propellant, while maintaining the total solid content of the formulation at 84%, the aluminum powder content is gradually decreased from 16% to 4%. Laser ignition combustion tests and condensed phase combustion product analysis were carried out, and the influence of metallic aluminum content on the combustion characteristics of solid propellants was obtained. The results show that with the gradual decrease of aluminum content, the overall combustion stability of the HTPB propellant weakens, the flame oscillation amplitude and the ignition delay time increase, the linear combustion time becomes longer, and the combustion temperature decreases. With the reduction of aluminum content, the aluminum agglomeration at the burning surface gradually develop from conventional ‘molten aluminum agglomeration balls' to ‘flakes'. After ultrasonic dispersion, particle size analysis shows that the size and number of large particle agglomerates are decreasing. Moreover, the combustion efficiency increases first and then decreases with the increase of aluminum content, and is optimal at the aluminum powder content of 8%, reaching 88.1%.

In order to study the impact energy release and crushing behavior of N b₁Zr₂Ti₁W₂ high entropy alloy, the test method of dynamic energy release testing during the bullet-target interaction was provided by ballistic gun and quasi-closed reaction tank. The impact energy release process and dynamic crushing law were analyzed, and the cumulative mass distribution model of fragments was established. The impact induced energy release characteristics of N b₁Zr₂Ti₁W₂ high entropy alloy were studied.The results show that N b₁Zr₂Ti₁W₂ produces “explosion-like” energy release effect under high-speed impact load, which releases a large amount of chemical energy mainly due to the oxidation reaction of Zr element. The 5.07g alloy material can produce 0.176MPa overpressure in the 32.7L quasi-closed vessel at the speed of 1631m/s. The distribution of fragments follows the power law, and the size of fragments is closely related to the energy release.

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.