Effect Of Aluminum Powder And Oxidizing Agent On The Safety And Energy Releasing Characteristics Of HMX-based Thermobaric Explosives

In recent years,the coordinated development of explosive high energy and safety has gradually become a hotspot in the field of ammunition.In this paper,HMX-based thermobaric explosives with different particle sizes and oxidizing agent were prepared.The safety and energy releasing characteristic of thermobaric explosives in confined space were studied by theoretical analysis,numerical simulation and experimental tests.The main contents and results were as follows:Firstly,the effect of aluminum powder particle size,the content and type of oxidizing agent on the safety of HMX based thermobaric explosive was studied by DSC and friction sensitivity.The results showed that as the aluminum particle size increased,the thermal stability increased.The addition of AP would greatly reduce the thermal stability of thermobaric explosives,and increased the friction sensitivity.The addition of KP would reduce the thermal stability of thermobaric explosives,and increased the friction sensitivity.Adding PTFE not only improved the thermal stability of thermobaric explosives,but also played a good role in reducing the sensitivity.Secondly,the propagation characteristics of the shock wave of the thermobaric explosive in the confined space were studied by theoretical analysis and numerical simulation.It is found that in confined space,the explosion wave has high reflected wave pressure and long quasi-static pressure duration.,and the focusing phenomenon appeared.Then,in order to study the effect of aluminum particle sizes and the contents of PTFE on the reflected wave pressure of HMX-based thermobaric explosives,the explosion test in confined space was carried out.It was found that as the aluminum powder particle size increased,the overpressure peak,specific impulse and positive phase time firstly increased and then decreased.Besides,with the increase of PTFE contents,the overpressure peak and specific impulse gradually decreased,and the positive phase time gradually increased.The results show that when the particle size of aluminum powder is 5.4?m,the explosive can release energy rapidly,while PTFE is not conducive to the explosive.Finally,the quasi-static pressure of thermobaric explosive with different formulations in confined space was studied.The average pressure method and curve fitting method were respectively used to calculate the quasi-static pressure.The results showed that the quasi-static pressure obtained by the two methods had the same trend.The quasi-static pressure first increased and then decreased as the particle size of the aluminum powder increased,and decreased as the PTFE contents increased.The curve fitting method could also obtain the quasi-static pressure rise time t _QS increased with the increase of aluminum particle sizes and PTFE contents,and pressure attenuation coefficient?decreased with the increase of aluminum particle sizes and PTFE contents.The results show that the large particle size aluminum powder and PTFE are beneficial to the slow release of energy.