Study on Correlative Techniques of Thermobaric Explosive Based on Combustion and Explosion Effect
|School||Nanjing University of Technology and Engineering|
|Keywords||thermobaric explosive explosion temperature blast overpressure shock wave damage thermal radiation effect restricted space|
In this dissertation, the action principle and design method of thermobaric explosive(TBE), as well as the blast field performance and the damage effect in free air and restricted space were studied both theoretically and experimentally.The design principle, the prediction methods of performance parameter and the solidification technique of TBE were proposed based on previous research results in literature. A solid thermobairc explosive was investigated whose main components were high explosive, metal powder and solid active agent. The solid thermobairc explosive had superior properties.Several transient high temperature measurement techniques were analyzed. A new method with double lines of atomic emission spectroscopy and infrared thermography was used to study the explosion temperature of TBE. According to the experimental results, the reaction process of TBE was analyzed. There were two temperature peaks of 2300K and 2050K in lms after the explosive acted, which were attributed to the first and second phase of the explosive reaction of TBE, respectively. The third phase of the explosive reaction was TBE’s afterburning with higher explosion fireball temperature. The duration of differenet high temperature and the volume of the high temperature cloud were 2～5 and 2～10 times as much as those of TNT with the same weight. The blast power of TBE was higher due to the enhancement of afterburning to shock wave. The percentage of total energy released in explosive reaction of TBE was about 42% as analysis, which indicated that it had potential to be improved.A modified thermobaric explosive(M-TBE) containing chemically active material was studied by experiment. There were two regular positive pressure zones on the overpressure curves. The second one was formed outside fireball and the pressure flat roof accumulated by compressed waves was inside fireball. The peak value of the second shock wave was no less than 40% of the first one’s and the second impulse was 12.5%～43.7% of overall impulse. Thus the effect of second shock wave to blast/shock wave power could not be neglected. The chemically active material could enhance the afterburing reaction of TBE and provide assistance to the formation and propagation of the second shock wave.The characteristic equation of shock wave overpressure, positive effect time and impulse of TBE was obtained by explosion experiment in free air. Two damage criterion of △P-I and CI were suitable for TBE as analysis. The damage diameter of human 50% casualty caused by 30kg TBE was 6.38m based on the experimental results.The dynamic calculation method with time property of TBE’s thermal radiation was proposed based on the dynamic model of fireball radiation and the experimental results of infrared thermography. The thermal radiation dosage of thermobaric bomb with 30kg TBE was calculated, which was 3.6～5.2 times of TNT with same quatity.The blast effect of TBE in restricted space was studied. The damage effect was enhanced obviously due to the restricted space and the complete explosion reaction of TBE. The overall positive impulse in restricted space was 5～10 times of that in free air. The overpressure and impulse measured by sensors on the wall were increased by the normal reflection of shock wave. The overpressure and impulse of reflected wave was 3.5 and 1.9 times of that of incident wave, respectively. The damage action of underpressure in half obturation space with venting effect could not be neglected in the experimental condition of this paper.