激波管模拟产生近场爆炸冲击波

Generation of near-field blast wave by means of shock tube

激波管可以在实验室环境下模拟爆炸产生冲击波,具有参数易于控制和测量手段准确多样等优势,在爆炸冲击效应的研究中被广泛应用。但与真实爆炸相比,尤其是近场爆炸,激波管产生的冲击波存在正压作用时间难以缩短、超压峰值难以提升的困难。通过对激波管运行理论和数值模拟分析发现:缩短正压作用时间的关键是让反射稀疏波尽快追上入射激波;提升超压峰值的关键是提高驱动气体的驱动能力。为此,设计了一种驱动段为锥形截面的激波管,使得反射稀疏波更快地追上入射激波,从而有效减小激波管设备长度并缩短正压作用时间;同时,采用正向爆轰驱动技术,利用化学能代替高压空气驱动提高驱动气体声速,在低爆轰初始压力下可以获得高的超压峰值。数值计算结果表明,在入射激波马赫数(MS=2.0)相同条件下,相对于等截面驱动方式,采用锥形截面驱动方式时,激波管长度可以减少近2/3,正压作用时间可以缩短近1/2。激波管实验结果表明,锥形截面驱动激波管产生的超压曲线满足近场爆炸冲击波形要求,并获得了超压峰值为64.7~813.4 kPa、正压作用时间为1.7~4.8 ms的爆炸冲击波波形。该研究可为近场爆炸冲击波致伤及装备防护效应评价实验提供参考。

Shock tubes can simulate blast waves in laboratory settings,offering advantages such as easily controlled parameters and varied measurement methods.It is widely used in the research of blast wave effects.However,in comparison to real blast,particularly in near-field blast,the blast waves generated by shock tubes has challenges in achieving shorter positive pressure durations and higher overpressure values.Through analysis of shock tube theory and numerical simulations,it has been determined that reducing positive pressure durations hinges on ensuring a swift catch-up by the reflected rarefaction wave with the incident shock wave.Similarly,increasing peak overpressure relies on enhancing the driving capability of the driving gas.Therefore,a conical cross-section driving approach is proposed to reduce the positive pressure durations,which allows the reflected rarefaction wave to catch up with the incident shock wave faster.By employing forward detonation driving technology and utilizing chemical energy to replace high-pressure air to increase the sound speed of the driving gas,high peak overpressure can be achieved at low detonation initial pressure.Numerical simulations show that under the same conditions of the incident shock Mach number(MS=2.0),the positive pressure durations can be reduced by nearly half and the device length can be reduced to nearly one-third by implementing the conical section-driven approach.Experimental results from the shock tube show blast wave characteristics,with peak overpressures ranging from 64.7 kPa to 813.4 kPa and positive pressure durations ranging from 1.7 ms to 4.8 ms.In blast wave simulation experiments,it is important to maintain the peak overpressure within a reasonable range to prevent the interface from reaching the test position.However,when the interface does reach the test position,it is possible to simulate the temperature field of the fireball in near-field blast waves.This research provides the necessary experimental conditions for evaluating the impact of near-field blast waves on injuries and investigating the protective performance of equipment.