激波风洞高低压段钢膜片破裂特性研究

激波风洞是用于高超声速飞行器气动外形设计和优化的常用地面试验装置,基于爆轰驱动技术,激波风洞能够在短时间(毫秒级)内产生高温、高压的驱动气体来模拟高超声速试验气流.主膜片位于激波风洞中的爆轰驱动段和激波管段之间,试验时膜片在爆轰脉冲压力下打开,膜片的打开状态和脱落情况对激波风洞气流品质有很大的影响. 同时,膜片也是形成激波的先决条件. 传统的风洞采用铝质膜片进行试验,在激波风洞中需要承压能力更强的膜片, 此时铝质膜片不再适用, 需要采用钢质膜片.因此, 对激波风洞中的钢膜片破裂特性进行研究很有必要.将数值计算结果与试验结果进行比较, 发现数值计算结果与试验结果吻合得比较理想,计算结果具有可靠性. 基于膜片的应力-应变模型, 建立了膜片打开的动力学模型,根据CJ爆轰理论, 采用有限元软件计算模拟了膜片破裂的过程,分析总结了膜片破裂的机制和力学特性规律.采用控制变量法对不同厚度和凹槽长度的膜片进行分析研究,得到了膜片破膜压力和有效破膜时间的变化规律. 在激波风洞试验中,根据膜片总破膜时间设计了适用于JF-12复现风洞的膜片参数. 

RESEARCH ON RUPTURE CHARACTERISTICS OF STEEL DIAPHRAGM BETWEEN HIGH AND LOW PRESURE SECTION IN SHOCK TUNNEL

Shock tunnel is a common ground test device used for aerodynamic shape design and optimization of hypersonic vehicles. Based on detonation driven technology, shock tunnel can generate high-temperature and high-pressure driver gas in a short test time (millisecond level) to simulate hypersonic test airflow. The main diaphragm is located between the detonation driver section and the shock tube section in the shock tunnel. During the test, the diaphragm is opened under the detonation impulse pressure. The opening state and falling off state of the diaphragm have a great influence on the air quality in the shock tunnel. At the same time, the diaphragm is also a prerequisite for the formation of shock wave. In the traditional wind tunnel, aluminum diaphragm is used for testing. In the shock tunnel, a diaphragm with stronger pressure bearing capacity is needed. At this time, aluminum diaphragm is no longer applicable, and steel diaphragm is needed. Therefore, it is necessary to research the rupture characteristics of steel diaphragm in a shock tunnel. By comparing the numerical results with the experimental results, it is found that the numerical results are in good agreement with the experimental results, and the calculated results are reliable. Based on the stress-strain model of the diaphragm, a dynamic model of the diaphragm opening was established. According to the CJ detonation theory, the process of the diaphragm rupture was simulated by finite element software, and the mechanism and mechanical characteristics of the diaphragm rupture were analyzed and summarized. The control variable method was used to analyze and study the diaphragm of different thickness and groove length, and the change rule of diaphragm rupture pressure and effective diaphragm rupture time was obtained. In the shock tunnel test, the diaphragm parameters suitable for JF-12 wind tunnel were designed according to the total rupture time of the diaphragm.