Study of real gas effects by using a Mach 20 hypersonic shock tube

在模拟航天器大气层再入的实验中，冲击波技术最适合用来创造高温条件，否则任何一种方法都不可能产生高温条件。到目前为止，大气层再入过程中出现的高温超过10000 K，导致空气分子解离并电离。这一过程被称为真气体效应。本研究的目的是利用1994年从多伦多大学航空航天研究所运来的100 mm×180 mm超高速激波管，对高超声速真实气体效应进行实验验证。本研究采用爆轰波在化学计量比氢氧混合物中的反射爆轰波驱动系统对该激波管进行改造，并采用二次曝光全息干涉法对高超声速激波进行了定量显示。对其特征进行了深入的研究。其重复性是现有激波管所没有的。(2)为了保证高压室中爆轰波的起爆，利用二次曝光全息干涉法实现了爆燃驱动冲击波向爆轰波的转化。引发化学反应的微小粒子从微电荷表面碎裂的效应。(3)将有限条纹全息干涉计量术应用于(2)中的实验。利用傅里叶条纹分析对有限条纹干涉图进行了定量分析。建立了其测量系统。(4)两年的研究成果已在国际学术研讨会上发表。与多伦多大学航空航天研究所开展了国际合作。

In simulating experimentally atmospheric re-entry of space vehicles, shock wave technology is best used to create high temperature conditions which are otherwise impossible to generate by any together methods. The high temperature so far appearing during the atmospheric re-entry exceed 10,000 K so that air molecules will dissociate and then ionized. This process is name real gas effect. The present study aims to experimentally verify the hypersonic real gas effect by using a 100 mm x 180 mm hypervelocity shock tube that has been transported from the Institute of Aerospace Studies, University of Toronto in 1994. The present study is to refurbish this shock tube by adopting a detonation driver system in which the reflection of detonation waves in stoichiometric oxyhydrogm mixture is used and to quantitatively visualize hypersonic shock waves using double exposure holography interferometry.The result obtained are summarized as following :(1) A diaphragmless operation system has been adopted successfully in this shock tube. Its characteristics have been throughly investigated. Its higher degree of repeatability that has not been achieved among existing shock tubes has been confirmed.(2) To ensure the initiation of detonations in the high pressure chamber, the transition from deflagration driven shock waves to detonation waves has been visualized using double exposure holographic interferometry. The effect of small particles shattering from the surface of micro-charges which initiate the chemical reaction.(3) Finite fringe holographic interferometry has been applied to the experiments in (2). Finite fringe interferograms were quantitatively analyzed by using Fourier fringe analysis. Its measuring system has been established.(4) Results obtained during two years of research works have been presented at international symposia. International collaboration with the Institute of Aerospace Studies, University of Toronto has been conducted.