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

在模拟航天飞行器重返大气层的实验中，冲击波技术最好用于创造高温条件，否则任何联合方法都无法产生高温条件。到目前为止，在大气层重返过程中出现的高温超过10,000 K，因此空气分子将解离并电离。这个过程是名副其实的气体效应。目前的研究旨在通过实验验证高超声速真实气体效应，使用一个100毫米x 180毫米的超高速激波管，该激波管已于1994年从多伦多大学航空航天研究所运来。本研究采用一种利用化学计量氢氧混合物中爆轰波反射的爆轰驱动系统对该激波管进行改造，并采用双曝光全息干涉法对高超声速激波进行定量可视化。结果表明：(1)在该激波管中成功地采用了无隔膜操作系统。它的特性已经被彻底研究过了。在现有激波管中尚未实现的更高程度的可重复性已得到证实。(2)为保证高压室内爆轰的起爆，采用双曝光全息干涉技术对爆燃驱动激波向爆轰波的过渡过程进行了可视化研究。微电荷表面的小颗粒破碎引起化学反应的效应。(3)有限条纹全息干涉法应用于(2)的实验。采用傅立叶条纹分析方法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会议上发表。与多伦多大学航空航天研究所进行了国际合作。

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.