摘要
激波管所产生的非定常运动激波,若强度和形状能够按照一定的设计要求进行可控条件下的调节,将可望为燃料点火燃烧试验等提供具有独到优势的研究手段。基于激波动力学理论,针对激波管中所产生的平面运动激波,通过设计特定的上下壁面收缩型线,使初始平面运动激波,经收缩段(包括光滑凹形曲线段、斜直线段和光滑凸形曲线段)的变形和强度增加,再以平面波面形状进入较小截面直管段的连续转变过渡,得到了强度增加的平面激波。进一步对所设计的典型型线分别采用数值计算和试验的方法,考核分析激波运动过程中的形状变化,验证了理论方法的可靠性。在此基础上,分析了型线设计的关键参数对激波增强幅度的影响,结果表明,相对于传统激波管方法,本文中所提出的收缩截面方法能更显著地增加平面激波强度;另外,还考察了初始入射激波马赫数对壁面型线和运动激波波面形状的影响,结果表明,对于较强的初始入射激波来说,壁面型线对入射激波强度依赖较小,也就是说,当实际入射激波马赫数即使稍偏离设计状态时,仍然能得到近乎完美的平面形状增强激波。
The generation of shape and strength controllable shock wave will offer a special way for ignition and combustion experiments.In this paper,a new method has been proposed for smooth enhancement of a shock wave in a shock tube.With the help of shock dynamics theory,aplanar-to-planar shock wave enhancement can be obtained through a convergent channel of specially designed smooth concave-convex wall contour,which bends the planar incoming shock wave into a cylindrical convergent one and then planarizes it and finally forms a strengthened planar shock wave.A typical designed wall profile is verified with both numerical simulation and experimental test.It is found that the agreement of shock wave shape is nearly perfect.Furthermore,the influence of some dominant parameters on the shock enhancement process is analyzed.Compared to the traditional way of increasing pressure ratio in a shock tube,the new method is more efficient to increase plane shock wave intensity.Meanwhile,the influences on wall profile and shock front shape are also performed.When the initial shock is relatively strong,the designed wall profile almost remains the same even though the incoming shock Mach number deviates to some extent,which means that a near-perfect straight shape of shock front can be obtained regardless of unavoidable experimental scatters.
出处
《航空学报》
EI
CAS
CSCD
北大核心
2016年第8期2408-2416,共9页
Acta Aeronautica et Astronautica Sinica
基金
国家自然科学基金(11132010)~~
关键词
激波动力学
激波管
激波增强
收缩管道
壁面型线
激波面形状
shock dynamics
shock tubes
shock wave enhancement
convergent channel
wall profile
shock front shape
