论文部分内容阅读
潮湿空气通过超音速喷管时，空气经过喷管喉部，水蒸汽便凝结成非常微小的雾状微粒．通常，在风洞的气动力研究中，当用激光面束照射雾状微粒时，便产生了所谓蒸汽屏．这种技术往往对给定的流场显示出重要的定性数据．本研究工作的目的，是要把通常的蒸汽屏定性技术应用到超音速流动中，转化为一种定量的密度测量工作．假定散射强度与微粒密度间成线性关系，在Ｍ＝２．８的条件下，从蒸汽屏的数值化图像，获得了绕二维双凸翼面流动的密度定量数据．在自由气流中和翼面的弓形激波条件，通过已知的状态，校准强度读数，把实验结果与用欧拉编码计算出的密度相比较，结果误差不超过１０％．由于实现并提供了高分辨率，这种方法是简便的，对于其它的非相关特征方法也具有一定的优点．然而。在翼展方向，在有不变强度的激光面束时，分析起来会变得非常的简单．
When damp air passes through the supersonic nozzle, the air passes through the throat of the nozzle and the water vapor condenses into very fine mist particles. Often, in aerodynamic studies of wind tunnels, so-called vapor screens are created when a mist of particles is irradiated with a laser facet. This technique often shows important qualitative data for a given flow field. The purpose of this research work is to apply the usual steam screen qualitative technology to supersonic flow and to transform it into a quantitative density measurement. Assuming a linear relationship between the scattering intensity and the particle density, quantitative data of the density around the two-dimensional lenticular airfoil are obtained from the numerical image of the vapor screen at M = 2.8. Under free-air flow and airfoil shock conditions, the intensity readings were calibrated by known conditions and the experimental results were compared to those calculated with the Eulerian code, with an error of no more than 10%. Due to the high resolution achieved and provided, this method is simple and has some advantages over other non-related feature methods. however. In the wingspan direction, with a constant intensity laser face beam, the analysis becomes very simple.