强激波背后发光形态观测及其结果的图像处理

Observation on Luminescent Form at the Back of Strong Shock-Wave and Image Processing of Its Results

本研究是用实验观测的方法判明低密度空气中发生的强激波的构造并进而分析其特性。为此,首先利用自由活塞二段隔膜激波管获得强激波,并以新型高速照相机拍摄激波背后的发光域,然后以SPICCA图像处理机对拍摄的照片进行等辉度线和浓度变换等处理。研究结果表明:(1)激波背后的发光受其速度影响很大,当激波速度U_s超过11.0km/s时,发光强度将出现两次峰值;(2)空气中氧元素对激波背后的发光情况有重要影响;(3)初压不同时,发光形态不同,当初压增高时,发光时间和强度都增加。这些结论为从理论上分析与研究强激波背后发光的形态与特性提供了可贵的参考资料。

The research tries to distinguish structure of strong shock-wave generated in low-density air by means of test and observation, and then analyse its characteristics. Therefore, first of all, two-section diaphragm shock tube with a free piston is used to obtain strong shock-waves, and luminescent area at the back of the shock-waves is taken by a new high-speed camera, and then equi-luminance line and variation of concentration are processed on photos taken by a SPICCA image processor. The results show that: (1) luminescence at the back of shock-wave is greatly affected by its velocity, when shock-wave velocity is more than 11.0 km/s, the luminous intensity will have two peak values; (2) oxygen element in the air has an important effect on luminescent condition at the back of shock-wave; (3)luminescent form is different as the primary pressures differ, and both luminous time and intensity increase when the primary pressures raises. These conclusions offer valuable references to analysing and researching luminescent forms and characteristics at the back of strong shock-wave theoretically.