利用光学层析技术重构超声速绕流流场密度分布

Reconstruction of density distribution in the supersonic flow field with optical computerized tomography

在连续式风洞中,采用单光路旋转流场干涉测量和计算机层析方法获得了含模型的超声速绕流流场密度分布。首先利用多种图像处理方法,并引入计算机辅助功能,对干涉图片进行精确判读和定量处理,准确重构波前相位信息;获得了相应的PV值、RMS值以及前15阶的Zernike多项式系数;通过同原始CFD模型波前数据的对比,系统的重构精度RMS优于λ/10。在获得一系列单帧干涉波前相位数据的基础上,采用光学层析技术,设计计算机迭代算法,构造内部旋转矩阵,重构了超声速绕流流场密度分布,可以非常直观地获得待测流场不同方向截面上的密度分布状况。

The density distribution of supersonic flow field including model in the wind tunnel have been reconstructed. The interferometry and optical computerized tomography have been used to accomplish this task. Firstly, several image processing methods and computer aided identify have been programmed to accurately dis- tinguish and quantificationally calculate the interference patterns. It＇s very important that the wave-front information has been reconstructed accurately. The correlative parameters including PV, RMS, and the coefficients of Zernike polynomial have also been obtained. Compared with the wave-front results of CFD calculation method, the reconstruction precision （RMS） has been determined to less than λ/10. Base on a series of wave-front data, the density distribution in the supersonic flow has been reconstructed by optical computerized tomography. And the density distribution on the different sections can also be offered easily.