激波风洞流场密度测量的聚焦纹影技术

Focusing schlieren technique applied to measure the flow density in shock tunnel

在激波风洞试验中发展了聚焦纹影显示技术,对流场的密度进行了定量测量。聚焦纹影显示具有对流场区域聚焦显示的特点,可获得流场某个聚焦测试区域的密度变化信息。依据聚焦纹影成像原理建立了密度计算数学模型,对试验中获得的带窗口模型流场聚焦纹影图像与试验前获得的流场图像灰度变化处理后,得到了流场聚焦区域的密度定量值。试验测量密度值与数值计算结果进行了比较,结果表明试验获得的密度值变化规律与数值模拟吻合较好,证实了利用聚焦纹影技术开展流场密度测量是可行的。

To achieve the quantitative measurement of flow density, the focusing schlieren system has been developed in the shock tunnel. The system has the characteristic of focusing on some region, and the flow density variety information of the focusing region can be gotten. Ac- cording to the focusing schlieren imaging theory, the math model of density calculation has been set up; the flow density of the region can be gotten after the grey degree changes of focusing schlieren images gotten before experiment and in experiment are processed. The flow density of experiment measurement has been compared with numerical simulation, and their density change rules are in good agreement, which improves that it is feasible to measure flow density using fo- cusing schlieren technique.