用双光收缩式径向剪切干涉仪测量气体温度场

Two-Beam-Contracted Radial Shearing Interferometer for Measuring the Gas Temperature Field

为了适应大测试区的相位物体的测试研究和控制光学系统的成本,设计出双光收缩式径向剪切干涉光学系统。通过实验得到干涉条纹,用CCD摄入计算机,经Matlab编制傅里叶变换、相位去包裹和其他数值计算程序,解调干涉条纹的相位,计算出温度扰动产生的波面畸变量,它等于折射率变化引起的相位偏移值,用轴对称气体温度场重建方法,再现了气体温度场一个层面上的温度分布。实验结果与铜康铜微型热电偶单点测温相比较,两者相差不大。实验表明该系统具有较高的精度和测试灵敏度,适于环境温差较小的相位物体热物理量的测量。

A new two-beam-contracted radial shearing interference optical system is developed to study on the large field of gas temperature. Methods of fast Fourier transform （FFT） and phase unwrap were used to demodulate the phase of the interferogram obtained from experiment, distortion of wavefront disturbed by temperature fluctuation which equals to phase shift induced by refractive index change was calculated, and a way of axisymmetric temperature field reconstruction was put into reshowing a layer of the gas temperature distribution. By comparing, the difference is equivalent to that of the mini-thermocouple. Experimental result shows that the optical system is reasonably sensitive and precise. It is suitable for measuring the phase object of which the lateral size is the larger and the longitudinal size is the shorter, when the difference of the temperature is little compared with the environment.