An analy of high entalpy flows using PLIF

O_2-LIPF方法是基于ArF准分子激光(193 Nm)的发射和O2的Schumann-Runge B(v‘=4)*X(v“=0)吸收系统的重叠，该系统在175~250 nm具有离散吸收线，在130~175 nm具有连续吸收带。由于B态是强预离解态，在分子间碰撞之前产生荧光，表现出很小的寿命，约为10^&lt；-12&gt；S。因此，在低压条件下不必考虑碰撞猝灭。我们提出了一种利用宽带ArF准分子激光激发的O2分子的激光诱导预解离荧光进行二维温度测量的新方法。在这种方法中，温度是通过在两个光谱区域积分的荧光强度之间的比值的温度依赖关系来测量的。利用一个摄像机和两个带通滤光片对热空气流动进行了数值模拟，验证了该方法的可行性。

O_2-LIPF method is based on using the overlap of ArF excimer laser (193nm) emission and the Schumann-Runge B (v'=4) * X (v"=0) absorption system of O_2, which has discrete absorption lines from 175 to 250 nm and continuum absorption band from 130 to 175 nm. Because the B state is predissociated strongly, the fluorescence yields prior to intermolecular collision, showing very small life time of 10^<-12>s. Therefore, the collisional quenching has not to be taken into account under the condition of low pressure.We propose a new method for the 2-D temperature measurement technique using the LIPF (Laser-induced predissociative fluorescence) of O_2 molecules excited by a broadband ArF excimer laser. In this method, temperature is measured by use of temperature dependence of rations between fluorescence intensities integrated in two spectral regions. The method is applied to heated air flows using a CCD camera and two band pass filters, which pass through the different spectral regions, and the feasibility of this methods is examined successfully.