Satti Rajani P, Kolhe Pankaj S, Olcmen Semih, Agrawal Ajay K
University of Oklahoma, Norman, Oklahoma 73019, USA.
Appl Opt. 2007 May 20;46(15):2954-62. doi: 10.1364/ao.46.002954.
Recent interest in small-scale flow devices has created the need for miniature instruments capable of measuring scalar flow properties with high spatial resolution. We present a miniature rainbow schlieren deflectometry system to nonintrusively obtain quantitative species concentration and temperature data across the whole field. The optical layout of the miniature system is similar to that of a macroscale system, although the field of view is smaller by an order of magnitude. Employing achromatic lenses and a CCD array together with a camera lens and extension tubes, we achieved spatial resolution down to 4 mum. Quantitative measurements required a careful evaluation of the optical components. The capability of the system is demonstrated by obtaining concentration measurements in a helium microjet (diameter, d=650 microm) and temperature and concentration measurements in a hydrogen jet diffusion flame from a microinjector (d=50 microm). Further, the flow field of underexpanded nitrogen jets is visualized to reveal details of the shock structures existing downstream of the jet exit.
近期对小型流动装置的关注引发了对能够以高空间分辨率测量标量流动特性的微型仪器的需求。我们展示了一种微型彩虹纹影偏折测量系统，用于非侵入式地获取整个场域的定量物种浓度和温度数据。尽管微型系统的视场比宏观系统小一个数量级，但其光学布局与宏观系统相似。通过使用消色差透镜、电荷耦合器件（CCD）阵列以及相机镜头和延长管，我们实现了低至4微米的空间分辨率。定量测量需要对光学组件进行仔细评估。通过在氦气微射流（直径d = 650微米）中进行浓度测量以及在微型注射器（d = 50微米）的氢气射流扩散火焰中进行温度和浓度测量，证明了该系统的能力。此外，对欠膨胀氮气射流的流场进行了可视化，以揭示射流出口下游存在的激波结构细节。
