Spatially Resolved Diagnostics Using Tunable Laser Absorption Spectroscopy

温度和物种的精确测量 浓度对于表征高浓度 温度气体流动，特别是在燃烧区域。 光学测量是期望的，因为它们是 非侵入性的，非扰动的，探测器不受 恶劣的环境。 吸收测量提供了 浓度的简单定量定义 沿着视线吸收物质;这有时是 足够的信息，但更多的是空间解析 需要测量。 原则上，二维 温度和浓度场应该是可恢复的 从有限数量的视线测量， 断层重建是一种广泛应用于医学领域的方法， 显像 然而，精确的定量重建 温度和浓度场很难 因为重建算法非常敏感 输入数据中的错误。 这一目标的主要目的 程序是测量温度和浓度场 同时利用重建技术 红外二极管激光器的调谐能力， 降低重建方法对这两种情况的敏感性 输入数据中的随机误差和系统误差。 研究 将开始重建径向温度， 轴对称流中的浓度分布（CO和CO2）， 随后将手术扩展到重建 三维流的二维截面。 定量激光诊断技术在 工业情景受到典型的高 所涉设备的成本和用户的复杂程度 取得量化成果所需的。 成功 有了这些成本更低、用户更友好的系统， 在工业中得到更广泛的应用;软件和硬件 开发应能够实现断层扫描 吸收诊断技术在各种各样的 应用. 可能，进一步发展这一 使用廉价激光二极管源的技术可以 使仪器包足够便宜和坚固， 在工厂过程控制系统中。

Accurate measurements of temperature and species concentrations are important for characterization of high temperature gas flows, particularly in the area of combustion. Optical measurements are desirable since they are nonintrusive, nonperturbing, and the probe is not subject to a hostile environment. An absorption measurement provides a simple quantitative definition of the concentration of the absorbing specie along a line-of-sight; this is sometimes adequate information, but more often spatially resolved measurements are needed. In principle, two-dimensional temperature and concentration fields should be recoverable from a limited number of line-of-sight measurements using tomographic reconstruction, a method widely used in medical imaging. However, accurate quantitative reconstructions of temperature and concentration fields have been difficult to achieve because reconstruction algorithms are very sensitive to errors in the input data. The principal objective of this program is to measure temperature and concentration fields simultaneously using a reconstruction technique that exploits the tuning capability of infrared diode lasers to greatly reduce the sensitivity of the reconstruction methods to both random and systematic errors in the input data. The study will begin with reconstruction of radial temperature and concentration profiles (CO and CO2) in an axisymmetric flow, with subsequent extension of the procedures to reconstruction of two-dimensional sections of three-dimensional flows. The application of quantitative laser diagnostics to industrial scenarios has been hampered by the typical high cost of equipment involved and by the user sophistication required for achievement of quantitative results. Success with the these lower-cost, more user-friendly systems may well lead to wider usage in industry; the software and hardware developed should enable implementation of tomographic absorption diagnostic techniques in a wide variety of applications. Potentially, further development of this technology, with use of inexpensive laser diode sources, may allow instrumentation packages cheap and robust enough for use in in-plant process control systems.