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Filtered Rayleigh scattering for multi-parameter fluid flow analysis

用于多参数流体流动分析的滤波瑞利散射

基本信息

批准号：
EP/G033900/1
负责人：
Ralph Tatam
金额：
$ 53.07万
依托单位：
CRANFIELD UNIVERSITY
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2009
资助国家：
英国
起止时间：
2009 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FG033900%2F1
关键词：
Filtered Rayleigh scattering multi parameter

项目摘要

In aerospace test facilities, for example wind tunnels, gas turbine compressors and combustion experiments, it is necessary to obtain data about the fluid flows in these experiments to improve performance thus reducing harmful emissions and noise and to gain a better understanding of the fundamental fluid processes. The data required includes the density, pressure, temperature and velocity of the flow. Presently available techniques allow the measurement of these flow properties but have limitations: multiple techniques may need to be used to measure the different properties. The techniques may be limited to making single point measurements, requiring an expensive and time-consuming scanning mechanism to 'map' the flow. Additionally some of the techniques for measuring flow velocity require small 'seed' particles to be added to the flow which may result in inaccurate velocity measurements if these seed particles do not follow the flow accurately. Also, the addition of 'seed' particles to the flow is limiting in some applications, causing optical windows to become fouled limiting the measurement time and increasing the expense of the technique.Filtered Rayleigh scattering (FRS) is a promising optical technique that can potentially measure multiple properties (temperature, pressure, density and velocity) of the flow simultaneously. The measurements are made non-intrusively, so the flow is not changed by the measurement. Measurements can be made at a single point, or more significantly at multiple points over a plane defined by the laser light sheet in the flow. In FRS the properties of the flow are determined by measuring the Rayleigh scattered light. This is light scattered from the molecules of the gas itself, and as such no 'seed' particles are required. When the light is scattered from the gas molecules it will have its spectrum altered by the properties of the gas. The density of the gas can be found from the scattered intensity. The temperature can be found from the width of the scattered spectrum and the velocity from the shift in frequency compared to the optical frequency of the laser. Both of these effects are due to the Doppler shift, with the flow velocity causing a shift from the illumination frequency and the temperature provide a widening of the spectrum due to the Doppler shifts from the thermal motion of the molecules. Finally the pressure can be found by looking at the shape of the spectrum.The research proposed is the development of FRS instrumentation as a multi-parameter measurement technique for application in wind tunnels, gas turbine compressor and combustion facilities. Trials of the instruments constructed will be made, but not sustained measurement campaigns, rather the capabilities and limitations of the technique will be disseminated to end-users and industry for subsequent collaborative programmes.

在航空航天测试设施中，例如风洞、燃气轮机压缩机和燃烧实验，有必要获得这些实验中流体流动的数据，以改善性能，从而减少有害排放和噪音，并更好地了解基本的流体过程。所需数据包括流体的密度、压力、温度和速度。目前可用的技术允许测量这些流动特性，但具有局限性：可能需要使用多种技术来测量不同的特性。这些技术可能仅限于进行单点测量，需要昂贵且耗时的扫描机制来‘绘制’流动图。此外，一些用于测量流速的技术需要向流动中添加小的“种子”颗粒，如果这些种子颗粒不能准确地跟随流动，则可能导致不准确的速度测量。此外，在流体中添加种子粒子在某些应用中也是有限的，导致光学窗口被污染，限制了测量时间并增加了技术成本。过滤瑞利散射(FRS)是一种很有前途的光学技术，可以同时测量流体的多种性质(温度、压力、密度和速度)。测量是非侵入性的，因此流量不会因测量而改变。测量可以在单个点上进行，或者更重要的是，在流中激光光片定义的平面上的多个点上进行测量。在FRS中，流动的性质是通过测量瑞利散射光来确定的。这是从气体本身的分子中散射出来的光，因此不需要“种子”粒子。当光从气体分子散射时，它的光谱会因气体的性质而改变。气体的密度可以从散射强度中得到。温度可以从散射谱的宽度和相对于激光光学频率的频率偏移的速度中得到。这两种效应都是由于多普勒频移造成的，其中流速引起照明频率的漂移，而温度由于分子热运动的多普勒频移而导致光谱的展宽。提出了FRS仪器作为一种多参数测量技术在风洞、燃气轮机压缩机和燃烧设施中应用的发展方向。将对建造的仪器进行试验，但不是持续的测量运动，而是将该技术的能力和局限性传播给最终用户和行业，以供随后的合作方案使用。