High precision temperature measurements for reacting flows

反应流的高精度温度测量

• 批准号: EP/K02924X/1
• 负责人: Simone Hochgreb
• 金额: $ 54.16万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FK02924X%2F1
• 关键词: precision; temperature; measurements; reacting; flows

The effective and fast design of low emission gas turbines depends critically on the ability of engineers to make accurate and precise predictions of gas temperatures within the combustion chamber. This project aims to produce instantaneous temperature measurements of the highest accuracy and precision ever in model and industrial scale combustors. These precision measurements aim not only provide the basis for validation of models by industrial and academic users, but also to create a path for development of a lower cost, high precision thermometry technique for deployment in realistic combustors. The two key factors governing the design of continuous flow combustors are maintaining low emissions - particularly nitric oxides - and keeping the system away from thermoacoustic instabilities. The spatial and statistical distribution of burned gas temperatures is the single most important factor governing the formation of nitric oxide (NO): a local change of 50 K can lead to a change of 70% in thermal NO formation rates at typical combustion temperatures. Validation of emission prediction models is hemmed by the lack of availability of statistical and spatial information on temperatures. Thermoacoustic instabilities are created by a feedback effect in which acoustic waves generated by the unsteady acceleration of the flow during combustion in a confined environment lead to further unsteadiness in heat release. Two factors associated with the flame are important: the response of the flame to acoustic perturbation, and the generation of temperature non-uniformities (called entropy spots): the former leads directly to density fluctuations and acoustic waves, and the latter couple the boundary conditions to reflect as pressure waves. The identification of the origin of combustion instabilities is complex, as several factors can contribute fluctuations, yet usually only pressure information is available, sometimes aided by relative total heat release fluctuations via chemiluminescence. Nevertheless, statistical measurements of temperatures in either model or industrial scale gas turbine flames are relatively uncommon, because of difficulties with physical probes or optical methods relying on calibration of signal amplitudes. The proposed measurements do not rely on amplitudes, but on the measurement of signal frequency, which can be made significantly more precisely (down to errors of 0.2%) than comparable techniques. Furthermore, the present measurements will enable the direct simultaneous measurements of NO and temperature with a single laser, thus creating a unique statistical database for model validation. Finally, the technique will enable for the measurement of temperature fluctuations through a nozzle at very high precision, which has not been done previously. The high precision measurements will have a direct impact on assessing the quality of model predictions for NO and instabilities, and when translated into design codes, into the design of cleaner and more stable power and propulsion systems.

低排放燃气轮机的有效和快速设计关键取决于工程师对燃烧室内气体温度进行准确预测的能力。该项目旨在对模型和工业规模燃烧器进行有史以来最高精度的瞬时温度测量。这些精确测量的目的不仅为工业和学术用户验证模型提供基础，而且还为开发用于实际燃烧室部署的低成本、高精度测温技术开辟了道路。控制连续流燃烧器设计的两个关键因素是保持低排放——尤其是一氧化氮——以及使系统远离热声不稳定。燃烧气体温度的空间和统计分布是控制一氧化氮 (NO) 形成的最重要因素：50 K 的局部变化可导致典型燃烧温度下热力 NO 形成率变化 70%。由于缺乏可用的温度统计和空间信息，排放预测模型的验证受到限制。热声不稳定性是由反馈效应产生的，其中在受限环境中燃烧期间流动的不稳定加速产生的声波导致热量释放进一步不稳定。与火焰相关的两个因素很重要：火焰对声扰动的响应，以及温度不均匀性（称为熵点）的产生：前者直接导致密度波动和声波，后者耦合边界条件以压力波的形式反射。燃烧不稳定性起源的识别很复杂，因为有几个因素可能导致波动，但通常只有压力信息可用，有时通过化学发光得到相对总放热波动的帮助。然而，由于依赖于信号幅度校准的物理探针或光学方法存在困难，模型或工业规模燃气轮机火焰中的温度统计测量相对不常见。所提出的测量不依赖于幅度，而是依赖于信号频率的测量，这可以比同类技术更加精确（误差低至 0.2%）。此外，目前的测量将能够使用单个激光直接同时测量 NO 和温度，从而为模型验证创建一个独特的统计数据库。最后，该技术将能够以非常高的精度测量通过喷嘴的温度波动，这是以前从未做过的。高精度测量将对评估 NO 和不稳定性模型预测的质量产生直接影响，并在转化为设计规范时，影响更清洁、更稳定的动力和推进系统的设计。

项目成果

Temperature and water measurements in flames using 1064 nm Laser-Induced Grating Spectroscopy (LIGS)

使用 1064 nm 激光诱导光栅光谱 (LIGS) 测量火焰中的温度和水分

• DOI: 10.17863/cam.38874
• 发表时间: 2019
• 作者: De Domenico F

Extracting flame describing functions in the presence of self-excited thermoacoustic oscillations

在存在自激热声振荡的情况下提取火焰描述函数

• DOI: 10.1016/j.proci.2016.06.050
• 发表时间: 2017
• 期刊: Proceedings of the Combustion Institute
• 影响因子: 3.4
• 作者: Balusamy S

Detection of direct and indirect noise generated by synthetic hot spots in a duct

检测管道中合成热点产生的直接和间接噪声

• DOI: 10.17863/cam.8524
• 发表时间: 2017
• 作者: De Domenico F

Tracer-free laser-induced grating spectroscopy using a pulse burst laser at 100 kHz.

使用 100 kHz 脉冲突发激光器的无示踪剂激光诱导光栅光谱。

• DOI: 10.17863/cam.44500
• 发表时间: 2019
• 作者: De Domenico F

Measurements of the Effect of Boundary Conditions on Upstream and Downstream Noise Arising From Entropy Spots

边界条件对熵点产生的上下游噪声影响的测量

• DOI: 10.1115/gt2017-64378
• 发表时间: 2017
• 作者: De Domenico F