Experimental study of thermo-chemical conditions in ethanol flames

乙醇火焰热化学条件的实验研究

• 批准号: 315820332
• 负责人: Professor Dr. Andreas Dreizler
• 金额: --
• 依托单位: Fachgebiet Reaktive Strömungen und Messtechnik (RSM)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/315820332?language=en
• 关键词: Experimental; study; thermo; chemical; conditions

The essential scientific aim of the project is to examine the physico-chemical processes of chemistry-turbulence interaction in premixed flames of complex, renewable fuels. Due to its technical relevance ethanol as a more complex fuel is particularly suitable for these investigations. A novel measurement apparatus based on spontaneous Raman/Rayleigh scattering has to be developed in order to quantify the thermochemical state vector as completely as possible. The aim is the simultaneous, quantitative measurement of temperature and all major species concentrations in premixed ethanol flames. This is challenging since the number as well as the concentration of intermediate (oxygenated) hydrocarbon species (HC(O)) in the reaction zone itself is markedly increasing in comparison to more simple fuels like methane. Thus, the number of major species to be measured is increasing. Work on three central topics is required, in order to develop a technique able to measure the concentrations of the intermediate HC(O) major species as well as ethanol in flames simultaneously for the first time: (1) To evaluate the concentration data in flames, the temperature-dependent Raman response of ethanol and HC(O) species arising with higher concentrations in premixed ethanol flames must be determined. These species are at least methane, ethene as well as the aldehydes formaldehyde and acetaldehyde. Such data is not published in the literature for the required temperature range or is not available at all. Three different flow apparatus are required for that purpose, which will be set up in the course of the project: first, a novel gas heater will be developed, that will allow for heating the HC(O)-species up to very high temperatures. Second, an apparatus for the continuous generation of a defined flow of formaldehyde will be established. Third, a jet burner configuration to stabilize flames of the prevaporized fuel ethanol will be realized. (2) For the investigations, a Raman/Rayleigh spectrometer is required, which allows the most prominent HC(O) intermediates to be measured simultaneously to the other major species (CO2, O2, CO, N2, fuel, H2O and H2). For that purpose a novel spectrometer shall be developed, which is able to separate the spectrally closely spaced Raman lines of the HC(O)-intermediates and the ethanol from each other. (3) The characteristic, temperature-dependent Raman spectra of the HC(O)-intermediates and ethanol will be measured and processed into a library. Raman measurements will then be performed initially at premixed, laminar ethanol flames in order to establish the method. These form the basis for the development of an appropriate data evaluation method and also for measurements of turbulent ethanol flames in a second project period. Both a significant advancement in laser combustion diagnostics as well as an improved understanding of major species concentrations in the context of turbulence-chemistry interaction in ethanol flames are expected.

该项目的基本科学目标是研究复杂的可再生燃料预混火焰中化学-湍流相互作用的物理化学过程。由于其技术相关性，乙醇作为一种更复杂的燃料特别适合于这些研究。为了尽可能完整地量化热化学态矢量，必须研制一种新的基于自发拉曼/瑞利散射的测量装置。其目的是同时、定量地测量预混乙醇火焰中的温度和所有主要组分浓度。这是具有挑战性的，因为与甲烷等更简单的燃料相比，反应区中中间(含氧)碳氢化合物物种(HC(O))的数量和浓度正在显着增加。因此，要测量的主要物种的数量正在增加。为了开发一种能够同时测量火焰中中间体HC(O)主要物种和乙醇浓度的技术，需要在三个中心课题上开展工作：(1)为了评估火焰中的浓度数据，必须测定乙醇和HC(O)物种在预混乙醇火焰中浓度较高时产生的随温度变化的拉曼响应。这些物种至少是甲烷、乙烯以及甲醛和乙醛。这样的数据没有在所需的温度范围内发表在文献中，或者根本无法获得。为此需要三种不同的流动装置，它们将在项目过程中设置：首先，将开发一种新型气体加热器，将允许将HC(O)-物种加热到非常高的温度。第二，将建立一个连续产生规定流量的甲醛的装置。第三，将实现喷射式燃烧器配置，以稳定预制燃料乙醇的火焰。(2)为了进行研究，需要一台拉曼/瑞利光谱仪，它可以同时测量其他主要物种(二氧化碳、氧气、一氧化碳、氮气、燃料、水和氢气)中最突出的HC(O)中间体。为此，应开发一种新的光谱仪，它能够将HC(O)中间体和乙醇的光谱间隔很近的拉曼线彼此分开。(3)测量HC(O)-中间体和乙醇的特征随温度变化的拉曼光谱，并将其处理到库中。然后，为了建立该方法，首先将在预混合的层流乙醇火焰中进行拉曼测量。这些是制定适当的数据评估方法的基础，也是在第二个项目期测量湍流乙醇火焰的基础。预计在激光燃烧诊断方面将取得重大进展，并在乙醇火焰中湍流-化学相互作用的背景下改善对主要物质浓度的理解。