Development of high-speed spectrometer system with high spatial and wavelength resolution and the application to flame diagnostics

先前研究的目的是从激发自由基的时空行为、火焰化学计量、放热和化学反应过程等方面研究局部火焰结构及其化学组成。用空间、时间和光谱分辨的化学发光方法测量了火焰中的电子激发自由基，观察了流体流动中化学反应的时间演化。首先，我们开发了一种光学测量技术，使用专门设计的卡塞格伦光学球差最小化来检测火焰和带光栅的高速(1 MHz)光谱探测器的局部发射。卡塞格伦光学系统与单芯光纤耦合，以便将具有良好空间分辨率的探测到的光引导到光谱仪。对得到的遗漏强度的时间序列信号进行了统计和瞬时分析。局部火焰温度和化学发光…的分布在层流扩散火焰和层流预混火焰中，同时测量到了更多的OH^*、CH^*和C2^*自由基。温度测量是基于瑞利散射法的。用卡塞格伦光学方法测量了高空间分辨率的化学发光和瑞利散射。研究了局部火焰温度与化学发光强度之间的关系，将C2波段发射强度比测温方法应用于预混火焰局部温度的时间分辨测量。首先，利用量子物理理论计算了温度与C_2发射强度各峰的关系。用实验方法研究了火焰局部温度与C2化学发光发射强度比之间的关系。由发射强度比得到的温度是C2在火焰局部区域的振动温度。C_2振动温度有可能高于热平衡温度。本研究采用热电偶测得的温度作为热平衡状态下的温度。本研究的目的是利用卡塞格伦光学系统和光谱装置测量丙烷或甲烷与空气的预混层流火焰的局部化学发光，并尽可能精确地研究热电偶测量的温度与C_2波段发射强度比之间的关系。通过当量比的不同改变丙烷/空气预混火焰中的温度，可以认为热电偶测量的温度与C_2波段发射强度比之间是线性函数关系。通过用氮气稀释来改变温度，这些关系也变得线性。这些测量方法被应用于甲烷/空气预混振动火焰。利用卡塞格伦光学系统和分光镜装置测量了振动预混火焰局部区域的化学发光。通过数值处理，选取了发射强度足够强的化学发光部分，这些部分与热电偶测量的温度关系与预混层流火焰中观察到的相似。较少

The purpose of the previous study was to investigate the local flamefiont structure and its chemistry by the spatial and temporal behavior of excited radicals, flame stoichiometry, heat release and chemical reaction process. Spatially, temporally, and spectrally resolved chemiluminescence measurements of electronically excited radicals in a flame such as OH^*, CH^*, and C_2^* was carried out to observe the time evolution of chemical reactions in fluid flows. Firstly, we developed an optical measurement technique using specially designed Cassegrain Optics minimized of spherical aberration to detect emissions locally in flames and highspeed (1 MHz) spectrum detectors with gratings. The Cassegrain Optics was coupled with a single core fiber optic so that the light detected with good spatial resolution was guided to spectrometers. Obtained timeseries signals of omission intensities were analyzed statistically as well as instantaneously.Distributions of local flame temperabe and chemilumine … More scence of OH^*, CH^* and C_2^* radicals were simultaneously measured in laminar diffusion flames and laminar premixed flames. The tempffature measurement is based on the Rayliegh scatering method. The Cassegrain optics was used-to measure the chemiluminescence and Rayleigh scattering with high spatial resolution. Relationships between the local flame temperature and chemiluminescence intensities were examined.Temperature measurement method using C_2 band emission intensity ratio is applied to the measurement of timeresolved local temperature in premixed flames. First of all, the relationship between temperature and each peaks of C_2 emission intensity is calculated by using quantum physical theory. We try to know te relationship between local temperature in flame and emission intensity ratio of C_2 chemiluminescence by using experimental method. The temperature obtained from emission intensity ratio is the vibrational temperature of C_2 in the local region of flame. The C_2 vibrational temperature has the possibility to be higher than the temperature in thermal equilibrium state. The temperature measured by thermocouples is used as the temperature in thermal equilibrium state in the present study. The objectives in the present study are to measure local chemiluminescence of premixed laminar flames of propane or methane and air with the Cassegrain optical system and spectroscope unit and to investigate the relationship between temperature measured by thermocouples and C_2 band emission intensity ratio as precise as possible. By changing the temperature in premixed laminar propane/air flames by the difference of the equivalence ratio, the relationship between temperature measured by thermocouples and C_2 band emission intensity ratio can be considered to be a linear fimction. By changing the temperature by diluting with N2, those relationships become linear as well. These measurement methods are applied to premixed methane/air vibrated flames. The Cassegrain optical system and the spectroscope unit are used to measure local chemiluminescence in local region of vibrated premixed flame. The measured chemiluminescence intensity parts with enough strong emission intensity are chosen by numerical processing and the parts show the similar relationships with thermal temperature measured by thermocouples as observed in premixed laminar flames. Less