A Study of Turbulent Combustion Mechanism in a High-Pressure, High-temperature and High Water-vapor Environment

本课题的目的是结合废气回收在高压高负荷燃烧中的应用，探索水蒸气高度稀释低氧混合气的湍流燃烧机理。由于废气由水蒸气、二氧化碳和氮气组成，因此系统地研究了稀释特别是水蒸气和二氧化碳稀释对燃烧特性的影响。对常压到高压的湍流和层流预混火焰，采用激光诊断法测量了火焰结构和燃烧速度。在第一年，与二氧化碳稀释高压湍流预混火焰的实验相平行，研制了一种高压环境下产生水蒸气的装置，该装置采用铜柱、棒式加热器和钢丝绳连接水蒸气质量流量控制器，证实了该装置在大范围内稳定地提供水蒸气S…更多的补给。利用该装置，证实了火焰发射光随混合物干燥程度的不同而不同。第二年，在高温高压下，成功地进行了掺入摩尔分数为0.1的水蒸气的湍流预混火焰实验。利用OHPLIF分析了基于500幅OHPLIF图像的平均进动变量的分布，测量了湍流火焰区域的湍流燃烧速度和平均体积，并与二氧化碳稀释的结果进行了比较。此外，还对层流火焰进行了OH-PLIF和PTV的同时测量，以测量层流燃烧速度和水蒸气的影响。结果表明，在富燃区，水蒸气稀释混合气的燃烧速度大于数值模拟的结果，表明燃料重整反应是导致这一现象的原因。此外，还发现由于水蒸气的加入，燃烧气体中的一氧化碳浓度降低了。较少

The purpose of this project is to explore turbulent combustion mechanism for low oxygen mixture highly diluted with water vapor considering the applications of exhaust gas recycling to high-load combustion at high pressure. Because the exhaust gas consists of water vapor, carbon dioxide and nitrogen, the effects of dilution especially with water vapor and carbon dioxide on combustion characteristics were investigated systematically. For turbulent and laminar premixed flames from ordinary pressure to high pressure, flame structure and burning velocity were measured using laser diagnostic methods.In the first year, parallel to the experiments on carbon dioxide dilution effects on high-pressure turbulent premixed flames, an apparatus to generate water vapor in a high-pressure environment using a copper cylinder, rod heaters and steel wool connected to a water mass-flow controller was developed and it was confirmed that the apparatus stably provided water vapor over a wide range of water s … More upply. Using the apparatus, differences in light emission from the flames depending on the dryness of the mixture were confirmed.In the second year, experiments for turbulent premixed flames diluted with water vapor up to 0.1 of moler fraction were successfully performed at high pressure and high temperature. By using OH-PLIF, profiles of the mean progress variable based on 500 OH-PLIF images were analyzed and the turbulent burning velocity and mean volume of the turbulent flame region were measured, and then compared with those for carbon dioxide dilution. Moreover, simultaneous measurement of OH-PLIF and PTV was performed for laminar flames to measure the laminar burning velocity and the effects of water vapor. As a result, it was found that the burning velocity for the mixtures diluted with water vapor was larger than that of numerical simulation in the fuel rich region and it was implied that fuel reforming reactions causes the phenomenon. Also, it was found that concentration of carbon monoxide in the burnt gas was reduced as an effect of the water vapor addition. Less