湍流热伴流中氢气与乙炔射流自着火实验  

Experiment on the autoignition characteristics of hydrogen and acetylene jets in a turbulent hot coflow

作　　者：刘贵军 刘佳悦 张扬[1] 吴玉新[1] LIU Guijun;LIU Jiayue;ZHANG Yang;WU Yuxin(Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Department of Energy and Power Engineering,Tsinghua University,Beijing 100084,China;School of Energy and Power Engineering,Dalian University of Technology,Dalian 116000,China)

机构地区：[1]清华大学能源与动力工程系,热科学与动力工程教育部重点实验室,北京100084 [2]大连理工大学能源与动力学院,大连116000

出　　处：《清华大学学报（自然科学版）》2023年第4期594-602,共9页Journal of Tsinghua University(Science and Technology)

基　　金：国家科技重大专项(2019-I-0022-0221)。

摘　　要：氢燃料燃气轮机是碳中和目标下氢燃料发电的关键设备,因此探究湍流热伴流中氢气自着火特征以及与碳氢燃料间的差异具有重要意义。该文采用湍流热伴流自着火实验系统,通过获取火焰图像和OH自由基分布,对比分析了氢气和乙炔在自着火类型、结构等方面的差异。结果表明:受氢气的高扩散系数和高火焰传播速度影响,氢气随机着火分布区域较紧凑,OH自由基分布较连续,同时难以观测到独立自着火核。此外,相较于乙炔,氢气自着火抬升高度对燃料射流速度敏感性较低,自着火位置波动性较弱。基于氢气射流自着火特征,该文还改进了自着火抬升高度预测模型,并证明了火焰传播在氢气射流自着火火焰稳定方面的重要作用。[Objective]Hydrogen fuel gas turbine is the key equipment for large-scale hydrogen fuel power generation toward realizing the goal of carbon neutrality.Lean premixed combustion is an important technology for reducing the NOx emissions of modern gas turbines.However,compared with those of traditional hydrocarbon fuels,the high flame-propagation speed,wide flammability limit,and extremely low ignition energy of hydrogen increase the risk of autoignition and flashback in the premixed duct.Besides,the high mass-diffusion rate and flame-propagation speed of hydrogen in the sequential combustor with the second(reheat)stage of autoignition-stabilized flame render the flame stabilization mechanism is different from that of traditional hydrocarbon fuels.This study aims to understand the difference between hydrogen and acetylene as a hydrocarbon fuel in turbulent hot coflow in terms of autoignition type,flame structure,and stabilization mechanism.[Methods]A jet-in-coflow burner is used to conduct autoignition experiments.Based on our previous studies,acetylene,as an important small-molecule hydrocarbon,is selected as a hydrocarbon fuel for comparison with hydrogen.The fuel jet is injected into the hot coflow air through the fuel injection tube installed at the center axis of the burner.After being heated via the electric preheater,the compressed air flowed into the quartz tube to form a turbulent hot coflow exceeding the fuel ignition temperature.The photographs and OH chemiluminescence images of autoignition are obtained using a digital camera and an intensified charge-coupled device camera.The liftoff height,defined as the distance between the fuel injector exit and flame base(autoignition location),is a crucial parameter determining autoignition characteristics that strongly correlates with the flame stabilization mechanism.A ruler is mounted parallel to the quartz tube as a reference to measure the average liftoff height by comparing the autoignition location with the ruler mark.[Results]The results showed that with de

关 键 词：燃气轮机 氢气 自着火 射流火焰 抬升高度 

分 类 号：TK16[动力工程及工程热物理—热能工程]