为了给我国F级燃气轮机燃烧系统的燃烧调整与自主升级提供技术参考,以某F级燃气轮机环管燃烧室单筒为三维物理模型,采用Realizable k-ε湍流模型与小火焰生成流形(flamelet generated manifold,FGM)燃烧反应模型,研究了过量空气系数、...为了给我国F级燃气轮机燃烧系统的燃烧调整与自主升级提供技术参考,以某F级燃气轮机环管燃烧室单筒为三维物理模型,采用Realizable k-ε湍流模型与小火焰生成流形(flamelet generated manifold,FGM)燃烧反应模型,研究了过量空气系数、主旋流叶片偏转角度及值班燃料占比等因素对燃烧室单筒内的温度分布规律、燃烧污染物NO_(x)的生成与排放特性的影响。结果表明:随着燃烧室单筒入口过量空气系数的增加,燃烧室单筒出口的平均温度与最大温度均下降,出口温度分布系数(out-let temperature distribution factor,OTDF)略微上升,出口温度分布均匀性降低,但NO_(x)排放量呈下降趋势;适当增大主旋流叶片偏转角度,可以降低燃烧室单筒内及过渡段出口截面的最高温度并提升温度均匀性,但出口NO_(x)排放量则呈先急剧下降后缓慢上升的趋势;在总燃料流量不变的情况下,值班燃料占比(质量分数)从4%增大到8%时,燃烧室单筒出口温度水平的变化很小,但会导致NO_(x)排放量明显增加。展开更多
Natural radionuclides are powerful tools for understanding the sources and fate of suspended particulate matter(SPM).Particulate matter with different particle sizes behaves differently with respect to adsorption and ...Natural radionuclides are powerful tools for understanding the sources and fate of suspended particulate matter(SPM).Particulate matter with different particle sizes behaves differently with respect to adsorption and desorption.We analyzed the activi-ties and distribution characteristics of multiple natural radionuclides(238U,226Ra,40K,228Ra,7Be and 210Pbex)on size-fractionated SPM at the Lijin Hydrographic Station(Huanghe or Yellow River)every month over a one-year period.Results showed that medium silt(16–32µm)was the main component.As expected,the activity of each radionuclide decreased with an increase of particle size.We examined the sources of SPM with different particle sizes using activity ratios of 226Ra/238U,228Ra/226Ra,40K/238U and 7Be/210Pbex,and concluded that SPM with different particle sizes originated from different sources.Our results indicate that fine SPM(<32µm)was mainly from the erosion of soil along the lower reaches of the Yellow River,while coarse SPM(>32µm)was mainly derived from resuspension of riverbed sediment.During high runoff periods,the concentration of SPM increased significantly,and the pro-portion of fine particles originating upstream increased.Naturally occurring radioactive isotopes,especially on size-fractionated par-ticles,are therefore seen as useful tracers to understand the sources and behaviors of riverine particles transported from land to sea.展开更多
文摘为了给我国F级燃气轮机燃烧系统的燃烧调整与自主升级提供技术参考,以某F级燃气轮机环管燃烧室单筒为三维物理模型,采用Realizable k-ε湍流模型与小火焰生成流形(flamelet generated manifold,FGM)燃烧反应模型,研究了过量空气系数、主旋流叶片偏转角度及值班燃料占比等因素对燃烧室单筒内的温度分布规律、燃烧污染物NO_(x)的生成与排放特性的影响。结果表明:随着燃烧室单筒入口过量空气系数的增加,燃烧室单筒出口的平均温度与最大温度均下降,出口温度分布系数(out-let temperature distribution factor,OTDF)略微上升,出口温度分布均匀性降低,但NO_(x)排放量呈下降趋势;适当增大主旋流叶片偏转角度,可以降低燃烧室单筒内及过渡段出口截面的最高温度并提升温度均匀性,但出口NO_(x)排放量则呈先急剧下降后缓慢上升的趋势;在总燃料流量不变的情况下,值班燃料占比(质量分数)从4%增大到8%时,燃烧室单筒出口温度水平的变化很小,但会导致NO_(x)排放量明显增加。
基金financially supported by the National Natural Science Foundation of China(Nos.U22A20580,42130410,and U1906210)the Fundamental Research Funds for the Central Universities(No.201962003).
文摘Natural radionuclides are powerful tools for understanding the sources and fate of suspended particulate matter(SPM).Particulate matter with different particle sizes behaves differently with respect to adsorption and desorption.We analyzed the activi-ties and distribution characteristics of multiple natural radionuclides(238U,226Ra,40K,228Ra,7Be and 210Pbex)on size-fractionated SPM at the Lijin Hydrographic Station(Huanghe or Yellow River)every month over a one-year period.Results showed that medium silt(16–32µm)was the main component.As expected,the activity of each radionuclide decreased with an increase of particle size.We examined the sources of SPM with different particle sizes using activity ratios of 226Ra/238U,228Ra/226Ra,40K/238U and 7Be/210Pbex,and concluded that SPM with different particle sizes originated from different sources.Our results indicate that fine SPM(<32µm)was mainly from the erosion of soil along the lower reaches of the Yellow River,while coarse SPM(>32µm)was mainly derived from resuspension of riverbed sediment.During high runoff periods,the concentration of SPM increased significantly,and the pro-portion of fine particles originating upstream increased.Naturally occurring radioactive isotopes,especially on size-fractionated par-ticles,are therefore seen as useful tracers to understand the sources and behaviors of riverine particles transported from land to sea.
