电站煤粉锅炉炉内压力波动的非线性特性分析

电站燃煤锅炉炉内过程是一个复杂的非线性时变过程,因此在传统的线性分析技术基础上引入非线性分析方法具有一定的现实意义.通过对可反映炉内瞬态过程的炉内压力信号的统计检验分析,确定炉内压力波动序列分布不服从正态分布,而是服从具有尖峰胖尾特性的分形分布;多变量影响造成的不可预测的压力间断性跳跃,是炉内压力波动服从分形分布特征的根本原因.利用最大拟然估计方法对压力波动的分形分布参数进行了估算,计算表明炉内压力波动信号的方差无统计意义.利用经典的R/S统计分析工具.计算得到炉内压力波动序列的Hurst指数,分析了炉内压力波动情况与其Hurst指数间的关系,这可为锅炉燃烧优化调整提供有益的指导.     

撞击式火焰噪声信号的分形特性分析

火焰噪声信号的Hurst分析可以作为火焰气化燃烧稳定性的一个判据.通过对气化火焰噪声信号的分析,研究了气化燃烧火焰的稳定性.采用域重新标度分析法研究了撞击火焰噪声波动信号,得到了相应的Hurst指数,结果表明:撞击火焰噪声波动具有分形特征;噪声波动信号中存在周期成分;气化燃烧工况的不稳定性会导致火焰噪声的明显提高;随着氧燃比的增加,Hurst指数减小.     

基于小波变换的气化燃烧状态诊断试验研究

提出了一种通过压力信号分析气流床气化炉火焰气化燃烧状态的有效方法,该方法运用尺度分解法分析炉膛压力时域信号。研究结果发现：在点火前冷态,没有特征频率存在;在点火和灭火状态下,压力信号有一阶跃变化,信号在0Hz处有一较大的冲击;火焰剧烈波动时,存在2Hz左右的特征频率;火焰稳定燃烧时,存在着一个40Hz左右的特征频率。这个现象表明,压力信号在一定频段内的分布与气化炉内火焰燃烧的状态密切相关,随着火焰燃烧稳定性加强,压力信号向高频方向移动。     

流化床风室与炉内压力波动信号的对比研究与分析

基于鼓泡流化床的冷态试验台,对流化床风室、炉内的压力信号进行采集,利用自相关函数的傅里叶变换和Welch功率谱估计法处理压力波动信号,得到了功率谱密度(power spectral density,PSD)随频率的分布情况。试验不同静床高下,研究不同压力测点的压力波动信号特性,并对风室与炉内的压力波动信号进行对比研究分析。结果表明:压力信号频谱的5~7 Hz频段表征了流化床内物料量特征信息,且风室和炉内测点压力波动信号都包含了流化床物料量的特征信息。对以后流化床压力测点位置的选择与炉内物料的实时检测与控制等提供了重要价值。     

喷嘴位置对新型水煤浆气化炉内流场的影响

为了考察气化炉炉侧喷嘴入射角对炉内流场分布、压力分布和颗粒浓度分布的影响，对一种600kg／h的新型水煤浆气化炉炉内三维流场进行了冷态数值模拟。结果表明，喷嘴距气化炉顶部0．9m时，气化炉炉内流场分布最合理，压力分布和颗粒浓度分布最均匀。分析结果为气化炉的设计和运行提供了参考。     

基于风帽压力波动的横截面位置对循环流化床气固流动影响研究

提出利用采集、分析床内横截面方向不同位置风帽压力波动信号的方法,实现对循环流化床内横截面方向上气固两相流动状态的监测。借助冷态循环流化床实验台,在不同一次风表观气速条件下,同时测量床内横截面方向不同位置风帽的入口压力波动信号。采用标准差、小波分析和均匀指数等方法对风帽压力波动信号进行分析,得到信号的特征参数。然后基于横截面方向不同位置风帽的压力信号特征参数随一次风表观气速的变化规律,研究床内横截面位置对床内气固流态化特征的影响。结果发现,床内横截面方向不同位置风帽的压力信号特征参数能反映循环流化床一次风表观气速变化引起的床内横截面方向上气固流动状态的变化,表明所提方法具有可行性,并可为基于风帽压力波动特性的大截面循环流化床的状态监测建立理论基础。     

抛煤机锅炉炉内增拱气固两相流研究

在抛煤机锅炉炉内增拱强化燃烧基础上,在6000m3/h的冷态试验台上,研究炉拱对炉内气体粒子携带能力及粒子捕捉能力的影响,确定炉拱最佳捕捉粒径范围为≥154μm,拱的最佳角度为与水平面成15°夹角。     

燃烧福建无烟煤循环流化床锅炉炉内脱硫对SO2、NOx和CO等污染物排放的影响

在一台燃烧福建无烟煤75t/h循环流化床锅炉上进行炉内添加石灰石脱硫的工业热态试验,测试了Ca/S摩尔比变化对燃烧福建无烟煤循环流化床锅炉炉内脱硫效果以及SO2、NOx、CO等污染物排放的影响.试验表明:燃烧福建无烟煤循环流化床锅炉自脱硫效率较高,并且脱硫效率随着Ca/S摩尔比增大而呈"S"型曲线变化,在Ca/S摩尔比...     

带中心管和多级切向进风的燃煤涡旋燃烧炉

对具有中心管多级发向进展结构的新型燃煤涡旋燃烧炉的冷态流动与混合特性及煤燃烧特性分别进行了冷，热态实验或数值模拟，冷态实验给出包括中心管在内的整个炉内流场的速度分布。冷态实验和数值模拟还给出分级喷入的二次风在炉内的混合特性，热态实验证实涡旋燃烧炉在较大的热负荷变化范围均具有较高煤粉燃烧效率，ＮＯＸ排放量可控制在一定范围以内，炉内的温度水平可保证固态排渣的实现。     

高温空气燃烧中燃气/空气速度比对NOX生成的影响

尽管高温空气燃烧技术被广泛地应用于工业炉中,但对高温空气燃烧的火焰特性以及氮氧化物生成机理还不是很清楚.研究目的是使用数值模拟方法来分析燃气/空气喷射速度比对NOx生成的影响.结果表明随着燃气/空气喷入速度比的增大,火焰峰值温度略有上升,但炉内温度分布趋于均匀,NOx的排放量从Vfuel/Vair=0.6时的202×10-6(3%O2)下降到Vfuel/Vair=2.4的111×10-6.另外进行了非稳态燃烧过程数值模拟,表明仅在烧嘴换向瞬间,火焰峰值温度波动较大,而炉内平均温度和NOx的排放量波动不大.     

Unerroric of control of mutual compliance of the efficiency of hydrogen engines of unmanned vehicles in the conditions of mass production

The issues related to the reliability of hydrogen engines of unmanned vehicles and increasing the efficiency of using hydrogen as fuel when using the method of its production during the decomposition of hydrogen-containing molecules of liquid-phase organic compounds in a plasma discharge under the action of intense ultrasonic exposure are considered. Experiments have shown that as a result of decomposition in the acoustoplasma discharge of liquid hydrocarbons, solid-phase carbon-containing products are formed, chemical transformations occur in the liquid phase and hydrogen-containing combustible gas is formed. Hydrogen-containing gas can be used as fuel immediately after synthesis, i.e. it does not require separation, since in addition to hydrogen it contains only impurities of CO₂ and water vapor. The purpose of the study is to formalize the basic conditions for tightening the control of mutual compliance with the efficiency of hydrogen engines of the same series in the conditions of their mass production. Methods of mathematical statistics and hardware-software modeling were used in the study. The term “unerroric of quality mutual compliance control” is introduced to describe a set of hardware and software tools for such control. The principle of in-depth testing of the technical condition of such engines of one series is described in a multidimensional formulation of the quality control problem for three of their operating parameters at once. The conditions for increasing the mutual correspondence of the measured values of such parameters in the conditions of serial production of hydrogen engines are formalized.     

小型锅炉烟尘测试时锅炉出力的计算

锅炉烟尘测试时,必须对锅炉出力进行测试。但监测中,许多小型锅炉往往不具备相关的计量装置和仪表,为解决这一问题,文章提出了用烟气量和空气过剩系数来计算锅炉的出力的公式,在实际使用中,该方法简单易行,其结果和实测值具有很好的一致怀。     

中国煤炭地下气化技术的发展

本文综述了煤炭地下汽化技术的国内外发展现状,对我国“长通道、大断面”煤炭地下气化新工艺给予了技术经济评述,并提出了发展煤炭地下汽化技术的政策建议。     

Review of theory of distortion and disintegration of liquid streams

Linear and nonlinear analyses of the instabilities and distortion of liquid streams injected into a gaseous media are discussed. The various fundamental mechanisms and the predictive capabilities for the distortions are emphasized. Round jets, planar sheets, annular sheets, and conical sheets are discussed in detail. The balance between capillary and inertial forces is primarily examined. The method for simplifying the analyses in the case of thin liquid sheets is discussed. The capabilities for representing the droplet size distribution that follows the stream disintegration are outlined.     

MgO膨胀剂细度对MgO水化和水泥浆体膨胀的影响

基于《水工混凝土掺用氧化镁技术规范》中的Ⅰ型氧化镁（MgO）,研究了该型MgO膨胀剂（MEA）细度对掺粉煤灰水泥浆体膨胀性能的影响。即采用X射线衍射分析(XRD)及同步热分析（TG DSC）分析了掺MEA水泥浆体中MgO的水化性。结果表明,养护温度相同时,MEA的细度对水泥浆体内MEA中MgO的水化和水泥浆体的膨胀无显著影响,产生的膨胀均能补偿水泥浆体的收缩;MEA的细度可从试验设计采用的45 μm筛筛余15%左右增加到30%左右,这将有利于MEA生产企业的节能降耗。     

机车车轮多轴疲劳强度安全评定的研究

使用ANSYS8.0软件对高速列车车轮进行了三维有限元分析,计算出车轮在直线、曲线和道岔条件下牵引、制动共6种工况时孔边薄弱部位的应力,分别通过Mises等效平均应力方法、Sines平均主应力方法和应力分量中考虑平均应力方法计算出应力在极值位置时的等效应力幅、等效平均应力,从而进一步算出车轮的安全系数,对其疲劳强度进行评定,并对3种方法进行了比较研究。     

Constructal optimization of the geometry of an array of micro-channels

This paper documents the geometric optimization of an array of circular and non-circular ducts. The optimization was carried out numerically using finite volume method. As optimal dimensions were independent of the array configuration, the numerical simulation was performed on a unit cell. Numerical optimization for circular, square and isosceles right triangle cross-sections of channels was performed. Based on the results of this investigation, some correlations were proposed to predict the optimal hydraulic diameter and dimensionless heat transfer per unit volume. In addition to examining the effect of pressure drop on these parameters, it was showed that among the different geometries of this study, square cross-section has the most efficiency for a given volume. The numerical results of the present study were compared with approximate results reported in the literature which a good agreement was observed.     

Heat of vaporization of mixtures

General expressions for the heat of vaporization of mixtures at constant pressure; at constant temperature; and at constant pressure, temperature, and composition are proposed. The last one is related to the liquid-vapor interface where steady vaporization or condensation is taking place. Numerical examples by the proposed expressions are shown for binary mixtures of HCFC22(R22) and (HCFC123(R123) © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(1): 12–24, 1996     

固体热辐射Yong性能分析

本文对漫灰均温物体在常物性条件下对外辐射传热的Ｙｏｎｇ值计算建立了数学模型。通过与物体内能Ｙｏｎｇ公式的数值计算比较,得出了辐射能量的Ｙｏｎｇ值不大于内能Ｙｏｎｇ值的结论。从初步的热射Ｙｏｎｇ值计算公式发现。Ｙｏｎｇ与物体表面辐射率有关。     

Measurements of concentration distribution of hydrogen jet using deflection of center of the laser spot

The main purpose of this work is to propose a new method to evaluate the concentration distribution of the hydrogen jet by using a He–Ne laser through the jet. This research attempts to apply the expression of concentration Gaussian distribution, the refraction formula of inhomogeneous refractive index medium, and the concentration inversion function to disclose the displacement of the center of the laser spot at different heights in the gas jet. The spot images of the laser beam passing through the gas jet at three vertical heights z = 10d, 20d, 30d, and different radial positions are obtained. The radial spatial asymmetry of the gas jet is also found in the experiment. Finally, the calculated concentration distribution curve and the fluent simulation curve, it is found that the two results are very similar. Our findings show that the error between the concentration distribution of this method and the simulated concentration distribution reaches 2.43%.