中心轴插式等离子体点火特性数值模拟

以Fluent软件为计算平台,针对中心轴插式等离子体点火燃烧器内部三维湍流流场及点火特性进行数值模拟,计算煤粉混合物在通过整个燃烧器时内部温度场、着火过程成分变化和煤粉的燃尽率等,分析其点火燃烧器内部的燃烧特征.分析了在给定来流条件下,不同等离子体喷枪功率下,点火煤粉燃烧器内中心截面温度分布;分析了点火煤粉燃烧器内CO、O2和CO2的质量浓度分布与温度分布的关系.     

煤粉直接点火燃烧器技术及其进展

煤粉直接点火燃烧器应是我国电站煤粉锅炉燃烧器改进的主要方向,提出把直接点火技术与稳燃技术结合设计直接点火燃烧器的思路,对该类燃烧器做了较合理的分类。指出了少油煤粉直接点火燃烧器及无油煤粉直接点火燃烧器两大系列燃烧器发展状况及存在的问题,并指出目前应大力开发无油煤粉直接点火系列燃烧器,对电站锅炉煤粉直接点火燃烧器的研究有指导意义。     

某480t／h供热机组燃烧器频繁烧损原因分析

针对某480t／h供热机组燃烧器频繁烧损和结渣的原因进行分析研究,运用计算流体力学软件对改造前后燃烧器内部的流场和煤粉颗粒运动轨迹进行数值模拟,提出了一系列改进措施和解决方法,并对其中一组燃烧器进行了微油点火技术改造。在煤质条件为Vdaf=18％～33％、Aar〈30％、Qnet,ar=17000～22000kJ／kg的情况下,机组燃烧器实际运行中淡侧频繁烧损和结渣问题消除,性能提高。     

旋流浓淡煤粉燃烧器出口区域冷态两相流场实验研究

采用三维相位多普勒颗粒分析仪（ＰＤＰＡ）对旋流浓淡煤粉燃烧器出口区域冷态两相流动特性进行了实验研究,获得了该燃烧器在不同旋流叶片开度、不同煤粉浓缩构件遮盖度、不同旋流二次风和直流二次风配比下的气固两相流场和浓度场的分布规律,并进行了讨论分析。     

液排渣燃烧器单颗粒捕集在实验基础上的数值求解

液排渣燃烧器二次风从端部高速通过轴向叶片、均匀贴壁进入燃烧室，形成对称的流场分布，其分布的对称性有利于液态颗粒的捕集。煤粉在燃烧器内欠氧燃烧，捕渣率最高可达90％，具有以煤代油的发展潜力，从而可以清洁地应用到工业炉窑等加热设备中。冷态实验条件下，在煤粉不同给入点的情况下，对单颗粒的运动和捕集进行数值求解，计算结果可为煤粉作为烯相的两相流动模拟及设计提供参考。     

侧插式等离子体点火特性数值模拟

以Fluent软件为计算平台,针对侧插式等离子体点火燃烧器内部三维湍流流场及点火特性进行数值模拟,计算了煤粉混合物在通过整个燃烧器时内部温度场、着火过程成分变化等。分析了在给定来流条件下,等离子体功率对燃烧器出口横截面、中心纵截面温度场局部及整体分布和燃烧器中心轴线上温度特性曲线的影响。分析了点火燃烧过程中CO2、CO、H2O和O2的质量浓度分布与温度分布的关系。     

煤粉复合旋流火焰燃烧特性研究（2）：数值模拟

本文数值模拟了煤粉旋流火焰燃烧过程，燃烧数值计算包括理论物理模型建立，数值方法两个大部分，计算模型处理了气相湍流与燃烧、气固两相流动、煤颗粒燃烧过程和辐射传热等物理化学过程，以ｋ－ε模型模拟湍流流动；ＰＤＦ法模拟气相扩散火焰燃烧；颗粒运动计算颗粒运动少颗粒湍流浓度方程模拟颗粒湍流扩散；通量法计算火焰辐射传热，煤粉颗粒复杂燃烧模型计算了颗粒尺寸、形状变化和颗粒孔隙内部燃烧、表面平度对整个颗粒的燃烧过程影响。计算获得了气相速度分布场、气相ｋ和ε分布场、气相温度场、气相组份场和颗粒浓度场及运动过程，揭示了煤粉复合旋流燃烧特性。     

具有偏流块的弯管文丘里管组合浓淡燃烧器数值分析

研究了一种新型煤粉燃烧器,该燃烧器是由偏流块、弯管和文丘里管组合而成.通过数值计算的方法研究了这种特殊燃烧器的浓度分布特性,分析内部的气固两相流动特性,并通过改变偏流块角度和对比有无文丘流管的情况,研究偏流块角度和文丘里管对燃烧器出口浓淡分离效果的影响.采用RNG k-ε模型和Euler多相流模型研究气固两相流动.结果...     

四角切向燃烧煤粉锅炉炉内气固两相流动的数值模拟

本文运用非错列网格的SIMPLE方法和随机的颗粒轨道模型对四角切向燃烧煤粉锅炉炉内的气固两相流动进行了数值模拟，了解了实际切圆直径及气流旋转强度沿炉膛高度方向的变化规律，得到了不同粒径的煤粉颗粒在炉膛中的运动轨迹及浓度分布。与实验结果的对比表明本文所编制的程序能够较准确地模拟炉内的流动状况，计算所得的数值结果对四角切向燃烧锅炉的设计和运行都有着一定的指导意义。     

基于Fluent的排气火花熄灭消声器性能仿真分析

为掌握火花熄灭消声器内部流动特性,采用湍流模型和离散相(DPM)模型对双级膨胀腔消声器内气固两相流动情况进行了数值模拟研究。通过建立的模型和边界条件模拟气体流动,利用双向耦合拉格朗日法追踪颗粒运动轨迹;讨论了不同颗粒粒径、入口颗粒浓度以及不同排气流速对火花熄灭效率和压力损失的影响。数值计算结果表明:随着颗粒粒径、入口颗粒浓度及排气流速的增加,火花熄灭效率逐渐增大,特别是颗粒粒径和排气流速对火花熄灭效率影响比较明显。     

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。     

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.     

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.     

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.     

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。     

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%.     

汽轮机零件防锈性能的改善

介绍了汽轮机零件的封存特点、防锈要求及防锈油性能对比试验的方法,通过对试验结果的对比分析,客观验证了各种防锈油的性能。试验表明,只有选择了合适的防锈油,才能保证汽轮机零件长期封存的质量。