旋流燃烧室内湍流流动的PIV实验研究

建立了微型燃气轮机旋流燃烧室实验台．采用二维粒子图像测速技术(PIV)测量了旋流燃烧室火焰筒内冷态速度场．旋流燃烧室主要由3个旋流器和1个侧壁开有测试视窗的圆筒段组成．在空气流量为0．114m^3／s的工况下，得到了燃烧室火焰筒内气体时均切向速度分布及旋流燃烧室火焰筒中心截面和不同轴向横截面位置的速度矢量分布图．实验结果及其分析为旋流燃烧室的数值模拟计算和进一步的实验研究提供了基础．     

火焰面方法进展及在燃机燃烧室模拟中的挑战

现代燃气轮机燃烧室参数持续提高，燃料种类不断丰富，燃烧技术深入开发，这对燃机燃烧过程数值模拟方法的发展提出了更高的要求。火焰面方法兼具准确性和计算效率高的特点，是燃气轮机燃烧室成熟数值模拟方法的主要选择之一。该文针对燃气轮机燃烧室未来多工况、高参数、低污染的发展趋势，从火焰面方法在自适应湍流燃烧模型中的应用、进度变量的优化选择、湍流燃烧耦合模型以及火焰面方法在污染物预测中的应用等4个方面，回顾了火焰面方法的相关模型及适用范围，分析了该方法在燃气轮机燃烧室中的应用及面临的挑战。在此基础上，对火焰面方法在未来燃气轮机燃烧室模拟中的发展方向提出了针对性建议。     

微型热光电系统中的微燃烧室研究

微型热光电TPV(thermo photovoltaic)系统是一种新型的微动力系(Power MEMS)，微燃烧室是微型TPV系统中最重要的部件之一．为了获得较高的电能输出，希望燃烧室壁面的温度高且分布均匀．由于微燃烧室面容比大，热损失显著增加，这会导致着火困难并使火焰淬熄．为了分析微燃烧室中燃烧的可行性和确定有关影响因素，对不同材料、不同结构的微燃烧室在不同工况下进行了实验．结果表明，在一定的流量和混合比范围内，可以在微燃烧器内维持稳定的燃烧，并在燃烧室壁面形成均匀分布的高温．     

燃空当量比对液体燃料无焰燃烧影响的研究

以微型燃气轮机为应用背景,设计了基于液雾无焰燃烧的模型燃烧室,以实验为主、数值模拟为辅的手段研究了0#柴油/空气的燃空当量比对模型燃烧室的流场结构、燃烧模式、无焰燃烧范围、燃烧温度及分布和污染物排放的影响.结果表明:燃烧室流场呈现明显的环形回流涡,为高温烟气循环提供了流体动力学基础;燃料喷孔附近的混合情况对整个燃烧模式的转变具有重要影响;该燃烧室工作在无焰燃烧模式的燃空当量比Φ范围为0.25～0.50,无焰状态下燃烧室内温度分布均匀;燃烧室平均温度Tavg和污染排放受到Φ和输入功率的影响,在实验范围内,输入功率相同时,随Φ减小,燃烧室平均温度降低,CO和NOx排放浓度增加,另外,Φ相同时,输入功率越低,Tavg越低,CO排放浓度越大,且输入功率越低CO排放浓度增长越快,NOx受输入功率的影响相对小得多.从实验结果分析,适当提高空气预热温度是增强低燃烧室热密度时的贫燃稳定性、拓展贫燃极限和强化燃烧的有效措施.     

微燃燃烧室流场结构及燃烧特性的初步优化

为了改进微型燃气轮机结构,优化燃烧室性能,采用UG及Ansys软件对微型燃气轮机燃烧室进行几何建模、网格划分、数学及物理模型建立。通过热态数值模拟,研究了叶片数目为12、18、24、30以及叶片安装角度为40°、45°、50°、55°时的燃烧室内流场及燃烧特性。模拟结果得出:随叶片数目及安装角度的增加,燃烧室内甲烷燃烧效率基本不变,均可达99%以上,总压恢复系数降低,出口温度分布因子降低,圆筒内壁温度升高,但一氧化氮排放无法降低。最终选择叶片数目为24、安装角度为45°作为优化结果。     

微型燃气涡轮发动机喷嘴雾化性能研究

针对微型燃气涡轮发动机喷嘴的雾化对燃烧室火焰稳定性、温度分布和燃烧效率的影响.对某微型燃气涡轮发动机喷嘴的雾化情况进行了数值模拟,并利用平面粒子图像测速仪(PIV)对雾化流场进行了测试,并与数值模拟结果进行相互验证.结果表明,实验结果与数值模拟结果符合较好.该研究为微型燃气涡轮发动机的喷嘴、燃烧室设计及燃烧数值计算提供理论及试验基础.     

贫燃预混燃烧室混氢燃烧性能研究

为加快实现碳中和，传统化石燃料燃气轮机逐步向含氢气燃料转型，因此需要掌握燃料中氢气对燃气轮机燃烧室性能影响，为燃气轮机燃氢化奠定理论基础。本文以国内某型现役低排放燃气轮机燃烧室参数与结构为例，采用氢气甲烷混合燃料燃烧，研究混氢比例对燃烧室性能影响。研究表明：氢气体积占比低于30%时，燃烧室喷嘴无回火；燃料中氢气占比由0增加至30%，燃烧室总压损失升高11%,NOx排放(@15%O₂干基)升高31%，火焰筒上游区域温度略有升高，燃烧效率升高，出口温度场均匀性几乎无变化。     

燃烧振荡声学抑制器的机理分析与设计优化

燃烧振荡是发展低排放燃气轮机燃烧室需要解决的关键问题之一，未来燃气轮机燃烧室运行温度更高、具有更宽的工况运行范围及更复杂的几何结构(如轴向分级、环形燃烧室等),燃烧振荡存在高振幅、多振荡频率、多振荡频率时变和多热声模态共存等特点。采用声学抑制器被动控制燃烧振荡具有抑制器结构简单、可靠性高、成本较低等优势。针对未来的燃烧室，现有抑制器方案将面临很大挑战，因此，亟需开展宽吸声带宽、可控制多模态的声学抑制器及系统级燃烧室多声学抑制器设计优化研究。该文概述了国内外声学抑制器机理和设计优化的研究进展，着重总结了作者近年来在常规及多频段声学抑制器机理、抑制效果分析计算和复杂热声系统参数对声学抑制器特性影响，以及基于伴随方法的多声学抑制器多参数快速优化等方面的研究工作，并对未来燃烧室声学抑制器的发展方向进行了讨论。     

回热型微型燃气轮机热力性能及CHP系统研究

根据化学燃烧理论和变比热容计算方法，提出了微型燃气轮机回热循环装置性能参数的计算和分析的方法；分析了压气机压比、加热比、燃料发热量以及回热度等参数对装置系统性能的影响，并以60kw燃气轮机装置为例进行了计算和分析，为微型燃气轮机装置的合理设计选择提供了实用可行的方法和参考依据．同时，对回热型燃气轮机和热水器组成的热电联供系统进行了计算分析。     

一种拓宽微型单管燃烧室流量范围的调节装置

为了能够拓宽微型单管燃烧室稳定燃烧的流量范围,设计了一种调节装置.利用CFD软件Fluent对微型单管燃烧室的内部冷态流场进行数值模拟,得到微型单管燃烧室主要结构参数对内部流场形态的影响规律并确定了其主要结构参数.通过冷态数值模拟,得到了调节装置对微型单管燃烧室内部流场的调节作用;通过试验研究,证明所设计的调节装置能够实现对单管燃烧室的稳定燃烧流量进行调节,从而扩大了该燃烧室的稳定燃烧流量范围.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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