多元非线性数学模型建立煤性-炉型耦合关系

论述了采用多元非线性数学模型建立煤性与炉膛性能参数耦合关系体系的方法，运用灰色关联分析方法，对炉膛燃烧器区域计算壁面热负荷与煤性因素进行关联度分析，确定主要影响因素，采用不同参数组合。运用多元非线性分析方法，建立了6种炉膛燃区计算壁面热负荷的数学模型，该模型具备较高精度，为锅炉选型提供了一种新的高效、可靠方法．     

350 MW电站燃煤锅炉NOx反应特性研究

对350 MW电站四角切圆燃煤锅炉的NOx反应特性进行了试验和数值模拟.结果表明:燃烧器氧的体积分数从3%增大到5%,NOx排放体积分数从392×10-6上升到535×10-6(氧占6%),上升幅度为33.8%.出口氧量(体积分数)为4%时,锅炉的飞灰含碳量最小,燃烧效率最高.随着氧量的增大,炉膛中心温度、炉膛截面平均温度和炉膛截面最高温度等沿高度的分布有减小的趋势,氧量从3%增大到5%,炉膛中心火焰温度的最大减小幅度为180℃.而随着氧量的增大,炉膛中心NOx体积分数、炉膛截面平均NOx体积分数和炉膛截面最大NOx体积分数等沿高度的分布有增大的趋势.炉膛截面最高温度和最大NOx体积分数沿高度的分布出现在燃烧器区域.截面平均温度和截面平均NOx体积分数沿高度分布的最大值出现在燃烧器上方5~10 m处.燃烧器区域炉膛横截面上NOx最大值出现在旋转火焰的环形区域,中心和四周的NOx体积分数较小,炉膛纵截面上的NOx最大值出现在燃烧器组喷口附近.燃煤锅炉的NOx主要在燃烧器区域生成,燃烧器区域的NOx生成速率是燃尽区域的3~5倍.     

电站锅炉燃烧特性的数值模拟

对 116 0t·h-1四角切圆电站锅炉的燃烧过程进行了数值模拟 ,燃烧器组采用常规直流煤粉燃烧器和低NOx煤粉燃烧器两种形式 .结果表明 ,大空间锅炉炉膛的速度场、温度场分布很不均匀 ;燃烧器上部附近的炉膛中心烟气上升速度最小 ,湍动能最大 ,温度最高 .烟气上升速度分布图形 ,在燃烧器区域为单峰形 ,即炉膛中心上升速度最大 ;在燃烧器上部为马鞍形 ,即截面环形区域的上升速度最大 .烟气温度分布图形 ,在燃烧器区域呈马鞍形 ,即中心区域和四周水冷壁附近的温度较低 ,截面环形区域的温度最高 ;在燃烧器上部区域为单峰形 ,即炉膛中心的温度最大 .水冷壁附近烟气温度的最大值 ,即结渣的可能区域位于旋转火焰的下游 .炉膛的切圆直径 ,在燃烧器区域随炉膛高度增大不断减小 ,至燃烧器上部附近急剧增大 ,之后随高度增大成一常数 .电站锅炉的常规直流煤粉燃烧器改造成低NOx 燃烧器时 ,炉膛的速度场、湍动能场、截面切圆直径和旋流强度以及温度场等保持不变 .     

灰色系统在电站锅炉燃煤结渣特性中的应用

为了准确评判锅炉燃煤的结渣特性,运用灰色系统理论针对煤灰结渣影响因素的模糊性、多样性等特点的非确定性问题,建立聚类决策方法,结合使用模糊TOPSIS法对电站锅炉燃煤的结渣特性进行综合评价.计算结果表明,判别结果与实际结果基本吻合.     

开缝钝体燃烧器冷热态试验研究及其应用

介绍了开缝钝体燃烧器实验室冷热态试验结果以及在实际锅炉炉膛中形成的冷热态空气动力场和不同负荷下热运行的结果．一系列测试结果表明，开缝钝体燃烧器能够合理组织四角切圆燃烧锅炉的炉内工况，并对劣质煤具有较好的稳定燃烧性能．对开缝钝体燃烧器的流动和稳定燃烧机理作出了解释．     

“燃用无烟煤锅炉煤种适应性研究”项目介绍

1．项目背景及内容简介 近年来，火电燃煤供应紧张，燃煤价格持续上涨。许多电站锅炉不得不燃用非设计煤种，燃煤品质也越来越差。这导致锅炉运行中出现燃烧不稳甚至灭火、燃烧效率降低、发电煤耗增加、汽温特性难以控制、爆管频繁、炉膛结渣等一系列问题，严重影响了锅炉运行的安全性和经济性，也对我国电力行业节能降耗提出了严峻的考验。     

煤改低浓度煤层气锅炉的燃烧及NOx排放特性

将燃煤链条炉改烧低浓度煤层气,运用数值模拟方法并结合实验对改造后的低浓度煤层气锅炉炉膛内的流动、燃烧及NOx排放特性进行了研究。结果表明,速度约在炉膛轴向距喷口0.5 m处达到最大值,在炉膛宽度方向-0.4 m相似文献   

带有屏式受热面的煤粉锅炉炉膛传热过程的数学模拟

本文研究了带有屏式受热面的大型煤粉锅炉炉膛传热过程的数学模拟方法，尽管这时炉膛的几何形状、边界情况比较复杂，但利用蒙特卡洛法和有限差分法可以使问题得到较好解决。作者利用这一方法计算了淮北电站２０万千瓦锅炉炉内烟气温度和壁面热流分布，并论述了它在锅炉设计和运行方面的应用。     

燃煤特性对电站锅炉性能的影响分析

锅炉是电站的重要发电组成部分,燃煤特性对锅炉性能的影响直接影响了电站运行的经济性。本文从燃煤的工业及元素特性方面分析其对锅炉性能的影响,旨在对煤质对电站经济性的影响有个更加情楚地认识。     

600 MW超临界压力W型火焰锅炉炉膛热负荷特性分析

环保要求的提高促使超临界锅炉的广泛应用,这不仅提高了对锅炉的操作要求,同时也更加容易出现水冷壁爆管事故,找出爆管事故的主要原因显得尤为重要.通过对金竹山电厂锅炉实运行实践及理论分析,试图找出爆管事故的主要原因."W"型火焰锅炉炉膛热负荷分布表明,该型锅炉炉膛中的大部分烟气辐射热都在燃烧器区段传递给水冷壁,是造成该区段容易发生爆管事故主要原因.另一方面,该型锅炉的低负荷区变工况运行时,烟气温度变化较大,是导致爆管事故的另一个原因.     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

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