工业锅炉炉内空气动力特性的PIV分析

工业锅炉炉内空气动力特性的研究对保证工业锅炉的正常工作具有重要的意义。利用粒子图像测速(PIV)技术研究旋流燃烧器一次风、二次风不同扩口角度和二次风旋流强度对炉内空气动力场的影响,结果表明,一次风扩口角度的增加使中心回流区由大变小,二次风扩口角度和旋流强度的增加均使中心回流区增大;射流边界随着一次风扩口角度的增加而减小,随二次风扩口角度和二次风旋流强度的增加而增加。研究结果可为工业锅炉和燃烧器的设计、改造和运行提供借鉴。     

前倾角对离心压气机叶轮性能的影响

为研究前倾角对离心压气机性能的影响,使用离心压气机计算机辅助集成设计系统设计了一个普通后弯叶轮,并通过改变叶轮出口角得到了带有30°和45°两个不同前倾角的离心压气机叶轮。利用三维Navier-Stokes方程对这3个叶轮的特性曲线进行了计算。计算结果表明,在相同流量情况下,随前倾角的增大,叶轮压比下降。合适的前倾角有利于扩大压气机工作范围,能够改善流道内的流动,提高等熵效率。     

车用催化转化器封装结构对其内部流动的影响

采用计算流体力学的方法，针对一典型催化转化器，研究了催化转化器封装几何结构对其内部流动特性的影响，分析了催化器扩压器的扩压角、收缩管的收缩角和载体的安装位置对催化器流动特性的影响，为催化转化器的结构优化设计提供了必要的指导．     

TRW燃烧器后置炉膛内流场的数值模拟

为配合液态排渣多级煤燃烧器（ＴＲＷ燃烧器）的应用示范工程,以质量、动量、能量守恒定理为基础,建立了ＴＲＷ燃烧器后置炉膛内三维流动的数学模型,采用经典的ＳＩＭＰＬＥ算法和混合差分格式,对炉膛内的流场及煤粉运动轨迹进行了数值模拟．从而为锅炉设计、三次风和顶部燃尽风（ＯＦＡ）的布置提供了大量的参考数据．根据ＴＲＷ燃烧器的出口尺寸以及某锅炉厂提供的炉膛尺寸和三次风、ＯＦＡ的布置原则,对４个布置方案进行了９种不同工况的计算．得到与ＴＲＷ燃烧器能较好匹配的炉膛结构及三次风、ＯＦＡ的布置方案,并对计算结果进行了详细地分析,确认计算结果符合炉内流动规律．计算程序中一些参数如网格、锅炉尺寸以及燃烧器的布置可以方便地进行修改,因而很容易计算其他炉内的流动过程和移植应用．     

面向锅炉燃烧优化的炉膛动态建模

为了设计炉膛燃烧动态优化控制器,提出了一种结合NOx产生机理的锅炉炉膛一维建模方法.通过将锅炉炉膛沿高度方向进行分层,并采用集总参数法分别描述锅炉各层内的流动、燃烧、传热和NOx生成过程,建立了能够表征锅炉燃烧特性的一维动态模型.通过对某HG220/100-10燃煤锅炉的建模仿真表明,所提出的模型能够正确反映出炉膛沿高度方向的一维温度分布及NOx分布,并能够准确反映不同配风方式对NOx排放的影响,以及各层风煤变化时炉膛出口处烟气温度、飞灰含碳量及NOx浓度的动态响应特性.相比传统三维模型,所建模型形式简单、计算量小,对于锅炉燃烧优化控制的设计能够起到关键的支撑作用.     

对扩铣组合刀切削引导锥角度的探讨

对扩铣组合刀切削引导锥的角度进行分析．分析表明,当引导锥角度在８°～２５°时,不但可以满足扩铣组合刀对工作稳定性的要求,还具有良好的导向作用．     

130t/h循环流化床锅炉冷态试验研究

循环流化床锅炉炉膛内配风及介质流动特性对锅炉燃烧效率、污染物生成和发电机组性能影响极大.对一台检修后的130 t/h循环流化床锅炉进行冷态试验,通过直接测量风速法研究不同负荷工况下锅炉炉膛内一次风布风特性和二次风配风特性.结果表明:在空床试验时,高负荷工况下的一次风分布均匀性要优于中、低负荷工况,中、低负荷工况时炉膛内...     

正反切圆燃烧器布置及其二次风分配的研究

对正反切圆燃烧器布置的煤粉锅炉燃烧过程进行了数值计算,模拟了该燃烧器在不同配风的情况下对炉膛出口过热器汽温偏差可能产生的影响．分析表明,烟气本身的温差和流动的残余旋转都将直接影响到炉膛出口两侧过热器的热量吸收．调整正、反切二次风配比和反切夹角可以改善炉膛出口的烟温偏差和速度偏差．     

超临界循环流化床锅炉水冷壁并联双通道内流动不稳定性数值分析

针对超临界循环流化床(CFB)锅炉环形炉膛水冷壁中可能出现的流动不稳定性,采用时域法建立了适用于并联双通道流动不稳定性分析的通用计算模型。通过对质量、动量及能量方程一阶迎风差分离散与求解,编写了以Fortran语言为基础的流动不稳定性数值计算程序Dynsys,采用Dynsys程序对并联双通道进行数值模拟,结果表明:并联双通道进口压力、温度、总质量流量不变时,在稳态基础上对并联双通道中的通道1施加1.2倍热负荷扰动,两通道的进口流量随时间变化呈反相脉动;通道内的进口流量与出口流量随时间脉动沿轴向存在180°的相位差,流量脉动的振幅随时间逐渐减小,最终恢复到稳态值;超临界CFB环形炉膛锅炉水冷壁并联双通道内流动是稳定的,与单通道内流动不稳定对比,环形炉膛锅炉水冷壁并联布置有利于提高系统的稳定性。     

肋角度对矩形带肋通道蒸汽流动和换热特性的影响

在带肋单通道蒸汽强化换热试验研究的基础上,采用SSG雷诺应力湍流模型,求解了三维定常雷诺平均Navier-Stokes方程,对30°、45°、60°和90°4种带肋通道进行了蒸汽流动的数值计算,同时研究了雷诺数对矩形带肋通道中冷却气体的流动和传热特性的影响,并比较分析了不同肋角度下带肋通道的流动和传热特性。结果表明:斜置肋片能有效提高带肋通道的换热效果,同时也将带来很大的流动阻力;与90°带肋通道相比,60°、45°和30°带肋通道的热力系数分别增加了约29.3%、24.6%和20.9%,就综合热力性能来说,60°带肋通道是最好的结构形式。     

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     

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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