环流式旋风除尘器分离效率数学模型的研究

研究者针对新型旋风除尘器的特点，推导出了计算环流式旋风除尘器内筒分级效率的数学模型，并与Ｌ－Ｌ横混模型相结合，把环流式旋风除尘器看作部分环流的两个常规旋风除尘器的串联，进行其分离效率的研究。理论计算与实验析比较表明，该数学模型基本反映了新型环流式旋风除尘器内粒子流动、粒子分布以及粒子分离的实际情况。     

二次扬尘对旋风器除尘效率影响分析与对策

讨论二次扬尘机理,建立了具有在紊流边界层中由于流速不等而导致粉尘下侧面压力不同所产生的二次扬尘影响下的旋风除尘器分级效率理论计算式。为削弱二次扬尘作用,提出在除尘器内壁设置环缝内衬的增效防磨新方法。 理论分析、半工业试验和工业应用的结果表明：环缝内衬旋风除尘器的除尘效率优于无环缝内衬旋风除尘器的除尘效率。     

几种新型旋风除尘器的简析

旋风除尘器经历了100 多年的发展历史,其被广泛应用于工业除尘特别是应用于小型锅炉和多级除尘的预除尘中它是利用旋转气流对粉尘产生离心力使其从气流中分离出来的我们根据旋风除尘的特点研制出除尘效率更高阻力损失更小的旋风除尘器从而达到环保节能的目的以下就几种新型旋风除尘器作简要介绍1 环流式旋风除尘器环流式旋风除尘器采用套筒锥体结构处于同轴心的内外筒体中间留有一定的环隙内外筒体靠支架相连内筒低于外筒一定距离外筒段上部中心为排气管排气管插入外筒内一定距离但不插入内筒进气管由外筒下端切向进入内筒外筒体下端接同径…     

新型旋风分离器的设计与应用

综合考虑旋风分离器的除尘机理和效率影响因素,设计了由旋风分离器和多孔材料相结合的复合除尘器。选用了铁合金冶炼粉尘、煤灰烟尘、瓜尔胶粉、硅酸盐水泥粉这4种物料进行分离与再生实验研究,结果表明,10μm孔径的多孔材料做滤柱时分离效率高、压降相对较小、再生性能较好。     

旋风除尘器性能分析

旋风除尘器是利用离心力将气流中粉尘分离并收集而达到净化气体的目的,其除尘性能以除尘效率和压降表示。总除尘效率可以从分离器的分级效率和粉尘粒度分布来求得,而分级效率则可表示为粉尘粒径的函数,因除尘器几何形状和尺寸以及操作条件(流速、压力、温度、气体和粉尘性质等)而定。 由于离心力和除尘器直径成反比,旋风除尘器的效率,在同样压降的条件下,一般来说随着除尘器直径的加大而显著地下降。因此当要求处理气量较大时,将单个除尘器加以放大     

活性炭在最佳构型旋风除尘器中的分离效率

<正>一前言 近年来,扩散式旋风除尘器(CLK型)在活性炭和栲胶等粉尘的产品回收中得到广泛应用。使用得当的扩散式旋风除尘器能提高产品的回收率,但存在设备庞大,流体阻力大等弊病。故探索具有分离效率高而流体阻力小的旋风除尘设备,对提高产品回收率,降低动力消耗,减少环境污染,以提高经济效益,是很有意义的。 文献指出:依据旋风除尘器里气流的流动型式及所谓“旋风自然长”的理论进行设计,可研制成一种满足效率高、压降低要求的旋风除尘器结构型式。为区别于其他构型旋风除尘器,将它称为“最佳构型”旋风除尘器。为此,我们用活性炭对它测定了总效率及粒级效率,并与目前采用的某些定型设备作对比。实验结果证实:“最佳构型”旋风除尘器的性能比林化行业中目前采用的CLT/A型、CLP/B型及扩散式等旋风分离器,在同一操作条件下,具有粒级效率高、压降低的优点。     

旋风式分流除尘器的研究

根据旋风除尘器内尘气两相流的运动规律,改进旋风除尘器的结构,研制出旋风式分流除尘器。用实验方法确定了旋风式分流除尘器小芯管的最佳插入深度和半径,并深入分析了此除尘器的除尘机理,提出了分级效率的理论计算式。根据此除尘器的特性,设计出经济节能的旁路除尘系统。这种旁路除尘系统可广泛应用于各种尘源。     

缝隙式排气管对旋风分离器的性能影响

为降低传统旋风分离器工作时排气管内气流高速旋转造成的大量能量损失,将Lapple型旋风分离器的排气管改进为缝隙式排气管,利用数值模拟和实验的方法分析了缝隙式排气管对旋风分离器的性能影响.采用RSM模型对气相流场的切向速度、静压、流动轨迹、湍流强度以及压降进行数值模拟,采用多相流模型中的DPM模型对分离器的分离效率和颗粒运动轨迹进行仿真分析.仿真分析结果与实验验证结果吻合度较好,有较高的预报精度.最终结果表明,缝隙式排气管可使传统旋风分离器的压降下降6.8%,分离效率提升5.5%;当排气管上缝隙长度或宽度增加至一定数值,分离器的分离效率达到最大.随着排气管上缝隙长度或宽度的增加,旋风分离器的分离效率逐渐趋于稳定,压降持续降低;排气管上的矩形缝隙可使排气管内产生旋进涡核(PVC)现象,随着缝隙长度的增加,旋进涡核现象有所减弱,缝隙宽度的变化对旋进涡核现象影响较小;缝隙式排气管可有效抑制普通排气管中心处回流区的产生,并使普通排气管底部以及外旋流的湍流强度降低,从而减少排气管底部的短路流,提高分离效率.通过观察不同颗粒粒径的电石渣颗粒的运动轨迹,可知Lapple型旋风分离器与新型旋风分离器内部流场呈现出有利于固体颗粒分离的组合涡结构,排气管结构的改变并未影响分离腔的原始涡流结构.     

催化裂化沉降器粗旋风分离器的工作性能

在直径300 mm的催化裂化沉降器粗旋风分离器冷态实验模型上测试入口气速、质量浓度,考察二者以及料腿末端设置重锤逆止阀对粗旋风分离器工作性能的影响.结果表明:固相加入后降低了气流旋转动能耗散,使粗旋风分离器压降降低,料腿排气率增大;提高入口气速有利于减小料腿泄气率、提高粗旋风分离器分离效率,尤其对细颗粒分离有利;随固相质量浓度增大,粗旋风分离器压降降低,分离效率和料腿排气率均有小幅上升;料腿末端安装重锤逆止阀可令料腿泄气率减小3%以上,并提高粗旋风分离器分离效率;针对粗旋风分离器结构特征提出的压降模型计算粗旋风分离器压降精度较高.     

电旋风壁面沉积特性及捕集效率的实验研究

研究在旋风和静电的综合作用下,电旋风除尘器的壁面沉积特性及影响因素,探讨壁面沉积过程与电旋风除尘器捕集效率的关系.实验得出,加静电强化后效率可提高3%～7%,电旋风的效率最高达99.6%;随着气流含尘浓度的增加及运行时间的延长,电旋风收尘极板上的沉积量增加,而除尘效率则呈现下降趋势;当入口气流速度达到15 m/s后,该实验模型可实现自动清灰.     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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