立筒旋风预热器

苏联卡塔夫-依万诺夫水泥厂3~#回转窑安装了全苏水泥设计研究院研制的立筒旋风预热器,用于生料预热及部分分解,然后将物料送入回转窑。立筒预热器由装在窑尾的圆截面立筒组成。立筒预热器与三级旋风筒连接,下面的旋风筒装有撒布器,保证沿立筒断面平均配给物料。窑机组试运转证明,立筒预热器在同样高度或比旋风预热器更高的情况下减少流体阻力50％(5200和6500帕斯卡)。     

高效蜗旋式旋风收尘器与传统收尘器的收尘效率及压损对比的模拟研究

对传统收尘器和我公司研发的高效蜗旋式旋风收尘器的收尘效率、压损等方面进行了CFD模拟,通过对收尘效率、压力损失、旋风收尘器内部气体流场的分析,为高效蜗旋式旋风收尘器的应用提供了理论依据。     

水泥生料预热器的改进

近年来为了提高旋风收尘器的效率,并降低其阻力损失,O&K 公司在 Gesamthoch 工程学院的协助下,进行了大量冷态和热态模型试验,在此基础上设计出最佳几何形状的预热器旋风筒。旋风筒的内管(即气体出口管道)是锥形的,并且伸入旋风筒内。它与园柱形内管相比,能降低20%的压力损失。这是由于扩散形的内管将一部分气体的动能,转化为压力能。他们也进行了内管伸入或不伸入的试验。发现仲入内管能显著提高旋风筒的收尘效率,但压力损失增加。在预热器系统中实际采用的旋风筒与理想的(收尘效率100%)旋风筒相     

烘干机收尘系统的改进

我厂烘干矿渣、粘土等物料用的烘干机,规格为φ1.5×12m,原来只用一級双管旋风收尘器收尘,效果不好,粉尘飞揚,影响工厂环境卫生。后經改用旋风收尘器和水收尘組合的两級收尘系統,不但收尘效果好,而且所需材料不多,投資少,簡单易行。烘干机的两級收尘系統如附图所示。开动排风机后,烘干机、旋风收尘器内均为負压,出烘干机的合尘气体即进入旋风收尘器。由于旋风收尘器内設有螺旋导流片,所以含尘气体进入旋风收尘器后即产生很强的旋风涡流,尘粒受离心力作用与收尘器管壁接触,旋轉速度减慢,因而沉落于集尘斗中。但含尘气体經旋风收尘器后,并不能将尘粒完全沉集,仍有部分粉尘随废气一起进入水收尘室。水收尘室用3mm鋼板制成,内設有叶式集尘板和噴水管。含尘气体进入水收尘室后,一方面由于速度减慢;另一方面由于高溫气体与池水接触产生蒸汽,将尘粒潤湿,重量增加,因而沉降于池中。当含尘气     

节能分解炉系统

宇部公司在广泛研究的基础上,推出一种低阻力旋风风筒和分解炉。这种新型设备先在500吨天NSP系统上验证,并预测到一台3300吨天的宇部NSP系统上。在5级预热器中间的旋风筒,采用低阻力形式,其特点为:在含尘气体进口处,装有弯曲的导向板。旋风筒的内筒是靴形的。弯曲导向板虽然减少了阻力,但同时也减少了分离效     

φ2.2×6.5米闭路生料磨管路系统的改造

吉林省交通水泥厂二线生料粉磨系统为φ2.2X6.5米闭路烘干磨。其工艺流程为:一、原设计存在的问题及使用情况 原设计中风机置于旋风收尘器与电收尘之间,由于管路设计中与旋风收尘器联接处呈现近90度弯管,近水平长度达1.75米,所以此段管路积灰严重,切线进入旋风筒的入口处经常被物料堵死,人磨原料含水量高时尤为严重,导致磨机产量骤减,被迫停机清理。 基于上述情况,不得已在人旋风收尘器前管路90度弯处开门,便于随时清理,杜绝被迫     

水泥窑燃煤热值贫化原因分析及解决技术措施

熟料生产线煤磨系统置于窑尾,采用窑尾废气作为烘干热源.由于窑尾废气中的生料粉含量较高,生料粉混入到煤粉中,使得煤粉热值降低约350 kcal/kg.解决措施:治理预热器系统漏风,提高预热器旋风筒的分离效率;将入煤磨热风系统的旋风收尘器改为袋式收尘器.     

减少窑内结球的措施

2005年元月河南省七里岗水泥厂与北京赛凯迪水泥技术公司合作对1000t／d线分解炉系统进行了技术优化改造：1）更换一级旋风筒，原一级旋风筒为2—φ3312mm，更换为一个φ4812mm的旋风筒，以提高一级分离效率，降低系统阻力；2）更换了各级锁风翻板阀，减少了系统漏风；3）扩大NMFC炉容积，将NMFC炉柱体增高，NMFC容增大50％，进一步延长了气体、物料停留时问、提高了热交换率。技术改造后人窑物料表观分解率达到了97％，     

无筒体旋风除尘器分级效率的实验研究

提出一种去掉筒体的新型结构的旋风除尘器,直接采用锥体进行使用,并将其与有筒体的旋风除尘器进行了分级效率的对比实验研究,结果表明在相同风量下,无筒体旋风除尘器的分级效率高于有筒体旋风除尘器。     

翻板阀的安装位置与工作效果

旋风收尘器或旋风预热器是在负压操作下,利用含尘气体沿切线方向进入旋风筒时所产生的离心力作用,使粉尘从气体中分离出来。其分离效率除本身结果,工作风速及粉尘性质外,还与旋风筒本身的密封性质密切相关,尤其是排灰口的漏风影响极大。因为从排灰口漏入空气的运动方向和灰尘落下的方     

Removal efficiency of swirl/vortex separators

In this paper an efficiency formula for swirl/vortex separators is proposed. It is based on the combination of scale model tests on a simple vortex separator and literature results from tests on similar devices. The formula predicts the removal efficiency of cylindrical overflow constructions as a function of flow conditions, chamber geometry and particle settling velocity. The formula has furthermore been used to make a comparison with the efficiency of a high-side weir overflow and a storage sedimentation tank.     

Experimental investigation of tornado-like vortex dynamics with swirl ratio: The mean and turbulent flow fields

An experimental simulation of tornado-like vortices is conducted in a small tornado vortex simulator in order to study the effect of swirl ratio on flow characteristics. Particle Image Velocimetry (PIV) method is employed to quantitatively determine the tornado-vortex velocity field for swirl ratios ranging from 0.08 to 1. The radial and tangential components of velocity as well as the core radius of the tornado increase with increase in swirl ratio. The location of the maximum radial and tangential velocities is adjacent to the ground where the tornado vortex interacts with the surface. The values of normal and shear turbulent stresses indicate the existence of a laminar core for small swirl. As expected the shear stresses increase with swirl ratio as the vortex becomes turbulent. The highest turbulent production corresponds to the critical case of vortex touchdown.     

Numerical study on flow fields of tornado-like vortices using the LES turbulence model

Flow fields of tornado-like vortices generated by a numerical tornado simulator have been investigated using the LES turbulence model for two typical swirl ratios. The core radii of simulated vortices with swirl ratios of 0.31 and 0.65 showed favorable agreement with visualized vortices by a laboratory tornado simulator. Mean velocity fields were examined to obtain detailed corner flow patterns. It was found that an one-cell type vortex with a central upward flow appears for the case of low swirl ratio and vertical velocities show peaks at the center of the vortex, while a two-cell type vortex with a central downward flow emerges for the case of high swirl ratio and the maximum tangential velocity appears near ground. The formations of one-cell and two-cell type vortices were investigated by examining the axisymmetric time averaged Navier-Stokes equations. The vertical pressure gradient generates vertical velocities at the center of vortex in the one-cell type vortex, whereas the centrifugal force balances with the radial pressure gradient and the vertical advection term of the radial velocity in case of the two-cell type vortex.     

火旋风燃烧过程中负压场的探究

为了探究自然驱动的四面夹缝火旋风装置中,火旋风燃烧过程中油层表面形成的负压场,在一定简化的假设条件下,建立了火旋风燃烧过程中产生的负压场模型,对火旋风的涡核半径、涡核强度进行了计算.实验室形成的小型火旋风涡核半径与油盘尺寸成正相关.涡核强度与涡核半径的关系则可用指数函数表示;气动力机制是决定火旋风质量燃烧速率的主导机制...     

A new laboratory apparatus for studying dynamic compaction grouting into granular soils

As granular soils may be compressible or have inadequate strength, compaction is particularly useful when soils are subjected to dynamic loading or cyclic loading. A new laboratory apparatus for investigating dynamic compaction has been designed and fabricated. The basic principle of this new technique is to introduce vibrations during the expansion process in static compaction grouting. In these tests, the injection pressure, the excess pore water pressure, and the change in void ratio of the specimens are measured. The main focus is to investigate the development of the injection pressure, the void ratio, and the excess pore water pressure due to dynamic compaction and the subsequent consolidation of the soils. In addition, the relative density of the soils is used to evaluate the dynamic compaction efficiency. Scaled laboratory experiments are conducted to study the effect of this dynamic compaction frequency on compaction efficiency. The experimental results show that the change in void ratio in the dynamic compaction tests is about four times greater than that in the static compaction tests. Dynamic compaction frequency plays an important role in soil densification due to dynamic compaction.     

静电增强布袋除尘器的实验研究及其应用

实验表明，粉尘预荷电技术能有效提高纤维过滤器性能，尤以双极不对称荷电方式为最佳。在实验研究成果基础上设计成的静电增强布袋除尘机组，通过工业性实验，除生效率和设备阻力等性能指标显著提高。     

Cyclone hazards in the Arabian sea–A numerical modelling case study of Cyclone Nilofar

Cyclones cause significant loss of life and damage to properties, ecosystems and marine facilities. To address such issues, Royal HaskoningDHV (RHDHV) has developed regional tidal hydrodynamic and wave models covering the Northern Arabian Sea. A total of 29 major cyclones were identified in the Arabian Sea since 1945. However, as less information is available on Cyclone Nilofar (2014), this paper has concentrated on this event to illustrate the use of numerical modelling to simulate waves and surge generated by cyclones. Sample results from the modelling study are presented in this paper. The methodology described in this paper for modelling cyclone waves and surges in the Arabian Sea could be applied to simulate such natural hazards at other sites around the world.     

A semi-mobile flash dryer/calciner unit to manufacture pozzolana from raw clay soils — application to soil stabilisation

The use of hydraulic binders in the construction of durable housing or roads in developing countries is an efficient technique, for which there is a demand at various times and in dispersed places throughout the world. The problem of the need for these perishable products could be resolved by the local production of pozzolana from clay soils using a semi-mobile dryer/calciner plant. By means of theoretical modelling of the thermochemical phenomena involved, and different small-scale pilot tests, we have developed a flash calcination process to this end. The Malet company has designed and built an industrial 800 kg/h production unit International patent PCT/FR98/01149—Publication No. W098/55418. It can be dismantled, moved over land (road network) and sea, and assembled within a few days. Once installed, it can be in production in 1 h. We have turned to our advantage the various benefits of the flash technique: the construction is light and compact, there is no need for grinding materials after calcination, and short materials residence time inside the unit results in short process response time and reduced start and shutdown operations duration. We describe the plant here, giving details of establishing the mass/thermal balance, the design of the gas and materials circuits, the process control system, and the construction and packaging. The plant is largely composed of a drying cyclone, a hammer mill, a preheating cyclone, a multi-burner combustion chamber with its separator cyclone and three cooling cyclones. We then compare the performances of the hydraulic binder elaborated from the pozzolana out of the unit plus lime, with those of an ordinary Portland cement.     

初始静孔隙水压力对砂土静动力剪切特性影响的试验研究

选取福建标准砂和滹沱河细砂,利用空心圆柱扭剪仪开展了一系列不同初始静孔隙水压力条件下的不排水循环扭剪试验和单调扭剪试验,着重探讨初始静孔隙水压力对超静孔隙水压力发展及其不排水抗剪强度的影响。试验结果表明:初始静孔隙水压力对超静孔隙水压力的发展产生显著的影响,从而影响砂土的静动力剪切特性。具体地,在不排水循环剪切过程中,初始静孔隙水压力越大,其超静孔隙水压力发展和变形发展越快;在不排水单调剪切过程中,初始静孔隙水压力越大,在砂土剪胀阶段产生负超静孔隙水压力越大,从而使砂土的强度显著提高。基于试验结果,初步探讨了初始静孔隙水压力对超静孔隙水压力及静动力剪切特性的影响机理。研究表明,研究地下水位以下土体(准饱和土)静动力剪切特性尤其是研究液化问题时,应充分考虑初始静孔隙水压力对砂土抗液化强度的影响,室内试验应根据砂土所处的地下水位深度来决定初始静孔隙水压力(反压)的大小。     

不同控制策略下变风量空调系统夏季运行工况

针对变风量空调实际运行中出现的冷热不均问题,通过运行两种变静压、一种定静压控制策略下的变风量系统,对比分析室温、风量、风机频率、最大阀位、设定静压值与风机能耗的关系。结果表明:变风量箱在设计控制阀门的算法中除设定温度之外还需要考虑IAQ、相对湿度等因素;使用变风量空调之前应将室温降至设定温度后再打开自动控制系统,避免受到算法的延迟影响;定静压输送单位冷负荷需要消耗的电量,比测点靠近风机的变静压控制策略多7.8%,且降温效果较差;外界环境几乎相同的情况下,变静压策略中,静压基础点远离风机的控制策略较靠近风机的控制策略降温效果好,速度至少快14%,消耗电量几乎相同。