涡轮旋流分级器分级性能与数值模拟研究

介绍了一种新型涡轮旋流分级器,通过实验研究了结构参数和操作参数对煤泥水的分级性能的影响,并通过单相流数值模拟计算,分析研究了分离器内流场分布规律,为提高细粒物料的分级效果提供了一种新的设备和方法.     

旋流式直立微滤膜器流场数值模拟及试验研究

采用RNG κ-ε模型对旋转横流管式微滤膜器流场进行了数值模拟,得出了膜器环隙内流场分布规律。与激光粒子成像测速系统PIV实测结果进行了比较,并以Delphi及Access 2000作为软件开发工具,研制了高精度的计算机控制的在线膜器环隙压力测试系统。实测了旋转横流膜器环隙内的压力分布规律,模拟计算结果与实验数据吻合较好。     

用于催化外甩油浆的微旋流分离流场的数值模拟

为了研究用于催化外甩油浆分离的一种微型旋流芯管内部的流场,采用雷诺应力模型(RSM),对旋流芯管内油浆单相流动进行了数值模拟,得到了其内部流场的轴向速度、切向速度、径向速度和压力分布规律。分析了压力场和速度场的分离特征,显示了高效工作区,为进一步数值模拟打下了基础。     

黄磷脱砷装置中分相器的CFD数值模拟研究

介绍了黄磷脱砷工艺及该工艺中黄磷-双氧水分相器的基本结构、工作原理、优点和应用,着重研究了分相器旋流腔内流场特性。由于通过实验的方法无法全面地揭示其流场性质,采用计算流体力学的方法,用Gambit对该分相器进行几何建模、网格划分和边界条件的定义,应用Fluent软件,选用雷诺应力模型(RSM模型)作为湍流模型对黄磷-双氧水分相器进行了数值模拟计算,得到分相器内部流场、速度场和压力场的信息,还有黄磷体积分数等物理量的变化规律,并将数值模拟分离效率与实验结果进行了比较,分析了分相器内部流场的分布规律和两相流的分离特性,为黄磷-双氧水分相器的工业化放大设计提供参考依据。     

无机微滤膜对W/O乳状液真空破乳的研究

本文采用乳液状液膜法对模拟的含酚废水脱酚进行了进一步研究,考察无机微滤膜真空破乳的重要参数如操作压力及其提供方式、膜面流速等对膜通量和破乳率的影响。并且讨论了破乳后的油相回用情况。实验结果表明:以外旋流进料和真空度提供操作压力的方式是一种较以错流进料和外压操作方式更有效的膜法破乳方法。实验数据表明:对于粒径为5～25μm乳液,用膜孔径为2.0μm的Al2O3微孔膜,在外旋流进料、膜面流速为4m/s、真空操作压差为100kPa的操作条件下破乳,破乳率可达96.2%,膜通量可达1400L/m2.h。     

旋转流强化管式膜微滤过程中分离因数研究

分离因数是影响旋转流强化管式膜微滤过程的关键操作变量之一。本文首先对管式膜分离器内分离因数的分布特征进行了研究,然后,不仅从理论上研究了分离因数对过滤过程行为的影响,而且进行了探讨分离因数对过滤性能影响的试验研究。结果表明,管式膜分离器内分离因数沿轴向从顶部到底部呈迅速减小的分布特征;分离因数的增大,可使过滤过程推动力提高,并使外旋流时过滤过程中固相颗粒不易向膜面迁移并沉积,但加剧了内旋流时过滤过程中固相颗粒向膜面迁移并沉积的趋势;在悬浮液固相浓度保持一定时,过滤通量随分离因数的增大而提高     

不同国产纳滤膜对饮用水中氟离子的去除影响研究

选用两种国产纳滤膜NF1和VNF2进行除氟的实验研究,考察了不同的原水pH、操作压力、进水F-浓度、温度以及腐殖酸的浓度对纳滤除氟截留率以及膜通量的影响.实验结果表明:VNF2膜的截留率高于NF1膜,而膜通量则低于NF1;同时两种膜的最佳操作条件为pH在6.5～7.0,温度在18～23℃,操作压力为0.4 MPa,进水...     

具有旋转横流的管式膜微滤的渗透通量及环隙压力分布

用自行研制的计算机控制的在线管式膜器环隙压力测试系统实测分析了不同入口压力、不同悬浮液浓度和不同膜器环隙大小下的旋转横流膜微滤渗透通量大小及环隙压力分布规律,与一般横流膜微滤的环隙压力分布及渗透通量大小进行了对比,为进一步研究膜微滤强化机理、探讨减少或解决浓差极化和膜污染的方法提供了实测依据.     

压力旋流式喷嘴喷淋液膜区换热过程的数值模拟

利用Fluent软件对压力旋流式喷嘴的内外流场进行了数值模拟,以等效的二维网格模型模拟圆周对称的三维流动,多相流和湍流模型分别采用VOF和雷诺应力模型。在两种条件下,对喷嘴流场进行模拟:1气相为空气,不发生相间热质传递;2气相为饱和水蒸气,发生相间热质传递。相变模型采取Fluent中内嵌的Lee模型。将数值模拟结果同实验结果进行对比,并以数值模拟的数据对喷嘴内外流场展开分析。模拟结果显示,由于液相在喷嘴旋流室内的螺旋运动,导致喷嘴内部形成"空气芯",液相速度在喷嘴旋流室与收缩段的连接处变化剧烈;另外,发生相间热质传递条件下,流场的压力要整体稍低且速度场的速度最大值更大;液膜的传热系数沿液膜流动方向不断减小;因气相冷凝使得液膜厚度更大,液膜破碎长度也因蒸气冷凝而变得更长。     

压力旋流式喷嘴喷淋液膜区换热过程的数值模拟

利用Fluent软件对压力旋流式喷嘴的内外流场进行了数值模拟，以等效的二维网格模型模拟圆周对称的三维流动，多相流和湍流模型分别采用VOF和雷诺应力模型。在两种条件下，对喷嘴流场进行模拟：①气相为空气，不发生相间热质传递；②气相为饱和水蒸气，发生相间热质传递。相变模型采取Fluent中内嵌的Lee模型。将数值模拟结果同实验结果进行对比，并以数值模拟的数据对喷嘴内外流场展开分析。模拟结果显示，由于液相在喷嘴旋流室内的螺旋运动，导致喷嘴内部形成“空气芯”，液相速度在喷嘴旋流室与收缩段的连接处变化剧烈；另外，发生相间热质传递条件下，流场的压力要整体稍低且速度场的速度最大值更大；液膜的传热系数沿液膜流动方向不断减小；因气相冷凝使得液膜厚度更大，液膜破碎长度也因蒸气冷凝而变得更长。     

Performance analysis of an integrated tangential microfilter‐fermenter

A specially designed bioreactor including an axial microfilter for cell retention was evaluated for continuous‐flow operation with selected liquid media as controls and in aerobic cultivations of Saccharomyces yeasts. In the initial tests, performance characteristics such as filtration rates and cell accumulation were assessed as a function of filter rotational speed, operating pressure, cultivation time and microfilter type (i.e. membrane or porous metal). The bioreactor did not perform satisfactorily when viscous extracellular polymer was present in the liquid. In the continuous‐flow culture enabling cell retention, Saccharomyces cerevisiae yeast cell concentrations were enhanced by as much as 16‐fold over ordinary batch growth. Concomitant filtration rates were stable over operating times of up to 130 h and hence were independent of the cell concentration. The maximum steady‐state flux was enhanced at rotational speeds up to 400‐700 rpm ranging from 22 to 42 L m^?2 h^?1. Higher rotation rates offered no further improvements. The maximum stabilized flux was independent of operating pressure. Pressure increases caused momentary flux improvements, which rapidly declined and eventually restabilized. Copyright © 2006 Society of Chemical Industry     

The magnetic assembly of polymer colloids in a ferrofluid and its display applications

Nonmagnetic polymer colloids have been assembled into colloidal photonic crystals in a ferrofluid by applying an external magnetic field based on the dipole-dipole interactions of "magnetic holes". The photonic crystal disassembles immediately when the magnetic field is removed. The mechanism of assembly can be explained by two simultaneous processes: phase separation and colloidal assembly. In this work, increasing the size of the building blocks still produces colorful photonic crystals due to their 2nd order diffraction. With a larger building block, the magnetic response between the polymer colloids is greatly enhanced so that an instant and reversible assembly/disassembly can be realized in a much weaker magnetic field and lower ferrofluid concentration. Based on these investigations, a magnetically controlled photonic display unit has been fabricated, which works in a weak magnetic field, has stable reflection signals and possesses fast and reversible on/off switching of reflections.     

循环流化床锅炉炉内组合式高温旋涡分离器性能试验

开发了一种适用于循环流化床锅炉的 ,具有独特结构和良好性能的新型内置组合式高温旋涡分离器 ,并在所建立的实验系统上对其进行了性能试验。研究结果表明 ,组合式高温旋涡分离器阻力小、分离效率高、性能稳定 ,并且具有结构紧凑、组合方便、烟气处理量大、材质要求低、制造成本低、运行维护方便等特点 ,可作为低倍率循环流化床锅炉的分离器或高倍率循环流化床锅炉的前级分离器 ,尤其适合具有矮小燃烧空间的循环流化床锅炉 ,具有广泛的工程应用领域和极高的工程应用价值。     

Low Pressure Microfilter Design Aspects and Filtration Performance

Abstract

A microfilter should retain micron-sized material yet provide minimal resistance to liquid flow. A slotted pore surface microfilter was oscillated while filtering yeast cells under constant rate. At shear rates over 7760 s^?1, a pore blocking model fitted the data. The operating pressure was very low (<1000 Pa), but particle retention was limited by the 4 micron pore slot width. A sintered glass micro-bead coating improved yeast rejection: 95% at 1.7 microns at a shear rate of 5000 s^?1, with a 1.2 kPa transmembrane pressure. Two models were validated to assist with the design of future micro-bead coatings constructed from spherical particles.     

陶瓷微滤膜在钛白水洗液处理中的应用

阐述了我国钛白水洗穿滤液的处理现状。介绍了陶瓷微滤膜在回收偏钛酸粒子和ＴｉＯ２颗粒中的应用。以日处理１５０ｔ废水的陶瓷膜回收ＴｉＯ２的工业示范装置为例，评价其经济效益     

欧盟压力管道标准EN13480与我国对应规范的比较

通过将《压力管道规范工业管道》与EN13480在设计、材料、制作和安装以及检验等方面内容进行对比,指出了两个标准内容上的异同点,对两个标准在这些方面所规定的要求和使用方法进行了说明,特别指出了两个标准所规定的不同要求和采用的不同方法对管道安全性的影响。     

Clarification of viscous poly tetramethylene ether glycol (PTMEG) containing solid suspension by dead‐end flow microfiltration under constant pressure

In this study, the microfiltration of polyester fluid containing solid suspension has been investigated under constant pressure. A membrane module, which consists of a microfilter paper of surface area of 19.4 cm² and a SS‐316 net support (160 mesh), was used. It was found that the homogeneous sodium acetate suspension in polymer can be completely removed by the membrane filter paper to yield a very clear polymer product. The property and rheology of polyester fluid with suspending solids have been studied. The polymer fluid can be viewed as a Newtonian fluid in this work. The filtration behavior in the membrane system was simulated by the blocking filtration law. Satisfactory fit between experimental data and theoretical calculations was demonstrated. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2303–2312, 1999     

Design of hybrid steel-composite interference fitted and adhesively bonded connections

The work deals with the definition of the axial push-out force in hybrid connections realized by means of a carbon-epoxy composite bush which is press fitted into a steel housing and, eventually, supplemented with anaerobic adhesive, in order to obtain an innovative (hybrid) journal bearing. Lamè's solution has been extended to orthotropic material (composite bush) in order to evaluate analytically the coupling pressure due to interference assembly, while experimental campaigns have provided the values of coefficient of friction and of the adhesive shear strength (steel-composite). The mere application of the anaerobic adhesive before the assembly operation does not provide any sensible increase in push out force especially if compared with metal–metal interference connections. In order to take advantage of the adhesive strength, specific hoop channels for the adhesive hosting have been realised on the external surface of the composite bush.     

熔融结晶洗涤分离过程的传递行为

通过对熔融结晶洗涤分离的操作模式和提纯机理进行分析,按照滤饼洗涤原理建立了流体流动模型,得到晶层内的压力分布。同时对晶层进行质量和热量衡算,建立了传质和传热模型,求得了晶层内杂质浓度分布和温度分布表达式。分布表达式表明了压力、浓度、温度与之相关的参数的关系,这个结果对熔融结晶洗涤分离过程的参数确定和操作过程的进一步实验研究具有重要的应用价值。