分层填料对旋转填料床气相流场影响的数值模拟

通过设计简化的分层填料旋转床(SP-RPB)模型,采用计算流体力学方法(CFD)对比同尺寸旋转填料床(RPB)的稳态气相流场。分析转速和进料速度对气相压力、相对速度及湍动能分布的影响,同时还考察了单位丝网圈上的压降情况。结果表明,在气体进入各级填料位置的相对速度出现峰值,湍动能分布与之相同,各峰的出现位置仅由填料位置决定,两者共同表明SP-RPB具有多个端效应区域。转速增加对相对速度峰值大小有更明显的提升,较大的进料速度使填料内气体的速度波动更大,也使湍动能的峰值有所增加。由于SP-RPB内填料厚度较RPB变薄,从整个设备范围上看,SP-RPB表现出更低的压降。进气速度提高和转速降低使SP-RPB两层填料间的高压范围变窄,但SP-RPB的单位丝网圈数压降更大。     

生物对流流场的数值分析

在微生物培养中,由于微生物的趋向性运动造成了流体的非稳定密度分布,由此引发的宏观对流称为生物对流。本文采用数值解析方法,对二维空间内负趋地性生物对流流场进行了模拟计算,考察了细胞密度和运动能力对流动形态的影响。结果表明：培养基内流体因微生物的趋向性运动引起的宏观流动,在中心处会逐步趋于稳定;微生物细胞密度和运动能力都可以促进对流;细胞密度增大可以抑止细胞向上运动,而运动能力的增强则加强向上的流动。     

干气密封螺旋槽内气体流场的有限元模拟

利用ANSYS8.0对螺旋槽干气密封槽内气体层流流场进行了二维模拟分析,得到了气体的压力分布及速度分布云图,并分析了运算结果。     

新型错流旋转填料床气相流场的三维CFD模拟

目前鲜有关于错流旋转填料床结构改进研究方面的报道。以自主研发的错流旋转填料床为计算模型,建立了三维物理模型,采用标准k-ε湍流模型和SIMPLE算法,填料层用多孔介质模型,运用CFD方法对其内部气相流场进行了模拟,研究了转速和气量对速度场和干床压降的影响规律,并通过实验进行了验证。由结果可知:干床压降几乎不受转速的影响,模拟值与实验值相对误差在11.2%以内;旋转填料层内气相流场主要以旋流场为主,切向速度与填料线速度大小相当,且不受气量的影响。轴向速度值受气量的影响,其径向分布受转速的影响。与切向速度和轴向速度相比,径向速度小1—2个数量级,说明气体在径向的偏移量很小;中间静止填料层能够有效减小气旋,强化气相流场扰动,表明新型错流旋转填料床能够强化气相传质。     

大型环流式旋风除尘器流场模拟

采用CFD模拟软件Fluent6．2提供的雷诺应力模型（RSM）对大型环流式旋风除尘器内的流场进行了数值模拟研究。结果表明：大型环流式旋风除尘器避免了顶部灰环,降低了设备的压降。但由于放大效应,内部流场出现局部涡,造成除尘效率降低,通过对顶部、灰仓等部位改进后,局部涡明显减少,除尘效率提高3％～6％。     

湍流模型在圆管螺旋流场模拟中的应用与对比

基于计算流体动力学分析软件Fluent,分别采用标准k-ε模型、RNG k-ε模型、Realizable k-ε模型及雷诺应力方程模型(RSM)4种湍流模型,对环空圆管内螺旋流单相流体流动进行模拟。重点分析了不同湍流模型计算的速度、速度矢量及涡量场分布,得出在模拟螺旋流道内强旋流方面,RSM具有更为明显的优势。利用量纲一分析方法将数值模拟结果与其他研究者的PIV实测结果对比,验证了RSM数值模拟结果的准确性。从量纲一压力随轴向位置变化曲线来看,环空圆管螺旋分离器虽然结构简单,但依然存在较为复杂的湍流流场分布,如何形成高效、稳定的分离流场是接下来研究的重点。     

转笼式悬浮填料生物反应器启动性能试验

为了研究转茏式悬浮填料生物反应器的启动性能,简化其启动工艺,进行了常温和变温时的反应器的自然挂膜启动实验。实验结果表明,转笼式悬浮填料生物反应器构造的特定微环境有利于自然挂膜,启动比传统生物转盘快10d以上：经过启动参数优化,在水流量为2m^3／h,曝气量为3．6m^3／h、转笼转速为1．5r／min时,启动效果较好。     

生物接触氧化池悬浮填料流动特性数值模拟分析

采用FLUENT多相流模型对生物接触氧化池悬浮生物填料流动特性进行数值模拟,分析了改变氧化池长宽比及调整曝气强度分布对改善填料分布状态的可行性。研究表明,通过添加隔墙将曝气池分成4个区后,分区内形成较明显涡流流场,改善了悬浮填料的空间分布均匀性;通过对分区内曝气强度分布进行优化,悬浮填料在氧化池内的混合状态得到进一步改善,氧化池末端和边壁不再发生填料团聚现象。因此,合理设计反应池的长宽比及优化曝气强度分布对悬浮生物填料能否在氧化池内混合均匀起到关键作用。     

生物填料的投加对厌氧序批式反应器启动影响研究

采用厌氧序批式反应器(ASBR)和厌氧序批式生物膜反应器(ASBBR),以相同的反硝化污泥作为接种污泥,自配模拟废水,调节进水pH为7.5~8.0,反应器中水体温度为(30±0.5)℃,研究了生物填料的投加对厌氧序批式反应器厌氧氨氧化反应的启动影响。经过120 d运行,ASBBR成功启动了厌氧氨氧化反应,NH3-N容积负荷为96mg/(L·d),NH3-N去除率达到81.53%,NH3-N、NO2--N减少量与NO3--N生成量之比为1:1.11:0.25。而未投加填料的ASBR没有发生厌氧氨氧化反应,NH3-N容积负荷为22 mg/(L·d),NH3-N去除率达到23.36%,NH3-N、NO2--N减少量与NO3--N生成量之比为1:0.91:1.18。实验结果表明,生物填料的投加使ASBBR易于形成厌氧环境,有利于厌氧氨氧化反应器的启动,同时有利于NH3-N的去除。     

用BF生物填料处理化工综合废水的应用研究

将新型的生物填料用于A/O工艺中,并在某化工污水处理厂进行了中间试验。结果表明:当HRT为28h,回流比为1,好氧池溶解氧为2～4mg/L,温度为18～27℃,进水CODCr为450mg/L,BOD5为200mg/L,SS为300mg/L,NH4 -N为40mg/L时,出水NH4 -N去除率约100%,其他指标的平均去除率均>80%,出水水质达到国家综合废水排放标准一级控制指标要求。同时MLSS产率为0.234kg/kg,污泥减量化效果明显。     

填料改性对胶接应力影响的仿真研究

利用弹塑性有限元法,研究了三种填料改性的不同弹性模量的环氧胶粘剂对铝合金单搭接胶接应力的影响.研究结果表明:碳化硅对环氧胶粘剂的弹性模量提高较大,碳酸钙对环氧胶粘剂的线膨胀系数降低较多;接头应力在沿搭接长度方向基本呈对称分布,在胶接边缘的位置出现峰值,胶层中部应力较小;随着弹性模量的增加,接头的应力峰值逐渐增大;填料改...     

Organic filler surface analysis by column wicking

Organic fillers derived from biomass waste streams are commonly formulated with phenol-formaldehyde resoles in the production of veneer-based wood composites. The surface characteristics of three fillers, flours of walnut shell (Juglans regia), red alder (Alnus rubra) bark, and corn cob (Zea mays) furfural production residue, were investigated with the column wicking method using the Washburn equation. A series of n-alkanes (spreading liquids) provided reliable estimates of interstitial pore radii, which then enabled contact angle estimates for a variety of non-spreading liquids. Among the three fillers, only alder bark data were complicated by swelling effects, which were eliminated with strict data quality criteria. Corn cob residue exhibited the highest total surface free energy, but all fillers had low energies that were dominated by dispersive effects. The minor polar contributions were basic. Specific surface areas determined from wicking substantially disagreed with Brunauer–Emmett–Teller measurements using N₂ adsorption, where the former were more consistent with measured particle size.     

BF生物填料污泥减量效果试验研究

为减少活性污泥法污水处理过程中剩余污泥的产生量,采用BF生物填料在缺氧—好氧工艺中组成复合生物氧化池,对其污泥减量效果进行了中间试验。结果表明:剩余污泥量减少89.5%,且对CODCr等也有比较高的去除效果。     

Hydrodynamic analysis of a spiral disc extruder

The flow of polymer melts in a rotating disc extruder is analyzed with the development of a mathematical model for drag flow in a contoured rotating disc. The model assumes a fully melted material which exhibits Newtonian flow behavior under isothermal conditions. Flow is evaluated in successive sections of the flow path, and the drag flow component is calculated by assuming a zero pressure gradient by analogy to the analysis of single screw extruder performance. The final expression involves a computer-assisted numerical solution. Results of the drag flow model are presented for three different disc geometries. A mathematical model of negative flow, and a comparison of the results with experimental data will be presented in followup papers.     

Determination of filler content in thermoplastic composites by FTIR analysis

FTIR quantitative analytical method is described as an alternative technique for computation of the filler content in polypropylene composites. White rice husk ash (WRHA) was incorporated as a filler material into polypropylene homopolymer. Absorption peaks at 480, 621, and 790 cm^?1 chosen for the quantitative analysis work have been shown to give good linearity with increasing filler contents. © 1995 John Wiley & Sons, Inc.     

换热管内插螺旋强化传热的数值模拟

换热管内插入钢丝螺旋改变了管内的流动状态。通过数值模拟,研究内插螺旋换热管内速度场与温度场的分布特性,对空管和内插螺旋换热管进行了比较。模拟结果表明,在相同条件下,内插螺旋能够有效地改善换热管内速度场和温度场,验证了管内插螺旋是提高换热性能的有效手段。     

填料对聚醚醚酮注射成型影响模流分析

采用Moldflow 软件对聚醚醚酮（PEEK）型材接头的注射成形进行了设计与模流分析,从注塑流动过程和成型件质量等角度,研究了PEEK物料中填料种类与含量对注射压力、锁模力、成型件纤维取向张量分布、成型件翘曲量等的影响。结果表明,添加填料可以改善物料流动特性,玻璃纤维填料可以优化其力学阈值,高模量碳纤维可以显著增强成型件刚度、降低翘曲度,增加填料含量可以优化成型件刚度;通过本研究可以有针对性地搭配PEEK型材的填料种类和含量,保证注射成型质量。     

BIMS/filler interactions. I. Effects of filler structure

Polymer/filler interactions have been found to affect the performance of tire tread, sidewall, innerliner, or carcass and other industrial rubber products that are all based on filled elastomers. Identification of types of various polymer/filler interactions and ranking of their impacts have been elusive. Isobutylene-based polymers have relatively saturated structures and contain very low concentrations of functional group. Examples are BIMS (a brominated isobutylene/p-methylstyrene copolymer) containing p-bromomethylstyrene and p-methylstyrene; bromobutyl rubber containing  Br and olefin; chlorobutyl rubber containing  Cl and olefin; and butyl rubber containing olefin. On the other hand, high diene rubbers, such as polybutadiene rubber, polyisoprene rubber, and styrene/butadiene rubber, have unsaturated backbones and high olefin contents. Hence, different types and extents of interaction with reinforcing fillers, such as carbon black (CB) or silica, are expected in these two classes of elastomer. This work employs bound rubber (solvent extraction), viscoelasticity, stress–strain measurements, and solid state NMR to identify, differentiate, and scale polymer/filler interactions in unvulcanized BIMS/CB, BIMS/silica, SBR/CB, and SBR/silica composites, where SBR denotes a styrene/butadiene rubber. Four different types of CB and one type of silica have been studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4943–4956, 2006     

A theoretical analysis of the strength of composite gels with rigid filler particles

The strength, under uniaxial load, of composite gels containing filler particles has been investigated by calculating the stress concentration in the gel matrix. The particles were assumed to be rigid spheres, and the interaction between the particles was taken into account based on a self-consistent model. The bonding between the particles and matrix was treated for two typical cases, (1) perfectly bonded, (2) smoothly connected. For case 1, the analytical result shows that the stress concentration factors decrease with the increasing of the volume fraction of filler. For case 2, the stress concentration factors are independent of the volume fraction of filler. The structural failure caused by the stress concentration was analyzed.