大长径比卧螺离心机转鼓的有限元分析

利用SolidWorks Simulation有限元分析软件建立了大长径比卧螺离心机转鼓的有限元模型。在高转速下对其正常工作状态下的整体结构进行了模态和静态仿真分析,得到了转鼓的前5阶固有频率、应力分布和径向、轴向变形。结果表明原设计的卧螺离心机转鼓的强度和刚度均满足要求。将有限元分析结果与传统解析解进行比较,结果基本一致。改变转鼓约束面积和约束形式,对转鼓进行优化,寻求了最佳的转鼓轴颈直径;采用柔性支撑消除了主轴承刚度对最高转速的限制性影响,可以将转速提高到3 900 r/min。     

虹吸式离心机转鼓结构的三维有限元安全分析

针对二维有限元分析对虹吸式离心机转鼓开孔对结构强度影响分析的不足,利用ANSYS有限元软件,采用参数建模的方法建立了三维GKH1250虹吸式离心机转鼓的实体模型,并将其离散化建立计算模型,进行了应力分析和刚度分析,同时,重点考察了过滤转鼓到虹吸室的滤液孔对转鼓结构强度的影响,得到其应力和变形云图,验证了该虹吸式离心机的设计符合刚度和强度的要求,也满足运转安全的要求。通过提供的建模和计算方法可对离心机转鼓设计提供参考。     

卧螺离心机分离PVC的FCPS分析

采用计算流体动力学(CFD)方法和计算软件FLUENT对分离聚氯乙烯(PVC)的卧式螺旋卸料沉降离心机转鼓内部流场进行数值模拟。通过对转鼓溢流口区域的涡流进行分析,确定溢流口轴向宽度、转鼓内液池深度、分离因数以及悬浮液流量与溢流口最大负径向速度和上浮临界粒度(FCPS)的关系。模拟结果表明:增大溢流口轴向宽度可以有效减小溢流口最大负径向速度,从而颗粒上浮临界粒度减小,可以提高离心机的分离效率;改变转鼓内液池深度对最大负径向速度影响很小,上浮临界粒度变化不大;当增大悬浮液流量和减小分离因数时,最大负径向速度增大,上浮临界粒度增大。模拟方法和结果可以为不同用途和结构的卧螺离心机设计提供更多参考。     

离心机转鼓整体三维有限元分析与强度计算

转鼓是离心机的关键部件,其设计正朝着转速更高,直径更大的方向发展,因此鼓壁鼓底等零部件间的相互影响和作用越来越大。这类结构的强度问题更为突出,对强度分析的要求也越来越高。为此,本文提出用三维立体单元对过滤式离心机整个转鼓进行分析。由于此方法对转鼓全部采用三维立体单元进行网格划分,因而可以模拟复杂的局部结构和边界条件。本文对某国产卧式刮刀卸料离心机大直径转鼓的有限元计算结果表明,在转鼓底和拦液板中的应力水平较低;在转筒体中应力水平较高,在开孔周围存在着应力集中现象,最大虚拟弹性应力值远大于材料的屈服限。最后,对该离心机转进行了强度评定     

转鼓反应器中油酸氧化裂解制备壬二酸的研究

在转鼓反应器中实现了油酸臭氧氧化裂解制备壬二酸的连续化操作。考察了转鼓转速、液体流量、气体流量对转鼓反应器内气液传质反应速率的影响。在双膜理论的基础上,利用恩田公式来计算气相传质系数、液相传质系数,建立了转鼓反应器中两步反应速率模型,并将模型预测值与实验值进行了比较。实验结果表明:在转鼓反应器中,油酸氧化裂解反应速率分别随转鼓转速和液体流量的增大,先增大后趋于平缓;随着气体通量的增加,转鼓反应器内油酸氧化裂解反应速率先增大然后减小;在转鼓转速为1 699 r/min、液体流量为45 mL/min、气体流量为3 L/min时,在转鼓内油酸氧化裂解可获得最大的气液传质反应速率。模型预测值与实验值比较,两者吻合得较好,验证了模型的可靠性。     

离心传质机转子结构及力学计算

在确定了离心传质机转子的结构和安装尺寸的基础上,进行了转鼓鼓壁的强度校核和轴系临界转速的计算,计算结果表明:鼓壁的最大主应力区在转鼓的中面附近,转子的第一临界转速为14200r/min左右,转子的结构尺寸满足工程应用要求。     

虹吸式离心机转鼓的有限元优化计算

本文在有限元应力分析的基础上建立了虹吸离心机转鼓整体优化计算的数学模型，并对实际转鼓进行了优化计算。优化结果表明，在满足强度、刚度的前提下，离心机转鼓质量明显降低     

卧式螺旋卸料沉降离心机沉渣的输送

本文定性地分析了卧螺离心机的沉渣输送与其转鼓的锥角β、螺旋推料器叶片的倾角θ、叶片的螺距、液池半径γ及差转速Δｎ之间的关系,阐述了改善卧螺离心机输渣条件的设计思想。     

基于流固耦合的大型卧螺离心机数值模拟及实验研究

采用ANSYS软件建立了卧螺离心机整机的流固耦合有限元模型,并通过流固耦合数值模拟分析得到了卧螺离心机负载工况下的滞后量、离心液压随转速变化关系以及转子系的真实应力状态。结果表明,离心机内部流场最大压力位于进料分布器出口段的转鼓内壁面处,转子系最大位移发生在螺旋输送器中部、最大应力位于螺旋叶片根部与螺旋筒体连接处,在正常工况下均满足强度、刚度要求;振动测试试验得到的临界转速与数值模拟结果相一致,验证了有限元模拟的准确性,并针对卧螺离心机独特的双转子结构提出测定副临界转速来推算临界转速的方法。     

离心传质机转子结构及力学计算

在确定了离心传质机转的结构和安装尺寸的基础上，进行了转鼓鼓擘 强度校核和轴系临界转速的计算，计算结果表明，鼓壁的最大主应力区在转鼓的中面附近，转子的第一临界转速为１４２００ｒ／ｍｉｎ左右，转子的结构尺寸满足工程应用要求。     

Determining the thickness of liquid film in laminar condition on a rotating drum surface using CFD

This is a pioneering paper that deals with the semi-steady-state liquid film thickness on a rotating drum partially submerged in liquid using CFD. The CFD predictions have been compared with both experimental results and analytical solutions. The liquid film thickness and the film rising on a circular curved wall were monitored for various rpm of the rotating drum. The 2D simulations were performed neglecting the end effects (assuming the rotating drum is very long). As the rotating drum speed was increased, the film thickness was found to increase at the film rising side and at the minimum film thickness point (top of the rotating drum). There was never been a steady-state condition reached, the opposite was expected as a wiper is used in the CFD calculation (same as the experimental investigation). The liquid that leaves the domain by the wiper (as outflow boundary condition) is forced to enter to the domain from far end to keep the level of the free surface constant.     

离心分离机开孔转鼓的设计计算

针对一种多鼓离心分离机的设计,介绍了其工作原理。考虑到传统转鼓厚度设计方法的片面性,对高速旋转引起的振动可能给转鼓带来的严重后果加以分析,从传统的强度公式进行转鼓厚度计算,并从振动学的角度按照基本刚度要求对厚度进行校核,充分体现了设计的全面性。     

基于Euler多相流模型的卧螺离心机速度场数值模拟与分析

应用计算流体力学软件Fluent,基于Euler多相流模型,在多重参考系坐标下,选用RNG k-ε湍流模型,对卧螺离心机内部的三维速度场进行了数值模拟和分析。结果表明：当液体进入转鼓后,对沉降分离起主要作用的周向速度迅速增大,经过较短的距离即可获得稳定的流动状态,且沿转鼓轴向变化较小;轴向速度沿径向的梯度在转鼓柱段较小,而在锥段较大,且在靠近转鼓的区域,锥段的轴向速度比柱段的大;径向速度复杂多变,无明显规律,流动受几何结构的影响很大。     

单组分液体蒸发过程动力学特性

引言 危险性液体或液化气体泄漏后不断向环境中挥发出有毒有害蒸气,不但污染环境,也会威胁人体健康[1].     

新型XJFH风动绞车卷简优化分析

在对新型XJFH风动绞车卷筒进行以去重为目的的结构优化时,通过ANSYS软件分析了卷筒的壁厚、筋板数量对卷筒强度、重量的影响.     

A Diffusion Model for a Drum Dryer Subjected to Conduction, Convection, and Radiant Heat Input

Drum dryers are commonly used for production of a flaky dry powder from thick suspensions. This article presents results of a simple diffusion-based model to predict the drying performance of a pilot-scale twin-drum dryer. Numerical results are compared with experimental data obtained for a biological sludge whose initial moisture content varied from 1.0 to 2.3 kg/kg db. The agreement of model predictions with the pilot-scale experimental data is favorable. Effects of film thickness, drum rotational speed, external air flow velocity, and its humidity are examined parametrically. Sludge film thickness is identified as the most critical operating parameter to control the final moisture content and productivity of the dryer. The validated model is used to predict performance of a drum dryer subjected to heat input by convection and radiation along with conduction through the drum wall. It is shown that dryer output can be enhanced significantly by increasing the film thickness and applying radiant heating in the initial period of drying. A simple mathematical model of this type can be used for the purpose of design and analysis as well as scale-up of industrial drum dryers based on simple laboratory-scale experiments.     

卧螺离心机内盐析流场的CFD-PBM耦合计算

目前对卧螺离心机内部流场的数值模拟大多采用传统欧拉模型,考虑其内部伴有盐析等固相粒子微观行为过程的研究少有报道。本文应用计算流体力学软件Fluent,基于群体平衡模型与多相流Eulerian模型、RNG k-ε模型耦合方法,对卧螺离心机内部盐析两相流场进行三维数值模拟,通过仿真与实验相结合的方式,得到卧螺离心机内盐析流场的晶体颗粒粒径分布、组分数分布和浓度分布及其变化规律,初步揭示了卧螺离心机内伴有盐析的流场晶体颗粒分布特性。研究结果表明：卧螺离心机内盐析晶体粒径的分布随液环半径的增大而增大,螺旋叶片正壁面粒径明显较背面大,从排液端至排渣端的晶体粒径分布有整体逐渐变大的轴向粒径梯度;流道内晶体粒径随转鼓转速的增大而减小,随进口固相体积分数的增大而增大;大粒径晶体的组分数在液环外侧及螺旋叶片正面附近相对较大,而中、小粒径晶体组分数的分布规律则与之相反;盐析颗粒浓度在液环外侧较高且分布均匀,且随转鼓转速的提高而提高,PBM模型与Euler模型计算结果有一定的相似与差异。     

Granular flow in a rotating drum with gaps in the side wall

This paper presents a numerical investigation of the motion of bi-sized particles in a short rotating drum by using Discrete Element Method (DEM). The side wall of the drum has equally spaced gaps whose width is just between the two particle diameters. One end wall of the drum is fixed while the other rotates with the side wall. Small particles are fed into the drum continuously at the center region in the axial direction. The effect of rotating speed on the volumetric holdup and residence time of small particle is investigated. A critical rotating speed is found, below which the decrease of rotating speed will increase the volumetric holdup and the residence time of the small particles sharply. A jump in the axial distribution of the outflow rate of the small particles is observed at the region adjacent to the fixed end wall. The flow pattern inside the drum is analyzed. In the region between the fixed end wall and the feeding point, all small particles, on average, move towards the fixed end wall. While in the region between the rotating end wall and the feeding point, the small particles curve away the rotating end wall in the upper part of the charge and return to this wall in the lower part. The particle temperature distributions at different rotating speeds are explored to understand the flow behavior observed in these simulations.