涡旋真空泵应力与变形的ANSYS模拟与研究

在对涡旋真空泵运行温度场采用大型有限元分析软件ANSYS进行模拟与研究的基础上，对其工作过程的应力与变形进行了模拟分析。相关结果表明，软件分析基本上可以反应涡旋真空泵运行过程中应力与变形分布及变化情况，并为其设计参数及相关因素的确定提供有效的分析手段。     

无油涡旋真空泵温度场、应力场和热变形的ANSYS模拟

本文运用有限元分析软件ANSYS对涡旋真空泵动、定涡旋盘的温度场及其产生的热变形、应力场进行了模拟和研究.模拟结果与实测数据进行了对比.首先对无油涡旋真空泵动、定涡旋盘体使用UG软件三维实体建模,再对三维实体模型进行转化处理,开启ANSYS系统将UG中建好的模型导入,输入所需参数以及相应热载荷进行运算,最终得出无油涡旋真空泵动、定涡旋盘盘体的温度场、应力场和热变形云图与数值信息并找到变化规律.其结果验证了涡旋真空泵动、定涡旋盘设计的合理性,对涡旋真空泵的设计有所帮助.     

涡旋真空泵运行工况流场的计算机模拟研究

在相关试验的基础上,通过分析软件ANSYS和C++语言编程对涡旋真空泵工作过程的流场进行了模拟分析,获得了涡旋真空泵运行工况下个月牙形封闭压缩腔内压力场分布和排气口速度场分布情况.相关结果表明,所进行的分析和研究基本上可以反映涡旋真空泵运行过程中流场分布及变化情况,从而为其设计参数及相关因素的确定提供有效的分析手段.     

滤油机涡旋真空泵泄漏损耗及密封研究

在真空滤油机研发过程中,对其真空获得设备前置涡旋真空泵的研究是一个重要的方面。涡旋真空泵在运行过程中,动、静涡旋盘之间间隙的存在导致了气体泄漏损耗,该因素会影响涡旋真空泵的极限真空度及其工作性能。分析了涡旋真空泵的径向泄漏及切向泄漏,计算了泄漏消耗的功率,说明了密封条原理和特点,提出了径向间隙和轴向间隙的密封措施,对提高涡旋真空泵抽速、改善其机构性能方面具有重要理论意义和工程实用价值,涡旋真空泵将在油处理行业得到进一步推广应用。     

单侧涡旋干式真空泵内气体流动的CFD模拟

本文建立了单侧涡旋干式真空泵流动区域的数值计算模型,并基于CFD通用软件ANSYS-CFX和动网格技术建立了干式涡旋真空泵内瞬态流动的仿真模型,分析了泵内的工作过程,及存在"欠压缩"和"过压缩"时涡旋干泵内热场分布。为进一步研究干式涡旋真空泵的理论和设计问题进行了有益的尝试。     

UG软件在真空泵涡旋盘建模与仿真中的应用

涡旋真空泵型线主要有圆渐开线、线段渐开线、正多边形渐开线、螺旋线、包络型线以及通用集成型线等.由于圆渐开线理论成熟且易于加工,一般用圆渐开线作为涡旋齿壁型线.但单一型线涡旋齿难以实现完全啮合,需对涡旋机械性能影响较大的涡旋齿齿头型线进行修正,以确保涡旋型线光滑连续,从而实现涡旋齿的正确啮合.介绍了基于圆渐开线参数方程和刘振全教授的图解修正法,通过UG软件平台对涡旋真空泵零部件进行参数化建模仿真,为涡旋真空泵涡旋盘的设计和生产提供有效方案.     

无油涡旋真空泵内部流场的数值模拟

在深入理解无油涡旋真空泵的工作原理基础上,对真空泵的主要部件进行三维实体造型,划分了若干月牙形工作压缩腔在不同角度的二维图,作为分析的控制容积。结合真空泵压缩腔的特点建立一系列控制方程,并对建立的数学模型进行了合理的简化和条件假设。利用FLUENT模拟真空泵内部流场,并对模拟结果进行了的分析和研究,得出无油涡旋真空泵内部流场的分布,获得无油涡旋真空泵流量场的流速场、压强场等重要信息。为无油涡旋真空泵的强度校核等优化设计提供一定参考。     

涡旋式真空泵——无油真空泵的发展趋势

涡旋真空泵具有简单,密封性有好,极限真空高（可达５×１０＾－１Ｐａ）等优点。作为一种高新技术产品,它不易仿制,目前在国外,仅有少数几个公司有产品问世。本从涡旋真空泵工作原理出发,研究了型线与密封机构,在型结构及特点进行分析,可以预言,涡旋真空泵的应用将会得到迅速发展     

螺杆真空泵转子热形变分析及转子优化

建立180L/s螺杆真空泵转子温度场有限元模型,得到其温度场和热形变分布情况,结合热形变结果推导出泵腔内各点冷配合间隙。利用分析结果对螺杆真空泵转子形状进行优化设计。分析结果显示:180L/s螺杆真空泵两转子之间间隙应大于0.28mm,泵腔和转子之间间隙应大于0.20mm。结合所述分析结果对转子形状进行优化,优化后的转子可以减少原有22%冷配合间隙,一定程度上降低泵工作过程中返流量。     

涡旋真空泵的设计与操作

本文总结了涡旋真空泵的工作原理、设计原则与经验、制造要点和使用注意事项；介绍了涡旋真空泵的设计与加工方法；讨论了涡旋盘的加工、密封的设计与选择、间隙的确定以及泵体的动平衡等问题并阐明这些问题是影响泵性能指标的几个重要因素；同时指出了涡旋真空泵使用的几个注意事项。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.