浅析离心式转动机械轴向力的产生与平衡

轴向力的存在严重影响离心式转动机械的正常工作,严重影响转机本身及原动机的使用寿命,本文从受力分析角度浅析了轴向力产生的根源,并由此提出了平衡轴向力的有力论断。     

浅谈离心泵的轴向力产生及解决方法

泵的轴向力尤其是多级离心式泵的轴向力不平衡在日常生产中常常遇到,较好的了解泵的轴向力的产生对于生产中有效缓解轴向力,延长设备使用寿命,从而提高设备的经济运行能力十分有必要。     

裂解气压缩机轴位移升高原因分析及对策

对裂解气压缩机轴位移缓慢升高的异常情况进行了介绍,通过故障排查,寻找离心压缩机中压缸转子轴向力变化原因.经过分析得出了造成中压缸转子轴位移持续增大的原因是压缩机静子部件出现结垢,通过在压缩机缸体注入馏程较高的洗油方法对压缩机通流部分垢物进行冲洗,解决了压缩机静子部件结垢问题,从而改变了转子轴向力的分布,最后成功消除了轴...     

BCL407型高压离心式压缩机轴向推力的计算

详细分析了离心叶轮外侧间隙内泄漏气体的流动规律和离心式压缩机轴向推力的组成。建立了离心叶轮盘、盖外侧间隙内泄漏气体流动的计算模型,采用了低Ｒｅ数κ ε紊流模型,并用ＳＩＭＰＬＥＣ方法求解控制方程。分别计算了离心叶轮盘、盖两侧不同间隙宽度及不同泄漏流量大小时的压力沿径向的分布。对一台化工用ＢＣＬ４０７型高压离心式压缩机高压缸的轴向推力进行了计算,结果令人满意。     

同向双螺杆挤出机螺杆轴向力的数值模拟和实验研究

应用 POLYFLOW 软件模拟计算了组合螺杆元件在流场中受到的轴向力。模拟结果表明,轴向力随螺杆相位角的变化而波动;螺杆构型对轴向力的影响较大;操作条件会对轴向力产生影响。自行设计了拉杆应变测量系统对螺杆轴向力进行了间接测试,结果表明螺杆轴向力由机头静压力和附加轴向力组成,使用实验螺杆组合时,附加轴向力约为机头静压力的0.4～1.6倍。     

LLY─3700型氯气压缩机的使用分析

对两台ＬＬＹ─３７００型离心式压缩机的运行情况进行了具体分析。通过收集氯气压缩机的运行数据可发现，轴位移上升快。由轴向力的产生及其计算，轴向力的平衡、轴承的润滑、维修质量、操作压力的控制等入手讨论并提出了保证压缩机平稳长周期运行的具体措施。     

CO_2离心式压缩机高压缸转子变转速、变流量工况下轴向推力的计算与分析

在测量ＣＯ２离心式压缩机高压缸转子各级叶轮性能曲线的基础上,研究了变转速、变流量工况下高压缸转子轴向推力的变化规律,揭示了ＣＯ２压缩机高压缸转子在启动过程中容易发生窜轴事故的原因。针对５２万ｔ／ａ尿素装置实际生产过程的特点,提出了控制轴向推力大小、防止窜轴事故的措施     

分段式多级叶片离心泵轴向力的计算

介绍了国内外常用的多级离心泵轴向力计算公式 ,分别用这些公式计算了TP 4 1 1 3 P5 1 2型泵的轴向力。通过轴向力在线监测装置对此泵的轴向力进行了在线监测 ,并将计算结果与实测结果进行了比较 ,确定了比较准确的轴向力计算公式 ,从而为多级离心泵的设计提供了一定的理论依据。     

透平循环压缩机转子轴向位移的原因和改进措施

我公司1998年5月份投入生产的TC620／32－12型透平循环压缩机为内置、多级离心式循环压缩机，使用3年以来，机组运转相对平稳。在历次检修过程中发现导致停机并严重制约运转率的主要原因是转子的轴向位移。     

甲醇合成压缩机干气密封的技术改造及效益分析

为解决传统甲醇合成压缩机在实际生产中由于干气密封失效所导致的停机而造成的损失,在对当前压缩机干气密封失效问题和主要原因分析的基础上,重点通过消除异常轴向力和保证供气满足密封气两方面对干气密封进行技术改造,并对改造后的经济效益进行分析。     

Axial thrust of axial flow impellers

This paper presents an analysis of the axial thrust of axial flow high-speed impellers under a turbulent regime of flow of an agitated liquid. The axial thrust is calculated from the measured total axial force affecting the cylindrical fully baffled mixing vessel and from the radial profile of the axial component of the ensemble-averaged mean velocity in the impeller discharge stream. The results of experimentally determined values of the dimensionless criteria (thrust number and momentum number) are successfully compared with the axial thrust of the pitched blade impellers calculated from the theoretically predicted simplified radial profiles of the axial component of the mean velocity in the impeller discharge stream.     

减速机在塑料机械中的应用

减速机是塑料机械设备的重要装置。挤出机专用的减速机具有许多特殊性。减速机的设计与制造水平直接关系到挤出机整机的使用寿命。本文分析了高性能挤出机专用减速机的必备条件。     

INVISCID LIQUID CIRCULATION IN BUBBLE COLUMNS

For circulation in axi-symmetric (cylindrical) bubble columns, the recently developed mathematical model^25,26 has been used along with the criterion of minimum circulation strength to determine the height of each circulation cell in a tall column. This is then used to derive a theoretical expression, first of its kind, for gas hold-up inside a bubble column. The predictions of this equation as well as the equation derived here for axial liquid velocity at column axis have been compared with available data and the comparison is found to be excellent for both the variables. An explicit relation is derived for the average liquid circulation velocity. The model is also used to derive an expression for liquid axial dispersion coefficient which compares almost exactly with Deckwer et al.'s⁴ correlation.

For circulation in two-dimensional bubble columns a new mathematical model is developed. The predictions of bubble envelope shape and bubble envelope area compare well with published data. The predictions of number of circulation cells in the horizontal direction also compare well with published data.     

INVISCID LIQUID CIRCULATION IN BUBBLE COLUMNS

For circulation in axi-symmetric (cylindrical) bubble columns, the recently developed mathematical model^25,26 has been used along with the criterion of minimum circulation strength to determine the height of each circulation cell in a tall column. This is then used to derive a theoretical expression, first of its kind, for gas hold-up inside a bubble column. The predictions of this equation as well as the equation derived here for axial liquid velocity at column axis have been compared with available data and the comparison is found to be excellent for both the variables. An explicit relation is derived for the average liquid circulation velocity. The model is also used to derive an expression for liquid axial dispersion coefficient which compares almost exactly with Deckwer et al.'s⁴ correlation.

For circulation in two-dimensional bubble columns a new mathematical model is developed. The predictions of bubble envelope shape and bubble envelope area compare well with published data. The predictions of number of circulation cells in the horizontal direction also compare well with published data.     

密螺旋体Reiter株轴丝的提纯及鉴定

将Reiter株菌体超声破碎,上清液经离子交换柱层析及凝胶过滤,得到纯化轴丝。该轴丝经SDS—PAGE检测分析,所得结果与丹麦参考品一致,分子量在3～4万之间,与文献报道相同。经电镜观察,产物均匀,未被杂质污染。按上述方法提取,3克湿重菌体最终可得2毫克左右轴丝蛋白。     

旋流器排口比对固粒轴向流场的影响

通过对ＰＤＡ测得的不同条件下的轴向场的分析，提出了水力旋流器内固相颗料向速度场的新的分析概念。并对测得的数据进行计算机拟合，得出了各区域内颗粒轴向速度的计算公式，为固相颗粒运动轨迹的计算提供了依据。     

离心泵叶轮轴面图的绘制

提出了一种用简单的几何分析与少量的数值计算相结合进行叶轮轴面投影图的绘制的方法,可用优化设计方法完成对流道型线进行反复的检验一调整、修改,以取得较为理想的叶轮轴面投影图.     

液液旋流器内径向速度分布计算

根据实测得到的轴向速度分布的数据及其规律,通过取控制体内质量守恒的方法,计算得到了导叶式液液旋流器内的径向速度分布及其规律,发现与相关学者的实测结果基本一致。     

AXIAL DISPERSION OF LIQUID IN MOBILE-BED CONTACTING

Axial dispersion of liquid in Mobile-Bed Contacting (MBC) was investigated employing transient-response technique with impulse input of NaCI tracer. Experiments were performed in a 0.195 m ID column. Three different packing diameters (15, 19.5 and 32 mm) and three different static bed heights (0.1, 0.195 and 0.3 m) were used. Gas flow rate was varied between 3.02 and 4.05 kg/m²/s and liquid flow rate from 2.4 to 10.4 kg/m²/s.

Transfer function analysis of data yielded that Peclet number was practically independent of liquid and gas flow rates and static bed height but depended on packing size only. A simple correlation for Peclet number was developed     

Estimation of axial dispersion in pulsed-plate extraction columns

In this study, a two-region physical model was used to quantitatively estimate axial dispersion in pulsed-plate extraction columns, considering the operating conditions, geometry parameters and the physical properties of the experimental system. The calculated results fit the experimental axial dispersion coefficients well in nine geometries of pulsed-plate columns. This model is of importance to the design and scale-up of pulsed-plate extraction columns.