离心油泵叶轮切割后效率升高现象

对65Y60型离心油泵进行了一系列输送不同粘度液体的叶轮切割性能实验，实验发现了叶轮切割以后泵效率升高现象，利用水力效率比、容积效率比和机械效率随直径和粘度的变化曲线，分析了效率升高的原因。研究表明，在直径为205mm时，泵效率出现升高现象，效率高与液体粘度有关，较高的液体粘度有助于诱发效率升高。容积效率的升高和机械效率的增大是离心油泵叶轮切割后效率升高的原因。     

输送水时离心油泵不同出口角叶轮切割性能实验

选取常用的65Y60型离心油泵为研究对象,对叶片出口角分别为15°、25°、45°和60°的4个叶轮进行切割试验,研究了泵性能随叶片出口角和叶轮直径的变化规律。研究表明,扬程曲线和轴功率曲线随叶轮直径的减小而下移。当叶轮直径切割到205mm时,泵效率出现不降反而升高现象;以后,随直径的减小而迅速下降。最优工况流量、扬程和轴功率随叶轮直径的减小而下降。叶片出口角对滑移系数、水力效率和机械效率的影响较大,对容积效率的影响较小。叶轮直径对水力效率和机械效率的影响较大,对滑移系数和容积效率的影响较小。切割指数同时受叶轮直径和叶片出口角的影响。对小出口角叶轮,流量切割指数、扬程切割指数和轴功率切割指数随叶轮直径的减小而下降;对大出口角叶轮,流量切割指数、扬程切割指数和轴功率切割指数随叶轮直径的减小而升高。效率切割指数随叶轮直径的减小而升高,并趋向某个值。由实验结果得到的4个切割指数都与现有的理论值不同。     

离心泵叶轮切割中被忽略的问题

论述了叶轮切割后,导致流道中心与泵体流道中心偏移,从而使水泵效率下降的现象。提出了改变泵体或者叶轮的某些结构尺寸,避免由于叶轮切割造成的流道中心偏移,从而保证泵的高效运行。     

离心泵叶轮切割实践

提出离心泵不同比转速及不同结构叶轮切割计算公式,根据实践结果给出公式的修正系数,论述了具体切割方法与效果。     

单级单吸离心泵叶轮切割量的研究

离心泵这种最常见叶片泵区别于其它种类泵的突出特点是可以通过切割叶轮来扩大工作范围,这样,用有限几台泵就可满足宽广的性能范围要求,从而节省大量设备投资。本文通过分析大量试验数据并结合相关标准,以及多位专家学者的研究结论,提出了不同比转速的离心泵叶轮的允许切割量。提升离心泵叶轮的允许切割量是一个值得研究的新课题。     

离心泵叶轮切割量的确定

介绍了离心泵在三种不同情况下切割叶轮外径时的切割量确定方法。     

离心泵叶轮切割方法及其实用性分析

根据泵的相似理论及切割理论给出几种实用的离心泵叶轮切割方法,并对每种切割方法的使用及实用性进行分析,选出更贴合实际操作的叶轮切割方法,从而更快捷、有效地指导实际生产。     

离心泵叶轮切割

通过实践总结出一种快捷、可靠曲离心泵叶轮切割方法。     

低比速离心泵叶轮切割实践

通过对不同转速的低比速离心泵的叶轮进行切割试验,从而对低比速离心泵叶轮在不同转速下的切割定律加深了解,对实际生产中低比速离心泵性能的准确掌握具有一定的实用意义。     

离心泵叶片型线参数方程的确定

基于固液两相流的边界层理论，建立了离心式固液两相流泵的型线方程。并给出了叶轮的部分参数为已知的条件下确定叶片型线的方法以及计算分析实例。为离心式固液两相叶片泵的设计提供了可靠的理论依据。     

离心泵叶轮叶形检测方法

利用三角函数中角度变化引起对边变化的原理，测量角度的变化，计算出相应的长度变化，间接地测量出离心泵叶轮的叶形。     

Static pressure recovery analysis in the vane island diffuser of a centrifugal pump

The overall performance of a vane-island type diffuser of a centrifugal pump model was obtained by means of directional probe traverses. These measurements were performed in an air model of a real hydraulic pump for five volume flow rates. Directional probe traverses are performed with a classical three-hole probe to cover most of the complete inlet section of the diffuser from hub to shroud and from pressure to suction side. Existing Particle image velocimetry (PIV) measurement results are also used to compare probe measurement results between the inlet and outlet throats of vane island diffuser at mid-span. Some assistance from already existing unsteady calculation, including leakage effects, is used to evaluate the numerical approach capability and to correctly define the mean initial conditions at impeller’s outlet section. Pressure recovery and the measured total pressure loss levels inside this particular vane diffuser geometry are then calculated. Detailed analysis of the flow structure at the inlet section of the vane island diffuser is presented to focus on pressure evolution inside the entire diffuser section for different flow rates. The combined effects of incidence angle and blockage distributions along hub to shroud direction are found to play an important role on loss distribution in such a diffuser.     

离心式叶片泵内三维流场的数值模拟

利用Fluent软件数值模拟了叶轮机械内的三维流动，计算了离心式叶片泵内的速度矢量、压力值和湍流强度。通过数值模拟结果来看，数值模拟方法能真实反映叶轮内部的复杂流动，为叶轮机械的设计和改进提供了理论依据。     

离心式叶片泵内二维流场的数值模拟

建立了离心式叶片泵一维流动的数学模型，利用fluent软件数值模拟了叶轮机械内的二维流动，计算了离心式叶片泵内的速度矢量，压力值和湍流强度。通过数值模拟结果来看，数值模拟方法能真实反映叶轮内部的复杂流动，为叶轮机械的设计和改进提供了理论依据。     

The Lubrication characteristics of the vane tip under pressure boundary condition of oil hydraulic vane pump

The Lubrication Mode of line contacts between the vane and the camring in an oil hydraulic vane pump has been investigated. First, the variations of the radial force of a vane were calculated from previous measurements of dynamic internal pressure in four chambers surrounding a vane. Next, the lubrication modes were distinguished with Hooke’s chart, which is an improvement over Johnson’s chart. Finally, the influence of the boundary conditions in the lubrication region on the fluid film lubrication was examined by calculating the film pressure distributions. The results showed that the lubrication mode of the vane tip exists in the rigidvariable-viscosity region, and that discharge pressure higher than 7 MPa greatly affects the oil film pressure in the small and the large arc section because of the Piezo-viscous effect.     

基于喉部参数控制的离心泵导叶扩散度研究

为研究导叶扩散段无量纲参数对离心泵水力性能的影响,通过控制导叶喉部参数设计出5种导叶扩散度方案,采用雷诺时均N-S方程和RNGκ-ε湍流模型对离心泵进行全流场计算,对比分析了不同扩散度方案对上游叶轮、导叶本身以及下游压水室水力性能的影响,并验证了数值分析的可靠性.研究表明:导叶扩散度对上游叶轮水力性能较大,叶轮效率随导...     

Investigation on complete characteristics and hydraulic transient of centrifugal pump

An improved method was developed to obtain the complete characteristic of centrifugal pump. The conversion formula of complete characteristics is established based on the normal performance curve. An example was presented to illuminate the new method, and the complete characteristic curves of 14SA-10 centrifugal pump were obtained by the new method. The hydraulic transient of the centrifugal pump failure and start-up was simulated by method of characteristics (MOC), which quote the complete characteristics data. The results show that the inversion method is available to obtain the complete pump characteristic curves provided the normal performance curve. For hydraulic transient simulation, more accurate numerical result can be obtained, if the new model is adopted to convert the experimental normal performance curve to complete characteristics curve of centrifugal pump.     

基于Visual C++的离心泵叶轮参数化设计软件的开发

通过对离心式叶片泵的优秀水力模型进行深入的研究，在一元和三元流动理论的基础上给出了叶轮设计中各种参数计算的经验公式；利用Visul C＋＋平台编制了叶轮参数化计算软件，实现了叶轮的参数化设计计算，提高了叶轮设计的准确性和效率；编制了基于Pro／E的三维参数化设计软件。