疏水泵叶轮切割实践

疏水箱配置的两台疏水泵运行中发生超民流，致使电动机频繁烧损。为此，根据疏水泵不同的比转数和不同的结构，选用的叶轮切割方法应不同，论述了具体切割方法和效果。     

循环水泵叶轮切割技术的应用

介绍供暖锅炉循环水泵耗电过多的问题,根据泵的基本理论,讲述叶轮切割的实施方法及经济效益。     

循环水泵叶轮切割技术的应用

介绍供暖锅炉循环水泵耗电过多的问题,根据泵的基本理论,讲述叶轮切割的实施方法及经济效益。     

用切割叶轮的方法解决射水泵电机过热的问题

针对射水泵电机存在过热的问题,提出切割叶轮的解决方法,并进行现场实施.实践证明所提出的方法是成功的,为电厂的安全、稳定和经济运行带来了可观的效益.     

水泵叶轮真实感图形绘制

本文给出了一种在微机上生成水泵叶轮真实感图形的方法，所绘图形具有较强的立体感真实感。这种真实感图形绘制方法和技术为机械产品计算机铺助设计提供了强有力的新手段和工具。     

离心水泵叶轮流埸计算方法研究

本文对准正交面法进行研讨,给出离心水泵叶片上游延伸流面计算方法,用二次函数求数值导数等措施来消除求解过程中多余的数值波动,有利于得到收敛的数值解。为将三元流场计算方法应用于离心水泵叶轮设计提供了更有利的条件。     

离心式水泵叶轮叶片计算机辅助几何设计

本文给出离心式水泵双曲率叶片几何设计方法,用直纹面来作为叶片中弧面和叶片面。用微型计算机计算坐标数据并给出叶片叶轮图形,比传统人工作图设计法速度快,精度高,并可据之进行三元流场计算选型,为研制高性能水泵叶轮创造了条件。     

低加疏水泵出口管道振动诊断与排除

对 5 0MW双抽汽轮发电机组低加疏水泵出口管道振动的情况进行了分析判断 ,提出了解决方案 ,较好地排除了低加疏水泵长期不能投用的问题     

叶轮切削律在调节水泵运行工况中的应用

本文叙述叶轮切削调节水泵的运行工况，提高了水泵的运行效率，取得了较好的经济效益，但通过叶轮发削提高水泵效率是有一定限度的，因此在实际应用中全面考虑确定水泵叶轮的切削量是非常重要的。     

热电厂低加疏水泵节能改造探讨

针对某210MW机组的低加疏水泵自投入运行以来一直存在频繁损坏及出力不足的缺陷,曾多次对该设备进行改造,未见明显改善。通过对疏水泵改造过程中所出现的问题进行深入分析,不断修正改造方案,解决了上述缺陷。改造时从理论上对系统进行了计算与分析,给出了解决问题的改造方向与方法,对于发电企业同类型设备改造具有参考意义。     

Research on performance of centrifugal pump with different-type open impeller

To investigate the influence of impeller type on the performance and inner flow of centrifugal pump, the numeri- cal simulation and experimental research were carried out on the same centrifugal pump with straight-blade and curved-blade open impeller. Based on SIMPLEC algorithm, time-averaged N-S equation and the standard k-e turbulence model, the numerical results are obtained. The pressure distribution in the different type impellers is uniform, while the low pressure area in straight-blade inlet is larger. The vortexes in the passage of impeller exist in both cases. Relative to curved-blade impeller, there are larger vortexes in most of the flow passages except the passage near the tongue in straight-blade impeller. Also some small backflow regions are found at the blade inlet of two impellers. The characteristic curves achieved by numerical simulation basieaUy agree with those by experiment, and straight-blade open impeller centrifugal pump has a better hydraulic performance.     

Performance enhancement of a pump impeller using optimal design method

This paper presents the performance evaluation of a regenerative pump to increase its efficiency using optimal design method.Two design parameters which defme the shape of the pump impeller,are introduced and analyzed.Pump performance is evaluated by numerical simulation and design of experiments(DOE).To analyze three-dimensional flow field in the pump,general analysis code,CFX,is used in the present work.Shear stress turbulence model is employed to estimate the eddy viscosity.Experimental apparatus with an open-loop facility is set up for measuring the pump performance.Pump performance,efficiency and pressure,obtained from numerical simulation are validated by comparison with the results of experiments.Throughout the shape optimization of the pump impeller at the operating flow condition,the pump efficiency is successfully increased by 3 percent compared to the reference pump.It is noted that the pressure increase of the optimum pump is mainly caused by higher momentum force generated inside blade passage due to the optimal blade shape.Comparisons of pump internal flow on the reference and optimum pump are also investigated and discussed in detail.     

Numerical simulation of flow in centrifugal pump with complex impeller

Based on the Navier-Stokes equations and the Spalart-Allmaras turbulence model, three dimensional turbulent flow fields in centrifugal pump with long-mid-short blade complex impeller are calculated and analyzed numerically. The relative velocity and pressure distributions in the flowpart are obtained. It is found that the flow in the passage of the complex impeller is unsymmetrical due to the joint action between volute and impeller. The back-flow region is at inlet of long-blade suction side, near middle part of long-blade pressure side and outlet of short-blade suction side. The flow near volute throat is affected greatly by volute. The relative velocity is large and it is easy to bring back flow at outlet of the complex impeller near volute throat. The static and total pressure rise uniformly from inlet to outlet in the impeller. At impeller outlet, the pressure periodically decreases from pressure side to suction side, and then the static pressure sharply rise near the throat. The experimental results show that the back flow in the impeller has an important influence on the performance of pump.     

Investigations on the flow field in an unshrouded pump impeller geometry

Transient CFD simulations are performed to investigate the flow behaviour inside an unshrouded pump using the SAS method. Two blade designs are compared at two different tip clearances and the results are validated by measurements. The detected vortex structure is visualized by the normalized helicity, further discussed regarding its development and behaviour and finally implicated to the efficiency of the two different blade designs.     

离心泵叶轮内流场数值模拟及分析

基于计算流体力学,对离心泵叶轮内部流场进行了数值模拟。采用有限体积中心格式、时间推进解法以及N-S方程计算。得到了叶轮压力分布等值线、叶轮相对速度矢量以及二次流分布,并进行详尽的分析,揭示了叶轮内部流动情况,为优化叶轮设计提供了理论依据和技术保障。     

Comparison of flow characteristics of enlarged blood pump models with different impeller design

In earlier studies, a 5:1 enlarged pump model of the Kyoto-NTN Magnetically Suspended Centrifugal Blood Pump has been constructed and the gap pressure and wall shear stress have been measured. With the satisfactory results obtained and also as air was the medium used in the previous investigations, another 5:1 enlarged pump model using water as the medium was thus designed and constructed. Five different impeller blade profile designs are used in the present study. By varying (1) the design of the blade profiles i.e. forward, radial and backward, (2) the number of blades used and (3) the rotating speeds, the flow characteristics of the pump are investigated. It is found that the impeller with the higher number of blades used with the forward and straight blade profiles have the best performance.     

热电厂给水泵车削叶轮节能技改应用研究

徐州华美热电公司2×55MW热电厂配备的额定流量为286t/h的锅炉给水泵,运行中暴露出来给水压力富裕量过大,存在着较大的压力节流损失,造成电能浪费等问题,由于电机常处于过负荷状态,影响设备安全。对给水泵的技术改造进行了研究,着重探讨了车削定速给水泵叶轮技改的节能机理,并对其改造方法、改造实例和改造效果进行了分析。     

Experimental study on a centrifugal pump with an open impeller during startup period

Transient performance of fluid machinery during transient operating periods,such as startup and stopping,has been drawn more attentions recently due to the growing engineering needs.In this paper,the transient behavior of a prototype centrifugal pump with an open impeller during rapid startup period is studied experimentally.The variations of the rotational speed,flow rate,head,and shaft power during rapid startup period are recorded in experiments at different discharge valve openings.In addition,the non-dimensional flow rate and head are also used to analyze the transient behavior.The research result shows that the rise characteristic of the rotational speed is not basically changed by working points,while mainly depends on the startup characteristics of the driving motor.Compared with the rapid rise of the rotational speed,the flow rate rises slowly in the initial stage of startup.Moreover,the flow rate lags behind the rotational speed to rise to final stable value,and the delay becomes more severe with the increase of the discharge valve opening.The shaft power impact phenomenon generally exists in the process of startup.The non-dimensional analysis shows that the non-dimensional head is very high at the very beginning of startup,and quickly falls to the minimum,then gradually rises to final stable value,while the non-dimensional flow rate always shows the rise tendency during whole startup period.In conclusion,it is found from the non-dimensional results that the quasi-steady analysis is unable to accurately assess the transient flow during startup period.     

Investigation of the flow in the impeller side clearances of a centrifugal pump with volute casing

The paper is concerned with the fluid flow in the impeller side clearances of a centrifugal pump with volute cas-ing.The flow conditions in these small axial gaps are of significant importance for a number of effects such as disk friction,leakage losses or hydraulic axial thrust to name but a few.In the investigated single stage pump,the flow pattern in the volute turns out to be asymmetric even at design flow rate.To gain a detailed insight into the flow structure,numerical simulations of the complete pump including the impeller side clearances are accom-plished.Additionally,the hydraulic head and the radial pressure distributions in the impeller side clearances are measured and compared with the numerical results.Two configurations of the impeller,either with or without balancing holes,are examined.Moreover,three different operating points,i.e.:design point,part load or overload conditions are considered.In addition,analytical calculations are accomplished to determine the pressure distri-butions in the impeller side clearances.If accurate boundary conditions are available,the 1D flow models used in this paper can provide reasonable results for the radial static pressure distribution in the impeller side clearances.Furthermore,a counter rotating wake region develops in the rear impeller side clearances in absence of balancing holes which severely affects the inflow and outflow conditions of the cavity in circumferential direction.