用自相关分析检测离心泵汽蚀的试验研究

汽蚀发生时,离心泵进口原有压力脉动成分和强度会发生变化,本文对离心泵进口压力进行了测试并进行了自相关分析,分析认为,通过自相关运算,能够提取压力脉动信号中的两种汽蚀特征量,所得结论有助于离心泵汽蚀的检测。     

离心泵的结构特征及维护技术分析

企业生产的过程中,如果离心泵产生故障,不但会影响生产线的正常运行,严重的还可能会引起安全事故。因此,为了更为安全的进行生产,企业必须重视离心泵的维护管理和检修工作。本文基于离心泵的结构特点,分析并讨论了离心泵的日常维护方法,并且对常见故障的检修做了详细的分析。     

离心泵诱导轮的数值模拟

本文概述了离心泵空化（汽蚀）产生的原因及改进的方法。分析了诱导轮在改善离心泵空化（汽蚀）特性上的独特作用,对雳导轮和离心叶轮的结构和性能匹配进行l『研究。并对同一离心泵叶轮分别加装一级诱导轮、两级诱导轮和三级诱导轮的不同结果进行了对比分析。对比分析表明,诱导轮在改善离心泵空化（汽蚀）性能方面效果明显。     

浅谈石油化工装置用多级离心泵的质量控制

本文分析了石油化工装置用多级离心泵质量要素,并结合作者长期从事石油化工用多级离心泵的采购质量管理经验,从泵的设计、制造、安装等方面进行分析,得到了石油化工用多级离心泵质量控制要点与方法。     

离心泵叶轮切割定律论述

随着离心泵应用范围越来越广,离心泵的叶轮切割在生产、生活中应用的频率越来越高。国内外存在许多不同的离心泵切割定律,本文以比转速200的单级单吸离心泵为例,应用不同切割定律进行计算,计算结果与试验结果进行对比分析,发现理论计算偏差较大,本文针对该现象产生的原因进行分析,并对切割公式进行了理论推导,为离心泵的叶轮切割奠定理论基础。     

离心泵零部件常见易损原因及解决措施

本文对离心泵在运行中一些零部件易损的原因进行了分析,并提出了相应的解决措施,从而降低离心泵的运行费用、延长使用寿命,使离心泵的最佳功能得到充分的发挥,减轻用户的经济负担。     

油田用离心泵汽蚀性能的数值分析与试验

为了准确预测油田用离心泵的汽蚀性能,本文使用计算流体力学软件Fluent中的Mixture多相流模型与汽蚀模型相结合对离心泵内的汽蚀现象进行数值模拟,并通过油田用离心泵汽蚀性能试验对数值计算结果进行验证。在验证模拟结果可行的基础上,对离心泵结构及工作参数对其汽蚀性能的影响进行了数值分析,结果表明:叶轮采用6叶片较4和8叶片汽蚀性能更优;叶轮转速越小,离心泵抗汽蚀性能越好;离心泵进口流量越大,抗汽蚀性能越差。     

离心泵内部不稳定流场压力脉动特性分析

离心泵内部不稳定流场压力脉动对于机组稳定性而言有着十分重要的影响作用。我们通过相关技术的分析能够对离心泵内的相关参数进行掌握和了解,并对压力脉动特性进行数据分析和阐述。对于离心泵而言,随着其近年来的应用与发展人们对离心泵的的压力脉动特性的重视度越来越高,在本文的研究和论述中,将对离心泵内部不稳定流场压力脉动特性进行分析。     

卧式多级离心泵故障分析及解决措施探讨

离心泵是现代工业生产当中常见的设备,本文分析了卧式多级离心泵发生故障的原因,并结合笔者多年工作的经验,探讨了相应的解决措施。     

刍议离心泵常见故障原因及维护保养

离心泵是一种常见的液体输送设备，具有极强的实用性，在很多行业获得了广泛应用。但实践应用环节中，很容易出现一些常见故障，造成离心泵故障，进而影响具体运输工作。要想合理确保离心泵的正常运转，本文对离心泵常见故障的判断方法进行分析，并且对离心泵日常维护方法展开讨论。     

提高离心泵可靠性的若干措施

现代化的生产中需要越来越多的高流量、高扬程离心泵,并对这些离心泵的可靠性也提出了更高的要求。故对影响离心泵可靠性的原因进行了分析,从离心泵的设计制造环节、安装维护角度,以及选型、操作、检修等过程进行了可靠性研究;探讨了提高离心泵可靠性的措施,为离心泵的设计研究提供依据,对于指导设计具有实用意义。     

Influence of blade wrap angle on centrifugal pump performance by numerical and experimental study

The existing research on improving the hydraulic performance of centrifugal pumps mainly focuses on the design method and the parameter optimization. The traditional design method for centrifugal impellers relies more on experience of engineers that typically only satisfies the continuity equation of the fluid. In this study, on the basis of the direct and inverse iteration design method which simultaneously solves the continuity and motion equations of the fluid and shapes the blade geometry by controlling the wrap angle, three centrifugal pump impellers are designed by altering blade wrap angles while keeping other parameters constant. The three-dimensional flow fields in three centrifugal pumps are numerically simulated, and the simulation results illustrate that the blade with larger wrap angle has more powerful control ability on the flow pattern in impeller. The three pumps have nearly the same pressure distributions at the small flow rate, but the pressure gradient increase in the pump with the largest wrap angle is smoother than the other two pumps at the design and large flow rates. The pump head and efficiency are also influenced by the blade wrap angle. The highest head and efficiency are also observed for the largest angle. An experiment rig is designed and built to test the performance of the pump with the largest wrap angle. The test results show that the wide space of its efficiency area and the stability of its operation ensure the excellent performance of the design method and verify the numerical analysis. The analysis on influence of the blade wrap angle for centrifugal pump performance in this paper can be beneficial to the optimization design of the centrifugal pump.     

离心泵叶片修正对运行效率影响分析

离心泵被广泛应用于舰艇,是其能源的重要消费者。由于舰艇设备众多,所有设备的效率包括离心泵的效率都是非常重要的。文中介绍了一种提高离心泵效率的方法。当需要调整离心泵的扬程和流量时,泵制造商或者用户对叶轮进行修正是一种常见的做法。修正后的泵和初始泵基本类似,因为只改变了泵的一些参数,其他结构都没变。尽管如此,有效的相似性假设还需要一系列实验验证,文中修正了一个低比转速的离心泵并进行了测试。     

Effects of Blade Number on Characteristics of Centrifugal Pumps

The blade number of impeller is an important design parameter of pumps,which affects the characteristics of pump heavily.At present,the investigation focuses mostly on the performance characteristics of axis flow pumps,the influence of blade number on inner flow filed and characteristics of centrifugal pump has not been understood completely.Therefore,the methods of numerical simulation and experimental verification are used to investigate the effects of blade number on flow field and characteristics of a centrifugal pump.The model pump has a design specific speed of 92.7 and an impeller with 5 blades.The blade number is varied to 4,6,7 with the casing and other geometric parameters keep constant.The inner flow fields and characteristics of the centrifugal pumps with different blade number are simulated and predicted in non-cavitation and cavitation conditions by using commercial code FLUENT.The impellers with different blade number are made by using rapid prototyping,and their characteristics are tested in an open loop.The comparison between prediction values and experimental results indicates that the prediction results are satisfied.The maximum discrepancy of prediction results for head,efficiency and required net positive suction head are 4.83%,3.9% and 0.36 m,respectively.The flow analysis displays that blade number change has an important effect on the area of low pressure region behind the blade inlet and jet-wake structure in impellers.With the increase of blade number,the head of the model pumps increases too,the variable regulation of efficiency and cavitation characteristics are complicated,but there are optimum values of blade number for each one.The research results are helpful for hydraulic design of centrifugal pump.     

EXPERIMENTAL STUDY ON HIGH-SPEED CENTRIFUGAL PUMPS WITH DIFFERENT IMPELLERS

The experimental study is carried out on high-speed centrifugal pumps with three different impellers. The experimental results and analysis show that high-speed centrifugal pumps with a closed complex impeller can achieve thehighest efficiency and the lowest head coefficient followed by those with half-open impeller and open-impeller, and canobtain much easily stable head-capacity characrastic curve, while those with a half-open complex impeller can't. Thecharacteristic curve with a open impeller is almost constant horizontal line before dropping sharply. The results also showthat the axial clearance between pump casing and impeller can influence greatly on the performance of centrifugal pumps.     

长输管道多工况输油泵国产化应用研究

根据长输管道下游炼厂的需求,本文论述的多工况高扬程单级双吸离心泵需满足1400、1100和650m3/h 3种运行工况。本文对其国产化应用进行了研究分析,着力解决了如下问题:国产泵组在偏离额定工况下的振动超标,泄漏、自润滑轴承温度高等问题。结果表明,该泵结构合理、流量范围宽,满足多工况工艺生产要求,振动、泄漏、温度等主要指标达到同类进口泵技术水平。该泵的成功应用,对提高长输管道输油泵国产化制造水平,优化离心泵的设计、选型、维护管理等有一定的借鉴意义。     

炼厂大型多级离心泵典型故障案例及分析

结合炼厂运行实际,对大型离心泵典型故障及其变化过程进行了论述,通过振动等状态监测以及数据分析,可以有效监测故障的发生。     

Evaluation of subgrid-scale models in large-eddy simulations of turbulent flow in a centrifugal pump impeller

The current research of large eddy simulation (LES) of turbulent flow in pumps mainly concentrates in applying conventional subgrid-scale (SGS) model to simulate turbulent flow, which aims at obtaining the flow field in pump. The selection of SGS model is usually not considered seriously, so the accuracy and efficiency of the simulation cannot be ensured. Three SGS models including Smagorinsky-Lilly model, dynamic Smagorinsky model and dynamic mixed model are comparably studied by using the commercial CFD code Fluent combined with its user define function. The simulations are performed for the turbulent flow in a centrifugal pump impeller. The simulation results indicate that the mean flows predicted by the three SGS models agree well with the experimental data obtained from the test that detailed measurements of the flow inside the rotating passages of a six-bladed shrouded centrifugal pump impeller performed using particle image velocimetry (PIV) and laser Doppler velocimetry (LDV). The comparable results show that dynamic mixed model gives the most accurate results for mean flow in the centrifugal pump impeller. The SGS stress of dynamic mixed model is decompose into the scale similar part and the eddy viscous part. The scale similar part of SGS stress plays a significant role in high curvature regions, such as the leading edge and training edge of pump blade. It is also found that the dynamic mixed model is more adaptive to compute turbulence in the pump impeller. The research results presented is useful to improve the computational accuracy and efficiency of LES for centrifugal pumps, and provide important reference for carrying out simulation in similar fluid machineries.     

离心泵内部空化流动的定常数值模拟及性能预测

为了研究离心泵内部的空化流动,利用fluent软件中的空蚀模型及混合流体两相流模型,对离心泵的三维湍流空蚀流场进行定常数值模拟,根据模拟计算结果显示的液相和空泡相流动特征,预测了离心泵在设计工况下运行时流道内空化发生的位置和程度;通过分析空蚀发生过程中叶片上的压力分布,揭示出离心泵流道内部流场的内在特性,最后对泵的性能进行了预测,说明数值模拟可以为离心泵在特定工况下运行时的空化性能预测提供依据。     

Performance study based on inner flow field numerical simulation of magnetic drive pumps with different rotate speeds

Magnetic drive pump has gotten great achievement and has been widely used in some special fields.Currently,the researches on magnetic drive pump have focused on hydraulic design,bearing,axial force in China,and a new magnetic drive pump with low flow and high head have been developed overseas.However,low efficiency and large size are the common disadvantages for the magnetic drive pump.In order to study the performance of high-speed magnetic drive pump,FLUENT was used to simulate the inner flow field of magnetic drive pumps with different rotate speeds,and get velocity and pressure distributions of inner flow field.According to analysis the changes of velocity and pressure to ensure the stable operation of pump and avoid cavitation.Based on the analysis of velocity and pressure,this paper presents the pump efficiency of magnetic drive pumps with different rotated speeds by calculating the power loss in impeller and volute,hydraulic loss,volumetric loss,mechanical loss and discussing the different reasons of power loss between the magnetic drive pumps with different rotated speeds.In addition,the magnetic drive pumps were tested in a closed testing system.Pressure sensors were set in inlet and outlet of magnetic drive pumps to get the pressure and the head,while the pump efficiency could be got by calculating the power loss between the input power and the outlet power.The results of simulation and test were similar,which shows that the method of simulation is feasible.The proposed research provides the instruction to design high-speed magnetic drive pump.