离心泵流量在油田生产实际中的确定

根据离心泵在工作时的电流I及压力p,利用H-Q离心泵的性能曲线法、理论计算法或容积法,可以简便快捷地确定离心泵的流量,为油田合理安排生产提供科学依据。

离心泵流量在生产实际中的确定

根据离心泵在工作时的电流I及压力P,利用H-Q离心泵的性能曲线、理论计算、容积法,简便快捷地确定离心泵的流量,为合理安排生产提供科学依据。

大流量自吸离心泵机组轴与曲轴的模态分析

为研究大流量自吸离心泵机组轴与曲轴的振动特性,基于ANSYS有限元分析软件对大流量自吸离心泵机组轴与曲轴的模态特性进行研究,分析了大流量自吸离心泵机组轴与曲轴前5阶振型图及固有频率,并对其各阶固有频率对应的临界转速进行研究.研究表明,大流量自吸离心泵机组轴在支撑间距以及形式的影响下,主要体现出扭曲振动,且第4阶发生了2次扭转变形,呈现对称变化分布.与此同时,大流量自吸离心泵机组轴的设计转速为2 200.00 r/min,而大流量自吸离心泵机组轴的最低临界转速达到2 848.07 r/min,高于实际转速2 200.00 r/min,从而避免了发生共振的可能.采用合理的结构设计可以有效地避免大流量自吸离心泵机组轴与曲轴发生共振,通过模态分析得到振型图和动画显示,清晰地展现出大流量自吸离心泵机组轴与曲轴的动态特性,为系统的安全运行、振动分析以及结构的优化设计提供重要的理论依据.

超小流量气液两相流离心泵数值分析及优化设计

本文应用计算流体力学(CFD)的方法研究了气液两相流对离心泵性能的影响。通过对设计工况三种不同含气率时的内部流动进行模拟计算,结果表明,含气率增大会导致泵扬程、效率下降。在此模拟分析基础上,对泵进一步优化设计,通过对比分析,得出在叶轮开设回流孔的方法可以有效改善两相流工况,明显提高了泵扬程、效率。

小流量离心泵长寿命结构设计及分析

对低比速、小流量的离心泵的长寿命设计进行了研究,通过对结构和轴承进行优化设计,极大地提高了工作寿命,样机已经连续正常工作了7年。

高扬程大流量离心泵CFD水力优化设计

选哈电A934模型叶轮作为对象叶轮,以预定的泵扬程流量特性(H-Q)为目标参数,在保证出口角不变的情况下,将对象叶轮出口直径延拓到目标叶轮直径,形成待优化的目标叶轮.使用CFX-TASCFlow软件进行改型设计,针对干河泵站最大扬程、最小扬程以及设计扬程对应的工况点,优化叶轮的轴面形状、叶片数量、叶片翼型以及进出口安放角等参数,直至CFD预测的H-Q特性接近或达到预期的目标,获得满足目标参数的目标叶轮.在此基础上,使用Ansys CFX对目标叶轮进行全通道水力设计,优化流道几何参数,匹配进水管、固定导叶以及蜗壳的几何形状,改善泵进出口区域的流场特性.在哈尔滨电机厂有限责任公司高水头试验II台上进行的模型试验表明,基于CFD技术开发的新型高扬程大流量离心泵在高海拔地区复杂工况条件下,扬程、流量、效率、空化性能等指标均达到了预定的设计目标.

矿用小流量离心泵空化实验研究

针对矿用小流量离心泵,采用可视化实验的方法对离心泵性能及空化特性进行了研究,首先对离心泵性能曲线进行了测定,然后对其空化特性进行了实验,结果表明,随着流量的增加,离心泵扬程下降;在空化特性实验中,采用高速相机对空化过程进行了捕捉,结果表明,空化现象最先出现在离心泵进口处的叶片的吸力面位置,并且由空化产生的气泡溃灭速度很快。

小流量高扬程离心泵设计中应注意的问题探讨

小流量高扬程离心泵的特点:扬程曲线易出现驼峰、效率偏低、大流量易过载、抗汽蚀性能差。本文针对这些特点,分析问题产生的原因,探究设计中如何通过调整各个设计参数来消除或减缓上述问题。

低比转速离心泵压力脉动特性研究

为了降低压力脉动对低比转速离心泵产生的不利影响,在固液两相流条件下,对离心泵内的压力脉动(尤其是隔舌处的压力脉动)以及径向力进行了研究。首先,以一台n_(s)为66的低比转速离心泵为研究对象,利用软件构建了离心泵三维仿真模型,并对模型进行了网格划分;然后,选用了Mixture多相流模型和RNG k-ε湍流模型作为计算模型,在离心泵叶片、蜗壳以及隔舌处设置了监测点,并设置了计算方案;最后,采用ANSYS CFX软件,通过数值模拟的方法,对低比转速离心泵内部各监测点的压力脉动和径向力规律进行了研究,以得到离心泵内颗粒粒径、颗粒浓度和离心泵流量对离心泵压力脉动特性的影响规律。研究结果表明:当d=1.0%时,随着颗粒粒径增大,各监测点的压力脉动幅值减小,叶轮处径向力总体下降,蜗壳处径向力总体上升;当d=0.5 mm时,随着液体浓度增加,离心泵内压力脉动幅值整体呈上升趋势,但隔舌处略有减小,叶轮处所受径向力不断增加,蜗壳处径向力减小;离心泵隔舌处监测点的压力脉动主要出现在叶频及其倍频处,叶片监测点处的压力脉动主要出现在小频率区间内,因此,适当减小离心泵内颗粒粒径,增加颗粒浓度及流量可以降低隔舌处的压力脉动。

大型自吸离心泵设计及试验研究

基于大流量自吸离心泵在结构上创新的设计了自吸系统,该系统主要由射流和排气装置组成,实现了大流量离心泵的自吸性能。对大流量自吸离心泵的性能进行了检测,结果表明,泵的各项指标都满足设计要求,扬程45.22 m,效率72.79%,自吸高度5.3 m时,自吸时间为62 s;自吸高度8.1 m时,自吸时间为173 s,自吸时间小于国家标准规定值。该泵设计合理,效率高,性能曲线平坦,高效率区宽。该泵的研制成功对于城市排涝、矿山排水、农业大型排灌具有重要现实意义。

DY85-67*6多级离心泵轴瓦温度异常分析

我单位一台DY85-67*6型号多级离心泵在运行过程中,轴瓦温度异常升高;对其解体分析,查找出故障原因,及时作出调整,避免该型号离心泵在日后运行过程中出现类似问题。

引进的氯乙烯单体进料泵失效分析及改造

通过对引进的输送氯乙烯(VCM)单体的多级离心泵平衡装置及机械密封失效原因进行分析,提出了对该小流量多级离心泵的改造方案,解决了该泵失效问题。

Design and Experimental Analyses of Small-flow High-head Centrifugal-vortex Pump for Gas-Liquid Two-phase Mixture

The design method of small-flow high-head centrifugal-vortex pump was presented. This pump, configured with inducer, complex-centrifugal impeller and open-vortex impeller, was put forward to deliver gas-liquid two-phase mixture. An HTB-5/60 type sample pump was developed and tested on a closed-loop test rig. Experimental studies on performance and cavitation tests for gas-liquid two-phase mixture were carried out compared with pure-water experimental results. Also the effect of gas phase on pump was analyzed and discussed. The experimental results show that performance and cavitation characteristics of the sample purnp deteriorates progressively with increasing volume fraction of gas. When the total capacity Qm is between 4.5 m^3·h^-1 and 6 m^3·h^-1 and the gas flow rate qg below 0.66 m^3·h^-1, or qg/Qm is lower than 15%, the characteristic curves are approximately parallel to those in pure water test, but the performance deteriorates sharply until an abrupt flow-cutting at a critical volume fraction of gas. This pump is found suitable for transporting gas-liquid two-phase mixture when working around rated capacity of 5 m^3·h^-1 with qglQm below 15%.

Left Ventricle Failure and Blood Flow Estimation for Centrifugal Blood Pumps

This paper shows the blood flow control （FwC） performance to adjust rotational speed of an ICBP （implantable centrifugal blood pump） in order to provide an adequate flow to left ventricle in different patient conditions. ICBP is a totally implantable LVAD （left ventricular assist device） with ceramic bearings developed for long term circulatory assistance. FwC uses PI （proportional-integral） control to adjust rotational speed in order to provide blood flow. FwC does not use sensor for feedback, as there is an estimation system to provide blood flow measurement. Control strategy has being studied in a HCS （hybrid cardiovascular simulator） as a tool that allows the physical connection of ICBP during evaluation. In addition, HCS allows changes of some cardiovascular parameters in order to simulate specific heart disease： ejection fraction （10-25%） and heart rate （50-110 bpm）. FwC was able to adjust blood flow with steady error less than 2%. Results demonstrated that FwC is adequate to LVAD control irL different left ventricle failure conditions.

Unsteady Flow Characteristic of Low-Specific-Speed Centrifugal Pump under Different Flow-Rate Conditions

To investigate the unsteady flow characteristics in centrifugal pump, the flow field in a low-specific-speed centri- fugal pump with complex impeller is numerically simulated under different conditions. The RNG r-e turbulence model and sliding mesh are adopted during the process of computation. The results show that the interaction be- tween impeller and volute results in the unstable flow of the fluid, which causes the uneven distribution of pres- sure fluctuations around the circumference of volute. Besides the main frequency and its multiple frequency of pressure fluctuations in the centrifugal pump, the frequency caused by the long blades of complex impeller also plays a dominant role in the low-frequency areas. Furthermore, there exists biggish fluctuation phenomenon near the tongue. The composition of static pressure fluctuations frequency on the volute wall and blade outlet is similar except that the fluctuation amplitude near the volute wall reduces. In general, the different flow rates mainly have influence on the amplitude of fluctuation frequency in the pump, while have little effect on the frequency compo- sition.

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.

PIV measurement on internal instantaneous flows of a centrifugal pump

In this paper,the internal flow field in a centrifugal pump working at the design flow rate operating condition has been measured using the particle image velocimetry(PIV)technique with the fluorescent particles and the index-matched fluid technology.The index-marching fluid with the same refractive index as the transparent material has been prepared and applied in the present test of pump with geometrical complex walls.The comparison between velocity distributions of PIV results both with and without fluorescent particles,as well as with and without index-marching fluid are conducted to find the differences.The DES(Detached Eddy Simulation)has been employed to calculate the three-dimensional unsteady turbulent flow in the pump to examine and to certify the PIV measurement results.The DES results of instantaneous flow velocity fields agree with PIV test results with fluorescent particles and index-marching fluid.It is necessary to perform the PIV measurement of pumps with fluorescent seeds and index-marching fluid in order to get exact results.The experimental results show the distributions of velocity,steamlines,and the principal Reynolds normal stress(PRNS)and the principal Reynolds shear stress(PRSS).

Flow Instability of a Centrifugal Pump Determined Using the Energy Gradient Method

The stability of the centrifugal pump has not been well revealed because of the complexity of internal flow. To analyze the flow characteristics of a centrifugal pump operating at low capacity, methods of numerical simulation and experimental research were adopted in this paper. Characteristics of the inner flow were obtained. Standard k-s turbulence models were used to calculate the inner flow of the pump under off-design conditions. The distri- bution of the energy gradient function K was obtained by three-dimensional numerical simulation at different flow rates. The relative velocity component was acquired from the absolute velocity obtained in particle image velocimetry. By comparing with experimental results, it was found that flow instability occurs at the position of maximum K. The flow stability reduces with an increasing flow rate. The research results provide a theoretical basis for the optimization design of a centrifugal pump.