螺旋流恒压泵内部流场分析及实验研究

螺旋流恒压泵是一种可自恒压输送水、石油产品和化工液体等的新型泵种。为得到螺旋流恒压泵内部流场的速度、压力分布情况,运用CFD软件进行有限元数值仿真,模拟型号为LXB 0.8/40-125-80-230的螺旋流恒压泵在实际工作情况下泵内部流场的分布情况,得到恒压泵在不同流量情况下的压力云图及速度矢量云图,对得到的数据进行相关计算,得到水泵的流量-扬程曲线与流量-效率曲线。为验证数值仿真的准确性,通过水泵试验微机测试系统对LXB 0.8/40-125-80-230螺旋流恒压泵进行性能测试实验,得到其性能曲线,将数值仿真与实验得到的性能曲线进行比较,结果证明,在误差允许范围内,水泵的出口压力、扬程与效率基本一致,充分说明数值仿真结果的正确性与可靠性。该研究为螺旋流恒压泵的内部流场数值仿真分析及实验研究提供了实验及理论指导,为设计螺旋流恒压泵提供了理论数据。     

低比转速双吸泵叶轮的几何参数对外特性的影响

对某比转速为56的双吸离心泵叶轮进行改进,并利用CFD软件分析不同的改进方案对水泵外特性的影响。具体是通过改变叶轮进口直径Dj、出口直径D2、出口宽度b2、叶片出口角β2以及叶片数Z等参数设计了6个方案,采用SSTk-ω湍流模型对各方案进行不同工况下的定常数值模拟。模拟得到各方案的外特性曲线,并对扬程、效率进行比较分析,同时分析泵内部流场的压力和速度分布规律。     

水泵模型内部流场PIV测试研究

本文采用PIV(粒子图像速度仪)测试系统来测量水泵模型内部流场的速度分布情况,同时采用NUMECA软件对试验工况进行数值计算。在试验前,对泵壳改造的可行性进行了性能计算验证,对可视化试验部件的强度进行了应力分析。在试验中共选取了4个转速,在每个转速下分别选取3个流量工况,每个工况测量3个流场截面。通过试验测得的整泵性能和泵内流场速度分布特性均与数值计算结果良好吻合,为数值计算方法的准确性提供了有力的验证,为计算方法和优化设计方法的改进方向提供了参考。     

叶片仿鲨鱼鳍的导叶式离心泵数值仿真研究

针对导叶式离心泵内部流场流动不稳定的问题,运用仿生学技术和原理对鲨鱼鳍结构做了适当抽象处理,并运用在导叶式离心泵叶轮叶片前缘位置。对叶片仿鲨鱼鳍的导叶式离心泵内部流场进行了数值计算,研究了3个典型工况下离心泵内部流场的流动特性,得到了叶轮和导叶径向力的变化特性,进而分析了离心泵内部流场的湍动能分布规律,并进行了试验验证。研究结果表明:相比原模型,叶片仿鲨鱼鳍的导叶式离心泵改善了泵内流动特性,减小了泵内的湍动能分布;同时降低了叶轮和导叶的径向力,减弱了叶轮与导叶的动静干涉作用;仿鲨鱼鳍叶片减轻了导叶式离心泵内部流动的不稳定,明显提高了泵的扬程和效率等外特性参数。     

移动泵站轴流泵的CFD数值模拟分析

为了研究轴流泵的水力特性,了解不同工况下轴流泵的工作状态并了解其流道内流场特性,基于福建侨龙公司多功能移动泵站轴流泵三维数模,采用fluent软件,选用k-ε湍流模型对模型泵进行数值模拟。通过数值模拟预测了轴流泵的水力特性,并与试验结果进行对比分析,验证了模型准确性。在此基础上,分析了两种不同工况下轴流泵叶轮叶片和导叶表面的压力及速度分布情况,揭示了叶片和导叶的流态以及表面压力在流场中的分布规律。数值模拟结果对深入了解轴流泵内部流动规律和指导水力机械设计有一定的参考价值。     

调速型液力偶合器制动工况流场分析

基于三维多相流动理论和计算流体动力学(CFD),对调速型液力偶合器制动工况下的非稳态两相流动进行数值模拟。结果表明:泵轮流道的压力分布较规律,沿径向成比例逐渐增大,而涡轮流道的内部流动则较复杂;涡轮吸力面出现了小范围的不规则流动现象;中间轴面的速度分布较复杂,涡轮速度小于泵轮速度;Interface中部的低速区出现降低偶合器效率的二次流。对调速型液力偶合器制动工况进行流场分析,揭示其泵轮和涡轮的流场流动规律和特性,有助于指导液力偶合器的设计,提高偶合器的性能。     

氟塑料离心泵性能预测及实验对比分析

以氟塑料离心泵IHF150-125-250为研究对象,运用流场计算软件FLUENT,对2种不同叶片形式叶轮氟塑料离心泵分别进行内部流场的数值模拟,同时在多功能水泵试验台上进行实验测试,将得到的外特性模拟预测数据与实验数据分别对比分析。结果表明,数值模拟的方法可以较好地对泵性能起到预测作用,改进后的扭曲叶片叶轮的氟塑料离心泵的性能优于现有的直叶片叶轮氟塑料离心泵。     

叶片交错布置对双吸离心泵外特性的影响

基于RANS方程、修正后的RNG湍流模型和壁面函数法,采用CFX软件分别对交错布置和对称布置叶片的高转速低比转速双吸离心泵进行了流场为三维不可压缩湍流流场的数值模拟,计算得到了各自的性能曲线以及叶片和蜗壳内的压力和速度分布。通过对比分析可知,采用交错布置叶片能有效降低泵的轴功率,且在设计工况和大流量工况提高泵的效率,能明显改善蜗壳内部流动特性,有效减小泵内气蚀的严重程度,增强离心泵的运行稳定性。     

叶轮背叶片对离心泵性能影响的研究与探讨

以IH100-65-250离心泵为研究对象,开展叶轮背叶片结构对离心泵外特性和轴向力大小影响的研究,利用CFD商用软件Fluent,对带有背叶片结构的离心泵内部流场进行了数值模拟研究,分析了内部流场分布状况,并根据模拟结果绘制水力性能特性曲线和轴向力曲线,选择一组方案进行试验研究,分析论证数值模拟结果的准确可靠性。研究结论可以为设计者自主开发设计轴向力平衡装置提供一定的理论依据。     

离心式水泵内部流场的面元法数值计算

本文介绍了面元计算方法,探讨了离心式水泵内部流场。分别采用了表面分布面元和叶轮骨线上分布面元,研究了不同工况下环量密度的分布规律及泵内部流场的速度分布,分析了泵内产生的倒流现象。数值计算结果表明,这种方法是有效的,为进一步研究泵内三维流场,性能及压力场提供了可能。     

EFFECTS OF SPLITTER BLADES ON THE LAW OF INNER FLOW WITHIN CENTRIFUGAL PUMP IMPELLER

Analysis on the inner flow field of a centrifugal pump impeller with splitter blades is carried out by numerical simulation. Based on this analysis, the principle of increasing pump head and efficiency are discussed. New results are obtained from the analysis of turbulence kinetic energy and relative velocity distribution: Firstly, unreasonable length or deviation design of the splitter blades may cause great turbulent fluctuation in impeller channel, which has a great effect on the stability of impeller outlet flow; Secondly, it is found that the occurrence of flow separation can be decreased or delayed with splitter blades from the analysis of blade loading; Thirdly, the effect of splitter blades on reforming the structure of "jet-wake" is explained from the relative velocity distribution at different flow cross-sections, which shows the flow process in the impeller. The inner flow analysis verifies the results of performance tests results and the PIV test.     

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.     

基于CFX的导叶与叶片间距对泵装置性能改变的研究

基于CFX采用数值模拟方法计算轴流泵导叶进口边与叶轮叶片出口边的平行间距S的变化对泵装置性能的影响。在质量守恒定理和动量守恒定理的基础上,应用Navier-Stoke方程和标准k-ε湍流模型,通过对轴流泵全流道三维湍流数值模拟,求解了导叶出口处的速度场和压力场。分析了S=9mm,S=12mm,S=15mm 3种情况下,流量、扬程、功率和效率的关系,研究了轴流泵导叶进口边与叶轮叶片出口边的平行间距的变化对泵装置性能的影响。     

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.     

单流道泵内部非定常流动特性

将叶片和蜗室作为一个整体,对单流道泵内部三维非定常流动特性进行研究,经分析提出了单流道泵内部三维非定常势流流动和三维非定常湍流流动的数值模拟方法,分别计算了单流道泵内部的速度场、压力场和叶片表面的压力分布,对进一步研究单流道泵内部流动具有重要意义。在此基础上计算了叶轮所受的径向力及其变化趋势,为提高单流道泵运行稳定性提供了理论依据。此外还计算了扬程、平均水功率和效率,并与试验值作对比。尽管忽略粘性使得势流计算得到的速度场在蜗壳的局部区域出现反方向流动,从而导致叶片压力面压力沿展向波动变化,但其性能曲线与试验值变化趋势一致,粘性计算结果与试验值相比,精度较高。     

开式离心叶轮内部流道的数值模拟

采用了多块网格技术、雷诺平均N-S方程和应用S-A湍流模型,对开式直叶高速离心泵叶轮内部流场进行了数值模拟,并对开式高速离心泵作出了试验研究。通过数值模拟与试验研究的结果比较分析,得出该数值模拟方法可以较好地模拟离心泵叶轮内流场,总结出了影响离心泵叶轮内流场和外部特性的因素及其变化规律。为优化设计、提高泵的效率提供了有价值的参考。     

大型斜式轴流泵装置能量特性研究

采用物理模型试验和数值模拟方法,对南方某大型斜式轴流泵装置的流态、能量特性等方面进行了分析和研究。研究表明,效率与流量关系曲线趋势吻合良好且随叶片安放角度的增大,吻合程度增高。在偏离设计工况时,效率误差在±5%之内,而在最优工况附近,误差进一步降低,-2°叶片安放角度时,最优工况效率误差为1.71%。     

3D Particle image velocimetry test of inner flow in a double blade pump impeller

The double blade pump is widely used in sewage treatment industry,however,the research on the internal flow characteristics of the double blade pump with particle image velocimetry(PIV) technology is very little at present.To reveal inner flow characteristics in double blade pump impeller under off-design and design conditions,inner flows in a double blade pump impeller,whose specific speed is 111,are measured under the five off-design conditions and design condition by using 3D PIV test technology.In order to ensure the accuracy of the 3D PIV test,the external trigger synchronization system which makes use of fiber optic and equivalent calibration method are applied.The 3D PIV relative velocity synthesis procedure is compiled by using Visual C++ 2005.Then absolute velocity distribution and relative velocity distribution in the double blade pump impeller are obtained.Test results show that vortex exists in each condition,but the location,size and velocity of vortex core are different.Average absolute velocity value of impeller outlet increases at first,then decreases,and then increases again with increase of flow rate.Again average relative velocity values under 0.4,0.8,and 1.2 design condition are higher than that under 1.0 design condition,while under 0.6 and 1.4 design condition it is lower.Under low flow rate conditions,radial vectors of absolute velocities at impeller outlet and blade inlet near the pump shaft decrease with increase of flow rate,while that of relative velocities at the suction side near the pump shaft decreases.Radial vectors of absolute velocities and relative velocities change slightly under the two large flow rate conditions.The research results can be applied to instruct the hydraulic optimization design of double blade pumps.     

叶片数对螺旋离心泵内部流场影响研究

利用工程上普遍采用的k-ε两方程模型和SIMPLE算法,对单叶片和双叶片螺旋离心泵的内部流场进行了数值模拟.得出了叶轮与蜗壳内的速度分布和压力分布等流场信息,比较了单叶片和双叶片螺旋离心泵的特性曲线,单叶片和双叶片螺旋离心泵内部流场的区别与联系,分析了叶片数对螺旋离心泵内部流动规律的影响.