Numerical and Experimental Investigation of High-efficiency Axial-flow Pump

The experimental investigation of axial-flow pump has been rapidly developed to meet the needs of South-to-North Water Diversion Project of China. Owing to the boundary conditions of hub, blade tip clearance, much of the physical phenomena and laws involved in this complex flow field can＇t be fully determined. The flow characteristics of the high efficiency axial-flow pump have been simulated by RNG k-e turbulence model and SIMPLEC arithmetic based on FLUENT software. Numerical results indicate that the data from the prediction show agreement with the experimental results, static pressure on pressure side of blades increases slightly at circumferential direction with radius increasing, and keep almost constant at the same radial while increasing gradually from inlet to exit on the suction side along flow direction at design conditions. The static pressure, total pressure and velocity at inlet, impeller outlet and vane outlet were measured by a five-hole probe, and a contrastive experiment was done to investigate the influence of hub leakage. The experimental results show that inlet flow is almost axial and the prerotation is very small at various conditions. The meridional velocity and circulation distribution are almost identical at impeller outlet at design conditions due to steady flow and high efficiency. The residual circulation exits at downstream of the guide vane, and the circumferential velocity component increases linearly from hub to tip at small flow rate conditions. Hub leakage in adjustable blades results in the decrease of the meridional velocity and circulation at blade exit near hub. The results of numerical simulation and experiments supply important flow structure information for the high-efficiency axial-flow pump.

Parameter Modeling and Kinematical Simulation for Rotor and Stator of Screw Pump

The research object used in the dissertation was screw pump, which was widely applied in engineering field. The analysis of end face profile formation was completed on its main working components, i.e., rotor and stator. With the purpose of finding optimal parameters to improve the efficiency of screw pump design, the key technologies involved in the parametric modeling of rotor and stator were analyzed. The three-dimensional (3D) design software SolidWorks was used for the secondary development and parametric modeling of rotor and stator. After that the simulation models of different kinds of screw pumps were established based on the cycloid type, variation coefficient, and screw head number. Finally the COSMOSMotion was used to analyze the motion characteristics on the equidistant line of rotor, including velocity and acceleration. This design and modeling method has been used in screw pump enterprises for design and development, laying the foundation for finite element analysis and further optimization of screw pump.

Theoretical study on the pressurization characteristics of disc-seal single screw pump used in high viscosity oily sludge conveying field

The disc-seal single screw pump(DSSP)used in the field of high viscosity oily sludge transport has a huge advantage.However,there is no research on the pressurization characteristics of the DSSP at present,which makes its application limited.In view of this,the pressurization process mathematical model of the DSSP was established based on the geometric model of the pump.By using this model,the pressurization characteristics of DSSP and the influence of working parameters on the pressurization process were studied combined with the principle of back-flow pressurization.Analysis results show that the instantaneous pressurization process could be realized mainly depending on the reflux pressurization from the outlet chamber to the pressurization chamber when the screw rotor rotating angle is located at-5°to+5°.The pressure in the pressurization chamber will increase with the increase of working parameters which include inlet pressure,outlet pressure,screw rotation velocity and dynamic viscosity of fluid medium in the area of flow-back pressurization.The screw rotation velocity and the viscosity of the conveying medium have significant effects on the peak pressure in the pressurization chamber,and the peak pressure in the pressurization chamber is proportional to the screw rotation velocity and the dynamic viscosity coefficient of the conveying medium.The proportional coefficient between the peak pressure and the screw rotation velocity is 6.29×10~4.The proportional coefficient between the peak pressure and the dynamic viscosity of the conveying medium is 6.28×10~6.

Power Stabilization by Windfarm Applied Statistical Model and Pumped Storage Generation Using Archimedean Screw

In this paper, a method of stabilizing electric power by a system which is a combination of wind power generation and pumped storage power generation is proposed. The system operates based on the output predicted value of the windfarm. When the measured windfarm output is larger than the predicted value, the system is pumping up water with surplus power. When the windfarm output is smaller than the predicted value, the system is filling up lack power by hydro generator. Also, since hydro generator works with a start-up delay time, output shortage occurs at this time. To improve output shortage at the time, we estimate the time below the predicted value by a statistical model. As the result, the system succeeded in stabilizing the power and improving the start-up delay time of the hydro generator.

Introduction of the Archimedean Screw Pump to East Asia during the Seventeenth and Eighteenth Centuries

The Jesuits played an important role in the transmission of Western science and technology to China during the seventeenth and eighteenth centuries,though their impact on water technology has received scant attention thus far.As a case in point,Sabatino de Ursis,Society of Jesus熊三拔,in collaboration with the Chinese official Xu Guangqi徐光啟,published in 1612 Hydraulic Methods of the Far West(Taixi shuifa泰西水法),the earliest book in China on Western water-lifting devices,which contained a detailed description of the Archimedean screw pump.While the impact of the Archimedean screw pump in China and Korea remained rather limited,the screw pump was used to drain water from gold mines in the Japanese Sado Island from as early as 1637.This fact became known in the West only in the very late 1800s when hand-colored picture scrolls about the Japanese gold mining process became available.These scrolls show various applications of Archimedean screw,which apparently were made according to the manufacturing instructions in Hydraulic Methods of the Far West.

基于Pumplinx的螺杆泵性能优化仿真研究

为了得到螺杆泵转子直径与定子导程对泵性能的影响规律,基于Pumplinx软件对橡胶定子单头单螺杆泵进行非稳态数值计算求解,在此基础上探究了不同压差条件下无量纲参数T/D对螺杆泵流量、水力效率以及轴向力的影响进行分析并基于此进行性能优化。结果显示,随着T/D的增大,泵流量增加,轴向力基本保持不变,而水力效率先增大后减小,其最优值出现在T/D=4.5时;螺杆泵定子转子啮合区域的泄漏较为明显,且随着T/D的增大泄漏量增多。因此为了得到更高的效率,T/D宜优化至4.5;为了得到更大流量的同时不牺牲效率,T/D宜优化至5.4。此外,数值计算与试验结果较为一致,偏差不超过3.5%,表明该螺杆泵仿真方法具有参考价值。

基于Pumplinx的双螺杆水泵水力特性数值模拟

为提升双螺杆水泵的水力效率,基于型线设计准则,建立上下对称结构、单头螺旋以及集成内外摆线和圆弧的双螺杆水泵型线方程,并根据各段螺杆型线方程绘制完整的螺杆型线曲线.利用SCORG软件生成双螺杆水泵螺杆转子面网格和体网格,基于Pumplinx软件对双螺杆水泵水力特性进行数值模拟,分析其进出口流动区域流态、转子流动区域水压力场和水力特性曲线.理论计算和数值模拟结果表明:研发的新型双螺杆水泵流量参数达到预期设计目标;双螺杆水泵内流态较均匀,无回流或偏流等不良流态;双螺杆水泵水力特性中水流量随扬程增大而减小;当泵主-从动螺杆啮合时,双螺杆水泵转子水压力值沿水流方向逐级增大,在螺杆出口断面处达最大值;在啮合过程中,随着泵扬程增大,螺杆转子表面水压力进入高压区,低压腔数量减少,高压腔数量增多.

Experimental study on inlet vortex in pump sump

In order to study the mechanism of the vortex generation at the bottom of the pump sump below the flare tube,twenty pressure pulsation monitoring points were arranged at the bottom of the pump sump below the flare tube,and the pressure fluctuation experiments were carried out under different flow conditions.The experimental results show that the frequency of pressure fluctuation at the bottom of the pump sump is twice of the rotational frequency of the impeller blade.The vortex below the flare tube is easy to generate under the large flow conditions and mainly concentrates at the right front position below the flare tube.The position of the vortex occurring is corresponding to the position of the low-pressure region below flare tube.

基于阿基米德螺旋转轮的自清洗泵前过滤器设计与试验

为提高泵前过滤器自清洗性能,解决过滤系统频繁中断问题,该研究将阿基米德螺旋转轮应用于泵前过滤器自清洗过程,通过数值仿真与物理试验,结合相关性分析和线性回归分析,探究叶片螺距、叶片角度、叶片数量对阿基米德螺旋转轮转速的影响规律。结果表明:转轮转速随螺距的增加逐渐下降,且降低幅度逐渐上升,随叶片角度和叶片数量的增加转轮转速的提升较小且提升幅度不断减小,对转轮转速影响程度由大到小为螺距、叶片角度和叶片数量。通过TOPSIS法(technique for order preference by similarity to an ideal solution)综合评价得到最佳结构参数组合为:螺距133 mm,叶片角度90°,叶片数量1。优化后水驱式自清洗泵前过滤器开展自清洗试验,结果显示流量经过最初下降阶段后稳定在294.9~296.6 m^(3)/h区间,流量降幅仅为1.13%~1.70%,利用水力驱动阿基米德螺旋转轮带动自清洗装置的滤网清洗效果良好。研究结果可为水驱式自清洗泵前过滤器的结构设计和优化提供参考。

“8”字形盘密封螺旋泵排液特性

圆盘密封螺旋泵具有排量大、磨损小、介质适应性强等优点,但其使用过程中存在振动大、不能实现完全的自驱动等问题。针对这些问题,提出“8”字形盘密封螺旋泵,基于其工作原理构建泵送过程的几何模型,建立“8”字形密封螺旋泵排液体积的数学模型,分析啮合副型面参数对排液过程工作特性的影响机制。结果表明:单个转动周期内螺杆增压段螺槽被密封盘分为两个腔室,“8”字形盘密封螺旋泵排液体积较同半径下的圆盘密封螺旋泵提高了约55.7%;排液体积随密封盘大圆半径、密封盘过渡圆弧半径、螺杆半径变化均呈近似正比例线性关系。

庆城页岩油水平井电潜螺杆泵举升工艺改进及矿场应用

庆城油田是近年来国内探明的首个10亿吨级整装页岩油田,实现规模效益开发对保障国家能源安全具有重要的战略意义。页岩油大平台多井丛三维水平井布井模式造成井眼轨迹复杂,常规有杆举升工艺管杆偏磨矛盾突出,检泵周期不足200 d,且难以满足大规模体积压裂开发初期快速排液的需求,基于“井筒高效举升、全生命周期排采、数智化转型”需要引入了电潜螺杆泵举升工艺。针对应用过程中存在的频繁卡阻、憋堵、机组断裂落井的问题,开展定子橡胶材质改进、定转子配合间隙优化、机组强度升级,完善砂、蜡、气、垢防治工艺配套,极大提升了电潜螺杆泵在页岩油复杂井况的工艺适应性,通过归纳总结各类故障的电参曲线特征,建立了5类电潜螺杆泵常见故障诊断模板,解决了电潜螺杆泵故障诊断困难的问题。经过工艺改进及配套升级,电潜螺杆泵维护性作业频次由2.62次/(口·年)下降至0.60次/(口·年),采油时率由97.5%上升至99.2%,检泵周期由140 d延长至480 d,实现了电潜螺杆泵的成熟应用。

螺杆泵转速对油水旋流分离管流场特性的影响

旋流分离器在井下采油螺杆泵作用下会发生复杂的振动现象,对旋流分离器内部流场造成一定影响。为研究螺杆泵不同转速下旋流分离器内部流场的变化规律,以同井注采工艺中螺杆泵作用下的旋流分离管柱为研究对象,针对振动壁面旋流分离管柱结构及工作特点,基于计算流体动力学方法、计算固体力学方法以及流固耦合理论,建立流固耦合力学模型;利用流固耦合分析方法,对双螺杆泵转动条件下井下旋流分离管柱内速度场、油相分布、涡量及湍动能等流场特性进行分析。分析结果表明:随着螺杆泵转速升高,分离器内切向速度和轴向速度强度逐渐减弱,径向速度的不对称性逐渐加剧,转速的周期性变化还会造成径向速度场分布的偏移;螺杆泵不同转速下旋流分离器内部涡量分布不同,随着转速升高,溢流管以及锥段部分附近相关流场的涡旋明显增强;旋流器溢流口附近油相体积分数会随着螺杆泵转速的升高而减小;不同螺杆泵转动状态下,大颗粒油滴的分布不同。所得结果可为螺杆泵井下旋流分离同井注采系统的设计及螺杆泵的转速设定提供参考。

井下旋流分离管柱的振动特性研究

为研究旋流分离管柱在注入泵和采出泵两螺杆泵抽吸条件下的振动特性,对其进行模态分析和瞬态动力响应分析。结果表明,不同工况下,旋流分离管柱的固有频率有所不同;固定注入泵一端和固定采出泵一端相比,固定采出泵一端各阶固有频率较小;螺杆泵转动引起的激振力和内部流量变化都会导致管柱变形,其中螺杆泵转动对旋流分离管柱变形影响较大;相对于固定采出泵,固定注入泵条件下旋流分离管柱产生的振动位移更大,是旋流分离管柱自身结构和注入泵转速产生更大激振力综合作用导致的结果;控制两个螺杆泵工作状态的时间差,理想情况下可以控制旋流分离管柱的总变形。

工况对双螺杆混输泵振动特性影响实验

为研究工况对双螺杆混输泵振动特性的影响,搭建双螺杆混输泵多通道振动测试系统,测试并分析不同含气率、转速及出口压力下混输泵振动参数。结果表明:排液开始时排液腔瞬时打开诱发射流,射流向竖直向的泵出口偏转从而产生压力脉动并诱发振动,导致泵竖直方向振动加速度有效值高于水平方向和轴向;含气率为7.5%时振动加速度有效值为纯液工况时的1.88倍,随着含气率进一步升高测量值降低;而含气率大于20%时,振动有效值继续升高。在转速为1450r/min时y方向振动加速度有效值是850r/min时的2.95倍;振动加速度有效值随出口压力变化较小。当转速由850r/min升高至1450r/min时,径向垂直方向振动加速度主频由75fn移动至50fn。研究可为提高双螺杆混输泵运行稳定性提供指导。

流热固耦合下间隙对三螺杆泵转子强度的影响研究

针对三螺杆泵工作中产生的流体载荷引起螺杆卡滞问题,分析三螺杆泵齿顶间隙、啮合间隙对螺杆形变的影响。以N-S方程为基础,基于k-ε湍流模型,通过流固耦合传热方法求解三螺杆泵螺杆在流场作用下的位移、应力。研究结果表明:随着齿顶间隙和齿间间隙的增大,螺杆泵内的最大压力和最大温度都逐渐降低;螺杆转子的变形主要集中在进口位置,最大变形为0.107 mm,应力主要集中在主从转子的啮合位置,最大应力为146.82 MPa,主动转子的变形和应力小于从动转子的变形和应力;转子的变形和应力随齿顶间隙、啮合间隙的增大而减小。因此,在满足螺杆泵压缩机比、温升的情况下,应尽可能增大间隙以提高螺杆转子强度。

煤层气L型水平井电潜螺杆泵井清防砂工艺技术创新及应用

套管完井压裂投产的煤层气L型水平井出砂严重,倒置式电潜螺杆泵举升工艺受压裂砂影响故障频繁,影响了连续稳定排采,因此确定了倒置式电潜螺杆泵排采过程中由于压裂砂导致的故障点,并针对性创新应用了井筒内、导流罩及泵内清砂工艺技术,同时优化防砂管柱设计,确保了连续稳定排采。

基于正交试验的全金属单螺杆泵转子最大转矩研究

通过正交试验对全金属单螺杆泵进行流场仿真,收集了在不同因素、不同水平下全金属单螺杆泵转子所受到的最大转子转矩数据,对其进行方差分析。分析结果反映出了各因素与转子最大转矩之间的关系,并判断出不同因素与研究目标的相关性强弱,并通过曲线图反映了这一现象。

双端面机械密封在双螺杆原油泵上的应用

基于原油库拆建工程项目,对双螺杆原油泵原采用的单端面金属波纹管机械密封改造为新型的带泵效环的背靠背双端面机械密封,并配套冷却循环辅助系统,经现场工业考核,背靠背双端面机械密封在双螺杆原油泵上得到良好应用。结果表明,新改造的双端面机械密封彻底解决了原密封存在的摩擦副磨损严重、泄漏量大、使用寿命短等问题,实现了工艺介质的零泄漏并确保设备长周期安全稳定运行。

在原油中老化的螺杆泵定子氢化丁腈橡胶胶料的性能变化研究

研究在原油中老化的螺杆泵定子氢化丁腈橡胶(HNBR)胶料的性能变化。结果表明:随着老化时间的延长,在25℃原油中老化的HNBR胶料的邵尔A型硬度先减小后增大、损耗因子(tanδ)减小;在60和100℃原油中老化的HNBR胶料的邵尔A型硬度和tanδ增大;在25,60和100℃原油中老化的HNBR胶料的拉伸强度和撕裂强度减小;在25和60℃原油中老化的HNBR胶料的拉断伸长率减小、压缩永久变形先减小后增大,在100℃原油中老化的HNBR胶料的拉断伸长率和压缩永久变形增大。随着老化温度的升高和老化时间的延长,HNBR胶料在25%压缩应变下的压缩应力减小,但相对于老化时间,老化温度对HNBR胶料的压缩应力影响较大。