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.

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.

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.

The effect of water content in crude oil on the tribological behavior of screw pump's stator rubber

It is worthy of studying the effect of water content in crude oil on tribological behavior of stator rubber,because the different water content would affect the swelling and wear of rubber.Compatibility of dewatered crude oil and water was observed after mixture of dewatered crude oil and water(called oil-water mixture)was mechanical stirred and statically placed.Static etching experiment of samples in oil-water mixture was performed using hanging patch test.Wetting contact angle of oilwater mixture on rubber surface was measured by contact angle meter.Tribological behavior of samples in mixture was measured using a ring-on-block tester.The result shows that when the water content is less than 15%,water can blend with dewatered crude oil,and oil-water separation happens when water content was more than 15%.With the increasing of water content in crude oil,Wettability of mixture and swelling increment of samples decrease.The wear loss of sample increases after treated by swelling experiment,and FKM owns better wear resistance than NBR.

Computational Study on the Influence of Number of Threads on the Perfor-mance of Single Screw Pump at High Angular Velocities

Fluid flow in a screw pump which rotates at very high angular velocity is numerically analyzed. In the present study, fluid flow in screw pumps under high Reynolds number, of the order of 105, is considered. Screw pump has two major elements, a plain shroud which is a stationary element and a rotating hub with helical grooves contained within the shroud. In this paper, three variants of hubs with different number of thread starts numbering six, eight and twelve in combination with a plain shroud is studied. Each of the three possible combinations are analyzed on the basis of pressure rise developed, efficiency and shaft power. It was seen that pressure rise, efficiency and shaft power increases as the number of threads increases in the range of mass flow rates studied.

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。

“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。

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。

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。

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。

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。

等螺距螺杆真空泵内气体流动的数值模拟研究

应用计算流体力学(CFD)方法对螺杆干式真空泵进行数值模拟计算,建立了针对螺杆干式真空泵流场的分析方法。对泵腔中流动区域进行三维建模,采用SCORG和ANSYS-ICEM软件对转动域和固定域分别进行了网格划分,利用瞬态模拟方法得到了泵内压力场、速度场和温度场的分布情况,并计算出抽气速率等参数。网格无关性分析结果与理论数据对比表明数值模拟结果可靠,符合预期。

基于模糊PID控制的点胶单螺杆泵流量控制方法研究

建立了单螺杆点胶泵流量控制系统数学模型,采用了一种模糊PID控制器以提高系统控制性能,并基于实际系统和Mamdani模糊推理算法确定偏差e,偏差变化ec,输出量K_(p),K_(i),K_(d)的论域变量范围、语言值、隶属度函数、模糊控制规则表,搭建了模糊PID控制器。使用MATLAB/Simulink软件对所搭建的系统控制器进行仿真实验,并通过对比传统PID控制与模糊PID控制的系统阶跃响应图,得出模糊PID控制器的效果最佳,并且具有调节时间快、超调量小、抗干扰强的优点,一定程度上提高了单螺杆泵流量控制系统的稳定性。

不同转子轴向间隙下双螺旋轴流泵的内部流动特性

通过改变两螺旋转子之间的轴向间隙(1、5、10 mm),研究双螺旋轴流泵在不同转子轴向间隙下的内部流动特性。基于CFD模拟平台,采用浸入实体法,运用N-S方程和标准k-ε湍流模型,对不同轴向间隙和不同工况下的瞬态特性进行数值模拟,得到双螺旋泵在不同转子间隙下各过流部件在运转过程中的瞬态流动特性。结果表明:转子间隙为1 mm时泵的扬程最高,增大转子间隙(5和10 mm)泵的扬程依次减小;1 mm间隙下泵的升压性能最好,但流体在刚进入转子域出现了明显的负压现象,间隙增大后转子内抗堵塞能力增强,负压现象得到改善;双螺旋轴流泵的主要泄漏区域在转子啮合区,随着转子轴向间隙的增大,啮合区的速度增大,出现较明显的泄漏;双螺旋泵的扬程与流量成反比,随着设计流量的增大,3种间隙泵的扬程均逐渐减小。

基于LSTM-PNN神经网络的电潜泵故障诊断方法

针对电潜螺杆泵故障预测中发生故障难以及时发现、发现难以准确判别故障类型等问题,提出一种基于深度学习长短期记忆网络(LSTM)结合概率神经网络(PNN)的电潜螺杆泵故障预测方法。以LSTM网络为回归模型,使用时间序列法预测故障信号的未来趋势,利用小波包分解螺杆泵的故障信号,提取其中的故障特征,再结合油压、产量等多个工作参数,构建电潜螺杆泵的故障特征向量,并凭借PNN网络判别预测信号故障类型。收集新疆油田120组故障数据作为数据集对预测模型进行训练,从中取出90组数据作为故障数据库对模型进行训练,取出30组数据作为测试组测试模型准确率,使用LSTM-PNN神经网络预测模型分别对两组数据进行电潜螺杆泵故障预测。结果表明:预测前提取故障信号特征可有效提高电潜螺杆泵的故障预测精度,较常规电潜螺杆泵故障预测方法,LSTM-PNN网络预测具有更高的准确率且准确率提升了3%~16%。

螺杆泵斜-平面固定瓦推力轴承润滑特性分析

为了提升润滑油系统可靠性,避免轴承磨损,采用CFD分析螺杆泵斜-平面固定瓦推力轴承的润滑特性。计算该螺杆泵螺杆轴向力,得到油膜承载力数值范围;采用有限差分法得到油膜压力分布与厚度分布,采用有限体积法仿真分析不同油膜厚度、不同进油温度时轴承的压力场。仿真结果表明:温度通过影响润滑油黏度对轴承压载产生影响,当油膜厚度固定时,进油温度越低,润滑油黏度越大,轴承所受压载越大;当进油温度一定时,油膜厚度降低,则承载能力增加。因此,在低温启动滑油泵时,油膜由薄变厚平衡螺杆轴向力的过程中,轴承压载可能会超过许用压载,从而导致轴承磨损。

基于MATLAB/GUI 的真空泵抽速曲线预测计算

从工程实际应用的角度出发,以螺杆真空泵转子的几何特性和螺杆真空泵内部的泄漏模型为基础,建立螺杆真空泵内部工作过程的数学模型,借助MATLAB软件,采用四阶龙格-库塔(Runge-Kutta)法将每次微分方程求解结果作为初始条件反复迭代求解,依据MATLAB/GUI界面设计了一款可以快速计算螺杆真空泵抽速曲线的应用程序。使用该程序对多种螺杆真空泵进行了抽速曲线的预测计算,并根据算例结果对程序进行了完善。