Cavitation of a Submerged Jet at the Spherical Valve Plate/Cylinder Block Interface for Axial Piston Pump

The spherical valve plate/cylinder block pair has the advantages of strong overturning resistance and large bearing area.However,the configurations of the unloading and pre-boosting triangular grooves on the spherical valve plate are different from those in the planar valve plate,resulting in special cavitation phenomenon on the spherical port plate pair.In order to study cavitation characteristics of spherical port plate pair,a dynamic CFD model of the piston pump including turbulence model,cavitation model and fluid compressibility is established.A detailed UDF compilation scheme is provided for modelling of the micron-sized spherical oil film mesh,which makes up for the lack of research on the meshing of the spherical oil film.In this paper,using CFD simulation tools,from the perspectives of pressure field,velocity field and gas volume fraction change,a detailed analysis of the transient evolution of the submerged cavitation jet in a axial piston pump with spherical valve plate is carried out.The study indicates the movement direction of the cavitation cloud cluster through the cloud image and the velocity vector direction of the observation point.The sharp decrease of velocity and gas volume fraction indicates the collapse phenomenon of bubbles on the part wall surface.These discoveries verify the special erosion effect in case of the spherical valve plate/cylinder block pair.The submerged cavitation jet generated by the unloading triangular grooves distributed on the spherical valve plate not only cause denudation of the inner wall surface of the valve plate,but also cause strong impact and denudation on the lower surface of the cylinder body.Finally,the direction of the unloading triangular groove was modified to extend the distance between it and the wall surface which can effectively alleviate the erosion effect.

Effects of Meridional Flow Passage Shape on Hydraulic Performance of Mixed-flow Pump Impellers

During the process of designing the mixed-flow pump impeller, the meridional flow passage shape directly affects the obtained meridional flow field, which then has an influence on the three-dimensional impeller shape. However, the meridional flow passage shape is too complicated to be described by a simple formula for now. Therefore, reasonable parameter selection for the meridional flow passage is essential to the investigation. In order to explore the effects of the meridional flow passage shape on the impeller design and the hydraulic performance of the mixed-flow pump, the hub and shroud radius ratio (HSRR) of impeller and the outlet diffusion angle (ODA) of outlet zone are selected as the meridional flow passage parameters. 25 mixed-flow pump impellers, with specific speed of 496 under the design condition, are designed with various parameter combinations. Among these impellers, one with HSRR of 1.94 and ODA of 90° is selected to carry out the model test and the obtained experimental results are used to verify accuracies of the head and the hydraulic efficiency predicted by numerical simulation. Based on SIMPLE algorithm and standard k-ε two-equation turbulence model, the three-dimensional steady incompressible Reynolds averaged Navier-Stokes equations are solved and the effects of different parameters on hydraulic performance of mixed-flow pump impellers are analyzed. The analysis results demonstrate that there are optimal values of HSRR and ODA available, so the hydraulic performance and the internal flow of mixed-flow pumps can be improved by selecting appropriate values for the meridional flow passage parameters. The research on these two parameters, HSRR and ODA, has further illustrated influences of the meridional flow passage shape on the hydraulic performance of the mixed-flow pump, and is beneficial to improving the design of the mixed-flow pump impeller.

Experimental Study of the Influence of Flow Passage Subtle Variation on Mixed-flow Pump Performance

In the mixed-flow pump design, the shape of the flow passage can directly affect the flow capacity and the internal flow, thus influencing hydraulic performance, cavitation performance and operation stability of the mixed-flow pump. However, there is currently a lack of experimental research on the influence mechanism. Therefore, in order to analyze the effects of subtle variations of the flow passage on the mixed-flow pump performance, the frustum cone surface of the end part of inlet contraction flow passage of the mixed-flow pump is processed into a cylindrical surface and a test rig is built to carry out the hydraulic performance experiment. In this experiment, parameters, such as the head, the efficiency, and the shaft power, are measured, and the pressure fluctuation and the noise signal are also collected. The research results suggest that after processing the inlet flow passage, the head of the mixed-flow pump significantly goes down; the best efficiency of the mixed-flow pump drops by approximately 1.5%, the efficiency decreases more significantly under the large flow rate; the shaft power slightly increases under the large flow rate, slightly decreases under the small flow rate. In addition, the pressure fluctuation amplitudes on both the impeller inlet and the diffuser outlet increase significantly with more drastic pressure fluctuations and significantly lower stability of the internal flow of the mixed-flow pump. At the same time, the noise dramatically increases. Overall speaking, the subtle variation of the inlet flow passage leads to a significant change of the mixed-flow pump performance, thus suggesting a special attention to the optimization of flow passage. This paper investigates the influence of the flow passage variation on the mixed-flow pump performance by experiment, which will benefit the optimal design of the flow passage of the mixed-flow pump.

Influence of specific speed on hydraulic performances and pressure fluctuations in mixed-flow pumps

A series of steady and unsteady numerical calculations of the internal flow in mixed-flow pumps with three different specific speeds were carried out based on the N-S equation coupled with the standard k-εturbulence model under different operating conditions to investigate the relationship between the impeller specific speed and the pump performance as well as pressure pulsations.Meanwhile,the pump performance and pressure pulsations inside the mixed-flow pump with three different specific speeds were also analyzed and compared with the corresponding test data.From the results,the averaged deviations between the predicted and tested head among different impellers are below 5%,and with respect to the equivalent impeller specific speeds of 280 and 260,the values are 4.30%and 3.69%,respectively.For all the impeller schemes,the best efficiency point of the mixed-flow pump is found at the flow rate of 1.2 Q_(d) and the higher head deviation occurs at lower flow rates.Especially,it can be found that the specific speed has a slight effect on the pressure fluctuation in the impellers.Eventually,it is determined that the pump performance curves calculated by numerical simu-lations have good agreement with the relevant experimental results,which verifies that the numerical methods used in the present study are accurate to a certain extent.Furthermore,the results also provide some references to the pressure pulsation analysis and the performance improvement of the mixed-flow pump design.

Robust optimization design on impeller of mixed-flow pump

To increase the robustness of the optimization solutions of the mixed-flow pump,the impeller was firstly indirectly parameterized based on the 2D blade design theory.Secondly,the robustness of the optimization solution was mathematically defined,and then calculated by Monte Carlo sampling method.Thirdly,the optimization on the mixed-flow pump′s impeller was decomposed into the optimal and robust sub-optimization problems,to maximize the pump head and efficiency and minimize the fluctuation degree of them under varying working conditions at the same time.Fourthly,using response surface model,a surrogate model was established between the optimization objectives and control variables of the shape of the impeller.Finally,based on a multi-objective genetic optimization algorithm,a two-loop iterative optimization process was designed to find the optimal solution with good robustness.Comparing the original and optimized pump,it is found that the internal flow field of the optimized pump has been improved under various operating conditions,the hydraulic performance has been improved consequently,and the range of high efficient zone has also been widened.Besides,with the changing of working conditions,the change trend of the hydraulic performance of the optimized pump becomes gentler,the flow field distribution is more uniform,and the influence degree of the varia-tion of working conditions decreases,and the operating stability of the pump is improved.It is concluded that the robust optimization method proposed in this paper is a reasonable way to optimize the mixed-flow pump,and provides references for optimization problems of other fluid machinery.

叶轮中心淹没深度对特低扬程下立式泵装置流道水力性能的影响

为提高特低扬程泵站立式轴流泵装置的水力性能,该研究对叶轮直径为3.0、2.5、2.0、1.5 m的立式轴流泵装置在不同叶轮中心淹没深度下的进、出水流道流场分别进行了三维湍流流动数值计算,并对流道流场和水头损失进行了分析比较;对某特低扬程泵站在叶轮中心淹没深度为3.08、2.38、1.68 m下的立式轴流泵装置水力性能分别进行了数值计算及比较,并进行了泵装置模型试验验证。研究结果表明:叶轮中心淹没深度对肘形进水流道的水流流态及水头损失的影响很小,但对虹吸式出水流道的流态和水头损失影响较大;随着叶轮中心淹没深度的增大,虹吸式出水流道内的流态逐渐改善,流道水头损失基本呈下降趋势,泵装置效率逐渐增大,特低扬程工况下泵装置模型试验最优工况点的效率达75.92%,泵装置能量性能数值模拟结果与模型试验结果基本一致。研究结果可为特低扬程泵站采用立式泵装置的设计提供一定参考依据。

基于遗传算法优化的潜液泵效率提升研究

为了提高潜液泵效率并解决潜液泵多部件多参数优化的难题,提出一种基于遗传算法优化的潜液泵效率提升优化设计方法。选取潜液泵效率作为优化的目标函数,以叶轮和诱导轮作为优化的核心部件,以潜液泵叶轮进口角β_(1)、叶轮出口角β_(2)、叶片包角ϕ、叶片进口宽度b_(2)、诱导轮进口角β_(3)、诱导轮出口角β_(4)、诱导轮叶片倾角γ作为约束条件,利用遗传算法进行优化,并利用ANSYS Fluent软件进行数值模拟验证。数值模拟结果表明:综合考虑叶轮与诱导轮优化的潜液泵与原泵相比,其工作效率由原来的71.65%提升至80.40%,且增压效果更明显,并且效率提升效果比单一优化叶轮或诱导轮的泵更好。通过遗传算法对LNG潜液泵的叶轮以及诱导轮进行综合优化,显著提高了泵的工作效率。

海洋平台潜海水电机绝缘失效解决方法探讨

针对目前国产电动海水提升泵电机绝缘失效率高、质量不够稳定的问题,结合实际案例,通过温度场仿真分析等方法,得出潜海水电机绝缘失效的主要原因包括绕组线选型缺陷、内部散热不足、密封性能差和缺少温度监控。针对上诉原因,逐条提出可行的改进方法,提高电动潜海水泵的产品质量。

气力输灰技术在电炉除尘系统的应用探索

在对电炉除尘输灰系统工艺流程及现状梳理的基础上,对气力输灰在电炉除尘灰输送中应用的可行性进行了论证,通过气力输灰技术在马钢特钢公司电炉除尘系统中的应用实践,证实了气力输灰技术在电炉除尘中可以取得较好的效果。

含沙条件下泵站进水池控涡技术研究

含沙水流会对沿黄泵站造成严重的磨损破坏。泵站进水池漩涡的存在将会加重水泵磨损,严重影响水泵的运行寿命。为探究含沙条件下泵站进水池控涡技术,基于仿生学原理研发了一种带波状前缘翼型喇叭口的消涡装置,并通过模型试验,在清水和含沙水两种环境下,研究波状前缘翼型喇叭口对进水池内漩涡的影响特性。结果表明:无论在清水还是含沙水条件下,波状前缘翼型喇叭口均能有效抑制附底涡的产生、降低附底涡的出现频率、减小进水管内水流的预旋强度,有利于改善水泵的进水流态,防止泥沙磨损的进一步加剧。

多指标排序优选抽油井工作参数软件研发

针对原有抽油机井工作参数软件与采油生产实际结合不够紧密、使用不方便的问题,经过技术攻关研发出多指标排序优选抽油井工作参数软件。首先确立以产液量指标为主、井下效率指标为辅、安全指标可靠的优选抽油井工作参数的设计思路,其次是建立以产液量计算为核心的系统算法。应用工程计算和经验公式相结合的方法,通过抽油泵沉没压力使供液量与排液量建立联系,将与供液量接近的排液量作为产液量,进而计算出井下效率、悬点载荷和抽油杆负载率。对所有“泵径、冲程、冲次”组合的优势产液量和优势井下效率及其对应的指标和下泵深度以列表方式输出,对所有指标与井下效率的关系以曲线方式输出,经过排序对比即可挑选出各项指标均占优势且稳定可靠的抽油井工作参数组合,实现抽油井工作参数优化设计的目标。该软件自2017年应用以来年均指导调参130井次,平均单井增产原油63.54 t,提高井下效率3.2%,取得了显著的应用效果。

基于地面大口径钻孔抽排的老空水害防治技术

为了安全高效治理矿井老空水害,在井下不具备疏放老空水的条件下,采用了地面大口径钻孔和接力抽排水的方案对老空水害进行治理。选取位于老空积水区最低点的水仓作为地面钻孔的终孔位置,施工三级变径的大口径钻孔。下设的一级套管对钻孔在松散层中进行了固井,二级套管对老空区及采动破坏范围上覆含水层进行了隔离,采用无线随钻测斜和定向钻进技术,保障了大口径钻孔的准确透巷。钻孔中下设潜水泵将老空水抽至地面,然后采用管道增压泵将老空水接力排至矿井水处理厂,实现了老空水抽排过程中不落地。通过对抽排水量和老空水位的观测,验证了基于地面大口径钻孔和接力抽排老空水的效果。结果表明:采用地面大口径钻孔和井下潜水泵联合地面增压泵接力抽排关闭矿井老空水效果较好,具有安全性和可靠性高、排水和水处理费用低等特点。

低渗透油田合理间抽制度确定及其应用效果分析

针对A油田低品位区块抽油机井常年存在液量不足、举升能耗高、系统效率低的问题,针对人工间抽和不停机间抽两种间抽方式,形成两种间抽方式运行制度模板和间抽参数控制模板,确定了抽油机井合理的停抽和启抽时间,有效避免“干抽”现象。区块实施人工间抽井2623口,间抽比例达89.0%;不停机间抽井1982口,占间抽井的75.6%。统计区块3口典型井,转间抽摇摆10 min正常运转20 min,实现平均单井日节电量18 kWh。间抽前后产液量保持稳定,抽油机采油能耗降低,碳排放量减少,抽油井采油效益得到提高,为油井经济开采提供关键技术与管理思路。

某非常规海况下新型海水提升系统选型设计

为维持风电安装平台在非常规海况下的生存需求,保证船员和乘客的正常生活,以及解决传统海水提升系统存在的缺陷和不足,提升其安全性、操作性和抵抗风浪的性能,满足第4代风电安装平台在各种海况下的运营需求,结合风电安装平台的用途和功能特点,同时基于工程实际,以平台工作气隙16 m、风速30 m/s及浪高20 m的非常规海况为设计工况,设计和提出一种新型海水提升系统的选型和设计方案。海水提升系统创新性的设计为国内外同类平台提供了重要参考。

基于AMESim的潜液泵专用液压控制阀动态特性分析

所研究的液压控制阀主要用于潜液泵的启停、扭矩调节和限制潜液泵最高转速,介绍了液压控制阀的工作原理和工况,利用AMESim软件对液压控制阀在扭矩调节工况和限速工况下的动态特性进行了仿真计算,分析了控制压力等因素变化对液压控制阀动态特性的影响,提出了在液压控制阀的控制油路中增加阻尼提高控制阀的稳定性的方法,并通过仿真进行验证;还分析了液压控制阀运行参数的变化对并联运行的其他潜液泵的影响,对液压控制阀样机性能进行了试验研究,对于提高潜液泵液压控制阀工作性能具有一定的实际意义。

抽油机井间抽制度合理性研究

在油田开采过程中,对于低效井往往采用间抽方式生产,为便于管理,通常采用统一固定的间抽制度。由于统一固定的间抽制度不利于挖潜和节能,因此,不同的低效井要具体井况具体分析,采用不同的间抽制度。通过对低效井进行动液面和示功图连续监测,找出其动液面变化规律,结合示功图确定间抽运行的合理沉没度范围和启停机时间,能够确保抽油泵在有足够供液能力的情况下运行,以达到挖潜节能的目的,通过试验证明这种方法是行之有效的。

实尺度浸没式喷水推进泵设计参数选择与性能分析

为设计某浸没式喷水推进泵,以某小型轴流式喷水推进泵为对象建立浸没式喷射模型,采用CFD方法模拟分析浸没喷射对喷泵水力性能的影响。研究表明,浸没式喷射对喷泵水力性能的影响变化不大。根据喷水推进和船体边界层基本理论,考虑喷泵工作环境不同时的水力特性变化,基于Matlab/simulink仿真平台建立浸没式喷水推进泵水力设计参数选型程序,实现快速高效地得到喷泵基本设计参数为设计者提供设计依据。根据选型结果运用三元理论设计出所需喷泵,运用CFD方法获取浸没式喷泵的敞水水力性能,并安装到实尺度船上预报推进性能,结果表明浸没式推进系统具有较高的推进效率、满足快速性要求,验证了设计参数选型程序的适用性。

抽油机井合理下泵深度的优化设计

针对抽油机井下泵深度往往是按经验选取一定的沉没度或利用泵效与沉没度关系确定的问题。通过对下泵深度与泵效和系统效率关系的对比分析,提出了以系统效率最高或产液量最大或经济效益最佳作为目标函数,对抽油机井系统的优化设计和多个设计方案进行了对比,认为目标函数最高的下泵深度才是合理的下泵深度,自喷转抽井、稠油井、间抽井、排水采气井等不同井况,目标函数的选取应有所区别。对油田开采具有较大的应用价值。

液化天然气潜液泵的研制

介绍了新研制潜液泵的结构组成和工作原理,论述了研制中对关键技术问题的分析和解决。经试验和初步使用证明满足使用要求,与普通的低温离心泵相比,具有零泄漏、绝热和防爆可靠等优点。

抽油泵合理沉没压力的确定方法

基于泵沉没压力的重要性和合理沉没压力研究存在的误区 ,讨论了泵沉没压力与上冲程时泵内压力的关系和流体通过泵吸入阀口所产生的节流阻力计算式 ,建立了以井下举升效率为目标确定油井工作制度和泵合理沉没压力的方法。计算结果表明 ,对具体油井 ,泵的合理沉没压力与油藏条件、油井产量、抽汲参数以及流体物性等有关 ,是各种因素影响的综合指标 ,且各因素之间也存在相关性。所以 ,泵沉没压力的选择取决于油井生产的协调 ,必须针对具体油井和油藏情况 ,以井下举升效率或经济效益为目标 ,进行动态模拟计算与分析 ,合理配置抽油设备和优化油井工作参数 。