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

小流动的高头的离心旋涡的泵的设计方法被介绍。这泵，与 inducer，建筑群离心的 impeller 和开旋涡的 impeller 设置了，被提出交付煤气液体的二阶段的混合。HTB-5/60 类型样品泵在一个靠近环的测试钻塔上被开发并且测试。为煤气液体的二阶段的混合的性能和成穴测试上的试验性的研究与纯水的试验性的结果相比被执行。另外，泵上的煤气的阶段的效果被分析并且讨论。样品泵的性能和成穴特征与增加气体的卷部分日益增多地败坏的试验性的结果表演。当全部的能力 Qm 在 4.5 m3 路h 之间时? 1 和 6 m3 路h ? 1 并且在 0.66 m3 路h 下面的煤气的流动率 qg ? 1 ，或 qg/Qm 比15%低，典型曲线与纯水里的那些近似平行测试，但是表演严厉地败坏直到一突然在气体的批评体积部分切流动。当在 5 m3 路 h 的评估能力附近工作时，这泵为搬运煤气液体的二阶段的混合被发现合适 ? 1 与低于 15% 的 qg/Qm。

Computational Analysis of Centrifugal Pump Delivering Solid-liquid Two-phase Flow during Startup Period

The transient behavior of centrifugal pumps during transient operating periods, such as startup and stopping, has drawn more and more attention recently because of urgent needs in engineering. Up to now, almost all the existing studies on this behavior are limited to using water as working fluid. The study on the transient behavior related to solid-liquid two-phase flow has not been seen yet. In order to explore the transient characteristics of a high specific-speed centrifugal pump during startup period delivering the pure water and solid-liquid two-phase flow, the transient flows inside the pump are numerically simulated using the dynamic mesh method. The variable rotational speed and flow rate with time obtained from experiment are best fitted as the function of time, and are written into computational fluid dynamics （CFD） code-FLUENT by using a user defined function. The predicted heads are compared with experimental results when pumping pure water. The results show that the difference in the transient performance during startup period is very obvious between water and solid-liquid two-phase flow during the later stage of startup process. Moreover, the time for the solid-liquid two-phase flow to achieve a stable condition is longer than that for water. The solid-liquid two-phase flow results in a higher impeller shaft power, a larger dynamic reaction force, a more violent fluctuation in pressure and a reduced stable pressure rise comparing with water. The research may be useful to tmderstanding on the transient behavior of a centrifugal pump under a solid-liquid two-phase flow during startup period.

Numerical Simulation and Analysis of Solid-liquid Two-phase Flow in Centrifugal Pump

The flow with solid-liquid two-phase media inside centrifugal pumps is very complicated and the relevant method for the hydraulic design is still immature so far. There exist two main problems in the operation of the two-phase flow pumps, i.e., low overall efficiency and severe abrasion. In this study, the three-dimensional, steady, incompressible, and turbulent solid-liquid two-phase flows in a low-specific-speed centrifugal pump are numerically simulated and analyzed by using a computational fluid dynamics （CFD） code based on the mixture model of the two-phase flow and the RNG k-~ two-equation turbulence model, in which the influences of rotation and curvature are fully taken into account. The coupling between impeller and volute is implemented by means of the frozen rotor method. The simulation results predicted indicate that the solid phase properties in two-phase flow, especially the concentration, the particle diameter and the density, have strong effects on the hydraulic performance of the pump. Both the pump head and the efficiency are reduced with increasing particle diameter or concentration. However, the effect of particle density on the performance is relatively minor. An obvious jet-wake flow structure is presented near the volute tongue and becomes more remarkable with increasing solid phase concentration. The suction side of the blade is subject to much more severe abrasion than the pressure side. The obtained results preliminarily reveal the characteristics of solid-liquid two-phase flow in the centrifugal pump, and are helpful for improvement and empirical correction in the hydraulic design of centrifugal pumps.

Numerical simulation and analysis of solid-liquid two-phase threedimensional unsteady flow in centrifugal slurry pump

Based on RNG k-ε turbulence model and sliding grid technique, solid-liquid two-phase three-dimensional(3-D) unsteady turbulence of full passage in slurry pump was simulated by means of Fluent software. The effects of unsteady flow characteristics on solid-liquid two-phase flow and pump performance were researched under design condition. The results show that clocking effect has a significant influence on the flow in pump, and the fluctuation of flow velocity and pressure is obvious, particularly near the volute tongue, at the position of small sections of volute and within diffuser. Clocking effect has a more influence on liquid-phase than on solid-phase, and the wake-jet structure of relative velocity of solid-phase is less obvious than liquid-phase near the volute tongue and the impeller passage outlet. The fluctuation of relative velocity of solid-phase flow is 7.6% smaller than liquid-phase flow at the impeller outlet on circular path. Head and radial forces of the impeller are 8.1% and 85.7% of fluctuation, respectively. The results provide a theoretical basis for further research for turbulence, improving efficient, reducing the hydraulic losses and wear. Finally, field tests were carried out to verify the operation and wear of slurry pump.

压水堆主泵及液态金属泵转子动力学研究进展

核主泵是核电站的关键设备之一,也是反应堆冷却系统的唯一旋转机械设备,其稳定运转对整个反应堆的正常工作至关重要,因此,针对核反应堆主泵开展转子动力学研究,探究主泵转子部件的模态振型、固有频率和支撑系统的刚度阻尼、液膜厚度十分必要。以国内外有关压水堆主泵及液态金属泵的转子动力学研究为重点,围绕压水堆主泵、钠冷快堆主泵、熔盐堆主泵、铅冷快堆主泵4种核主泵类型,从核主泵及其转子部件的结构特点出发,对现阶段主泵导轴承润滑性能和主泵转子结构固有频率、模态分析、临界转速等转子动力学特性的研究进展进行综述和展望,以期对有关核主泵转子动力学特性的计算分析起到一定的借鉴和指导作用。

化工用低温液氢泵密封相变性能分析及验证

低温液氢泵在石油、空分等装置中起着输送低温产品的作用,低温泵用机械密封是确保低温泵安全运转、影响低温泵工作性能的关键因素。为满足低温泵用机械密封长期可靠使用的要求,采用动压型非接触式机械密封方案,建立考虑相变的流固热耦合数值分析模型,对低温液氢泵密封的相变和密封特性进行分析,给出密封端面结构的推荐值;并通过试验验证数值模型的正确性。

诱导轮对高速液氧泵空化流场影响研究

高抗空化诱导轮可以改善液氧泵的空化特性,提高大推力火箭的可靠性。基于计算流体力学方法,建立了高速液氧泵的流动仿真模型,通过三组试验工况验证了模型准确性,研究了诱导轮叶片数对液氧泵性能和空化特性的影响。结果表明:使用诱导轮可以减小离心轮空化面积,代偿离心轮的汽蚀,提高液氧泵扬程;在入口流量和出口压力不变的条件下,增加诱导轮叶片数,液氧泵的效率增加,扬程降低,离心轮空化面积增加,诱导轮代偿离心轮汽蚀能力削弱。综合考虑液氧泵性能参数和空化特性,三叶片诱导轮能够满足大推力液体火箭的高可靠性要求。

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。

旋流泵叶轮流道固液两相流动不稳定性分析

由于结构的特殊性以及固液两相存在的密度差,旋流泵在输送固液两相介质过程中,内部会出现多方面的不稳定性特征,基于Particle模型,运用ANSYS CFX软件对额定转速下旋流泵在不同流量下输送不同固相体积分数的多种工况进行了非定常数值模拟,分析了叶轮流道内的固相分布、压力脉动和叶轮径向力,从而深入了解叶轮内部不稳定性。结果表明:在C_(v)=5%体积分数下,0.8 Q_(d)、1.0 Q_(d)流量下叶轮流道内固相体积分布均匀,1.2 Q_(d)分布不均匀;在C_(v)=10%体积分数下,0.8 Q_(d)流量下分布均匀,1.0 Q_(d)和1.2 Q_(d)流量下分布不均匀;在C_(v)=20%体积分数下,0.8 Q_(d)、1.2 Q_(d)流量下分布均匀,1.0 Q_(d)分布不均匀;在C_(v)=20%、1.0 Q_(d)工况的一个旋转周期内,叶轮内部始终存在一个条形固相分布区域,且其旋转速度滞后于叶轮旋转速度。在1.0 Q_(d)流量下,随着固相体积分数的增加,各监测点压力系数幅值波动逐步变大;后缩腔监测点叶频处的幅值基本不变,叶轮流道内监测点轴频处的幅值逐步变大;在C_(v)=20%体积分数下,随着流量的增加,各监测点压力系数幅值波动先增后减,后缩腔监测点叶频处幅值逐步增大,流道内监测点轴频处的幅值先增后减。相同固相体积分数下,随着流量的增加,径向力逐步增大;不同固相体积分数下,随着体积分数的增加,0.8 Q_(d)流量下径向力波动不大,1.0 Q_(d)流量下波动逐步变大,1.2 Q_(d)流量下波动逐步变小。

气液两相条件下叶片开孔对电潜泵性能和内部流场的影响

为了研究电潜泵内部流动机理,从而改善高含气工况下电潜泵的气液混输性能,文中基于欧拉-欧拉非均相流模型,对不同入口含气率工况下叶片开孔前后的气液两相流动特性进行了数值模拟分析,探究了气液两相流条件下叶片开孔对电潜泵性能和内部流场的影响.结果表明,在纯水工况以及低含气率、小流量工况下,叶片开孔会降低电潜泵性能;但是叶片开孔可以改善电潜泵在大流量下的气液混输性能.叶片开孔后会改变叶轮内部压力分布,使电潜泵叶轮内部平均压力升高,进而改善叶轮内部流态.叶片开孔后会冲散气相聚集,使气体分布更加均匀,叶轮流道内涡核分布明显减少,减少了能量耗散.该研究为改善电潜泵气液混输性能提供了理论依据.

不同密度下水力射流泵动态特性方程建立及应用

水力射流泵具有无运动部件,产量调节范围广,检泵不动管柱,作业时间短且作业成本低等优点,因次,该设备在海上油田前期排液注水井将有广泛的应用前景。然而,当前水力射流泵选型所用的特性方程是建立在动力液密度和产液密度相同的假设条件下推导的。该特性方程对流体密度相近的排液井选择出的射流泵型较合适,而对流体密度差异大的排液井,选出的泵型及工作参数与泵实际运行参数差异较大,影响了泵排液效果。为更准确描述流体密度差异对泵特性影响,进一步提高选泵水平。根据能量方程和动量方程,我们建立了不同密度下水力射流泵动态特性方程,并将该方程应用于选泵中,油井排液效果良好。

MVR低放废液热泵蒸发系统设计及性能分析

为了研究MVR技术在低放废液中的可行性,构建了系统热力学数学模型,设计了MVR低放废液热泵蒸发系统工艺路线,并进行了AspenPlus模拟分析,根据模拟结果搭建了试验系统台架,分析了系统性能,研究了压缩机压比、蒸发温度、进料温度对系统蒸发量、传热效率的影响。结果表明:设计的MVR热泵蒸发系统连续运行稳定,系统平均蒸发量5.13t/h,每处理1吨模拟料液平均耗电量44.78 kW,净化系数达到1.02×10^(6),净化系数达到;蒸汽压缩机压比较低时有助于提高系统的节能效果,但系统蒸发量下降,会增加系统设备腐蚀的风险;系统蒸发量、制热系数受蒸发温度影响较大,随着蒸发温度的升高呈现上升趋势;随着料液温度的升高,系统中二次蒸汽将进料液加热至沸点所需要的热量降低,在增加系统蒸发量的同时降低了能耗。

泥浆射流泵冲蚀磨损特性

为了研究泥浆射流泵的冲蚀磨损特性,基于欧拉-拉格朗日方法对泥浆射流泵内部的固液两相流动开展了数值模拟,重点对泥浆射流泵内部液固两相流的冲蚀磨损规律进行了研究。结果表明:泥浆射流泵喉管进口和喉管中后段是产生冲蚀磨损的主要部位,吸入室和扩散管未产生明显冲蚀磨损。颗粒质量流量从1 kg/s增大到1.8 kg/s时,泥浆射流泵最大冲蚀速率增大了93.7%;泥浆流速从2 m/s增大到5 m/s时,最大冲蚀速率增大了11.48倍;颗粒直径从200μm增大到450μm时,最大冲蚀速率先减小后增大。相较于颗粒质量流量和颗粒直径,泥浆流速对射流泵内表面的冲蚀磨损影响更大,但产生冲蚀磨损的主要部位不会随泥浆流速、颗粒质量流量和颗粒直径发生明显改变。研究成果可为射流泵的设计提供参考。

基于Fluent的多级串联喷嘴液气射流泵的抽气性能研究

为提高液气射流泵的抽气性能,在其主喷嘴后设置了多级串联喷嘴,通过Fluent软件对常规液气射流泵和多级串联喷嘴液气射流泵内气液两相流体运动情况进行了数值模拟,对比分析了相同工况下两种类型液气射流泵的抽气性能、压力场分布、速度场分布和气相体积分数分布。结果表明:在工作流体进口压力(表压)为0.3 MPa、0.35 MPa和0.4 MPa下,多级串联喷嘴液气射流泵的抽气性能较常规液气射流泵分别提高了18.1%、13.4%和20%,多级串联喷嘴结构有利于气液两相流体的混合和动量交换。研究结果对液气射流泵的优化设计和抽气性能提高具有一定的参考意义。

浸出器负压强制沥干装置分析

浸出器是浸出制油的重要设备,提高浸出器的性能不但能降低粕中残油,而且能够减轻后续高温脱溶或低温脱溶的负荷,进而节省蒸汽消耗。浸出器负压强制沥干装置是用不同的方式使沥干封闭油斗为负压,强制沥干湿粕物料中的低浓度混合油,达到湿粕含溶量进一步降低的目的。为了降低湿粕含溶量,提高企业经济效益,分别介绍了用液环真空泵、蒸汽真空泵、负压风机抽取浸出器沥干段负压装置的工艺,特点和适用范围,同时也阐述了不同类型的常用浸出器强制沥干封闭油斗的方式,最后对沥干效果和经济效益进行综合分析。通过浸出器负压强制沥干装置可以有效降低湿粕含溶量,在高温蒸脱时节省蒸汽消耗量进而为企业带来一定的经济效益。

液环式航空燃油离心泵自吸性能

基于Mixture模型对液环式航空燃油泵进行自吸阶段的非稳态数值计算,研究自吸过程中燃油泵内气液两相分布的变化过程,对不同时刻下燃油泵内部含气率、气液两相分布、压力及速度流线、熵产率和湍动能变化规律进行分析.结果表明:燃油泵的吸气和排气主要集中在自吸过程的前期和中期;随着自吸时间的增加,各监测面的含气率逐渐降低,当自吸时间为3.00 s时,蜗壳出口含气率接近于0,自吸过程结束;泵内压力随相对距离的增加而增大,泵内同一相对距离平面压力随自吸时间的增加而增大;在气液混合时,高速区域主要集中在叶轮中间流道和蜗壳壁面处,低速区域则集中分布在隔舌附近和导叶出口;随着自吸过程的进行,泵内湍动能和熵产率也随之增大,泵内能量损失增大,主要集中在叶轮叶片、导叶叶片和蜗壳出口处.

基于CFD-DPM的离心泵内颗粒性质对泵性能与磨损的影响

为揭示离心泵在输送固液两相流时颗粒密度和粒径对泵性能和磨损的影响,采用Realizable k-ε湍流模型(液相)和DPM离散相模型,对模型泵内固液两相流动进行定常数值模拟,研究固液两相流场中颗粒的运动轨迹以及磨损规律。结果表明:随着颗粒密度和粒径的增大,模型泵的扬程和效率均下降;密度、粒径越大的颗粒,其运动轨迹越易偏向叶片工作面;随着颗粒密度的增加,叶片工作面以及蜗壳内的磨损程度加剧,但是叶片背面的磨损减轻,颗粒相应地在叶片工作面和蜗壳外壁边缘聚集;随着颗粒粒径的增大,蜗壳整体磨损程度加重,其中蜗壳的隔舌区域、Ⅱ区域和Ⅵ区域磨损程度最严重;叶片整体磨损程度逐渐降低,且叶片工作面磨损程度大于叶片背面。

表面波度对液体椭圆孔端面密封上游泵送特性的影响

表面波度与端面几何型槽的耦合影响使得密封性能的变化规律更为复杂。基于粗糙和波度表面假设,建立空化效应下端面椭圆孔液体上游泵送密封的理论分析模型,对上游泵送端面密封的压力分布和泄漏率进行数值求解计算,分析周向表面波度幅值、数量等几何参数和转速、密封压力等操作参数对开启力和泄漏率的影响规律。结果显示:表面波度使得密封端面产生更高的流体动压效果,并减弱上游泵送效果,容易导致密封介质的泄漏;随着波高和周向波数的增加,开启力略有增加;泄漏率随着波高的增加呈现正向增强趋势,但波数对泄漏率没有明显影响;在空化效应和表面波度的影响下,速度剪切产生的密封端面开启力可增加50%以上,并形成流体的完全上游泵送;密封压力和膜厚的增加,使得流体的上游泵送性能和密封性下降。

Design and analysis of an advanced thermal management system for the solar close observations and proximity experiments spacecraft

In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relationship and functions of the integrated database,the intelligent thermal control system and the efficient liquid cooling system in the ATMS are elaborated upon.For the complex thermal field regulation system and extreme space thermal environment,a modular simulation and thermal field planning method are proposed,and the feasibility of the planning algorithm is verified by numerical simulation.A solar array liquid cooling system is developed,and the system simulation results indicate that the temperatures of the solar arrays meet the requirements as the spacecraft flies by perihelion and aphelion.The advanced thermal management study supports the development of the SCOPE program and provides a reference for the thermal management in other deep-space exploration programs.

长柱塞防气泵室内试验及模拟研究

目前国内各油田开发逐步进入中后期,高气液比油井举升问题日益突显,长柱塞防气泵在原有泵筒外设计排气结构,使进泵气体由此返回环空,达到防止气锁和提高泵效的目的。然而,由于适用界限未知,且缺少经济高效的评价手段,限制了其推广应用。采用CFD方法,引入动网格技术,基于控制方程和波动方程,建立长柱塞防气泵泵筒内气液瞬态流动和泵阀运动规律数值模型;开展室内可视化试验,验证了建立数值模型的准确性,模型平均误差为5.84%;基于数值模型,模拟分析了长柱塞防气泵上、下冲程泵筒内部气液两相流动规律,以及冲程、冲次对泵效率的影响,明确了其适用的气液比范围,当气液比大于400m^(3)/m^(3)时,长柱塞防气泵泵效低于经济泵效。