共查询到19条相似文献,搜索用时 187 毫秒
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为设计效率高、性能稳定的低比转数离心泵,结合传统的速度系数法和内部流动分析技术进行了水力设计和改进。给出了低比转数离心泵的初步设计思路、内部流动分析和性能预测方法,基于速度系数法设计的模型的实验结果验证了数值方法的合理性。在初步设计基础上,针对传统设计难以把握的蜗壳关键尺寸参数对性能的影响进行了分析,以此为依据对关键结构与参数进行改进设计,数值模拟和实验表明,改进设计使性能得到了提高。该设计方法与流程的采用,可有效提高泵的水力性能的同时减少试验次数,从而缩短了离心泵产品开发周期。 相似文献
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穆道彬 《中国石油和化工标准与质量》2023,(10):113-115
环管轴流泵是应用在聚丙烯装置上特殊用途的泵,固液气介质特性决定了轴流泵设计研究的特殊性,导叶改变着流体内部流动方向,导叶结构参数的设计研究尤为重要。应用流体数值模拟软件对两种导叶数、相同叶轮的不同流量进行内外特性的研究,采用SST湍流模型,首先模拟两种导叶数在0.2~1.4Q t流量的外特性,结果显示七叶片导叶的泵性能优于五叶片导叶的泵;同时对两种导叶数的导叶进行内特性研究,通过出口断面压力和出口断面流线模拟分析,导叶片数对泵水力性能影响很大,采用七叶片导叶的泵内部流动平稳,水力损失小,效率更高;内外特性分析研究表明,相同性能参数相同叶轮的条件下选取七叶片导叶水力性能更佳。本文的研究对环管轴流泵的设计应用具有借鉴意义。 相似文献
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采用正交试验和计算流体力学(CFD)的方法,对固-液微型水力旋流器进行了初步研究。实验采用的微米级固体颗粒分别为1250目和2500目的滑石粉颗粒。首先通过正交试验研究了微型旋流器处理量和进料浓度对两种粒径的滑石粉溶液的分离效率的影响,得到较优的分离操作条件。然后利用CFD的方法对微型水力旋流器的内部流场进行数值模拟,湍流相采用雷诺应力(RSM)模型,再加入离散颗粒进一步模拟微型水力旋流器内颗粒运动,其中离散相采用离散相(DPM)模型。最终得到水力旋流器的流场的压力和速度分布云图及固体颗粒运动轨迹,为进一步优化微型水力旋流器的结构参数提供了参考。 相似文献
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简要阐述了目前研究流体运动规律普遍使用的三种方法:实验研究、理论分析、CFD分析及其应用要点,并对某公司最新研发的化工流程泵做了深入研究,即通过先进的CFD软件,基于全三维不可压缩的Reynolds时均Navier-Stokes方程和Realizable K-ε湍流模型,采用三维无结构化网格和压强连接的隐式修正SIMPLEC算法及多重参考系MRF,分别对泵的不同工况点进行内部流动数值模拟,根据计算结果和实验结果对比,并结合工作经验,提出优化改善措施.运用此方法,可以比以往更方便的设计和优化泵的水力结构,既提高了产品性能水平,又缩短了设计和生产周期,还节约了很多制造成本,从而使企业在市场竞争中更具有优势. 相似文献
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基于FLUENT数值模拟软件,利用有限体积法对雷诺时均Navier-Stokes方程进行离散,选用标准k-ε湍流模型,压力和速度耦合采用SIMPLEC算法,对5种不同密度流体在3种不同工况下分别进行数值计算,由数值计算结果分析得出离心泵内部三维流场随流体介质密度的变化而变化的规律。同时,将5种情况下的预测扬程和效率进行对比分析,得出不同密度流体对离心泵外特性的影响情况。相同流量下,随密度增大,离心泵的轴功率增大。这对于输送不同密度介质时离心泵内流体流动状态的变化以及离心泵性能的变化起到了指导作用。 相似文献
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为提高多级悬臂式小流量泵的效率,其叶轮叶片采用低比转数离心泵叶片设计原理进行设计,并采用螺旋形出水室结构,该结构具有水力性能优良、结构简单及便于拆装等特点;采用多级悬臂式直锥形吸入室结构;独特的密封装置能够有效减小密封泄漏,保证其安全可靠运行;复合限流环结构能够有效减小口环处泄漏损失,进而提高其装置效率。 相似文献
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The heat transfer and flow characteristics of air jet impingement on a curved surface are investigated with computational fluid dynamics(CFD)approach.The first applied model is a one-equation SGS model for large eddy simulation(LES)and the second one is the SST-SAS hybrid RANS-LES.These models are utilized to study the flow physics in impinging process on a curved surface for different jet-to-surface(h/B)distances at two Reynolds numbers namely,2960 and 4740 based on the jet exit velocity(U_e)and the hydraulic diameter(2B).The predictions are compared with the experimental data in the literature and also the results from RANS k-εmodel.Comparisons show that both models can produce relatively good results.However,one-equation model(OEM)produced more accurate results especially at impingement region at lower jet-to-surface distances.In terms of heat transfer,the OEM also predicted better at different jet-to-surface spacings.It is also observed that both models show similar performance at higher h/B ratios. 相似文献
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Sieve trays are widely used in fractionating devices like tray distillation towers existing in separation and purification industries. The weeping phenomenon that has a critical effect on the efficiency of tray towers was studied by a numerical model and some experiments. The experiments were carried out in a pilot scale column with the diameter of 1.22 m that includes two test trays and two chimney trays. Weeping rates and some hydraulic parameters were measured in sieve trays with the hole area of 7.04%. Furthermore, the total weeping rate and weeping rate in inlet and outlet halves of the test tray were determined. It was also used an Eulerian–Eulerian computational fluid dynamics (CFD) method for the present study. The model was able to predict the dry tray pressure drop, total pressure drop, clear liquid height, froth height, and weeping rate simultaneously. Furthermore, the obtained CFD results were in a good agreement with the experimental data in terms of pressure drop and the model properly predicted several hydraulic parameters like the liquid weeping behavior along the tray. 相似文献
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对小型有机朗肯循环系统中工质泵的性能进行了实验研究,建立了应用R245fa工质的小型工质泵性能研究试验台,针对容积型工质泵的效率展开实验研究,对工质泵出口压力、进出口压差和系统质量流量分别进行控制,获得了工质泵等熵效率随上述3个变量的变化曲线.实验结果表明,在蒸发温度75℃、冷凝温度11℃条件下,有机朗肯循环系统中工质泵的等熵效率范围为15%~47%,随着系统质量流量的增大和工质泵进出口压差的增加,工质泵等熵效率升高,且受到系统质量流量的影响较大.实验证实了有机朗肯循环系统中工质泵的实际运行效率比以往模拟、理论计算研究中应用的工程经验值低.依据本研究实验结果,工质泵等熵效率宜取平均值30%;基于理论循环等熵过程的分析,泵功占膨胀机输出功的比例约为8%,而实际过程中,综合考虑泵的效率、电机效率、膨胀机机械效率,其比值可达到12%以上. 相似文献
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We present theoretical and experimental studies of an active water management system for proton exchange membrane (PEM) fuel cells that uses integrated wicks and electroosmotic (EO) pumps. The wicks and EO pumps act in concert to remove problematic excess liquid water from the fuel cell. In a previous paper, we showed that this system increases maximum power density by as much as 60% when operating with low air stoichiometric ratios and a parallel channel flow field. The theoretical model we develop here accounts for several key factors specific to optimizing system performance, including the wick's hydraulic resistance, the variation of water pH, and the EO pump's electrochemical reactions. We use this model to illustrate the favorable scaling of EO pumps with fuel cells for water management. In the experimental portion of this study, we prevent flooding by applying a constant voltage to the EO pump. We experimentally analyze the relationships between applied voltage, pump performance, and fuel cell performance. Further, we identify the minimum applied pump voltage necessary to prevent flooding. This study has wide applicability as it also identifies the relationship between active water removal rate and flooding prevention. 相似文献