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k-ε涡粘湍流模型用于离心泵数值模拟的适用性 总被引:13,自引:0,他引:13
以IS80-65-160离心泵为研究对象,对设计工况和八种非设计工况进行了整机系列相对位置定常流动数值模拟.计算中分别采用标准k-ε模型、RNG缸k-ε模型和Realizable k-ε模型三种k-ε涡粘湍流模型,以考察比较它们对离心泵内流模拟计算的适用性.计算中考虑了叶轮和蜗壳之间相对位置变化对流场的影响,较全面反映叶轮与蜗壳间的相互作用.在数值模拟的基础上,计算了基于三种湍流模型的扬程、轴功率、效率及性能曲线,并与试验性能曲线进行对比.研究表明:三种肛k-ε涡粘湍流模型均可用于离心泵内部流动数值模拟计算,采用Realizable k-ε模型的离心泵仿真结果与试验吻合最好. 相似文献
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为了探讨不同湍流模型在小型潜水泵性能预测中的适用性,本文以QDX6-18-0.75型潜水电泵为研究对象,分别选取Standard k-ε、Reliable k-ε、RNG k-ε、RSM 4种不同湍流模型对小型潜水电泵进行全流场模拟,得到6种工况下泵扬程和效率的预测值,并与试验台测得的数据进行对比分析。结果表明:设计工况下,4种湍流模型的扬程相对误差均小于1.5%,效率相对误差均小于2.5%,满足工程应用需求;小流量工况下,Reliable k-ε模型相对误差最小,扬程最大偏移0.75%,效率最大偏移4.36%;大流量工况下,Standard k-ε模型扬程预测精度高于其它3种湍流模型,RSM模型的效率预测精度最高。综上Reliable k-ε模型的适用性最强,Standard k-ε模型次之。该结论为小型潜水电泵性能预测的可靠性提供依据,并已在产品改型中得以应用。 相似文献
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采用RANS/LES混合模式对汽车外部的平均流场进行计算分析。采用三方程的k-ε-v~2湍流模型作为RANS/LES混合模式中的RANS部分。针对k-ε-v~2湍流模型中的正应力(v 2)输送方程以及用于构造松弛函数f22的椭圆方程引起数值计算不稳定等问题,根据Boussinesq假设和量纲一分析对微分形式的v 2方程进行合理的简化,推导出代数形式的正应力v 2方程以及新的湍动粘度方程。最终获得新的准k-ε-v~2/LES混合模型,并将其应用于汽车外部流场计算仿真中。准2k-ε-v~2/LES模型的控制方程借用商业软件Fluent中的Realizable k-ε/LES模型中的k方程和方程,并采用Fluent UDF将代数形式的v 2方程以及新的湍动粘度方程写入计算程序中。计算结果与其他RANS/LES混合模型、完全大涡模拟以及风洞试验进行对比分析,结果表明,在同等的计算条件下该混合模型能更加准确且高效地模拟车身表面的气流分离以及尾部流场。 相似文献
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湍流模型在离心泵偏工况性能预测中的适用性分析 总被引:2,自引:0,他引:2
选取5个不同比转数的优秀离心泵水力模型作为研究对象,使用Fluent软件中的5种两方程湍流模型进行离心泵非设计工况下的数值计算,并将计算结果与试验值进行对比分析.研究表明:在低比转数和高比转数离心泵的非设计工况中,SST k-ω型能够得到比较小的误差,最小误差不超过1%;对于中比转数离心泵,小流量工况下,RNG k-ε模型的计算结果最接近实验值,大流量工况下,SST k-ω模型的误差最理想,其最小值为0.2%,最大值不超过4%;5种湍流模型所计算的涡量大小分布规律比较类似,但是湍流强度分布有明显区别,RNG k-ε模型在蜗壳扩散段处的湍流强度特征不是十分明显.通过分析,建议在离心泵非设计工况的数值模拟中采用SST k-ω模型. 相似文献
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To investigate unsteady flow in the low specific speed centrifugal pump, a three-dimensional model of a pump that n s is equal to 50 is modeled with the software Pro/E. With standard k-?, SST k-ω and RNG k-? turbulence model, the testing performance of pump is compared with the simulated results. Based on the result of steady flow, the unsteady flow of RNG k-? turbulence model and large eddy simulation (LES) are calculated at both design and off-design conditions. The time domain of pressure fluctuation value of indicator points, which are located interfaces between volute and impeller, has been investigated numerically. The unsteady flow characteristic of pump with RNG k-? turbulence model is compared with LES. The distribution of vortex in the volute is discovered. The results show that in steady flow, an error of 2.6% of RNG k-? is the lowest, SST k-ω of 3.65% is second and the worst is standard k-? of 4.78% at design condition. The calculated precision using RNG k-? model is highest in steady condition. Because of the interaction of relative movement between volute and impeller, the pressure fluctuation can clearly be observed. The flow separation of the blade pressure surface and the stall channels in off-designed condition is the reason that the efficiency of pump operating under off-design condition is low. The vortex intensity is obviously different in the eight sections of the volute and is gradually increasing from first section to eighth section. Large eddy simulation can discover the unsteady flow of the centrifugal pump effectively. 相似文献
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利用FLUENT6.3软件对ISG65-125离心泵过流部件全三维流场区域进行数值模拟。在多重参考系坐标下,基于雷诺时均N-S方程与标准k-ε模型,采用非结构化网格和标准SIMPLE方法求解,对离心泵内流现象和规律进行了分析,并将数值模拟结果与实验值进行对比,验证了模拟结果的可靠性,总结了产生误差的因素。 相似文献
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通过对100QJ 3.2型高速深井离心泵在不同网格数、不同湍流模型、不同模拟级数条件下进行三维定常数值模拟,分析了不同条件对其性能的影响,从而选出合适的数值模拟设置方法。将性能预测结果与样机试验结果对比,验证利用CFX软件预测高速深井离心泵性能的可行性。结果表明:采用叶轮网格数为40万、Standard k-ε湍流模型、两级全流场模型对高速深井离心泵进行全流场三维定常数值模拟最为合适。 相似文献
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基于Lightill声类比理论,采用计算流体力学(Computational fluid dynamics, CFD)和计算声学(Computational acoustics, CA)相结合的算法对离心泵内部声场进行求解。基于SST k-ω湍流模型封闭雷诺时均方程,对离心泵内流场进行三维非定常计算。在流场计算的基础上采用边界元法对叶片偶极子源和蜗壳偶极子源的辐射声场进行求解,研究了蜗壳振动对声压级分布的影响,并搭建试验台对所提出的算法进行验证。结果表明,叶频及其倍频是流动诱导噪声的主要频率,隔舌附近监测点的压力脉动强度最大;声振耦合作用对声压级分布的影响不可忽略,模态振型所在的频率(580 Hz)下声振耦合作用的影响较大;泵出口场点的声压级比进口大,且均在叶频处最大,效率最高的工况点声压级最小;声场模拟和试验结果在趋势上基本吻合,最大相差3.1%,肯定了所提数值算法的预测作用,可为离心泵低噪声优化设计提供参考。 相似文献
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Evaluation of subgrid-scale models in large-eddy simulations of turbulent flow in a centrifugal pump impeller 总被引:5,自引:1,他引:4
The current research of large eddy simulation (LES) of turbulent flow in pumps mainly concentrates in applying conventional subgrid-scale (SGS) model to simulate turbulent flow, which aims at obtaining the flow field in pump. The selection of SGS model is usually not considered seriously, so the accuracy and efficiency of the simulation cannot be ensured. Three SGS models including Smagorinsky-Lilly model, dynamic Smagorinsky model and dynamic mixed model are comparably studied by using the commercial CFD code Fluent combined with its user define function. The simulations are performed for the turbulent flow in a centrifugal pump impeller. The simulation results indicate that the mean flows predicted by the three SGS models agree well with the experimental data obtained from the test that detailed measurements of the flow inside the rotating passages of a six-bladed shrouded centrifugal pump impeller performed using particle image velocimetry (PIV) and laser Doppler velocimetry (LDV). The comparable results show that dynamic mixed model gives the most accurate results for mean flow in the centrifugal pump impeller. The SGS stress of dynamic mixed model is decompose into the scale similar part and the eddy viscous part. The scale similar part of SGS stress plays a significant role in high curvature regions, such as the leading edge and training edge of pump blade. It is also found that the dynamic mixed model is more adaptive to compute turbulence in the pump impeller. The research results presented is useful to improve the computational accuracy and efficiency of LES for centrifugal pumps, and provide important reference for carrying out simulation in similar fluid machineries. 相似文献
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为了研究多级离心泵的性能及其内部流场分布,采用SST k-ε湍流模型对原型泵的首级、第二级及第三级叶轮进行定常和非定常数值模拟计算,分析其外特性、内部流场和压力脉动。研究表明,通过前三级叶轮的扬程能较准确地预测原型泵的扬程。不同流量工况下隔舌处均易出现低压区域,大流量工况蜗壳出口近隔舌处也易出现局部低压区和高压区,隔舌处压力梯度较大。小流量下首级叶轮近隔舌区域的压力脉动不稳定,周期性较差,频域幅值主要集中在低频率区域;对于设计流量和大流量工况,首级叶轮近隔舌区域和远离隔舌区域的压力脉动较为稳定,呈现出较明显的周期性,主频在1倍和2倍叶片通过频率处,频域幅值主要集中在叶片通过频率及其高次谐波频率处。 相似文献