Flow characteristics in a volute-type centrifugal pump using large eddy simulation

Kye, Beomjun; Park, Keuntae; Choi, Hyo Geun; Lee, Myungsung; Kim, Joo-Han

doi:10.1016/j.ijheatfluidflow.2018.04.016

Cited by 74 publications

(24 citation statements)

References 23 publications

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“…(node,t) = P(node)+P(node,t) (11) where the numerical value of P(node) is defined the arithmetic mean value of pressure in one revolution (12) where N is the number of time steps, t0 is the initial moment and ∆ is the time step length. Thus the value of P(node,t) is the difference between instantaneous pressure value (node,t) and P(node) P(node,t)=P(node,t)-P(node) (13) ̃( , ) is worth in-depth study as it indicates the instability of the inner flow of centrifugal pump. Hence, the dimensionless quantity namely the pressure fluctuation intensity coefficient C P ' is defined as the root-mean-square of P(node,t) divided by reference pressure Pref C P ' = P rms (node) P ref (14) where P rms (node) and Pref are shown in Equations (15) and (16), respectively.…”

Section: Pressure Pulsation Characteristicsmentioning

confidence: 99%

“…In addition, there are also other obvious frequency components rather than f BPF or multiple f n , which are stimulated by a serious complex unsteady flow behaviors, such as the jet-wake pattern along the blade extension direction, the flow impact on the tongue, and the flow separation on the blade suction surface [10][11][12]. The above behaviors usually become more evident under off-design conditions and would take much greater risks for the operation of centrifugal pump [13,14].…”

Section: Introductionmentioning

confidence: 99%

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CFD-Rotordynamics Sequential Coupling Simulation Approach for the Flow-Induced Vibration of Rotor System in Centrifugal Pump

Zhang

You

et al. 2020

Applied Sciences

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Featured Application: The numerical approach in this article can provide abundant information about the flow induced vibration of the pump rotor and may offer theoretical guidance to the design of reducing vibration and safety monitoring of centrifugal pumps.Abstract: Vibration of the rotor system is closely related with the operation stability of centrifugal pump, and it is inevitably induced by the unsteady inner flow. An unsteady computational fluid dynamics model coupling with a rotordynamics model was presented, and the corresponding numerical calculation program, including a self-designed rotordynamics code, was developed on the commercial package ANSYS Workbench. The validity of the numerical calculation model was verified by a hydraulic performance and vibration test based on an industrial centrifugal pump. The hydraulic radial forces on impeller, pressure pulsation, deformation, and vibration of the main shaft under nine different flow rates were systematically investigated and explained preliminarily from the view of inner unstable flow. Results show that the blade passing frequency is the dominant frequency in the fluctuation of the above dynamical behaviors, which is closely related to the rotor-stator interaction between the impeller and volute casing. This study built the connection between internal fluid flow in the centrifugal pump and the vibration of its external rotor structure, and may provide theoretical references for the design of vibration-reducing and safety monitoring strategies design of centrifugal pumps.3 of 33 former works, the first and foremost improvement of this work is the application of rotordynamics in the CSD, where the bearing damping matrix and gyroscopic matrix have been added to the general dynamic equation. With this advantage, the above new approach is able to provide a wealth shaft oscillation information including vibration velocity and shaft centerline orbit, with both the unsteady hydraulic force on the impeller and the rotor dynamic properties in consideration.In this article, an industrial split-case double suction centrifugal pump was chosen for study, and the unsteady flow as well as rotor assembly vibration behaviors under different operation conditions were investigated. The remaining of this article was organized as follows. In Section 2, the mathematical model and its overall frame are presented. Section 3 describes the computation details and experiment setup for a research case. Sections 4 and 5 are the analysis and discussion for the numerical and experimental results, followed by the conclusions in Section 6. Sequential Coupling Model Hypothesis and SimplificationThis study constructs the CFD-rotordynamics sequential coupling numerical model of centrifugal pump mainly based on following hypotheses and simplifications:(1) The coupling between flow field and rotordynamics belongs to one-way coupling. It means that only influences of flow induced exciting force on the vibration behavior of the rotor system were considered, but interferences of the deformati...

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Section: Pressure Pulsation Characteristicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

CFD-Rotordynamics Sequential Coupling Simulation Approach for the Flow-Induced Vibration of Rotor System in Centrifugal Pump

Zhang

You

et al. 2020

Applied Sciences

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“…In order to explain the pressure fluctuation process under such a working condition, accurate data of the centrifugal pump impeller are required. Compared with the data obtained by ex-perimental measurements [28] and Reynolds-averaged Navier-Stokes (RANS) [29][30][31][32], large eddy simulation (LES) can solve the model with more accurate data of internal flow and has been applied to the centrifugal pump impeller [33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Large Eddy Simulation of Periodic Transient Pressure Fluctuation in a Centrifugal Pump Impeller at Low Flow Rate

et al. 2021

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This paper presents a large eddy simulation of a centrifugal pump impeller during a transient condition. The flow rate is sinusoidal and oscillates between 0.25Qd (Qd indicates design load) and 0.75Qd when the rotating speed is maintained. Research shows that in one period, the inlet flow rate will twice reach 0.5Qd, and among the impeller of one moment is a stall state, but the other is a non-stall state. In the process of flow development, the evolution of low-frequency pressure fluctuation shows an obviously sinusoidal form, whose frequency is insensitive to the monitoring position and equals to that of the flow rate. However, inside the impeller, the phase and amplitude in the stall passages lag behind more and are stronger than that in the non-stall passages. Meanwhile, the strongest region of the high-frequency pressure fluctuation appears in the stall passages at the transient rising stage. The second dominant frequency in stall passages is 2.5 times to that in non-stall passages. In addition, similar to the pressure fluctuation, the evolution of the low-frequency head shows a sinusoidal form, whose phase is lagging behind that by one-third of a period in the inlet flow rate.

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“…Based on the published works, unsteady pressure pulsation energy within the centrifugal pump is affected by two factors, and one is the fluid distribution characteristics at the BTE and the other is the corresponding intense interacting effect with the tongue. So, if we can control and reduce the striking effect between the fluid discharged from the BTE and the volute tongue, then pressure pulsation energy could be decreased [19][20][21]. For the commonly used impeller, when the wrap angles from the shroud to the hub streamlines are identical, fluid discharged from the impeller will hit and interact with the tongue simultaneously [22,23], namely with the same phase.…”

Section: Introductionmentioning

confidence: 99%

Effect of the staggered impeller on reducing unsteady pressure pulsations of a centrifugal pump

Jiang

Zhang

Liu

et al. 2021

Preprint

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High pressure pulsations excited by rotor stator interaction is always focused in pumps, especially for its control considering the stable operation. In the current research, a special staggered impeller is proposed to reduce intense pressure pulsations of a centrifugal pump with ns=69 based on alleviating rotor stator interaction. The numerical simulation method is conducted to illustrate the influence of staggered impeller on the pump performance and pressure pulsations, and three typical flow rates (0.8ФN-1.2ФN) are simulated. Results show that the staggered impeller will lead to the pump head increasing, and at the design working condition, the increment reaches about 3% compared with the original impeller. Meanwhile, the pump efficiency is little affected by the staggered impeller, which is almost identical with the original impeller. From comparison of pressure spectra at twenty monitoring points around the impeller outlet, it is validated that the staggered impeller contributes significantly to decreasing pressure pulsations at the concerned working conditions. At the blade passing frequency, the averaged reduction of twenty points reaches 89% by using the staggered impeller at 1.0ФN. The reduction reaches to 90%, 80% at 0.8ФN, 1.2ФN respectively. Caused by the rib within the staggered impeller, the internal flow field in the blade channel will be affected. Finally, it is concluded that the proposed staggered impeller surely has a significant effect on alleviating intense pressure pulsation of the model pump, which is very promising during the low noise pump design considering its feasibility for manufacturing.

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Flow characteristics in a volute-type centrifugal pump using large eddy simulation

Cited by 74 publications

References 23 publications

CFD-Rotordynamics Sequential Coupling Simulation Approach for the Flow-Induced Vibration of Rotor System in Centrifugal Pump

CFD-Rotordynamics Sequential Coupling Simulation Approach for the Flow-Induced Vibration of Rotor System in Centrifugal Pump

Large Eddy Simulation of Periodic Transient Pressure Fluctuation in a Centrifugal Pump Impeller at Low Flow Rate

Effect of the staggered impeller on reducing unsteady pressure pulsations of a centrifugal pump

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