Numerical Investigation of Periodic Fluctuations in Energy Efficiency in Centrifugal Pumps at Different Working Points

Zhang, Hehui; Deng, Shengxiang; Qu, Yingjie

doi:10.3390/en10030342

Cited by 10 publications

(5 citation statements)

References 16 publications

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“…A numerical study found that the volume flow rate of the leakage flow directly affected the liquid pressure in the balance chamber, and the calculation of the impeller cover plate force (i.e., the axial force of the centrifugal pump) and an appropriate balance hole diameter could balance the axial force to its maximum [9]. Other studies [10][11][12][13][14][15][16] found that the characteristics of leakage flow in the balance chamber directly influence the accuracy of the axial force prediction. Other studies [17,18] on the centrifugal pump have concluded that the distribution of axial velocity in the lateral chamber of the back cover plate is similar to that in the closed cylinder.…”

Section: Introductionmentioning

confidence: 99%

Influence of Balance Hole Diameter on Leakage Flow of the Balance Chamber in a Centrifugal Pump

Dong

Chen

Sun

et al. 2021

Shock and Vibration

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The balancing holes in centrifugal pumps with seals mounted in both suction and discharge sides are one of the approaches used by pump manufacturers to reduce the axial thrust. The balance hole diameter directly affects the axial force of the centrifugal pump. The flow characteristics in the balance chamber are closely related to the balance hole diameter. However, research is not very clear on the internal flow of the balanced chamber, due to the small axial and radial sizes and the complicated flow conditions in the chamber. In this paper, we analyzed the influence of the balance hole diameter on the liquid leakage rate, flow velocity, and vortex motion in the balance chamber. The results indicated that when the balance hole diameter was lower than the design value, the volume flow rate of leakage flow was proportional to the diameter. The liquid flow rate and vortex distribution rules in the balance chamber were mainly associated with the coeffect of radial leakage flow in the rear sealing ring interval and the axial balance hole leakage flow. The research has revealed the mechanisms of leakage flow of the balance chamber in the centrifugal pump and that this is of great significance for accurate calculation and balancing of the axial force.

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Section: Introductionmentioning

confidence: 99%

Influence of Balance Hole Diameter on Leakage Flow of the Balance Chamber in a Centrifugal Pump

Dong

Chen

Sun

et al. 2021

Shock and Vibration

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“…Based on the previous work by Zhang et al [1,24,25], this research presents a new one-way coupling simulation approach for the flow-induced vibration of rotor assembly in centrifugal pump, with special attention on the association features of unsteady internal flow and shaft vibration. Compared with…”

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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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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“…Zhang et al. 14 investigated the efficiency fluctuation in a centrifugal pump with six blades and argued that fluid was distributed unevenly and caused the periodic fluctuation when the discharge was larger than the optimal point.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic analysis of energy dissipation and unsteady flow characteristic in a centrifugal dredge pump under over-load conditions

Zhao

Wang

Xiao

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part C:

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The present paper aims to investigate the energy dissipation related to unsteady flow phenomena inside a three-bladed impeller of a centrifugal dredge pump under over-load operating conditions. Three-dimensional unsteady numerical simulations of the centrifugal pump are performed by adopting the SAS SST-curvature correction turbulence model with the total energy equation. The simulating results are verified by comparing the performance results and pressure fluctuation with available experimental data. The unsteady flow patterns and energy dissipation in the rotating impeller are analysed by entropy distribution and pressure fluctuation spectra. A high-entropy area appears in the impeller flow passage when the discharge increases. It is indicated in the unsteady simulation results that a vortex flow with high entropy generates and detaches periodically, which causes the hydraulic energy loss under over-load operating conditions. In numerical simulations, a frequency as 3.3 times of rotating frequency is found in the pressure spectral analysis at 1.45 Q0 operating condition, which is related to the unsteady flow structure. The secondary flow near the volute tongue is found at 1.45 Q0 operating condition due to the large angle of attack when discharge increases.

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Numerical Investigation of Periodic Fluctuations in Energy Efficiency in Centrifugal Pumps at Different Working Points

Cited by 10 publications

References 16 publications

Influence of Balance Hole Diameter on Leakage Flow of the Balance Chamber in a Centrifugal Pump

Influence of Balance Hole Diameter on Leakage Flow of the Balance Chamber in a Centrifugal Pump

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

Thermodynamic analysis of energy dissipation and unsteady flow characteristic in a centrifugal dredge pump under over-load conditions

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