Comparisons of Hydraulic Performance in Permanent Maglev Pump for Water-Jet Propulsion

Cao, Puyu; Wang, Yang; Qian, Kunxi; Li, Guidong

doi:10.1155/2014/438176

Cited by 6 publications

(5 citation statements)

References 8 publications

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“…According to previous research [29][30][31], non-uniform inflow conditions of waterjet pumps exhibit four distinct vortex structures: concentrated separation vortex (CSV), circumferential vortex (CV), hub spanwise vortex (HSV), and flow separation. To investigate the relationship between these vortex structures and pump performance, four modalities were utilized as boundary conditions in the subsequent CFD calculation for further study of flow field analysis.…”

Section: Resultsmentioning

confidence: 99%

Proper Orthogonal Decomposition Based Response Analysis of Inlet Distortion on a Waterjet Pump

Cao,

Yue,

Zhang

et al. 2024

Water

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This study addresses the challenge of performance degradation in waterjet pumps due to non-uniform suction flow. Utilizing the Proper Orthogonal Decomposition (POD) method, it decomposes and reconstructs the flow features within a waterjet pump under non-uniform inflow into a series of modes ranked in descending order of energy. By analyzing the modes with dominant energy, which contain complex information about the flow field, it is revealed that modes 1 and 2 predominantly represent the formation of a concentrated vortex, whereas modes 3 and 4 illustrate its spatial offset. Notably, in the hub section, mode 3 exhibits a delayed flow separation caused by the reduction of circumferential vortex (CV), with a consequent lift in blade loading at the leading edge and a higher head compared to mode 1. In the shroud section, the delayed flow separation in mode 3 suppressed reverse flow and the concentrated separation vortex (CSV) and then increased the blade loading, ultimately enhancing the pump head. The findings provide significant insights into optimizing waterjet pump performance by detailing the interactions between various flow structures and pump components, effectively filling a knowledge gap in applying dimensionality reduction techniques within the distorted flow fields of water jet pumps.

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Section: Resultsmentioning

confidence: 99%

Proper Orthogonal Decomposition Based Response Analysis of Inlet Distortion on a Waterjet Pump

Cao,

Yue,

Zhang

et al. 2024

Water

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“…Assuming that the semi-submersible non-axial current generator [8] designed in this project is applied to the coastal scene where the current velocity is 1-2 m/s, the above simulation results show that after the airfoil deflector accelerates 1 m/s and 2 m/s ocean currents, the average current velocity through the non-axial current generator's non-axial rim is 2.02 m/s and 4.1 m/s respectively. By referring to relevant literature, it is obtained that the generator power coefficient Cp is 0.31, Șe is the generator efficiency is 0.9, ȡ is the density of seawater, which is 1.05 × 10 ଷ ݇݃/݉ ଷ .…”

Section: Power Calculation Of Semi-submersible Shaftless Ocean Curren...mentioning

confidence: 99%

Semi-submersible non-axial current generators based on improving current energy conversion efficiency

Wang,

Liu,

et al. 2024

J. Phys.: Conf. Ser.

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With the development and utilization of ocean current energy, how to improve the efficiency of ocean current energy utilization has become the focus of attention in many countries. In this paper, the optimal design of the structure of the ocean current generator is mainly used to improve the energy capture power and the conversion efficiency of the ocean current energy unit under the condition of low flow rate. The effect of peripheral fluid growth on the generator is analyzed using finite element analysis. The three-dimensional finite element model of the semi-submersible axial-current generator is established by using the ANSYS finite element method, and the calculation and analysis of the peripheral fairing are simplified. Through finite element calculation and analysis, the velocity cloud diagram and velocity linear vector diagram are obtained, respectively. The results show that the semi-submersible axial current generator has the ability to start and generate electricity at low velocity and can use the current resources for power supply in situ. Its application can maximize the current capture and greatly improve the utilization rate of current energy.

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“…In recent years, many studies have confirmed that numerical simulations can accurately predict performances of a water-jet pump and a complete water-jet propulsion system. 7,8,10 In this article, the commercial software ANSYS-CFX is used to simulate the threedimensional (3D) flow within a complete water-jet propulsion system, where the pump suction flow is non-uniform. Meanwhile, the steady simulation of a single water-jet pump is also performed to obtain performances under the uniform suction flow.…”

Section: Numerical Setupmentioning

confidence: 99%

“…The boundary layer thickness was calculated by Wieghardt equation. 10,12 All the physical walls were set as nonslip walls…”

Section: Geometry Of the Water-jet Pumpmentioning

confidence: 99%

Concentrated separation vortex induced by non-uniform suction flow and its role in performance breakdown of a water-jet pump

Cao

Wang

Zhang

et al. 2017

Advances in Mechanical Engineering

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Many water-jet pumps have a suction velocity profile, which is non-uniform and unfavorable for the pump performance. This article applies the numerical method to investigate the generation mechanism of performance breakdown in a water-jet pump under non-uniform suction flow. The mechanism dictating flow details in the impeller, including the inlet velocity, flow angle, and boundary layer separation, is systematically studied at the design point. Observations show that the nature of non-uniform inflow is a circumferential distortion upstream of the impeller shroud, which is proved to be a stationary stall cell associated with a velocity deficit near the top sector. Meanwhile, a detailed analysis allows the identification of flow separation and vortex in the impeller. The circumferential distortion gives rise to a high incidence, the occurrence of suction surface separation, and the consequent formation of a concentrated separation vortex near the blade shroud. Furthermore, particular attentions are devoted to the pressure distribution and blade loading in the shroud section. Deviating from the suction surface, the concentrated separation vortex produces a considerable pressure rise on the suction surface and generates a remarkable drop in blade loading. Consequently, the concentrated separation vortex associated with circumferential distortion is a major reason for the head breakdown of a water-jet pump.

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Comparisons of Hydraulic Performance in Permanent Maglev Pump for Water-Jet Propulsion

Cited by 6 publications

References 8 publications

Proper Orthogonal Decomposition Based Response Analysis of Inlet Distortion on a Waterjet Pump

Proper Orthogonal Decomposition Based Response Analysis of Inlet Distortion on a Waterjet Pump

Semi-submersible non-axial current generators based on improving current energy conversion efficiency

Concentrated separation vortex induced by non-uniform suction flow and its role in performance breakdown of a water-jet pump

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