Numerical and experimental investigation of tip leakage vortex trajectory and dynamics in an axial flow pump

Zhang, Desheng; Shi, Weidong; Esch, B.P.M. van; Shi, Lei; Dubuisson, Michel

doi:10.1016/j.compfluid.2015.01.010

Cited by 155 publications

(64 citation statements)

References 22 publications

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“…Zhang et al [10][11][12] numerally investigated the tip leakage vortex structure and trajectory in an axial flow pump by combining the shear stress transport k-ω turbulence model with a cavitation model. Yang et al [13] used the standard k-ε turbulence model to investigate the effect of the radial gap between impeller tips and volute tongue on efficiency and pressure pulsation of pumps used as turbines.…”

Section: Introductionmentioning

confidence: 99%

Energy Performance and Flow Patterns of a Mixed-Flow Pump with Different Tip Clearance Sizes

et al. 2017

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Tip clearance between blade end and shroud is inevitable in pump operation and of great importance on pump energy performance and pressure fluctuation. As the tip clearance size increases, the head and efficiency of the mixed flow pump drop accordingly. The simulation results show that the development of a leakage vortex is observed as the tip clearance increases, and the trajectory of this leakage vortex remains in the same direction along the blade suction side for different tip clearances. With the increase in tip clearance size, the intensity of the leakage vortex is enhanced, and the separation between the main leakage vortex and the secondary leakage vortex is also strengthened. The leakage separation angle near the blade tip remains at the same value of 10° for different tip clearance sizes. As for the spectrum analysis, the maximum amplitudes of pressure fluctuations dramatically increase in the impeller when the tip clearance increases from 0.0 mm to 1.0 mm, and the dominant frequencies go from 145 Hz to 184 Hz due to the considerable leakage flow.

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Section: Introductionmentioning

confidence: 99%

Energy Performance and Flow Patterns of a Mixed-Flow Pump with Different Tip Clearance Sizes

et al. 2017

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“…The meshes of tip clearance domain are generated separately to guarantee the mesh quality, and 20 layers are set in the clearance. 15 Before the calculation, the grid independence test has been carried out on the no-tip clearance pump, which shows that when the grid number exceeds 3,500,000, the performance error is below 2%. So the topology for the 3,500,000 grid is chosen for the calculation and the tip clearance domain grid number is mainly controlled by layer number and mesh quality.…”

Section: Comparison Between Experimental Data and Numerical Resultsmentioning

confidence: 99%

Pressure fluctuation and flow pattern of a mixed-flow pump with different blade tip clearances under cavitation condition

Tan

Liu

et al. 2017

Advances in Mechanical Engineering

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Cavitation phenomenon has strong transient characteristics and is highly influenced by geometric structure. In this study, the cavitation performance with influence of blade tip clearance for a mixed-flow pump is studied using the renormalization group (RNG) k-e turbulence model and the Zwart-Gerber-Belamri cavitation model. The dominant frequency and maximum amplitude values at non-cavitation condition and different cavitation conditions are compared and associated with flow field features. The results show that the dominant frequency value under incipient cavitation and critical cavitation is 3.2f i and when the cavitation is severe, the frequency value changes to 3.5f i . Then, the influence of tip clearance width on cavitation performance of the mixed-flow pump is also discussed. The results show that the increase in tip clearance will significantly aggravate the performance drop of the pump under cavitation conditions. The critical net positive suction head value increases in 4.79% of the value under no-tip clearance condition. At the same time, by the inner flow field observation and analysis, the morphological of cavitation bubbles is also changed, and the cavitation bubbles tend to attach to the blade suction side and the attachment length increases as the tip clearance increases.

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“…The trajectory of TLV will significantly influence the workability and flow instability in the flow passage. By using both numerical and experimental methods, Zhang et al [42] investigated the characteristics of TLV trajectory and associated cavitation structures in an axial pump. As shown in Figure 16, the streamlines twist through each section, and the center of the streamlines corresponds to the maximum swirling strength.…”

Section: Tlv Trajectory and Related Factorsmentioning

confidence: 99%

A Review of Tip Clearance in Propeller, Pump and Turbine

2018

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Propellers, pumps, and turbines are widely applied in marine equipment, water systems, and hydropower stations. With the increasing demand for energy conservation and environmental protection, the high efficiency and the stable operation of pumps and turbine have been drawing great attention in recent decades. However, the tip clearance between the rotating impeller and the stationary shroud can induce leakage flow and interact with the main stream, introducing complex vortex structures. Consequently, the energy performance and the operation stability of pumps and turbines deteriorate considerably. Constant efforts are exerted to investigate the flow mechanism of tip-clearance flow and its induced influence on performance. However, due to various pump and turbine types and the complexity of tip-clearance flow, previous works are usually focused on a specific issue. Therefore, a systematic review that synthesizes the related research is necessary and meaningful. This review investigates related research in the recent two decades in the perspectives from fundamental physics to engineering applications. Results reveal the vortex types, trajectory, evolution, and cavitation behaviors induced by tip-clearance flow. It is concluded that the influence characteristics of tip clearance on energy performance are closely related to the machinery type. Tip-clearance size and tip shape are found to be crucial parameters for tip-leakage vortex (TLV). The proposed optimization schemes are also demonstrated to provide inspiration for future research. Overall, this review article provides a coherent insight into the characteristics of tip-clearance flow and the associated engineering-design applications. On the basis of these understandings, comments on conducted research and ideas on future research are proposed.

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Numerical and experimental investigation of tip leakage vortex trajectory and dynamics in an axial flow pump

Cited by 155 publications

References 22 publications

Energy Performance and Flow Patterns of a Mixed-Flow Pump with Different Tip Clearance Sizes

Energy Performance and Flow Patterns of a Mixed-Flow Pump with Different Tip Clearance Sizes

Pressure fluctuation and flow pattern of a mixed-flow pump with different blade tip clearances under cavitation condition

A Review of Tip Clearance in Propeller, Pump and Turbine

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