Transient characteristics of internal flow fields of mixed-flow pump with different tip clearances under stall condition

Ji, Leilei; Li, Wei; Shi, Weidong; Agarwal, Ramesh K.

doi:10.1177/0957650920962250

Cited by 12 publications

(6 citation statements)

References 45 publications

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“…To solve the problem, Kock 18 and Mathieu 29 proposed an effective approximate model that connected the entropy production rate with indirect eddy frequency, which has been verified to be credible in energy dissipation analysis. 30–31 When the Reynolds number approaches infinity, the indirect entropy production rate can be calculated using equation (6) where ρ is the fluid density, and ε is the indirect eddy frequency.…”

Section: Entropy Production Theorymentioning

confidence: 99%

Entropy production analysis for energy dissipation of a vertical mixed-flow pump device under asymmetric inflow conditions

Zheng

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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To investigate the influence of the inflow angle on the hydraulic loss and internal flow fields of a vertical mixed-flow pump device, unsteady numerical simulations were performed under different inflow angles ( θ = 0°, 10°, 20°, and 30°). The calculation results were validated using an external characteristic test at an inflow angle of 0°. The entropy production theory was applied to analyse the energy loss and dissipation rate distribution in a vertical mixed-flow pump device under different inflow angles. Influenced by asymmetric inflow, the design point of the external characteristics deviated towards the overload flow rate, and the maximum deviations were obtained under 1.2 Qdes, whereas the influence of the inflow angle on the internal flow fields was the most significant under the part-load flow rate. When the inflow angle increased from 0° to 30°, the total entropy production in the pump device increased by 18.35% under 0.6 Qdes, and indirect dissipation accounted for the largest proportion. The internal flow patterns in the impeller and guide vane were also distorted by asymmetric inflow. The indirect dissipation rate on the suction side of the impeller blade, interface between the impeller and diffuser, and pressure side of the guide vane increased significantly with an increase in the inflow angle. To restrain the influence of asymmetric inflow, it is of great significance to optimise the hydraulic design structure of the inflow runner. In this study, a middle spacer pier was used to improve the operational efficiency of the pump device.

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Section: Entropy Production Theorymentioning

confidence: 99%

Entropy production analysis for energy dissipation of a vertical mixed-flow pump device under asymmetric inflow conditions

Zheng

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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show abstract

“…Using numerical calculations and verification tests, Yang et al [10] investigated the effect of the tip clearance size on a sewage pump's operation and internal flow field distribution. Ji et al [11] investigated the effects of varying the tip clearance on the transient properties of mixed-flow pumps under stall conditions using unsteady time-accurate simulations. Yu et al [12] studied the effect of tip clearance on the propulsion efficiency and pressure pulsations of a pump-jet propeller.…”

Section: Introductionmentioning

confidence: 99%

Leakage Flow Characteristics in Blade Tip of Shaft Tubular Pump

Lin

Yang

Guo

et al. 2023

JMSE

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The shaft tubular pump device is widely used in various water diversion projects because of its ultra-low head and large flow characteristics. Due to the tip clearance between the blade and the shroud, it is easy to cause hydraulic mechanical performance changes, induced vibration, and noise, which seriously affects the safe and stable operation of the pump. Steady and unsteady three-dimensional flow field numerical simulations of a shaft tubular pump device were carried out using computational fluid dynamics to investigate the impeller flow properties of the device under various flow conditions, including the tip clearance leakage flow (TCLF) and change rule of pressure pulsation. The TCLF, vortex morphology evolution, and pressure pulsation properties of the impeller tip clearance were analyzed. The results show that with an increase in the flow rate, the influence of the tip clearance size on the tip clearance flow decreases, the TCLF decreases, and the axial velocity of the water flow at the tip clearance increases. When the flow rate increases, the swirling strength of the tip leakage vortex decreases, and the distance between the tip leakage vortex and the suction surface of the blade increases. With the increase in flow rate, the pressure pulsation amplitude at the tip clearance increases first and then decreases. The focus of this study is to analyze the variation of tip clearance flow field and pressure pulsation under multiple working conditions, aiming to provide some help for improving the performance of the pump device and ensuring its safe operation.

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“…Shi Guangtai et al [9] analyzed the internal flow and velocity distribution characteristics of the multiphase pump under different tip clearances, by employing the high-speed photography and numerical simulation, it found that tip leakage vortex has significant effect on the tip separated vortex and the hydraulic loss of pump. Li Wei et al [10][11] proposed a mixed-flow pump model with non-uniform tip clearance, through the technology of particle image velocimetry to analyze the effect of flow rate and eccentricity on the flow characteristics. Parikh Trupe et al [12] employed the Volume of Fluid (VOF) method and k-omega SST model to conduct the transient simulations of centrifugal pumps, and the relationship between the tip clearance gap and transport of air-water twophase flow was obtained.…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Research on the Influence of Clearance Between Impeller and Cover on the Pump Performance

Peng

Hong

Chang

et al. 2022

mech

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Centrifugal pump is widely used and plays an important role in national economy. However, according to plenty of engineering practice and model tests, it indicated that the clearance between the impeller and pump cover is an important parameter for leakage loss and hydraulic efficiency. In this paper, a single stage centrifugal pump was selected to study the influence of clearance between impeller and pump cover on the hydraulic performance through combination of experiment and numerical simulation. Commercial software ANSYS CFX was employed to simulate the internal flow field with a clearance of 0 mm, and the experimental verification was carried out. The results presented that only a small difference was generated between experiment and numerical simulation, the maximum error is less than 4%, which can ensure the accuracy of the numerical calculation. At the same time, by comparing the simulation results with clearance of 0.1 mm, 0.22 mm, 0.42 mm and 0.62 mm, it found that with the increase of clearance, the impact loss at the tongue was significantly improved. In addition, with the increase of clearance, the effect of water flowing out from clearance interferes with the water at impeller inlet gradually improve. Finally, the hydraulic experiment with different clearance were carried out to verify the numerical result. Therefore, this research results have significant guiding effect for the design of clearance between impeller and cover in the future.

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Transient characteristics of internal flow fields of mixed-flow pump with different tip clearances under stall condition

Cited by 12 publications

References 45 publications

Entropy production analysis for energy dissipation of a vertical mixed-flow pump device under asymmetric inflow conditions

Entropy production analysis for energy dissipation of a vertical mixed-flow pump device under asymmetric inflow conditions

Leakage Flow Characteristics in Blade Tip of Shaft Tubular Pump

Numerical and Experimental Research on the Influence of Clearance Between Impeller and Cover on the Pump Performance

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