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22 pages, 8614 KiB

Open AccessArticle

Experimental Visualization Study on Flow Characteristics Inside a Self-Priming Sewage Pump

by Mingjie Xu, Shuihua Zheng, Yiliang Li, Qing Huang, Zenan Sun and Jianlin Hu

Water 2025, 17(5), 735; https://doi.org/10.3390/w17050735 - 3 Mar 2025

Viewed by 454

Abstract

To investigate the motion patterns of flexible fibers inside a sewage pump and their impact on internal flow characteristics, visualization experiments were conducted to compare the pump flow when transporting water—0.3% CMC solution and 0.3% CMC solution containing flexible fibers under different operating [...] Read more.

To investigate the motion patterns of flexible fibers inside a sewage pump and their impact on internal flow characteristics, visualization experiments were conducted to compare the pump flow when transporting water—0.3% CMC solution and 0.3% CMC solution containing flexible fibers under different operating conditions. The results showed that changes in the rheological properties of the 0.3% CMC solution primarily affected fluid viscous dissipation. Under the same rotational speed, the flow rate increased by only 2.4%, but power consumption decreased by 9.1%, resulting in a 6.4% improvement in efficiency. The curvature and distribution of fibers within the impeller flow channel remained stable. Their impact on the flow was characterized by an overall reduction in velocity within the impeller region, with the peak velocity decreasing by up to 26.3%. The primary cause of pump failure due to fibers was their tendency to repeatedly accumulate and detach at the tongue, leading to blockages. Fiber length had a more significant impact on the blockage rate than mass concentration. Full article

(This article belongs to the Special Issue Hydrodynamics in Pumping and Hydropower Systems)

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26 pages, 9954 KiB

Open AccessArticle

Optimization of Pumping Station Inlet Channel Based on Stress-Blended Eddy Simulation Turbulence Model and Entropy Generation Theory

by Rui Jiang, Yi Zhang, Jianzhong Zhu, Buqing Chen, Yiping Tang, Xu Yang, Yuan Zheng and Huiling Duan

Water 2025, 17(3), 378; https://doi.org/10.3390/w17030378 - 30 Jan 2025

Cited by 1 | Viewed by 522

Abstract

The optimization of pumping station inlet channels is a key research area for improving the operation efficiency, reducing the energy consumption, and enhancing the operation reliability of pumping stations. For the elbow inlet channel of the Majinggang Pumping Station project, based on the [...] Read more.

The optimization of pumping station inlet channels is a key research area for improving the operation efficiency, reducing the energy consumption, and enhancing the operation reliability of pumping stations. For the elbow inlet channel of the Majinggang Pumping Station project, based on the Stress-Blended Eddy Simulation (SBES) turbulence model and entropy generation theory, an optimization design plan is proposed by altering the inclination angle of the flow channel base plate, the length of the transitional arc segment, and the length of the curved segment. Various schemes were analyzed and comprehensively compared in terms of the hydraulic loss, the velocity-weighted average angle, and the axial-velocity distribution uniformity of the channel. The results indicate that optimal hydraulic performance is achieved when the inclination angle of the base plate is between 8° and 10°. In a reasonable range of values, appropriately increasing the length of the transitional arc and reducing the section width (throat width) can improve the hydraulic performance of the inlet channel. The optimal model obtained achieved an impressive velocity-weighted average angle of 89.25°, along with an axial-velocity distribution uniformity of 97.5%. Its excellent hydraulic performance not only meets the design requirements of the pumping station in terms of functionality but also takes into account economic efficiency, and it serves as a valuable reference for similar projects, contributing to the more refined and intelligent development of the optimization of pumping station inlet flow channels. Full article

(This article belongs to the Special Issue Hydrodynamics in Pumping and Hydropower Systems)

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21 pages, 10392 KiB

Open AccessArticle

The Effect of the Reservoir Regulation Ability on the Water Consumption Rate During the Hydro–Wind–Photovoltaic Integration

by Guanghui Li, Tingxuan Yang, Yiyang Ma, Shutong Yang and Xianxun Wang

Water 2025, 17(3), 351; https://doi.org/10.3390/w17030351 - 26 Jan 2025

Viewed by 587

Abstract

The combined operation of hydropower and renewable energy impacts the hydropower operation efficiency, which exhibits different effects while the reservoir is deployed various regulation abilities. This study attempts to investigate the effect of reservoir regulation storage on the average daily water consumption rate. [...] Read more.

The combined operation of hydropower and renewable energy impacts the hydropower operation efficiency, which exhibits different effects while the reservoir is deployed various regulation abilities. This study attempts to investigate the effect of reservoir regulation storage on the average daily water consumption rate. A case study of the integration of hydro–wind–photovoltaic located in Western China shows the differences mentioned above and explains the mechanism of the effect on the daily water consumption rate. It was concluded that (1) with increasing penetrations of renewable energy (from 0 to 90%), the daily water consumption rate mostly displays a trend of descent and then ascent; (2) with the increasing regulation ability of the reservoir (from 0.8 to 5.35 × 10⁸ m³), the water consumption rate increases in the dry season but decreases in the flood season; (3) the hydropower output and net water head are two factors that cause the water consumption rate to rise and fall; and (4) a balance point between the net water head rise and the output reduction is pointed out. The findings of this study provide technique support for the research of water utilization efficiency during the renewable energy mix. Full article

(This article belongs to the Special Issue Hydrodynamics in Pumping and Hydropower Systems)

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16 pages, 10642 KiB

Open AccessArticle

Stability Analysis of Pump-Turbine in Hump Zone Based on Omega Vortex Identification Method

by Yuan Zheng, Kui Tang, Lianchen Xu, Shenming Ren, Junhui Xu, Yirong Wang, Dongsen An and Changliang Ye

Water 2024, 16(23), 3443; https://doi.org/10.3390/w16233443 - 29 Nov 2024

Viewed by 802

Abstract

As the central component of a pumped storage power station, the pump-turbine frequently enters the hump region during operation, which impacts the safe functioning of the unit. This study investigates the flow patterns at various guide vane openings within the hump area, employing [...] Read more.

As the central component of a pumped storage power station, the pump-turbine frequently enters the hump region during operation, which impacts the safe functioning of the unit. This study investigates the flow patterns at various guide vane openings within the hump area, employing the Omega vortex identification method. The results reveal that transitioning into the hump region from design conditions results in an unsteady flow state in the vaneless space, seriously threatening the stability of the pump-turbine. Notably, at the lowest point in the hump zone, the vaneless space generates high-speed circulation characterized by large velocity gradients and severe flow separation. The region of high turbulent kinetic energy intensifies with increasing guide vane opening. Additionally, low-frequency pressure pulsations become the predominant frequency in the hump zone, and the relative amplitude of these pulsations reach higher values, which is caused by rotating stall. The Omega vortex identification technique illustrates that the vortex structure is minimized during optimal efficiency in the vaneless space. As the flow rate in the hump region decreases, persistent high-energy vortices accumulate in the vaneless space, resulting in a significant increase in vorticity intensity and causing unsteady flow in the pump turbine. Full article

(This article belongs to the Special Issue Hydrodynamics in Pumping and Hydropower Systems)

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15 pages, 13165 KiB

Open AccessArticle

Numerical Study of Low-Specific-Speed Centrifugal Pump Based on Principal Component Analysis

by Yangyang Wei, Han Zhu, Quanwang Fan, Ning Qiu, Jie Wu and Weibin Zhang

Water 2024, 16(13), 1785; https://doi.org/10.3390/w16131785 - 24 Jun 2024

Viewed by 1278

Abstract

The characteristics of pressure pulsations in centrifugal pumps have attracted considerable attention. In this study, principal component analysis is used to discuss the pressure pulsations in a centrifugal pump with a low specific speed, and the primary causes for these pressure pulsations are [...] Read more.

The characteristics of pressure pulsations in centrifugal pumps have attracted considerable attention. In this study, principal component analysis is used to discuss the pressure pulsations in a centrifugal pump with a low specific speed, and the primary causes for these pressure pulsations are analyzed in conjunction with experimental results. The results indicate that principal component analysis effectively separates the primary modes that influence the flow field characteristics. An excessive wrap angle results in the formation of a backflow vortex on the working face of the blade. Obvious stratification of the zero-order modal pressure indicates that the geometric structure of the impeller is rational and that the transient flow field is stable. The second- and third-order modes are conjugates, and their dominant frequency coincides with the dominant rotating frequency of the impeller, indicating that the pulsations of a single channel are the primary component of the pressure pulsations. The primary frequency (148.54 Hz) of the pressure pulsations at monitoring points distributed across the volute is three times the rotational frequency (49.51 Hz) of the impeller. The different positions and sub-frequencies of the monitoring points mean that the principal component analysis can effectively identify the impeller-induced sub-frequency difference. Full article

(This article belongs to the Special Issue Hydrodynamics in Pumping and Hydropower Systems)

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18 pages, 9440 KiB

Open AccessArticle

Research on the Flow Characteristics of Power-Law Fluids in Self-Priming Sewage Pumps

by Xukan Li, Shuihua Zheng, Zhenghao Shao, Mingjie Xu, Yiliang Li, Qing Huang, Min Chai and Zenan Sun

Water 2024, 16(11), 1526; https://doi.org/10.3390/w16111526 - 26 May 2024

Cited by 1 | Viewed by 1291

Abstract

To conduct a more in-depth study of the flow mechanism of power-law fluids within sewage pumps, this paper focuses on self-priming sewage pumps, with typical power-law fluid (Carboxymethyl Cellulose, CMC) as the conveying medium. The constitutive equations for sewage and typical power-law fluid [...] Read more.

To conduct a more in-depth study of the flow mechanism of power-law fluids within sewage pumps, this paper focuses on self-priming sewage pumps, with typical power-law fluid (Carboxymethyl Cellulose, CMC) as the conveying medium. The constitutive equations for sewage and typical power-law fluid (CMC solution) were established using the power-law model. Through numerical calculation methods, the non-steady flow field inside the pump of different concentration power-law fluids was analyzed from various aspects such as velocity, pressure, vorticity, and wall shear stress. The pressure pulsations at key locations in the pump flow field were monitored and analyzed. At the rated flow rate, when the concentration of CMC solution increased from 0.5% to 2.0%, the channel pressure and tongue pressure decreased by 16.5% and 3.5%, respectively. This indicates that the pressure on the impeller blades, within the flow passages, and at the tongue of the volute all decrease with the increase in concentration of CMC solution. This may alter the fluid flow pattern, leading to more vortex motion and shear deformation, while also reducing the pump’s pressure boosting capability, thereby affecting the pump’s performance stability. It can be inferred from quantitative comparisons that changes in rheological properties had a significant impact on the flow characteristics of sewage pumps. This paper reveals that some flow characteristics of power-law fluids in sewage pumps, providing a theoretical and reference basis for the performance optimization and flow mechanism research of sewage pumps. Full article

(This article belongs to the Special Issue Hydrodynamics in Pumping and Hydropower Systems)

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16 pages, 10841 KiB

Open AccessArticle

Numerical Simulation of a Three-Stage Electrical Submersible Pump under Stall Conditions

by Yuqiang Wang, Zhe Wang, Xiangyu Song, Ling Bai, Mahmoud A. El-Emam and Ling Zhou

Water 2023, 15(14), 2619; https://doi.org/10.3390/w15142619 - 19 Jul 2023

Cited by 1 | Viewed by 2023

Abstract

This paper focuses on investigating the stall phenomenon of a three-stage electrical submersible pump using numerical methods by examining the internal and external characteristics of the pump under design conditions and critical stall and deep stall conditions. The energy losses inside the impeller [...] Read more.

This paper focuses on investigating the stall phenomenon of a three-stage electrical submersible pump using numerical methods by examining the internal and external characteristics of the pump under design conditions and critical stall and deep stall conditions. The energy losses inside the impeller and diffuser are also discussed. The internal flow at all pump stages under stall conditions is analyzed, highlighting differences and correlations. Under critical stall conditions, multiple vortices appear in the impeller channel of the first stage, while the flow in the secondary and final impeller remains smooth. Flow separation occurs in the diffusers at all three stages. Under deep stall conditions, the inlet setting angle causes all stages to enter a synchronous stall state. The range and intensity of vortices in the diffusers of all stages are further increased, seriously affecting the mainstream. This paper provides valuable insights for the research of internal flow and optimal design of electrical submersible pumps. Full article

(This article belongs to the Special Issue Hydrodynamics in Pumping and Hydropower Systems)

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Review

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19 pages, 1782 KiB

Open AccessReview

Application of the 3D Inverse Design Method in Reversible Pump Turbines and Francis Turbines

by Giacomo Zanetti, Monica Siviero, Giovanna Cavazzini and Alberto Santolin

Water 2023, 15(12), 2271; https://doi.org/10.3390/w15122271 - 17 Jun 2023

Cited by 7 | Viewed by 3199

Abstract

The increasingly stringent requirements in terms of flexibility and efficiency for hydraulic turbines pose new challenges for designers. Although computational fluid dynamics has offered new opportunities to significantly improve the performance in the preliminary design phase, the design of a hydraulic turbine still [...] Read more.

The increasingly stringent requirements in terms of flexibility and efficiency for hydraulic turbines pose new challenges for designers. Although computational fluid dynamics has offered new opportunities to significantly improve the performance in the preliminary design phase, the design of a hydraulic turbine still represents a challenging task requiring considerable engineering input and know-how. In such a scenario, the inverse three-dimensional design strategy has recently demonstrated its effectiveness in improving the machine performance, and interesting applications have been proposed for Francis turbines and reversible pump turbines. This paper presents and discusses the most interesting design solutions so far documented. The influence of blade staking and load distribution on the hydrodynamic performance is discussed. Finally, optimized blade load distributions are reported to provide useful design guidelines for the development of the new generation of hydraulic turbines. Full article

(This article belongs to the Special Issue Hydrodynamics in Pumping and Hydropower Systems)

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