Numerical Characterization of the Performance Curve of a Regenerative Pump-as-Turbine

2021 ◽  
Author(s):  
Giulio Cantini ◽  
Simone Salvadori
Keyword(s):  
Helical Structure ◽  
Operating Mode ◽  
Numerical Approach ◽  
Pollutant Emissions ◽  
Small Scale ◽  
Centrifugal Pumps ◽  
Green Technologies ◽  
Small Hydropower ◽  
Hydropower Plants ◽  
Working Region

Abstract Energy companies in the power generation field are continuously searching for green technologies to reduce pollutant emissions. In that context, small hydropower plants represent an attractive solution for distributed electricity generation. Reverse-running centrifugal pumps (also known as "pump-as-turbines", PaT) are increasingly selected in that field. Amongst the existing type of pumps, drag-type regenerative pumps (RP) can perform similarly to radial centrifugal pumps in terms of head and efficiency for low specific speed values. For a fixed rotational speed, RPs with linear blades work as pump or turbine only depending on the flow rate. Such peculiarity makes it particularly intriguing to evaluate RPs working characteristic in the turbine operating mode. In the present paper, the performance of three Regenerative Pump-as-Turbines (RPaT) are analyzed using Computational Fluid Dynamics (CFD). The numerical approach is validated using experimental data for both an RP (in the pump working region) and a regenerative turbine (RT) (in the turbine working region). Finally, the numerical simulation of a small-scale RP allows for characterizing both the pump and the turbine regions. Results shows that for a RPaT it is possible to find a "switch region" where the machine turns from behaving as a pump to behaving as a turbine, the losses not being overcome by the turbine power output. The analysis of the RPaT also shows the inversion of the flow pattern and the constant positioning of the pivot around which the flow creates the typical helical structure that characterizes RPs.

Numerical Characterization of the Performance Curve of a Regenerative Pump-As-Turbine

2020 ◽  
Author(s):  
Giulio Cantini ◽  
Simone Salvadori
Keyword(s):  
Helical Structure ◽  
Operating Mode ◽  
Numerical Approach ◽  
Pollutant Emissions ◽  
Small Scale ◽  
Centrifugal Pumps ◽  
Green Technologies ◽  
Small Hydropower ◽  
Working Region

Abstract Energy companies in the power generation field are continuously searching for green technologies to reduce pollutant emissions. In that context, small hydropower plants represent an attractive solution for distributed electricity generation. Reverse-running centrifugal pumps (also known as “pump-as-turbines”, PaT) are increasingly selected in that field. Amongst the existing type of pumps, drag-type regenerative pumps (RP) can perform similarly to radial centrifugal pumps in terms of head and efficiency for low specific speed values. For a fixed rotational speed, RPs with linear blades work as pump or turbine only depending on the flow rate. Such peculiarity makes it particularly intriguing to evaluate RPs working characteristic in the turbine operating mode. In the present paper, the performance of three Regenerative Pump-as-Turbine (RPaT) are analyzed using Computational Fluid Dynamics (CFD). The analysis is supported by an already validated in-house 1D code developed in cooperation with Pierburg Pump Technology Italy SPA. The obtained results are also discussed considering the theoretical behavior of the circulatory velocity in a regenerative machine as described by a widely used 1D model, which is extended in the present paper to the turbine working region. The numerical approach is validated using experimental data for both an RP (in the pump working region) and a regenerative turbine (RT) (in the turbine working region). Finally, the numerical simulation of a small-scale RP allows for the detailed characterization of both the pump and the turbine regions. The numerical analysis shows that for a RPaT it is possible to find a “switch region” where the machine turns from behaving as a pump to behaving as a turbine, the losses not being overcome by the turbine power output. The analysis of the RPaT also shows the inversion of the flow pattern and the positioning of the pivot around which the flow creates the typical helical structure that characterizes RPs.

scholarly journals The Influence of Changing Hydropower Potential on Performance Parameters of Pumps in Turbine Mode

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2103 ◽  
Author(s):  
Martin Polák
Keyword(s):  
Flow Rate ◽  
Water Distribution ◽  
Distribution Networks ◽  
Small Scale ◽  
Operational Parameters ◽  
Small Hydropower ◽  
Hydropower Plants ◽  
Total Head ◽  
Hydropower Potential ◽  
Water Turbines

Pumps as turbines (PAT) are used as an alternative to water turbines in small hydropower plants. The same devices can also be used for energy recovery in water distribution networks. They can replace pressure reduction valves that often lead to energy loss. However, PATs lack the parts that regulate flow so that when a hydropower potential change occurs, efficiency is reduced, as is economic gain. This article summarizes the influence of changing hydropower potential on PAT efficiency and presents comparisons of experimental results with the commonly used predictive model stemming from the theory of physical similarity, which presumes constant PAT efficiency. Our research indicates that the deviation between the model and the real power output calculation at varying potentials was minimal. Similarly, the affine parabola can be used to determine the relationship between total head and flow rate. Other relationships differ from reality the more the PAT efficiency changes. The flow rate and total head dependence on shaft speed are the main factors when setting the optimum operational parameters at varying hydropower potentials. Therefore, a change in efficiency must be included in predictive calculations to correctly optimize PAT operation. The problem is that a change in efficiency cannot be reliably predicted in advance, especially in the case of small-scale devices. For this reason, further research on the issue of changes in PAT efficiency is necessary.

scholarly journals The influence of hydrotechnical conditions on energy production in small-scale hydropower plants / Wpływ warunków hydrotechnicznych na wielkość produkcji energii w małych elektrowniach wodnych

2013 ◽  
Vol 18 (9) ◽  
pp. 29-35
Author(s):  
Marcin Bukowski
Keyword(s):  
Energy Production ◽  
Biomass Combustion ◽  
Small Scale ◽  
Small Hydropower ◽  
Total Energy Consumption ◽  
Factors Affecting ◽  
Technical Parameters ◽  
Energy Factors ◽  
Hydropower Plants ◽  
The Eu

Abstract Polish accession to the EU was followed by a need of adaptation of Polish legislation to the European requirements, also with regard to the energetic sector. The need of achieving 15% share of electric power from renewable sources in the total energy consumption till the year 2010 is a consequence of this decision. This target may be achieved in Polish conditions based on water and wind energy and from biomass combustion. The paper presents the influence of hydrologic conditions and technical parameters on the amount of produced energy. Factors affecting energy production in small hydropower plants were analysed. The formula was proposed to describe the effect of water flow in a river on energy production in small hydropower plants.

scholarly journals Recloser-Based Decentralized Control of the Grid with Distributed Generation in the Lahsh District of the Rasht Grid in Tajikistan, Central Asia

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3673
Author(s):  
Anvari Ghulomzoda ◽  
Aminjon Gulakhmadov ◽  
Alexander Fishov ◽  
Murodbek Safaraliev ◽  
Xi Chen ◽  
...  
Keyword(s):  
Power Supply ◽  
Renewable Energy Sources ◽  
Automated System ◽  
Normal Operation ◽  
Small Scale ◽  
Stable Operation ◽  
System Control ◽  
Small Hydropower ◽  
Power System Control ◽  
Hydropower Plants

Small-scale power generation based on renewable energy sources is gaining popularity in distribution grids, creating new challenges for power system control. At the same time, remote consumers with their own small-scale generation still have low reliability of power supply and poor power quality, due to the lack of proper technology for grid control when the main power supply is lost. Today, there is a global trend in the transition from a power supply with centralized control to a decentralized one, which has led to the Microgrid concept. A microgrid is an intelligent automated system that can reconfigure by itself, maintain the power balance, and distribute power flows. The main purpose of this paper is to study the method of control using reclosers in the Lahsh district of the Rasht grid in Tajikistan with distributed small generation. Based on modified reclosers, a method of decentralized synchronization and restoration of the grid normal operation after the loss of the main power source was proposed. In order to assess the stable operation of small hydropower plants under disturbances, the transients caused by proactive automatic islanding (PAI) and restoration of the interconnection between the microgrid and the main grid are shown. Rustab software, as one of the multifunctional software applications in the field of power systems transients study, was used for simulation purposes. Based on the simulation results, it can be concluded that under disturbances, the proposed method had a positive effect on the stability of small hydropower plants, which are owned and dispatched by the Rasht grid. Moreover, the proposed method sufficiently ensures the quality of the supplied power and improves the reliability of power supply in the Lahsh district of Tajikistan.

scholarly journals CFD Analysis on Pumps Working as Turbines

1970 ◽  
Vol 6 ◽  
pp. 35-37 ◽  
Author(s):  
Himanshu Nautiyal ◽  
Varun Kumar ◽  
Anoop Thakur
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Design Tool ◽  
Recent Attempt ◽  
Cfd Analysis ◽  
Centrifugal Pumps ◽  
Small Hydropower ◽  
Hydropower Plants ◽  
Computational Fluid Dynamics Cfd ◽  
Turbine Mode

 Reverse running centrifugal pumps are  an effective source of reducing the equipment cost in small hydropower plants. The manufacturers do not provide any information on the performance and fow characteristics when pumps are operated in turbine mode. Lack of Pump as Turbine (PAT) performance data is a signifcant barrier to the wider use of PAT. Application of Computational Fluid Dynamics (CFD) is a recent attempt for predicting the performance of PAT. CFD analysis is an effective design tool for predicting the performance of reverse running operation of centrifugal pumps. But some deviationsstill exist in experimental and CFD results of reverse operation of pumps. Future works in the feld of computational analysis can further improve the prediction of pumps in reverse operation. Key words:  Pump as Turbine (PAT); Computational Fluid Dynamics (CFD); PumpDOI: 10.3126/hn.v6i0.4191   Hydro Nepal Vol 6, January 2010 Page : 35-37 Uploaded Date:24 January, 2011

scholarly journals How to Improve the Performance Prediction of a Pump as Turbine by Considering the Slip Phenomenon

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 683 ◽  
Author(s):  
Tommaso Capurso ◽  
Michele Stefanizzi ◽  
Marco Torresi ◽  
Giuseppe Pascazio ◽  
Giovanni Caramia ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Characteristic Curve ◽  
Operating Mode ◽  
Blade Angle ◽  
Small Hydropower ◽  
Reverse Mode ◽  
Slip Factor ◽  
Hydropower Plants ◽  
1D Model ◽  
The Mean

Nowadays Pumps working as Turbines (PaT) are devices widely used to perform energy recovery in hydraulic grids, thus improving their overall efficiency, and to build small hydropower plants. In this work, a centrifugal pump has been numerically investigated in turbine operating mode by means of the open-source CFD code OpenFOAM with emphasis on the flow field at the runner outlet. Due to the reduced number of blades in a PaT, the mean outlet relative velocity angle differs from the blade angle. In order to account for this phenomenon, the slip factor is introduced. The slip factor is investigated and its application to a 1D model is shown in order to highlight the improvement in predicting the characteristic curve of a centrifugal pump used in reverse mode as a turbine (PaT) especially at its part-load.

scholarly journals Development of a Hydropower Turbine Using Seawater from a Fish Farm

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 266
Author(s):  
Md Rakibuzzaman ◽  
Sang-Ho Suh ◽  
Hyoung-Ho Kim ◽  
Youngtae Ryu ◽  
Kyung Yup Kim
Keyword(s):  
Power Plants ◽  
Guide Vane ◽  
Cross Flow ◽  
Synchronous Generator ◽  
Fish Farm ◽  
Hydropower Plant ◽  
Fish Farms ◽  
Data Simulation ◽  
Small Hydropower ◽  
Hydropower Plants

Discharge water from fish farms is a clean, renewable, and abundant energy source that has been used to obtain renewable energy via small hydropower plants. Small hydropower plants may be installed at offshore fish farms where suitable water is obtained throughout the year. It is necessary to meet the challenges of developing small hydropower systems, including sustainability and turbine efficiency. The main objective of this study was to investigate the possibility of constructing a small hydropower plant and develop 100 kW class propeller-type turbines in a fish farm with a permanent magnet synchronous generator (PMSG). The turbine was optimized using a computer simulation, and an experiment was conducted to obtain performance data. Simulation results were then validated with experimental results. Results revealed that streamlining the designed shape of the guide vane reduced the flow separation and improved the efficiency of the turbine. Optimizing the shape of the runner vane decreased the flow rate, reducing the water power and increasing the efficiency by about 5.57%. Also, results revealed that tubular or cross-flow turbines could be suitable for use in fish farm power plants, and the generator used should be waterproofed to avoid exposure to seawater.

scholarly journals Assessment of the Impact of Small Hydropower Plants on the Ecological Status Indicators of Water Bodies: A Case Study in Lithuania

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 433
Author(s):  
Laima Česonienė ◽  
Midona Dapkienė ◽  
Petras Punys
Keyword(s):  
Water Quality ◽  
Benthic Macroinvertebrates ◽  
Suspended Solids ◽  
Ecological Status ◽  
Fish Abundance ◽  
Water Bodies ◽  
Small Hydropower ◽  
Hydropower Plants ◽  
Physico Chemical ◽  
The Impact

Hydropower plants produce renewable and sustainable energy but affect the river’s physico-chemical characteristics and change the abundance and composition of the aquatic organisms. The impact of large HPPs on the ecological conditions of surface water bodies have been extensively studied, but less attention has been paid to environmental impact studies of small hydropower plants (SHPs). The impact of hydropeaking on both the river flow regime and ecosystems has been well-studied for peaking mode plants, mainly medium to large-sized ones. However, for small hydroelectric power plants, and especially for those in lowland rivers, the available information on water quality, benthic macroinvertebrates communities and fish abundance, and biomass is not sufficient. Ten small hydropower plants were selected, and the ecological status of water bodies was assessed in different parts of Lithuania. The studies were performed at the riverbed upstream from the SHPs, where the hydrological regime has not changed, and downstream from the SHPs. It was found that the small hydropower plants do not affect the physico-chemical values of the water quality indicators. This study demonstrated that the total number of benthic macroinvertebrates taxa (TS) is influenced by the concentration of nitrogen and suspended solids, the water flow, the river area, and the current speed; the number of EPT (Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies)) taxa is influenced by the concentration of nitrogen and suspended solids. The studied indicators do not have a significant impact on biomass. The SHPs affect the fish abundance and biomass. The Lithuanian fish index (LFI) is influenced by the average depth and area of the river. Some SHPs operating in lowland areas may yield somewhat significant hydrograph ramping but more detailed investigation is needed to support the significance of this impact on the biological indices.

scholarly journals Fishways as Downstream Routes in Small Hydropower Plants: Experiences with a Potamodromous Cyprinid

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1041
Author(s):  
Francisco Javier Sanz-Ronda ◽  
Juan Francisco Fuentes-Pérez ◽  
Ana García-Vega ◽  
Francisco Javier Bravo-Córdoba
Keyword(s):  
General Assumption ◽  
Downstream Migration ◽  
Life Cycles ◽  
Hydropower Plant ◽  
Small Hydropower ◽  
Pit Tag ◽  
Safe Alternative ◽  
Hydropower Plants ◽  
Longitudinal Connectivity ◽  
Alternative Routes

Fish need to move upstream and downstream through rivers to complete their life cycles. Despite the fact that fishways are the most commonly applied solution to recover longitudinal connectivity, they are not considered viable for downstream migration. Therefore, alternative facilities are recommended to facilitate downstream migration. However, a few recent studies have disagreed with this general assumption, showing the potential for bidirectional movements. This study advances our understanding of the potential of fishways for downstream migration by studying their efficiency in a run-of-the-river hydropower plant in the Duero River (Spain). To achieve this, downstream movements of the Iberian barbel (n = 299) were monitored in a stepped fishway for two years with passive integrated transponder (PIT)-tag technology, considering the effect of fish origin and release zone. The results showed that 24.9% of barbels descended through the fishway, with the origin and release zone affecting the fishway location. In addition, downstream movements were observed throughout the whole year, except in winter. The study concludes that, under specific scenarios, fishways could act as safe alternative routes for downstream migration.

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