scholarly journals Effects of the Splitter Blade on the Performance of a Pump-Turbine in Pump Mode

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Guidong Li ◽  
Yang Wang ◽  
Puyu Cao ◽  
Jinfeng Zhang ◽  
Jieyun Mao
Keyword(s):  
Energy Storage ◽  
Large Scale ◽  
Tangential Velocity ◽  
Model Performance ◽  
Flow Characteristics ◽  
Entropy Generation Rate ◽  
Pump Mode ◽  
Pump Turbine ◽  
Blade Runner ◽  
Operation Stability

The pumped hydro energy storage is the most effective way to store large-scale electricity and has been widely used in the world. As the key equipment in the pumped hydro energy storage, it is significant and urgent to improve the performance and operation stability of the pump-turbine. In this study, the effect of runners with and without splitter blade on the performances and inner flow characteristics of a pump-turbine in pump mode was analyzed by the method of numerical calculation. The results suggest that larger tangential velocity at runner outlet and higher pressure at the trailing edge of pressure side in splitter blade runner scheme contribute to higher head. The area of backflow at runner outlet, the highest values of entropy generation rate, and vorticity distribution in splitter blade runner scheme are well smaller than those in prototype runner without splitter blade, which is conducive to improving model performance.

Unsteady flow characteristics regarding hump instability in the first stage of a multistage pump-turbine in pump mode

2018 ◽  
Vol 127 ◽  
pp. 377-385 ◽  
Author(s):  
Jun Yang ◽  
Giorgio Pavesi ◽  
Xiaohua Liu ◽  
Tian Xie ◽  
Jun Liu
Keyword(s):  
Unsteady Flow ◽  
Flow Characteristics ◽  
Pump Mode ◽  
Pump Turbine ◽  
Multistage Pump

scholarly journals Empirical Validation and Numerical Predictions of an Industrial Borehole Thermal Energy Storage System

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2263
Author(s):  
Emil Nilsson ◽  
Patrik Rohdin
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Large Scale ◽  
Storage System ◽  
Flow Characteristics ◽  
Heat Extraction ◽  
Short Term ◽  
Numerical Predictions ◽  
Heat Injection

To generate performance predictions of borehole thermal energy storage (BTES) systems for both seasonal and short-term storage of industrial excess heat, e.g., from high to low production hours, models are needed that can handle the short-term effects. In this study, the first and largest industrial BTES in Sweden, applying intermittent heat injection and extraction down to half-day intervals, was modelled in the IDA ICE 4.8 environment and compared to three years of measured storage performance. The model was then used in a parametric study to investigate the change in performance of the storage from e.g., borehole spacing and storage supply flow characteristics at heat injection. For the three-year comparison, predicted and measured values for total injected and extracted energy differed by less than 1% and 3%, respectively and the mean relative difference for the storage temperatures was 4%, showing that the performance of large-scale BTES with intermittent heat injection and extraction can be predicted with high accuracy. At the actual temperature of the supply flow during heat injection, 40 °C, heat extraction would not exceed approximately 100 MWh/year for any investigated borehole spacing, 1–8 m. However, when the temperature of the supply flow was increased to 60–80 °C, 1400–3100 MWh/year, also dependent on the flow rate, could be extracted at the spacing yielding the highest heat extraction, which in all cases was 3–4 m.

scholarly journals Flow Characteristics of Preliminary Shutdown and Startup Sequences for a Model Counter-Rotating Pump-Turbine

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3593
Author(s):  
Jonathan Fahlbeck ◽  
Håkan Nilsson ◽  
Saeed Salehi
Keyword(s):  
Large Scale ◽  
Reverse Flow ◽  
Renewable Energy Sources ◽  
Flow Characteristics ◽  
Head Model ◽  
Pump Turbine ◽  
Design Point ◽  
Electrical Grid ◽  
The Individual ◽  
Eu Project

Pumped Hydropower Storage (PHS) is the maturest and most economically viable technology for storing energy and regulating the electrical grid on a large scale. Due to the growing amount of intermittent renewable energy sources, the necessity of maintaining grid stability increases. Most PHS facilities today require a geographical topology with large differences in elevation. The ALPHEUS H2020 EU project has the aim to develop PHS for flat geographical topologies. The present study was concerned with the initial design of a low-head model counter-rotating pump-turbine. The machine was numerically analysed during the shutdown and startup sequences using computational fluid dynamics. The rotational speed of the individual runners was decreased from the design point to stand-still and increased back to the design point, in both pump and turbine modes. As the rotational speeds were close to zero, the flow field was chaotic, and a large flow separation occurred by the blades of the runners. Rapid load variations on the runner blades and reverse flow were encountered in pump mode as the machine lost the ability to produce head. The loads were less severe in the turbine mode sequence. Frequency analyses revealed that the blade passing frequencies and their linear combinations yielded the strongest pulsations in the system.

Flow characteristics prediction in pump mode of a pump turbine using large eddy simulation

2016 ◽  
Vol 231 (5) ◽  
pp. 961-977 ◽  
Author(s):  
De-You Li ◽  
Lei Han ◽  
Hong-Jie Wang ◽  
Ru-Zhi Gong ◽  
Xian-Zhu Wei ◽  
...  
Keyword(s):  
Large Eddy Simulation ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Pump Mode ◽  
Pump Turbine ◽  
Recirculation Flow ◽  
Eddy Simulation ◽  
Eddy Viscosity Model ◽  
Large Eddy ◽  
Operating Points

To obtain more accurate flow characteristics of pump turbines, the method of large eddy simulation with wall-adapting local eddy viscosity model is applied in simulating several operating points in the pump mode. Firstly, based on the experimental validation, the method of large eddy simulation could better predict the external performance and internal flow characteristics in a pump turbine in the pump mode compared with the method of Reynolds-averaged Navier–Stokes with two-equation turbulence model shear stress transport k–ω. Then, flow characteristics under 1.00 QBEP (best efficiency point), 0.91 QBEP, 0.88 QBEP, and 0.85 QBEP operating points are investigated to find out the causes of the head drop in the energy-discharge curve through large eddy simulation. The detailed analysis reveals that the head drop at the point 0.85 QBEP is related to the recirculation flow at the runner inlet. Finally, unsteady studies confirm that vortex movement at the runner inlet lead to the variation of the amplitudes and directions of the velocity, which generates the rotation of the separation vortices in the runner and stay vane channels.

Effect of Interface Condition on the Hydraulic Performance of a Pump-Turbine at Various Guide Vane Opening Conditions in Pumping Mode

2019 ◽  
Author(s):  
Jun-Won Suh ◽  
Seung-Jun Kim ◽  
Young-Seok Choi ◽  
Jin-Hyuk Kim ◽  
Won-Gu Joo ◽  
...  
Keyword(s):  
Stokes Equations ◽  
Guide Vane ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Rotating Stall ◽  
Interface Condition ◽  
Navier Stokes ◽  
Pump Mode ◽  
Pump Turbine ◽  
High Flexibility

Abstract Nowadays, pumped-storage power stations require high flexibility and reliability in operation under off-design conditions, especially in the pump mode. When a pump-turbine operates under various part load conditions in pump mode, highly dynamic phenomenon such as stationary vortex and rotating stall occur. Therefore, the performance characteristics in pump mode are vital for the safe and effective operation. A number of studies have been conducted to investigate the flow characteristics in turbine or pump mode under different GVOs through numerical simulations. However, the studies about influence of the position of interface and interface condition on the pump characteristics of pump-turbines are not completely clear. In this paper, the three-dimensional steady and unsteady Reynolds-averaged Navier–Stokes equations were solved for a detailed analysis of the influence of interface conditions with various guide vane opening conditions in pump mode. To ensure the reliability of the numerical analysis, the numerical results were validated in comparison with the experimental data.

scholarly journals Research on capacity optimization of micro-grid hybrid energy storage system based on simulated annealing artificial fish swarm algorith with memory function

2020 ◽  
Vol 185 ◽  
pp. 01023
Author(s):  
Yuan An ◽  
Jianing Li ◽  
Cenyue Chen
Keyword(s):  
Simulated Annealing ◽  
Energy Storage ◽  
Large Scale ◽  
Memory Function ◽  
Storage System ◽  
Energy Storage System ◽  
Hybrid Energy ◽  
Hybrid Energy Storage ◽  
Hybrid Energy Storage System ◽  
With Memory

The intermittence and uncertainty of wind power and photovoltaic power have hindered the large-scale development of both. Therefore, it is very necessary to properly configure energy storage devices in the wind-solar complementary power grid. For the hybrid energy storage system composed of storage battery and supercapacitor, the optimization model of hybrid energy storage capacity is established with the minimum comprehensive cost as the objective function and the energy saving and charging state as the constraints. A simulated annealing artificial fish school algorithm with memory function is proposed to solve the model. The results show that the hybrid energy storage system can greatly save costs and improve system economy.

Trust is Good, Control is Better: A Review on Monitoring and Characterization Techniques for Flow Battery Electrolytes

2021 ◽  
Author(s):  
Ulrich Sigmar Schubert ◽  
Oliver Nolte ◽  
Ivan Volodin ◽  
Christian Stolze ◽  
Martin D. Hager
Keyword(s):  
Energy Storage ◽  
Electricity Generation ◽  
Large Scale ◽  
Good Control ◽  
Renewable Electricity ◽  
Flow Battery ◽  
Large Share ◽  
Characterization Techniques ◽  
Renewable Electricity Generation ◽  
Storage Technologies

Flow Batteries (FBs) currently are one of the most promising large-scale energy storage technologies for energy grids with a large share of renewable electricity generation. Among the main technological challenges...

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