Improvement of flow behavior in the spiral casing of Francis hydro turbine model by shape optimization

Shrestha, Ujjwal; Choi, Young‐Do

doi:10.1007/s12206-020-0817-9

Cited by 8 publications

(7 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Impact: Too many nodes, the training time increases, and the network is easy to overfit. According to the optimal hidden layer node number selection formula, we determine the range of hidden layer node number selection interval (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). The relationship between the number of hidden layer nodes and the stability prediction error rate of the BP neural network of the HTGS is shown in Fig.…”

Section: Model Training and Testingmentioning

confidence: 99%

“…Hydro-turbine governing system is a comprehensive control system that integrates water, machinery, electricity, and magnetism, and is affected by different inertia, time-varying parameters, and changes in grid load in each link. [4][5][6] This adds the difficulty to the theoretical analysis and research on the stability of the HTGS. At present, the research method of the stability of the HTGS is mainly carried out by establishing the corresponding mathematical model and combining with the stability theory.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Stability analysis of hydro-turbine governing system based on machine learning

Chen¹,

Tong²

2021

Chinese Phys. B

View full text Add to dashboard Cite

Hydro-turbine governing system is a time-varying complex system with strong non-linearity, and its dynamic characteristics are jointly affected by hydraulic, mechanical, electrical, and other factors. Aiming at the stability of the hydro-turbine governing system, this paper first builds a dynamic model of the hydro-turbine governing system through mechanism modeling, and introduces the transfer coefficient characteristics under different load conditions to obtain the stability category of the system. BP neural network is used to perform the machine study and the predictive analysis of the stability of the system under different working conditions is carried out by using the additional momentum method to optimize the algorithm. The test set results show that the method can accurately distinguish the stability category of the hydro-turbine governing system (HTGS), and the research results can provide a theoretical reference for the operation and management of smart hydropower stations in the future.

show abstract

Section: Model Training and Testingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Stability analysis of hydro-turbine governing system based on machine learning

Chen¹,

Tong²

2021

Chinese Phys. B

View full text Add to dashboard Cite

show abstract

“…The spiral casing shape is dependent on the cross-section radii [20]. Figure 4a,b indicates the parametric design parameters and initial shape design of the casing, respectively.…”

Section: Casing Designmentioning

confidence: 99%

“…In order to evaluate the flow condition in the casing, the flow uniformity γ(d CA ) and head loss H l (d CA ) were examined. The flow uniformity, which determines the deviation of flow velocity in the casing shape, is calculated as in Equation (20). The flow uniformity was measured as an averaged value at the location of the whole casing outlet of 1.00 D e from the runner axis center, which is shown in Figure 4a by a red circle.…”

Section: Process Of Casing Shape Optimizationmentioning

confidence: 99%

A CFD-Based Shape Design Optimization Process of Fixed Flow Passages in a Francis Hydro Turbine

Shrestha

Choi

2020

Processes

Self Cite

View full text Add to dashboard Cite

In recent times, optimization began to be popular in the turbomachinery field. The development of computational fluid dynamics (CFD) analysis and optimization technology provides the opportunity to maximize the performance of hydro turbines. The optimization techniques are focused mainly on the rotating components (runner and guide vane) of the hydro turbines. Meanwhile, fixed flow passages (stay vane, casing, and draft tube) are essential parts for the proper flow uniformity in the hydro turbines. The suppression of flow instabilities in the fixed flow passages is an inevitable process to ensure the power plant safety by the reduction of vortex-induced vibration and pressure pulsation in the hydro turbines. In this study, a CFD-based shape design optimization process is proposed with response surface methodology (RSM) to improve the flow uniformity in the fixed flow passages of a Francis hydro turbine model. The internal flow behaviors were compared between the initial and optimal shapes of the stay vane, casing, and the draft tube with J-Groove. The optimal shape design process for the fixed flow passages proved its remarkable effects on the improvement of flow uniformity in the Francis hydro turbine.

show abstract

“…Observation was made that trapezoidal configuration is most appropriate for such applications [2]. Shrestha and Choi [3] numerically optimized the spiral casing shape using response surface methodology (RSM) and multi-objective genetic algorithm. Improvement of the stay vanes inlet conditions are shown by the optimal design.…”

Section: Introductionmentioning

confidence: 99%

Automated hydraulic design procedure for a Francis turbine spiral casing

Lazarevikj

Markov

2022

IOP Conf. Ser.: Earth Environ. Sci.

View full text Add to dashboard Cite

The spiral casing of a Francis turbine distributes the water from the penstock to the stay and guide vanes circumferentially and uniformly, which is important for achieving the required flow conditions at the runner entrance. Moreover, the spiral casing is supposed to provide the required inlet velocity in front of the stay vanes and create minimal hydraulic losses. The dimensions and shape of the spiral casing depend on the hydraulic and energy parameters of the turbine. A calculation methodology for a Francis spiral casing hydraulic design is presented in this paper. The methodology developed is based on the main condition to achieve a uniform water flow rate into the stay vanes system and the wicket gate over the entire perimeter. The free vortex flow theory is implemented in this research, where the design is based on the law of constant velocity moment. The parametric definition of the spiral casing makes the geometries generated for certain input combinations suitable for numerical analysis using commercially available Computational Fluid Dynamics (CFD) software. The calculation procedure can be used for any set of energy and geometry turbine parameters, such as water discharge, angle of streamline departing from the spiral casing, and stay ring diameter and height. The automated approach integrating MATLAB and ANSYS Workbench capabilities is presented as a spiral casing design tool. The product is a design solution proposed on basis of the turbine parameters. The spiral casing geometry generation is followed by a CFD analysis. Considering input parameters of different existing Francis turbines, the spiral casing is redesigned accordingly. One of the obtained spiral casings geometry is numerically tested. The results show that the uniform discharge distribution is achieved. The automation of the design procedure allows further optimization based on chosen input parameters.

show abstract

Improvement of flow behavior in the spiral casing of Francis hydro turbine model by shape optimization

Cited by 8 publications

References 17 publications

Stability analysis of hydro-turbine governing system based on machine learning

Stability analysis of hydro-turbine governing system based on machine learning

A CFD-Based Shape Design Optimization Process of Fixed Flow Passages in a Francis Hydro Turbine

Automated hydraulic design procedure for a Francis turbine spiral casing

Contact Info

Product

Resources

About