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The present work focuses on the evaluation, by best efficient point (BEP), Nash–Sutcliffe efficiency (NSE), mean square relative error (MSRE), relative mean error (RME) and residual bias (BIAS) of a prototype of a gravitational water vortex turbine. The analysis performed using computational fluid dynamics was experimentally validated to quantify the accuracy of the mathematical model. The estimation of the statistical parameters mentioned was made for different response variables, such as vortex height H v , torque T s , mechanical power P m and efficiency η t , in order to identify biases in different areas of the simulation. The BEP was determined for a flow rate of 6.0 l / s with an efficiency of 58.13% in the experimental part and 54.62% in the numerical modeling, with the vortex height as the critical parameter of the system due to its influence on performance. The NSE and MSRE indicators were positioned as the functions with the best adaptability for the response parameters by criteria and sensitivity. Meanwhile, the RME, MSRE and BIAS presented significant differences for the values of mechanical power and torque. Regarding the electrical efficiency of the generator, it was estimated at 27.68% for the BEP with an average decrease of 3.1% per unit of flow supplied from this point. Therefore, the turbine is subject to the conditions of the generator (torque and number of revolutions per minute) and vortex height, which control the optimization of the system. [ABSTRACT FROM AUTHOR]

The hydraulic turbine is considered as a heart of the hydropower plant because of its important function in the whole process of electrical energy production. Turbine´s efficiency calculation is analytically demanding and dependent on parameters that are often obtained only by a theoretical estimation. Therefore, using its accurate model, which takes into account its efficiency, is necessary to achieve realistic and relevant results. The article briefly surveys current knowledge and methods of designing the hydraulic turbine model. The new idea consists in that a fuzzy system was used to create turbine´s efficiency model based on a measured operating data of the turbine flow rate and its mechanical speed without any need of knowing exactly the turbine parameters. Such a model can be used in the design and development process of an optimal energy control of a hydraulic turbine, as well as in the effective process of determination the actual turbine’s wear rate. The achieved results were obtained using the computational tools of the Fuzzy Toolbox in the MATLAB.

The hydraulic turbine is considered as a heart of the hydropower plant because of its important function in the whole process of electrical energy production. Turbine´s efficiency calculation is analytically demanding and dependent on parameters that are often obtained only by a theoretical estimation. Therefore, using its accurate model, which takes into account its efficiency, is necessary to achieve realistic and relevant results. The article briefly surveys current knowledge and methods of designing the hydraulic turbine model. The new idea consists in that a fuzzy system was used to create turbine´s efficiency model based on a measured operating data of the turbine flow rate and its mechanical speed without any need of knowing exactly the turbine parameters. Such a model can be used in the design and development process of an optimal energy control of a hydraulic turbine, as well as in the effective process of determination the actual turbine's wear rate. The achieved results were obtained using the computational tools of the Fuzzy Toolbox in the MATLAB. [ABSTRACT FROM AUTHOR]

The article presents an analysis of the experience of conducting field power tests of hydraulic units with the measurement of water flow rate by different methods at a number of domestic and foreign dam-type hydropower plants. [ABSTRACT FROM AUTHOR]

Due to the large number of aging hydraulic turbines in North America, rehabilitation is a growing market as these turbines have low efficiency compared to modern ones. Computational Fluid Dynamics identifies components with poor hydraulic performance. The models often used in industry are based on individually analyzing the sub-components of a turbine instead of full turbine simulations due to computational and time limitations. An industrial case has shown that such analyses may lead to underestimating the efficiency increases by modifying the stay vane. The unsteady full turbine simulation proposes to simulate all components simultaneously to assess this efficiency augmentation due to stay vane rehabilitation. The developed simulation methodology is used to evaluate the efficiency increase and the flow of two rehabilitated turbines with stay vane modifications. Comparison with model tests shows the accuracy of the simulations. However, the methodology used shows imprecision in predicting the efficiency increase compared to model tests. Further works should consider the use of more complex flow modeling methods to measure the efficiency increase by the stay vane modifications.

The paper presents methodology used for determining the efficiency of a low head Kaplan hydraulic turbine with short converging intake. The measurement method used was the current meters method, the only measurement method recommended by the IEC 41standard for flow measurement in this case. The paper also presents the methodology used for measuring the flow by means of the current meters method and the various procedures for calculating the flow. In the last part the paper presents the flow measurements carried out on the Fughiu HPP hydraulic turbines for determining the actual operating efficiency.

The condition of the hydraulic turbines with service life (30 years) expired long ago still operating at the Verkhnyaya Tuloma HPP is described. Parameters of the new hydraulic turbine that provides more efficient use of water flow at the HPP and improves the reliability of equipment are proposed. [ABSTRACT FROM AUTHOR]

The paper presents methodology used for determining the efficiency of a low head Kaplan hydraulic turbine with short converging intake. The measurement method used was the current meters method, the only measurement method recommended by the IEC 41standard for flow measurement in this case. The paper also presents the methodology used for measuring the flow by means of the current meters method and the various procedures for calculating the flow. In the last part the paper presents the flow measurements carried out on the Fughiu HPP hydraulic turbines for determining the actual operating efficiency. [ABSTRACT FROM AUTHOR]

Abstract: The design of runner blade of turbine is done for certain flow velocities and angles but these parameters vary with operating conditions. The experimental testing of turbine model is costly, time consuming and gives performance characteristics of turbine as whole based on global parameters. The component wise performance of turbine based on local parameters is more useful for efficient design and it is very difficult to get these from model testing. The computational fluid mechanics (CFD) is an effective tool to provide detailed flow information inside turbine space and it can also give performance characteristics of turbine in terms of global as well as local parameters. The viscous 3D turbulent simulation has been carried out in an experimentally tested model of axial flow hydraulic turbine at different operating regimes and global and local parameters have been computed. The variation of computed parameters justifies with the characteristics of axial flow turbine. The computed efficiencies at some regimes of operation are critically compared with experimentally tested model results and found to bear close comparison. [Copyright &y& Elsevier]

Field performance testing of hydraulic turbines is undertaken to define the head-power-discharge relationship that identifies the peak operating point of the turbine. This relationship is essential for the efficient operation of a hydraulic turbine. Unfortunately, in some cases it is not feasible to field test turbines because of time, budgetary, or other constraints. Gordon (2001) proposed a method of predicting and (or) simulating the performance curve for several types of turbines. However, a limited data set was available for the development of his model for certain types of turbines. Moreover, his model did not include a precise method of developing performance curves for rerunnered turbines. Manitoba Hydro operates a large network of hydroelectric turbines, which are subject to periodic field performance testing. This provided a large data set with which to refine the model proposed by Gordon (2001). Furthermore, since these data include rerunnered units, this provides an opportunity to refine the effects of rerunnering. Analysis shows that the accuracy of the refined model is within 2% of the performance test results for an "old" turbine, while for a newer turbine or a rerunnered turbine the error is within 1%. For both an old turbine and a rerunnered turbine, this indicates an accuracy improvement of 3% over the original method proposed by Gordon (2001). [ABSTRACT FROM AUTHOR]

Due to the large number of aging hydraulic turbines in North America, rehabilitation is a growing market as these turbines have low efficiency compared to modern ones. Computational Fluid Dynamics identifies components with poor hydraulic performance. The models often used in industry are based on individually analyzing the sub-components of a turbine instead of full turbine simulations due to computational and time limitations. An industrial case has shown that such analyses may lead to underestimating the efficiency increases by modifying the stay vane. The unsteady full turbine simulation proposes to simulate all components simultaneously to assess this efficiency augmentation due to stay vane rehabilitation. The developed simulation methodology is used to evaluate the efficiency increase and the flow of two rehabilitated turbines with stay vane modifications. Comparison with model tests shows the accuracy of the simulations. However, the methodology used shows imprecision in predicting the efficiency increase compared to model tests. Further works should consider the use of more complex flow modeling methods to measure the efficiency increase by the stay vane modifications. [ABSTRACT FROM AUTHOR]

Abstract: To cope with the warming global environments, the authors had proposed the counter-rotating type hydroelectric unit, which is composed of the tandem runners and the peculiar generator with double rotational armatures. This unit can be supplied to various water circumstances, for instance, the traditional large hydropower, the mini/micro hydropower, and the tidal power. The fundamental performances and the flow conditions around the runners have been investigated and the design materials for the runners have been presented. Continuously, this paper discusses the performances at the on-cam operation, in the large tidal power station. The model unit was operated while keeping the relative rotational speed constant nT =900min−1, namely 60Hz, irrespective of the hydropower circumstances. The output and the hydraulic efficiency are affected by the blade setting angles of the front and the rear runners. Resultantly, both optimum angles giving the maximum output and/or the maximum efficiency are presented at the various discharges/heads. [Copyright &y& Elsevier]