Evaluation criteria for velocity distributions in front of bulb hydro turbines

Gabl, Roman; Innerhofer, Daniel; Achleitner, Stefan; Righetti, Maurizio; Aufleger, Markus

doi:10.1016/j.renene.2018.01.027

Cited by 8 publications

(13 citation statements)

References 47 publications

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“…The reduction of the cross section behind the trash rack leads to an acceleration of the flow velocity. Such an increase in the velocity homogenises the flow [3]. Consequently, the main influence of the chosen values for the local loss is in the pressure distribution after the trash rack respectively in the local head loss h v of the complete intake.…”

Section: Discussionmentioning

confidence: 99%

“…The wide diversity of structures can be subdivided due to the source of the water, namely rivers or reservoirs. In case of energy production in a run-of-river power plant with a comparable small usable energy head, the inlet head losses and the velocity distribution in front of the turbine are key concerns in the design process [1][2][3]. Furthermore, the entrance of air and swirl can reduce the durability and the energy production of the turbine [4][5][6][7][8][9].…”

Section: Generalmentioning

confidence: 99%

“…Hager and Boes [29] highlighted the strong connection between both approaches and the need of a wide validation. Based on such an independent comparison, the confidence in the 3D-numerics can be strengthened, which allows to deliver forces and velocities [3,30,31] as an input for the structural design process.…”

Section: Generalmentioning

confidence: 99%

“…The kinetic energy correction coefficient α compensates an inhomogeneity in the velocity distribution [3]. Therefore, the kinetic energy E kin of the actual velocity profile is compared to the theoretical one based on a constant velocity distribution with a mean velocity v over the complete cross section with an area A [3,42,51,52]:…”

Section: Local Head Lossmentioning

confidence: 99%

“…This value is used to define the location of the second cross section in the laboratory model [42] as part of the preliminary phase of the project (Section 2.1). A typical α-value for a turbulent velocity distribution in a pipe is in the range of 1 (uniform constant velocity distribution) and 2 for laminar condition (parabolic distribution) [3,52].…”

Section: Local Head Lossmentioning

confidence: 99%

See 4 more Smart Citations

Adaptation of an Existing Intake Structure Caused by Increased Sediment Level

Gabl

Gems

Birkner

et al. 2018

Water

Self Cite

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An unexpected and massive redistribution of fine sediment in a large Alpine reservoir was triggered by a further lowering of the water level to conduct maintenance work. This caused the need of a total redesign of the existing head race intake for a high head power plant in the Austrian Alps. Two main geometry options for the trash rack support structure are compared with numerical simulations (ANSYS-CFX) as well as with a scale model test (scale 1:20). The laboratory experiment substantially benefited from the preliminary numerical investigation in respect of the location and implementation of the model boundaries. In return was the confidence in the numerics strengthened by the successful validation of the local head loss and the velocity distribution for the main operation cases. This allowed that the main inputs for the structural design and the further optimisation is conducted only with the 3D-numerical tool. The paper presents the interlaced concept as well as the main finding of the investigation, which lead to a successful adaptation of the intake structure.

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Section: Discussionmentioning

confidence: 99%

Section: Generalmentioning

confidence: 99%

Section: Generalmentioning

confidence: 99%

Section: Local Head Lossmentioning

confidence: 99%

Section: Local Head Lossmentioning

confidence: 99%

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Adaptation of an Existing Intake Structure Caused by Increased Sediment Level

Gabl

Gems

Birkner

et al. 2018

Water

Self Cite

View full text Add to dashboard Cite

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Computational investigation and optimization of the bulb turbine for ultra-low head application

Maisuria,

Ratadiya,

Patel

2024

Renewable Energy

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Design criteria for a type of asymmetric orifice in a surge tank using CFD

Gabl

Righetti

2018

Engineering Applications of Computational Fluid Mechanics

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An asymmetric orifice can be added to a surge tank of a hydro power plant to dampen the mass oscillation. This allows a reduction of the required volume and a more stable behavior of the overall hydraulic system. In this paper, the advantage of a typical asymmetric orifice is shown in comparison with a sharp-edged geometry with two different pipe diameters. The software ANSYS-CFX is used to investigate the influence of the individual geometry parameters (radius, length, angle at the forefront) on the local head loss coefficients and the ratio of the two flow directions. Furthermore, a coefficient is analyzed based on an equation from the literature for the sharp-edged structure, which can be used comparably for the asymmetric orifice. This allows us to reach preliminary assumptions of the losses at an early state of the design process. The following adaptation can be supported by the presented guidance for the optimization process, so that a suitable geometry for the specific boundary conditions can be found. ARTICLE HISTORY KEYWORDSControl structures; flows in pipes and nozzles; hydraulics of renewable energy systems; hydraulic structure design and management; RANS model

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Evaluation criteria for velocity distributions in front of bulb hydro turbines

Cited by 8 publications

References 47 publications

Adaptation of an Existing Intake Structure Caused by Increased Sediment Level

Adaptation of an Existing Intake Structure Caused by Increased Sediment Level

Computational investigation and optimization of the bulb turbine for ultra-low head application

Design criteria for a type of asymmetric orifice in a surge tank using CFD

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