Transient Simulation of Speed-No Load Conditions With An Open-Source Based C++ Code

Casartelli, Ernesto; Mangani, Luca; Romanelli, Giulio; Staubli, Thomas

doi:10.1088/1755-1315/22/3/032029

Cited by 15 publications

(7 citation statements)

References 4 publications

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“…Also, under-relaxation can be completely avoided using so-called false transient time stepping. The solution of its discretized system of equations therefore turns out to be numerically much more stable than that of segregated algorithms and also significantly faster in terms of calculation time, which has been demonstrated by Mangani et al [8][9][10][11][12]. Therein, a k-ω SST turbulence model has been solved in addition to momentum and continuity equations.…”

Section: Block Coupled Incompressible Cfd Solver: Coupledsteadyincfoamentioning

confidence: 97%

“…In order to overcome these shortcomings, Mangani et al [8][9][10][11][12] developed a block coupled incompressible solver using the open-source CFD library OpenFOAM as programming platform. Therein the algebraic equations resulting from the Navier-Stokes equations are solved simultaneously.…”

Section: Block Coupled Incompressible Cfd Solver: Coupledsteadyincfoamentioning

confidence: 99%

“…Because speed and robustness are very important for CFD software, two solvers based on the C++ OpenFOAM library [7] will be used and compared to a commercial code. The performance of the new fully coupled block solver developed by the University of Lucerne [8][9][10][11][12] and Andritz will be compared to the standard 1.6ext segregated simpleFoam solver and to a commercial code.…”

Section: Introductionmentioning

confidence: 99%

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3D Casing-Distributor Analysis for Hydraulic Design Application

Devals

Zhang

Dompierre

et al. 2015

International Journal of Fluid Machinery and Systems

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Nowadays, computational fluid dynamics is commonly used by design engineers to evaluate and compare losses in hydraulic components as it is less expensive and less time consuming than model tests. For that purpose, an automatic tool for casing and distributor analysis will be presented in this paper. An in-house mesh generator and a Reynolds Averaged Navier-Stokes equation solver using the standard k-ω shear stress transport (SST) turbulence model will be used to perform all computations. Two solvers based on the C++ OpenFOAM library will be used and compared to a commercial solver. The performance of the new fully coupled block solver developed by the University of Lucerne and Andritz will be compared to the standard 1.6ext segregated simpleFoam solver and to a commercial solver. In this study, relative comparisons of different geometries of casing and distributor will be performed. The present study is thus aimed at validating the block solver and the tool chain and providing design engineers with a faster and more reliable analysis tool that can be integrated into their design process.

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Section: Block Coupled Incompressible Cfd Solver: Coupledsteadyincfoamentioning

confidence: 97%

Section: Block Coupled Incompressible Cfd Solver: Coupledsteadyincfoamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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3D Casing-Distributor Analysis for Hydraulic Design Application

Devals

Zhang

Dompierre

et al. 2015

International Journal of Fluid Machinery and Systems

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“…Therefore, hydraulic fluctuation is an important challenge for the safe operation and lifespan of a pump-turbine unit. 11–13 However, the mechanism and influence factors of hydraulic fluctuations in a pump-turbine are complicated and yet to be determined. Consequently, relevant studies are significant in hydro-power engineering and theories.…”

Section: Introductionmentioning

confidence: 99%

Mechanism and influence factors of hydraulic fluctuations in a pump-turbine

Wang

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part A:

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Pumped-storage power technology is currently the only available energy storage technology in the grid net, and its reliability is receiving attention increasingly. However, when a pump-turbine unit undergoes runaway transitions, hydraulic fluctuations intensively affect the reliable operation of a pumped-storage power station. To reduce hydraulic fluctuations, this study investigated the formation mechanism of hydraulic fluctuations and explored its influence factors. In this study, a developed one-dimensional and three-dimensional (1 D-3D) coupling simulation method was adopted. Transient runaway transitions of a pump-turbine with three different inertias (0.5 J, 1 J, and 2.0 J) at three different guide vane openings (21°, 15°, and 12°, respectively) were simulated and compared. The results suggest that, at smaller guide vane openings (15° and 12°), water hammer owing to the increase in rotational speed is the primary unstable issue compared to the pulsation of radial hydraulic exciting forces on the runner. However, at a larger guide vane opening (21°), the latter owing to the back-flow near the runner inlet is the primary unstable issue. Moreover, it is found that a sufficiently large inertia improves the hydraulic fluctuations of the pump-storage power station, particularly in reducing the pulsation of radial hydraulic exciting loads on the runner. The findings of this study provide a valuable reference for determining suitable rotor inertia.

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“…The Reynolds stresses are often modeled using Boussinesq's assumption, which requires computing the eddy viscosity, usually calculated using a two-equation turbulence model. Such an approach has been used to compute full head Francis turbines at the Best Efficiency Point (BEP) including also full load [10][11][12][13], partial load [13][14][15], and Speed-No-Load (SNL) [16][17][18] operating points or transition from pump to turbine mode [19], start-up [20], or the S-shaped region of pump-turbines [21]. The Francis-99 workshop, whose summary is available in [22,23], gave an overview of the state of the art for the simulation of high head Francis turbines at design and off-design operating points.…”

Section: Introductionmentioning

confidence: 99%

CFD Investigation of a High Head Francis Turbine at Speed No-Load Using Advanced URANS Models

Decaix

Hasmatuchi

Titzschkau³

et al. 2018

Applied Sciences

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Due to the integration of new renewable energies, the electrical grid undergoes instabilities. Hydroelectric power plants are key players for grid control thanks to pumped storage power plants. However, this objective requires extending the operating range of the machines and increasing the number of start-up, stand-by, and shut-down procedures, which reduces the lifespan of the machines. CFD based on standard URANS turbulence modeling is currently able to predict accurately the performances of the hydraulic turbines for operating points close to the Best Efficiency Point (BEP). However, far from the BEP, the standard URANS approach is less efficient to capture the dynamics of 3D flows. The current study focuses on a hydraulic turbine, which has been investigated at the BEP and at the Speed-No-Load (SNL) operating conditions. Several “advanced” URANS models such as the Scale-Adaptive Simulation (SAS) SST k - ω and the BSL- EARSM have been considered and compared with the SST k - ω model. The main conclusion of this study is that, at the SNL operating condition, the prediction of the topology and the dynamics of the flow on the suction side of the runner blade channels close to the trailing edge are influenced by the turbulence model.

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Transient Simulation of Speed-No Load Conditions With An Open-Source Based C++ Code

Cited by 15 publications

References 4 publications

3D Casing-Distributor Analysis for Hydraulic Design Application

3D Casing-Distributor Analysis for Hydraulic Design Application

Mechanism and influence factors of hydraulic fluctuations in a pump-turbine

CFD Investigation of a High Head Francis Turbine at Speed No-Load Using Advanced URANS Models

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