On the performance of a high head Francis turbine at design and off-design conditions

Aakti, B; Amstutz, O; Casartelli, Ernesto; Romanelli, Giulio; Mangani, Luca

doi:10.1088/1742-6596/579/1/012010

Cited by 8 publications

(5 citation statements)

References 3 publications

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“…In addition, because of the turbine geometry there are areas in which when refining them too much the elements started to become distorted to such an extent that pyramids cells were generated instead of hexahedra cells, causing a numerical simulation crash. According to Aakti et al [21], residuals with values under 10e-3 shows an acceptable convergence trend.…”

Section: Mesh Independence Analysismentioning

confidence: 92%

Rotatory 3D structured mesh study using openFOAM to simulate the flow in francis turbine

Hidalgo

Velasco

Cando

et al. 2022

Materials Today: Proceedings

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Section: Mesh Independence Analysismentioning

confidence: 92%

Rotatory 3D structured mesh study using openFOAM to simulate the flow in francis turbine

Hidalgo

Velasco

Cando

et al. 2022

Materials Today: Proceedings

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“…The mesh specifications for each component are shown in Table 1. The mesh has 20.88 M cells, which according to the mesh dependency studies performed for simulations of the Francis-99 turbine found in the literature [35][36][37][38][39] is enough for mesh-independent results of the flow in the draft tube. The table also shows that the average y + value is larger than 1 for all components; therefore, the wall function based on Spalding's law is used at the walls [25,40,41].…”

Section: The Francis-99 Turbine and Computational Meshmentioning

confidence: 99%

Investigation of Flow-Induced Instabilities in a Francis Turbine Operating in Non-Cavitating and Cavitating Part-Load Conditions

Arabnejad

Nilsson

Bensow

2023

Fluids

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The integration of intermittent renewable energy resources to the grid system requires that hydro turbines regularly operate at part-load conditions. Reliable operation of hydro turbines at these conditions is typically limited by the formation of a Rotating Vortex Rope (RVR) in the draft tube. In this paper, we investigate the formation of this vortex using the scale-resolving methods SST-SAS, wall-modeled LES (WMLES), and zonal WMLES. The numerical results are first validated against the available experimental data, and then analyzed to explain the effect of using different scale-resolving methods in detail. It is revealed that although all methods can capture the main features of the RVRs, the WMLES method provides the best quantitative agreement between the simulation results and experiment. Furthermore, cavitating simulations are performed using WMLES method to study the effect of cavitation on the flow in the turbine. These effects of cavitation are shown to be highly dependent on the amount of vapor in the RVR. If the amount of vapor is small, cavitation induces broadband high-frequency fluctuations in the pressure and forces exerted on the turbine. As the amount of cavitation increases, these fluctuations tend to have a distinct dominant frequency which is different from the frequency of the RVR.

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“…They stated that the modern Francis turbine is the most widely used turbine design today, particularly for medium head and large flow rate situations, and can achieve over 95% efficiency. Aakti et al, (2015) performed the fully 360 degrees transient and steady-state simulations of a Francis turbine at three operating conditions, namely at part load (PL), best efficiency point (BEP), and high load (HL), using different numerical approaches for the pressure-velocity coupling. They simulated the spiral casing with stay and guide vanes, the runner and the draft tube.…”

Section: Introductionmentioning

confidence: 99%

Numerical Evaluation of Francis Turbine Test Rig at Different Loads

Murari¹,

Prasad²

2020

Int.J.Curr.Microbiol.App.Sci

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The lab experiment was carried out to study the performance and characteristics of a Francis turbine test rig, in the Hydraulics Lab of the College Agricultural Engineering under Dr. Rajendra Prasad Central Agricultural University, Pusa (Bihar) India. The performance of the rig was evaluated at various loads ranging from 0 to 7.0 kg at a constant head of 7.68 m, 0 to 5.0 kg at a constant head of 9.09 m and 0 to 4.0 kg at a constant head of 10.22 m of water, respectively. Results showed that as the loads applied increases, the water flow rate and input power to the rig increases, reaches up to the peak and then decreases at constant heads. Inverse relationship was observed between the torque developed due to the loads applied and the speed of the runner of the turbine operating at a constant head. The excellent correlation between the torque generated and the speed were found to be 99.87 % at constant heads of 7.68 m and 9.09 m; and 99.80 % at constant head of 10.22 m of water. As the load applied increases, the torque developed increases but at the same time speed of the runner of the turbine decreases. The output power developed by the rig increases with increase in load applied and reaches up to the peak values of 0.212 HP at load of 4.0 kg, 0.534 HP at load of 5.0 kg and 0.277 HP at load of 3.0 kg at constant heads of 7.68 m, 9.09 m and 10.22 m of water, respectively and then decreases. The efficiency of the rig increases and reaches up to the maximum values of 32.23 %, 39.09 % and 37.56 % at the same value of load of 4.0 kg and at constant heads of 7.68 m, 9.09 m and 10.22 m of water, respectively and then decreases.

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On the performance of a high head Francis turbine at design and off-design conditions

Cited by 8 publications

References 3 publications

Rotatory 3D structured mesh study using openFOAM to simulate the flow in francis turbine

Rotatory 3D structured mesh study using openFOAM to simulate the flow in francis turbine

Investigation of Flow-Induced Instabilities in a Francis Turbine Operating in Non-Cavitating and Cavitating Part-Load Conditions

Numerical Evaluation of Francis Turbine Test Rig at Different Loads

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