3D Numerical Simulation versus Experimental Assessment of Pressure Pulsations Using a Passive Method for Swirling Flow Control in Conical Diffusers of Hydraulic Turbines

Tănasă, Constantin; Muntean, Sebastian; Ciocan, Tiberiu; Susan-Resiga, Romeo

doi:10.1088/1755-1315/49/8/082018

Cited by 5 publications

(9 citation statements)

References 5 publications

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Section: Pressure Pulsations Decompositionsupporting

confidence: 91%

“…However, the goal was to mitigate the rotating part associated to the vortex rope. This conclusion supports our previous recommendation about selecting a diaphragm with a shutter area ratio from 40% to 60% [34]. Synchronous (plunging) pressure fluctuations can produce variations in head, discharge, torque, and output power known in the literature as a power swing [13].…”

Section: Pressure Pulsations Decompositionsupporting

confidence: 89%

“…Tănasă et al [34] revealed that the hydraulic losses are less than half of the value received for the case with the vortex rope up to the relative shutter area of 50% (d = 0.113 m), and no larger than twice up to the relative shutter area ratio of 70% (d = 0.088 m), respectively.…”

Section: Mean Pressure Analysismentioning

confidence: 98%

“…A compromise between the pressure pulsation mitigation and the hydraulic losses has to be performed when this method is used. For this reason, the shutter area ratio of a diaphragm between 40%-60% is recommended to be operated at part-load conditions to maintain a good balance between the hydraulic losses and the pressure fluctuation mitigation [34]. As a result, the dimensionless equivalent amplitudes on the cone wall obtained for the diaphragm control method with the shutter area ratio of 50% are compared against swirling flow with vortex rope and the method of axial water jet method with 10% discharge, developed by Bosioc et al [26] (Figure 9).…”

Section: Unsteady Pressure Analysismentioning

confidence: 99%

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A Novel Passive Method to Control the Swirling Flow with Vortex Rope from the Conical Diffuser of Hydraulic Turbines with Fixed Blades

et al. 2019

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In this paper, we introduce a novel passive control method to mitigate the unsteadiness effects associated to the swirling flows with self-induced instabilities. The control method involves a progressive throttling cross-section flow at the outlet of the conical diffuser. It adjusts the cross-section area with a diaphragm while maintaining all positions of the circular shape centered on the axis. It improves the pressure recovery on the cone wall while the pressure fluctuations associated with the self-induced instability are mitigated as it adjusts the cross-section area. It can adjust the diaphragm in correlation with the operating conditions of the turbine. We investigated the passive control method on a swirl generator, which provides a similar flow as a hydraulic turbine operated at a partial discharge. The plunging and rotating components are discriminated using the pressure fluctuation on the cone wall to provide a clear view of the effects induced by this passive control method. As a result, the novel proof of concept examined in this paper offers valuable benefits as it fulfils a good balance between the dynamical behavior and the hydraulic losses.

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Section: Pressure Pulsations Decompositionsupporting

confidence: 91%

Section: Pressure Pulsations Decompositionsupporting

confidence: 89%

Section: Mean Pressure Analysismentioning

confidence: 98%

Section: Unsteady Pressure Analysismentioning

confidence: 99%

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A Novel Passive Method to Control the Swirling Flow with Vortex Rope from the Conical Diffuser of Hydraulic Turbines with Fixed Blades

et al. 2019

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“…Moreover, the studies are related to the fluid flow and carried out in a laboratory [13][14][15][16][17][18][19]. The only way to determine the effects of extreme off-design operation in an actual turbine is by measuring it in existing machines because the dynamics of the whole system (fluid and structure) cannot be reproduced in a laboratory.…”

Section: Introductionmentioning

confidence: 99%

Extension of Operating Range in Pump-Turbines. Influence of Head and Load

Valero

Egusquiza

et al. 2017

Energies

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Due to the increasing share of new renewable energies like wind and solar in the generation of electricity the need for power regulation and energy storage is becoming of paramount importance. One of the systems to store huge amounts of energy is pumped storage using reversible hydropower units. The machines used in these power plants are pump-turbines, which can operate as a pump and as a turbine. The surplus of electrical energy during low consumption hours can be converted into potential hydraulic energy by pumping water to a higher level. The stored energy can be converted into electricity again by operating the runner as a turbine. Due to new regulation requirements machines have to extend the operating range in order to match energy generation with consumption for the grid stability. In this paper the consequences of extending the operating range in existing pump-turbines have been studied. For that purpose, the data obtained after two years of condition monitoring were analyzed. Vibrations and pressure fluctuations of two pump-turbines of 85 MW each have been studied during pump and turbine operation. For turbine operation the effects of extending the operating range from the standard range of 45-85 MW to and increased range of 20-85 MW were analyzed. The change in vibration levels and signatures at very low load are presented with the identification of the phenomena that occur under these conditions. The influence of head in the vibration behavior is also presented. The appearance of fluid instabilities generated at part load that may produce power swing is also presented. Finally, the effect of head on the vibration levels for pump operation is shown and analyzed.

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3D numerical analysis of pulsating water jet in the draft tube cone of hydraulic machinery

Tănasă¹,

Stuparu²,

Stroita³

et al. 2019

Proceedings of the International Conference of Computational Methods in Sciences and Engineering 2019 (Iccmse-2019)

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3D Numerical Simulation versus Experimental Assessment of Pressure Pulsations Using a Passive Method for Swirling Flow Control in Conical Diffusers of Hydraulic Turbines

Cited by 5 publications

References 5 publications

A Novel Passive Method to Control the Swirling Flow with Vortex Rope from the Conical Diffuser of Hydraulic Turbines with Fixed Blades

A Novel Passive Method to Control the Swirling Flow with Vortex Rope from the Conical Diffuser of Hydraulic Turbines with Fixed Blades

Extension of Operating Range in Pump-Turbines. Influence of Head and Load

3D numerical analysis of pulsating water jet in the draft tube cone of hydraulic machinery

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