2023
Zanetti, Giacomo; Cavazzini, Giovanna; Santolin, Alberto
Effect of the von Karman Shedding Frequency on the Hydrodynamics of a Francis Turbine Operating at Nominal Load Journal Article
In: International Journal of Turbomachinery, Propulsion and Power 2023, Vol. 8, Page 27, vol. 8, iss. 3, pp. 27, 2023, ISSN: 2504-186X.
Abstract | Links | BibTeX | Tags: Francis Turbine, Interblade vortex, mechanical resonance, von Karman vortices
@article{Zanetti2023b,
title = {Effect of the von Karman Shedding Frequency on the Hydrodynamics of a Francis Turbine Operating at Nominal Load},
author = {Giacomo Zanetti and Giovanna Cavazzini and Alberto Santolin},
url = {https://www.mdpi.com/2504-186X/8/3/27/htm https://www.mdpi.com/2504-186X/8/3/27},
doi = {10.3390/IJTPP8030027},
issn = {2504-186X},
year = {2023},
date = {2023-01-01},
journal = {International Journal of Turbomachinery, Propulsion and Power 2023, Vol. 8, Page 27},
volume = {8},
issue = {3},
pages = {27},
publisher = {Multidisciplinary Digital Publishing Institute},
abstract = {This paper presents a numerical analysis of the influence of the von Karman vortex shedding at the blade trailing edge on the hydrodynamics of a recently installed small hydro Francis turbine manifesting very loud and high-frequency acoustic pulsations when operating close to the nominal load. A reduced single-passage numerical model is developed to reduce the computational effort of the simulation while ensuring high accuracy in the assessment of fluid flow. The accuracy of the proposed numerical approach is investigated by comparing the frequency spectrum of the experimentally acquired acoustic frequency and the numerical pressure signals, confirming the nature of the machine’s vibrations. The validated numerical model represents a useful tool for an in-depth analysis of the machine’s hydrodynamics in the preliminary design phases. The proposed approach represents a valid alternative to the traditional correlation-based approach for the evaluation of the von Karman shedding frequency with less computational effort compared with a transient simulation of the entire machine.},
keywords = {Francis Turbine, Interblade vortex, mechanical resonance, von Karman vortices},
pubstate = {published},
tppubtype = {article}
}
This paper presents a numerical analysis of the influence of the von Karman vortex shedding at the blade trailing edge on the hydrodynamics of a recently installed small hydro Francis turbine manifesting very loud and high-frequency acoustic pulsations when operating close to the nominal load. A reduced single-passage numerical model is developed to reduce the computational effort of the simulation while ensuring high accuracy in the assessment of fluid flow. The accuracy of the proposed numerical approach is investigated by comparing the frequency spectrum of the experimentally acquired acoustic frequency and the numerical pressure signals, confirming the nature of the machine’s vibrations. The validated numerical model represents a useful tool for an in-depth analysis of the machine’s hydrodynamics in the preliminary design phases. The proposed approach represents a valid alternative to the traditional correlation-based approach for the evaluation of the von Karman shedding frequency with less computational effort compared with a transient simulation of the entire machine.
