2014
Rossetti, Antonio; Pavesi, Giorgio; Ardizzon, Guido; Santolin, Alberto
Numerical Analyses of Cavitating Flow in a Pelton Turbine Journal Article
In: Journal of Fluids Engineering, vol. 136, iss. 8, pp. 081304, 2014, ISSN: 0098-2202.
Abstract | Links | BibTeX | Tags: Cavitation, CFD, Multiphase Flow, Pelton
@article{pop00014,
title = {Numerical Analyses of Cavitating Flow in a Pelton Turbine},
author = {Antonio Rossetti and Giorgio Pavesi and Guido Ardizzon and Alberto Santolin},
url = {http://fluidsengineering.asmedigitalcollection.asme.org/article.aspx?doi=10.1115/1.4027139 http://biomechanical.asmedigitalcollection.asme.org/article.aspx?articleid=1846558},
doi = {10.1115/1.4027139},
issn = {0098-2202},
year = {2014},
date = {2014-01-01},
urldate = {2014-01-01},
journal = {Journal of Fluids Engineering},
volume = {136},
issue = {8},
pages = {081304},
publisher = {… .asmedigitalcollection.asme.org},
abstract = {Erosion and wear of hydraulic surfaces are frequent problems in hydraulic turbines, which lead to a decrease of the performance in time and/or in extreme cases to the rotor mechanical failure. These circumstances have negative repercussions on the annual produced power due to the decay of the efficiency, the delivered power, and to the off line periods as result of ordinary and extraordinary hydraulic profiles maintenances. Consistently, the study of this wearing process is an important step to improve the impeller design, and to avoid or minimize the rise of extraordinary maintenance. While mechanical damages are well documented and studied, little information can be found on cavitation in Pelton turbines. In this paper, a CFD model was applied to study the cavitation mechanics on a Pelton turbine. A Pelton runner affected by pitting cavitation was taken as a test case. The bucket geometry was modeled and analyzed using unsteady Reynolds averaged Navier-Stokes (RANS) multiphase analyses. Numerical results allowed us to highlight the different vapor productions during the cut-in water jet processes by the bucket. Furthermore, a simple procedure to identify the locations of higher damage risk was presented and verified in the test case runner.},
keywords = {Cavitation, CFD, Multiphase Flow, Pelton},
pubstate = {published},
tppubtype = {article}
}
Erosion and wear of hydraulic surfaces are frequent problems in hydraulic turbines, which lead to a decrease of the performance in time and/or in extreme cases to the rotor mechanical failure. These circumstances have negative repercussions on the annual produced power due to the decay of the efficiency, the delivered power, and to the off line periods as result of ordinary and extraordinary hydraulic profiles maintenances. Consistently, the study of this wearing process is an important step to improve the impeller design, and to avoid or minimize the rise of extraordinary maintenance. While mechanical damages are well documented and studied, little information can be found on cavitation in Pelton turbines. In this paper, a CFD model was applied to study the cavitation mechanics on a Pelton turbine. A Pelton runner affected by pitting cavitation was taken as a test case. The bucket geometry was modeled and analyzed using unsteady Reynolds averaged Navier-Stokes (RANS) multiphase analyses. Numerical results allowed us to highlight the different vapor productions during the cut-in water jet processes by the bucket. Furthermore, a simple procedure to identify the locations of higher damage risk was presented and verified in the test case runner.
2011
Rossetti, Antonio; Santolin, Alberto; Cavazzini, Giovanna; Pavesi, Giorgio; Ardizzon, Guido
Analysis of pelton bucket efficiency Proceedings Article
In: ETC 9 - 9th European Turbomachinery Conference, pp. 1-10, 2011.
Abstract | Links | BibTeX | Tags: Bucket Efficiency, Pelton
@inproceedings{Rossetti2011a,
title = {Analysis of pelton bucket efficiency},
author = {Antonio Rossetti and Alberto Santolin and Giovanna Cavazzini and Giorgio Pavesi and Guido Ardizzon},
url = {https://www.euroturbo.eu/},
year = {2011},
date = {2011-01-01},
urldate = {2011-01-01},
booktitle = {ETC 9 - 9th European Turbomachinery Conference},
pages = {1-10},
abstract = {This paper presents a method for the investigation of a Pelton bucket efficiency based on the analysis of the particles flow tracks. The fluid particles trajectories on the rotating bucket were determined integrating the re- sults obtained by the unsteady numerical analyses carried out on the jet-bucket interaction. The computation was performed using a transient multi-phase homogeneous model and the jet was supposed to have constant diameter and axial-symmetric velocity profile. The numeri- cal results were integrated by means of a predictor-corrector system, which combined two lin- ear multi-step methods: a forth-order Adams-Bashford method as predictor and a fifth-order Adams-Multon method as corrector. The analysis of the fluid particle trajectories in the bucket together and of the single-parti- cle momentum variation during the jet-bucket interaction allowed to examine the influence of the bucket geometry on the energy exchange of the turbine. The lagrangian approach of the proposed method also allowed to consider the losses associated with the leakage flow rate through the intake in the evaluation of the bucket efficiency.},
keywords = {Bucket Efficiency, Pelton},
pubstate = {published},
tppubtype = {inproceedings}
}
This paper presents a method for the investigation of a Pelton bucket efficiency based on the analysis of the particles flow tracks. The fluid particles trajectories on the rotating bucket were determined integrating the re- sults obtained by the unsteady numerical analyses carried out on the jet-bucket interaction. The computation was performed using a transient multi-phase homogeneous model and the jet was supposed to have constant diameter and axial-symmetric velocity profile. The numeri- cal results were integrated by means of a predictor-corrector system, which combined two lin- ear multi-step methods: a forth-order Adams-Bashford method as predictor and a fifth-order Adams-Multon method as corrector. The analysis of the fluid particle trajectories in the bucket together and of the single-parti- cle momentum variation during the jet-bucket interaction allowed to examine the influence of the bucket geometry on the energy exchange of the turbine. The lagrangian approach of the proposed method also allowed to consider the losses associated with the leakage flow rate through the intake in the evaluation of the bucket efficiency.
Santolin, Alberto; Cavazzini, Giovanna; Pavesi, Giorgio
Effect of penstock length variation on hydraulic transients Journal Article
In: Energy Conversion and …, 2011.
Links | BibTeX | Tags: Pelton, Pelton Turbine
@article{pop00065,
title = {Effect of penstock length variation on hydraulic transients},
author = {Alberto Santolin and Giovanna Cavazzini and Giorgio Pavesi},
url = {http://www.indianjournals.com/ijor.aspx?target=ijor:tidee&volume=10&issue=2&article=013&type=pdf},
year = {2011},
date = {2011-01-01},
urldate = {2011-01-01},
journal = {Energy Conversion and …},
publisher = {indianjournals.com},
keywords = {Pelton, Pelton Turbine},
pubstate = {published},
tppubtype = {article}
}
