Publications

@inproceedings{pop00020,

title = {Numerical characterization of pressure instabilities in a vaned centrifugal pump under partload condition},

author = {Jun Yang and Giorgio Pavesi and Giovanna Cavazzini and Shouqi Q. Yuan},

url = {http://iopscience.iop.org/article/10.1088/1757-899X/52/2/022044/meta http://stacks.iop.org/1757-899X/52/i=2/a=022044?key=crossref.51f7846194288a9a6286cc200d28e156},

doi = {10.1088/1757-899X/52/2/022044},

issn = {17578981},

year  = {2013},

date = {2013-01-01},

urldate = {2013-01-01},

booktitle = {IOP Conference Series: Materials Science and Engineering},

volume = {52},

issue = {2},

pages = {022-044},

publisher = {iopscience.iop.org},

abstract = {This paper studies the hysteresis/saddle phenomena of the head-drop in a scaled model pump turbine using CFD methods. This lag was induced by complicated flow patterns, which influenced the reliability of rotating machine that was analysed by a commercial code with DES model for computing turbulence. Analyses were carried out on the pressure signals both in frequency and time-frequency domains at full and part load conditions. The results highlighted the remarkable interaction between the unsteady structures in diffuser and return. © Published under licence by IOP Publishing Ltd.},

keywords = {Francis-type Reversible Turbine, hump-instability region, Pressure fluctuations},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{Cavazzini2012a,

title = {Influence of the Return Channel Geometry on the Perfomance Stability of a Centrifugal Pump},

author = {Giovanna Cavazzini and Giorgio Pavesi and Guido Ardizzon},

year  = {2012},

date = {2012-01-01},

urldate = {2012-01-01},

booktitle = {14th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, ISROMAC-14 February 27th - March 2nd, 2012},

issue = {January 2016},

pages = {1-8},

abstract = {The paper reports on fluid-dynamical investigations of largescale instabilities in a radial multistage pump with a vaneless return channel. To establish a relation between the flow field structure at high/partial load and acoustic radiation, numerical analyses were carried out by means of the commercial code CFX 12.0 on the entire machine so as to study the unsteady phenomena developing in the pump. All the computations were performed using the unsteady "transient" model. The time step for the calculation will be chosen according to a rotation of the runner of about 1 degree. Turbulence will be modelled by DES model. To validate the numerical analysis, numerical pressure signals were compared with experimental signals. Further numerical analyses were also carried out on simplified configurations in order to determine the geometrical and fluid-dynamical parameters affecting the development of the identified unsteady phenomena.},

keywords = {Francis-type Reversible Turbine, hump-instability region},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{pop00027,

title = {Pressure instabilities in a vaned centrifugal pump},

author = {Giovanna Cavazzini and Giorgio Pavesi and Guido Ardizzon},

url = {http://pia.sagepub.com/content/225/7/930.short http://journals.sagepub.com/doi/10.1177/0957650911410643},

doi = {10.1177/0957650911410643},

issn = {0957-6509},

year  = {2011},

date = {2011-01-01},

booktitle = {ETC 9 - 9th European Turbomachinery Conference},

volume = {225},

issue = {7},

pages = {1-10},

publisher = {pia.sagepub.com},

abstract = {This article reports the acoustic and fluid-dynamical analyses of large-scale instabil- ities in a vaned centrifugal pump. The unsteady pressure fields at full/part load were measured by dynamic piezoresistive transducers placed at the impeller discharge and on an instrumented diffuser vane. To spectrally characterize the inception and the evolution of the unsteady phe- nomena, spectral analyses of the pressure signals were carried out both in frequency and time– frequency domains. Numerical analyses were carried out on the same pump with the help of the commercial code CFX. All the computations were performed using the unsteady ‘transient’ model with a time step corresponding to about 1? of the impeller rotation. The turbulence was modelled by the detached eddy simulation model. Numerical pressure signals were compared with the experimental ones to verify the development of the same pressure instabilities. The unsteady numerical flow fields were analysed to study the fluid-dynamical evolution of the instabilities},

note = {<b>From Duplicate 2 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G.; Pavesi, G.; Ardizzon, G.)<br/></b><br/><b>From Duplicate 1 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/><b>From Duplicate 1 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/><b>From Duplicate 1 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G.; Pavesi, G.; Ardizzon, G.)<br/></b><br/><b>From Duplicate 1 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G.; Pavesi, G.; Ardizzon, G.)<br/></b><br/><b>From Duplicate 2 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/>Query date: 2017-05-06<br/><br/><b>From Duplicate 2 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/>Query date: 2017-05-06<br/><br/><b>From Duplicate 2 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/>Query date: 2017-05-06<br/><br/><b>From Duplicate 2 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G.; Pavesi, G.; Ardizzon, G.)<br/></b><br/><b>From Duplicate 2 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/><b>From Duplicate 1 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/><b>From Duplicate 1 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G.; Pavesi, G.; Ardizzon, G.)<br/></b><br/><b>From Duplicate 1 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G.; Pavesi, G.; Ardizzon, G.)<br/></b><br/><b>From Duplicate 2 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/>Query date: 2017-05-06<br/><br/><b>From Duplicate 2 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/>Query date: 2017-05-06<br/><br/><b>From Duplicate 2 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/>Query date: 2017-05-06<br/><br/><b>From Duplicate 3 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, Giovanna; Pavesi, Giorgio; Ardizzon, Guido)<br/></b><br/><b>From Duplicate 1 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/><b>From Duplicate 1 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/><b>From Duplicate 1 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G.; Pavesi, G.; Ardizzon, G.)<br/></b><br/><b>From Duplicate 1 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G.; Pavesi, G.; Ardizzon, G.)<br/></b><br/><b>From Duplicate 2 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/>Query date: 2017-05-06<br/><br/><b>From Duplicate 2 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/>Query date: 2017-05-06<br/><br/><b>From Duplicate 2 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/>Query date: 2017-05-06<br/><br/><b>From Duplicate 2 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, Giovanna; Pavesi, Giorgio; Ardizzon, Guido)<br/></b><br/><b>From Duplicate 2 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/>And Duplicate 3 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/><b>From Duplicate 1 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/><b>From Duplicate 1 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G.; Pavesi, G.; Ardizzon, G.)<br/></b><br/><b>From Duplicate 1 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G.; Pavesi, G.; Ardizzon, G.)<br/></b><br/><b>From Duplicate 2 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/>Query date: 2017-05-06<br/><br/><b>From Duplicate 2 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/>Query date: 2017-05-06<br/><br/><b>From Duplicate 2 (<i>Pressure instabilities in a vaned centrifugal pump</i> - Cavazzini, G; Pavesi, G; Ardizzon, G)<br/></b><br/>Query date: 2017-05-06},

keywords = {Blockage, Centrifugal pump, Francis-type Reversible Turbine, hump-instability region, part load, Return channel, Rotating Instability, Unforced unsteadiness},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{Pavesi2009c,

title = {Experimental Charactization of Rotating Instabilities in a Centrifugal Pump},

author = {Giorgio Pavesi and Giovanna Cavazzini and Guido Ardizzon},

url = {https://www.researchgate.net/profile/Giorgio_Pavesi/publication/277598782_Experimental_characterization_of_rotating_instabilities_in_a_centrifugal_pump/links/556e803208aefcb861db9cbc.pdf},

year  = {2009},

date = {2009-01-01},

urldate = {2009-01-01},

booktitle = {ETC 8 - 8th European Turbomachinery Conference},

abstract = {The paper presents experimental investigations of large-scale instabilities in a centrifugal pump. Pressure fluctuations were measured with transducers placed flush with the inlet duct and at the impeller discharge. Two impeller rotation speeds and two configurations with a vaneless and a vaned diffuser, were utilized in the study, as well as several angular and radial transducer positions at design and at off design flow rates. The spectra analyses of the pressure signals were carried out both in frequency and time-fre- quency domains to identified precursors, inception and evolution of the pressure instabilities. Be- cause of the non-linearity of the unsteady phenomena developing in the pump, high-order moment functions were applied to discriminate between non-linearly coupled pulsations and self-excited pulsations and to determine the fraction of the power of each pulsation that was due to the non- linear interaction of unsteady phenomena. The results highlighted the existence of an asymmetrical rotating pressure structure at the im- peller discharge, having a fluid-dynamical origin and propagating both in the radial and circumferential direction, inside and downstream of the impeller. Nomenclature},

note = {Query date: 2017-05-06},

keywords = {Francis-type Reversible Turbine, hump-instability region},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{Pavesi2006a,

title = {Experimental and computation investigation of the rotating instability in a centrifugal pump impeller},

author = {Giorgio Pavesi and Guido Ardizzon and Giovanna Cavazzini},

year  = {2006},

date = {2006-01-01},

urldate = {2006-01-01},

booktitle = {Proceedings of ISROMAC2006: The Eleventh International Symposium on Transport Phenomena and Dynamics of Rotating Machinery},

pages = {1-10},

abstract = {The paper reports on experimental and numerical investigations aimed at understanding the mechanisms of rotating instabilities in a centrifugal pump. The phenomena of rotating instabilities in the impeller were first identified with an experimental study. Afterward an unsteady numerical analysis was applied to confirm the phenomena and to detail the mechanisms behind them. The experimental study was conducted with high-response pressure measurements at three planes, at the pump, and at diffuser inflows. The numerical investigation, for the entire pump, was performed with an unsteady 3-D Navier-Stokes method. Turbulence was modelled both by the k-ω transport equations model and Reynolds Stress Model. The effects of the tip leakage flow were considered by meshing the tip clearance between rotor blade and casing The current study reveals that a vortex structure forms near the leading edge plane. The formation and movement of this vortex seem to be the main causes of unsteadiness when rotating instability develops. This unsteady phenomenon was highlighted both at design flow rate and at low flow rates. The azimuthal distributions exhibited no significant uniformities and the amplitude of this non-uniformity was sensitive to the flow rate.},

keywords = {Francis-type Reversible Turbine, hump-instability region},

pubstate = {published},

tppubtype = {inproceedings}

}