2013
Cavazzini, Giovanna; Dupont, Patrick; Dazin, Antoine; Pavesi, Giorgio; Bayeul-Lainé, Annie-Claude; Bois, Gérard
Unsteady velocity piv measurements and 3D numerical calculation comparisons inside the impeller of a radial pump model Proceedings Article
In: 10th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics, ETC 2013, pp. 1-10, 2013, ISSN: 24104833.
Abstract | BibTeX | Tags: PIV, Pump
@inproceedings{Cavazzini2013,
title = {Unsteady velocity piv measurements and 3D numerical calculation comparisons inside the impeller of a radial pump model},
author = {Giovanna Cavazzini and Patrick Dupont and Antoine Dazin and Giorgio Pavesi and Annie-Claude Bayeul-Lainé and Gérard Bois},
issn = {24104833},
year = {2013},
date = {2013-01-01},
urldate = {2013-01-01},
booktitle = {10th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics, ETC 2013},
pages = {1-10},
abstract = {PIV measurements were performed at mid hub to shroud section inside the impeller of a vaned diffuser pump model working with air. Several previous papers have already presented part of impeller flow characteristics mainly for vaneless diffuser and near nominal mass flow rate. This paper concerns the pump configuration where the diffuser blades interacted with the impeller flow. Each PIV measuring plane was related to one particular impeller blade to blade channel and analyzed according to different relative positions of the vaned diffuser. A fully unsteady calculation of the whole pump has been performed and comparisons between numerical and experimental results are presented and discussed for four different mass flow rates. The present analysis is restricted to the outlet section of the impeller blade to blade passage for one particular impeller blade position relative to the diffuser.},
keywords = {PIV, Pump},
pubstate = {published},
tppubtype = {inproceedings}
}
PIV measurements were performed at mid hub to shroud section inside the impeller of a vaned diffuser pump model working with air. Several previous papers have already presented part of impeller flow characteristics mainly for vaneless diffuser and near nominal mass flow rate. This paper concerns the pump configuration where the diffuser blades interacted with the impeller flow. Each PIV measuring plane was related to one particular impeller blade to blade channel and analyzed according to different relative positions of the vaned diffuser. A fully unsteady calculation of the whole pump has been performed and comparisons between numerical and experimental results are presented and discussed for four different mass flow rates. The present analysis is restricted to the outlet section of the impeller blade to blade passage for one particular impeller blade position relative to the diffuser.
2012
Cavazzini, Giovanna; Dazin, Antoine; Pavesi, Giorgio; Dupont, P.; Bois, Gerard
Post-processing methods of PIV instantaneous flow fields for unsteady flows in turbomachines Book
hal.archives-ouvertes.fr, 2012.
Abstract | Links | BibTeX | Tags: PIV, Pump as Turbine
@book{pop00022,
title = {Post-processing methods of PIV instantaneous flow fields for unsteady flows in turbomachines},
author = {Giovanna Cavazzini and Antoine Dazin and Giorgio Pavesi and P. Dupont and Gerard Bois},
url = {https://hal.archives-ouvertes.fr/hal-00794858/},
doi = {10.5772/37273},
year = {2012},
date = {2012-01-01},
urldate = {2012-01-01},
journal = {The Particle Image Velocimetry - Characteristics, Limits and Possible Applications},
publisher = {hal.archives-ouvertes.fr},
abstract = {Among the experimental techniques, the particle image velocimetry (PIV) is undoubtedly one of the most attractive modern methods to investigate the fluid flow in a non-intrusive way and allows to obtain instantaneous fluid flow fields by correlating at least two sequential exposures. This technique was successfully applied in several fields in order to study high complex three-dimensional flow velocity fields and to provide a significant experimental data base for the validation of combined numerical analysis models. However, on one side, experimental limits and possible perturbing phenomena could negatively affect the PIV experimental accuracy, altering the real physics of the studied fluid flow field. On the other side, the huge amount of data obtainable by means of the PIV technique requires properly post-processing tools to be exploited in an in-depth study of the fluid-dynamical phenomena. To avoid misinterpretation of the phenomena, complex cleaning techniques were developed and applied at the different steps of the PIV processing, starting from the acquired images (background subtraction, mask application, etc.) so as to increase the signal to noise ratio, and finishing to the instantaneous flow fields by means of statistical methods applied in order to identify residual spurious vectors [Raffel et al., 2002]. Even though all these methods allows to obtain a good filtering of the instantaneous flow fields, however they are not able to completely eliminate all the outliers in the results since the removal criteria are always dependent on the choice of a threshold value [Heinz et al., 2004; Westerweeel, 1994; Westerweel and Scarano, 2005]. To overcome this problem, the most common approach is to average the instantaneous PIV flow fields so as to improve the quality of the resulting flow field reconstruction and to more easily identify the flow field characteristics in the investigated area.},
keywords = {PIV, Pump as Turbine},
pubstate = {published},
tppubtype = {book}
}
Among the experimental techniques, the particle image velocimetry (PIV) is undoubtedly one of the most attractive modern methods to investigate the fluid flow in a non-intrusive way and allows to obtain instantaneous fluid flow fields by correlating at least two sequential exposures. This technique was successfully applied in several fields in order to study high complex three-dimensional flow velocity fields and to provide a significant experimental data base for the validation of combined numerical analysis models. However, on one side, experimental limits and possible perturbing phenomena could negatively affect the PIV experimental accuracy, altering the real physics of the studied fluid flow field. On the other side, the huge amount of data obtainable by means of the PIV technique requires properly post-processing tools to be exploited in an in-depth study of the fluid-dynamical phenomena. To avoid misinterpretation of the phenomena, complex cleaning techniques were developed and applied at the different steps of the PIV processing, starting from the acquired images (background subtraction, mask application, etc.) so as to increase the signal to noise ratio, and finishing to the instantaneous flow fields by means of statistical methods applied in order to identify residual spurious vectors [Raffel et al., 2002]. Even though all these methods allows to obtain a good filtering of the instantaneous flow fields, however they are not able to completely eliminate all the outliers in the results since the removal criteria are always dependent on the choice of a threshold value [Heinz et al., 2004; Westerweeel, 1994; Westerweel and Scarano, 2005]. To overcome this problem, the most common approach is to average the instantaneous PIV flow fields so as to improve the quality of the resulting flow field reconstruction and to more easily identify the flow field characteristics in the investigated area.
2011
Dazin, Antoine; Cavazzini, Giovanna; Pavesi, Giorgio; Dupont, P.; Coudert, S.; Ardizzon, Guido; Caignaert, Guy; Bois, Gerard
High-speed stereoscopic PIV study of rotating instabilities in a radial vaneless diffuser Journal Article
In: Experiments in …, vol. 51, iss. 1, pp. 83-93, 2011, ISSN: 07234864.
Abstract | Links | BibTeX | Tags: PIV, Pump, Rotating Instability
@article{pop00025,
title = {High-speed stereoscopic PIV study of rotating instabilities in a radial vaneless diffuser},
author = {Antoine Dazin and Giovanna Cavazzini and Giorgio Pavesi and P. Dupont and S. Coudert and Guido Ardizzon and Guy Caignaert and Gerard Bois},
url = {http://link.springer.com/article/10.1007/s00348-010-1030-x},
doi = {10.1007/s00348-010-1030-x},
issn = {07234864},
year = {2011},
date = {2011-01-01},
urldate = {2011-01-01},
journal = {Experiments in …},
volume = {51},
issue = {1},
pages = {83-93},
publisher = {Springer},
abstract = {PIV; Pump; Radial Vaneless Diffuser},
keywords = {PIV, Pump, Rotating Instability},
pubstate = {published},
tppubtype = {article}
}
PIV; Pump; Radial Vaneless Diffuser
Cavazzini, Giovanna; Dupont, Patrick; Pavesi, Giorgio; Dazin, Antoine; Bois, Gérard; Atif, Abdelmadjid; Cherdieu, Patrick
Analysis of Unsteady Flow Velocity Fields Inside the Impeller of a Radial Flow Pump: PIV Measurements and Numerical Calculation Comparisons Proceedings Article
In: ASME-JSME-KSME 2011 Joint Fluids Engineering Conference: Volume 1, Symposia – Parts A, B, C, and D, pp. 747-754, ASME, 2011, ISBN: 978-0-7918-4440-3.
Abstract | Links | BibTeX | Tags: PIV, Pump
@inproceedings{Cavazzini2011c,
title = {Analysis of Unsteady Flow Velocity Fields Inside the Impeller of a Radial Flow Pump: PIV Measurements and Numerical Calculation Comparisons},
author = {Giovanna Cavazzini and Patrick Dupont and Giorgio Pavesi and Antoine Dazin and Gérard Bois and Abdelmadjid Atif and Patrick Cherdieu},
url = {http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1625836},
doi = {10.1115/AJK2011-22055},
isbn = {978-0-7918-4440-3},
year = {2011},
date = {2011-01-01},
booktitle = {ASME-JSME-KSME 2011 Joint Fluids Engineering Conference: Volume 1, Symposia – Parts A, B, C, and D},
volume = {1},
issue = {PARTS A, B, C, D},
pages = {747-754},
publisher = {ASME},
abstract = {PIV measurements were performed at mid hub to shroud section inside the impeller of a vaned diffuser pump model working with air. The measurements were restricted to the outlet section of the impeller where the diffuser blades interacted with the impeller flow. Each PIV measuring plane was related to one particular impeller blade to blade channel and analysed according to different relative positions of the vaned diffuser. Two frame change models were considered: the so-called frozen rotor approach for different impeller passage positions relative to the vaned diffuser and a fully unsteady calculation of the whole pump. Comparisons between numerical and experimental results are presented and discussed for a specific mass flow rate corresponding to an off-design point for the impeller and a design point for the vaned diffuser. Copyright © 2011 by ASME.},
keywords = {PIV, Pump},
pubstate = {published},
tppubtype = {inproceedings}
}
PIV measurements were performed at mid hub to shroud section inside the impeller of a vaned diffuser pump model working with air. The measurements were restricted to the outlet section of the impeller where the diffuser blades interacted with the impeller flow. Each PIV measuring plane was related to one particular impeller blade to blade channel and analysed according to different relative positions of the vaned diffuser. Two frame change models were considered: the so-called frozen rotor approach for different impeller passage positions relative to the vaned diffuser and a fully unsteady calculation of the whole pump. Comparisons between numerical and experimental results are presented and discussed for a specific mass flow rate corresponding to an off-design point for the impeller and a design point for the vaned diffuser. Copyright © 2011 by ASME.
Pavesi, Giorgio; Dazin, Antoine; Cavazzini, Giovanna; Caignaert, Guy; Bois, Gerard; Ardizzon, Guido
Experimental and Numerical Investigation of Un-Forced Unsteadiness in a Vaneless Radial Diffuser Proceedings Article
In: ETC 9 - 9th European Turbomachinery Conference, pp. 1-12, 2011.
Abstract | BibTeX | Tags: PIV, Pump, unsteady flow fields, vaneless diffuser
@inproceedings{Pavesi2011a,
title = {Experimental and Numerical Investigation of Un-Forced Unsteadiness in a Vaneless Radial Diffuser},
author = {Giorgio Pavesi and Antoine Dazin and Giovanna Cavazzini and Guy Caignaert and Gerard Bois and Guido Ardizzon},
year = {2011},
date = {2011-01-01},
urldate = {2011-01-01},
booktitle = {ETC 9 - 9th European Turbomachinery Conference},
issue = {1989},
pages = {1-12},
abstract = {The paper reports combined experimental and numerical investigations of unforced un- steadiness in a vaneless radial diffuser. Experimental data were obtained within the diffuser using stereoscopic time resolved Particle Image Velocimetry (PIV) recording three velocity components in a plane (2D/3C), coupled with unsteady pressure transducers. To characterize the inception and the evolution of the unsteady phenomena, spectral analyses of the pressure signals were carried out both in frequency and time-frequency domains and the PIV results were post processed by an original averaging method. Two partial flow rates were investigated in detail in this paper. A single unforced unsteadiness was identified for the lowest flow rate, whereas, two competitive intermittent modes were recognized for the higher mass flow. Numerical analyses were carried out on the same pump by the commercial code CFX. All the computations were performed using the unsteady transient model and the turbulence was modelled by the Scale-Adaptive Simulation (SAS) model. Numerical pressure signals were compared with the experimental data to verify the development of the same pressure fluctuations.},
keywords = {PIV, Pump, unsteady flow fields, vaneless diffuser},
pubstate = {published},
tppubtype = {inproceedings}
}
The paper reports combined experimental and numerical investigations of unforced un- steadiness in a vaneless radial diffuser. Experimental data were obtained within the diffuser using stereoscopic time resolved Particle Image Velocimetry (PIV) recording three velocity components in a plane (2D/3C), coupled with unsteady pressure transducers. To characterize the inception and the evolution of the unsteady phenomena, spectral analyses of the pressure signals were carried out both in frequency and time-frequency domains and the PIV results were post processed by an original averaging method. Two partial flow rates were investigated in detail in this paper. A single unforced unsteadiness was identified for the lowest flow rate, whereas, two competitive intermittent modes were recognized for the higher mass flow. Numerical analyses were carried out on the same pump by the commercial code CFX. All the computations were performed using the unsteady transient model and the turbulence was modelled by the Scale-Adaptive Simulation (SAS) model. Numerical pressure signals were compared with the experimental data to verify the development of the same pressure fluctuations.
2010
Dazin, Antoine; Cavazzini, Giovanna; Pavesi, Giorgio; Dupont, Patrick; Ardizzon, Guido; CAIGNAERT, Guy; Bois, Gérard
Rotating Instabilities in a Radial Vaneless Diffuser Proceedings Article
In: 13th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery 2010 (ISROMAC-13), pp. 1-6, 2010, ISBN: 9781617388484.
Abstract | BibTeX | Tags: Analysis, Flow instability, Numerical Analysis, part load, PIV, radial flow pump, spectral, vaneless diffuser
@inproceedings{Dazin2010,
title = {Rotating Instabilities in a Radial Vaneless Diffuser},
author = {Antoine Dazin and Giovanna Cavazzini and Giorgio Pavesi and Patrick Dupont and Guido Ardizzon and Guy CAIGNAERT and Gérard Bois },
isbn = {9781617388484},
year = {2010},
date = {2010-01-01},
urldate = {2010-01-01},
booktitle = {13th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery 2010 (ISROMAC-13)},
pages = {1-6},
abstract = {The paper reports on the flow field in a vaneless diffuser of a radial flow pump at partial flow conditions. Experimental data were obtained within the diffuser using 2D/3C high repetition rate PIV coupled with unsteady pressure transducers. The pressure measurements were acquired on the shroud wall of the vaneless diffuser and on the suction pipe of the pump. Pressure signals were investigated by frequency and time frequency analyses. PIV results were post processed using original averaging methods. Two partial flow rates were investigated in detail in this paper. Rotating instability occurred for both flow rates. A single instability mode was identified for the lowest flow rate whereas, for the higher one two competitive modes were recognized intermittently. Their spatiotemporal characteristics were described in the paper.},
keywords = {Analysis, Flow instability, Numerical Analysis, part load, PIV, radial flow pump, spectral, vaneless diffuser},
pubstate = {published},
tppubtype = {inproceedings}
}
The paper reports on the flow field in a vaneless diffuser of a radial flow pump at partial flow conditions. Experimental data were obtained within the diffuser using 2D/3C high repetition rate PIV coupled with unsteady pressure transducers. The pressure measurements were acquired on the shroud wall of the vaneless diffuser and on the suction pipe of the pump. Pressure signals were investigated by frequency and time frequency analyses. PIV results were post processed using original averaging methods. Two partial flow rates were investigated in detail in this paper. Rotating instability occurred for both flow rates. A single instability mode was identified for the lowest flow rate whereas, for the higher one two competitive modes were recognized intermittently. Their spatiotemporal characteristics were described in the paper.
2009
Dazin, Antoine; Cavazzini, Giovanna; Pavesi, Giorgio; Dupont, Patrick; Coudert, Sebastien; Ardizzon, Guido; Caignaert, Guy; Bois, Gérard
Rotating Instabilities in a Radial Vaneless Diffuser - Part I: High Speed Stereoscopic Measurements Proceedings Article
In: 8th Conference on Turbomachinery, Fluid Dynamics and Thermodynamics, pp. 1-10, 2009, ISBN: 9783851250367.
Abstract | Links | BibTeX | Tags: Analysis, Flow instability, Numerical Analysis, part load, PIV, radial flow pump, spectral, vaneless diffuser
@inproceedings{pop00063,
title = {Rotating Instabilities in a Radial Vaneless Diffuser - Part I: High Speed Stereoscopic Measurements},
author = {Antoine Dazin and Giovanna Cavazzini and Giorgio Pavesi and Patrick Dupont and Sebastien Coudert and Guido Ardizzon and Guy Caignaert and Gérard Bois },
url = {http://www.academia.edu/download/39639243/Rotating_instabilities_in_a_radial_vaneless_diffuser_Part_I_High_speed_stereoscopic_measurements.pdf},
isbn = {9783851250367},
year = {2009},
date = {2009-01-01},
urldate = {2009-01-01},
booktitle = {8th Conference on Turbomachinery, Fluid Dynamics and Thermodynamics},
pages = {1-10},
abstract = {The paper refers to the behaviour of a vaneless diffuser of a radial flow pump in partial flow operating conditions. Experimental data have been obtained within the diffuser using 2D/3C high repetition rate PIV coupled with unsteady pressure transducers. The pressure measurements were acquired on the shroud wall of the vaneless diffuser and on the suction pipe of the pump. Various operating conditions were investigated in order to characterize the unsteady flow field especially at partial flow rates when the rotating instability appears. A Fourier analysis has been carried out both on the pressure and velocity signals to identify the characteristics of the rotating instability. Averaged results of the PIV data allowed the topology of the instability cells to be visualized and described. Nomenclature},
keywords = {Analysis, Flow instability, Numerical Analysis, part load, PIV, radial flow pump, spectral, vaneless diffuser},
pubstate = {published},
tppubtype = {inproceedings}
}
The paper refers to the behaviour of a vaneless diffuser of a radial flow pump in partial flow operating conditions. Experimental data have been obtained within the diffuser using 2D/3C high repetition rate PIV coupled with unsteady pressure transducers. The pressure measurements were acquired on the shroud wall of the vaneless diffuser and on the suction pipe of the pump. Various operating conditions were investigated in order to characterize the unsteady flow field especially at partial flow rates when the rotating instability appears. A Fourier analysis has been carried out both on the pressure and velocity signals to identify the characteristics of the rotating instability. Averaged results of the PIV data allowed the topology of the instability cells to be visualized and described. Nomenclature
2008
Cavazzini, Giovanna; Dazin, Antoine; Pavesi, Giorgio; Dupont, P.; Coudert, S.; Caignaert, Guy; Bois, Gerard; Ardizzon, Guido
Rotating Instabilities in a Radial Vaneless Diffuser Journal Article
In: IAHR 24th Symposium on Hydraulic Machinery and Systems, pp. 1-10, 2008.
Abstract | BibTeX | Tags: Analysis, Flow instability, Numerical Analysis, part load, PIV, radial flow pump, spectral, vaneless diffuser
@article{Cavazzini2008,
title = {Rotating Instabilities in a Radial Vaneless Diffuser},
author = {Giovanna Cavazzini and Antoine Dazin and Giorgio Pavesi and P. Dupont and S. Coudert and Guy Caignaert and Gerard Bois and Guido Ardizzon },
year = {2008},
date = {2008-01-01},
urldate = {2008-01-01},
journal = {IAHR 24th Symposium on Hydraulic Machinery and Systems},
pages = {1-10},
abstract = {The paper reports on experimental and numerical investigations of large-scale instabilities in a vaneless diffuser of a radial flow pump. The flow field structures were analysed at off-design operating conditions by a stereoscopic time resolved PIV technique and pressure transducers, placed flush with the diffuser walls. Spectral analyses were carried out both on the velocity and pressure signals to identify the characteristics of the instabilities. The experimental data were compared with the numerical results obtained by ANSYS CFX computer code to study the evolution of the flow field instabilities at part load. The numerical computation was performed on the entire pump with the transient sliding faces and the turbulence DES model. The leakage effects were taken into account. The time step for the calculations was chosen according to a runner rotation of about 1 degree.},
keywords = {Analysis, Flow instability, Numerical Analysis, part load, PIV, radial flow pump, spectral, vaneless diffuser},
pubstate = {published},
tppubtype = {article}
}
The paper reports on experimental and numerical investigations of large-scale instabilities in a vaneless diffuser of a radial flow pump. The flow field structures were analysed at off-design operating conditions by a stereoscopic time resolved PIV technique and pressure transducers, placed flush with the diffuser walls. Spectral analyses were carried out both on the velocity and pressure signals to identify the characteristics of the instabilities. The experimental data were compared with the numerical results obtained by ANSYS CFX computer code to study the evolution of the flow field instabilities at part load. The numerical computation was performed on the entire pump with the transient sliding faces and the turbulence DES model. The leakage effects were taken into account. The time step for the calculations was chosen according to a runner rotation of about 1 degree.
