2023
Zhou, Yunkai; Pavesi, Giorgio; Yuan, Jianping; Fu, Yanxia; Gao, Quanlin
In: Ocean Engineering, vol. 281, 2023, ISSN: 00298018.
Abstract | Links | BibTeX | Tags: Duct profile parameters, Flow characteristics, Hydrodynamic performance, Numerical simulation, Pump-jet
@article{Zhou2023,
title = {Effects of duct profile parameters on flow characteristics of pump-jet: A numerical analysis on accelerating and decelerating ducts distinguished by cambers and angles of attack},
author = {Yunkai Zhou and Giorgio Pavesi and Jianping Yuan and Yanxia Fu and Quanlin Gao},
doi = {10.1016/j.oceaneng.2023.114733},
issn = {00298018},
year = {2023},
date = {2023-01-01},
journal = {Ocean Engineering},
volume = {281},
publisher = {Elsevier Ltd},
abstract = {The aim of this study is to investigate the effects of duct profile parameters cambers and angles of attack that distinguish accelerating and decelerating ducts on the flow characteristics of pump-jet. A detailed numerical analysis is carried out to compare the properties of pump-jets with different cambers and attack angles, and to explore the mutual interaction between the duct and components of pump-jet. Beforehand, the numerical methodology is validated by comparing the experiment and simulation results of the pump-jet under mooring conditions and propeller VP1304. Five cambers (f = 0.5t, 0.25t, 0, −0.25t, −0.5t) and three attack angles (α = 4°, 0°, −4°) of duct profile are considered carefully to distinguish accelerating and decelerating ducts, focusing on the propulsion performance and flow field information. The results show that the flow velocity at the outlet of the accelerating ducts is significantly higher compared to the inlet velocity, as opposed to the phenomenon produced by decelerating ducts. The variation of camber makes the internal evolution of the flow field more intuitive compared with the change of angles of attack. Further results indicate that the maximum efficiency of pump-jet drops after the modest growth as the cambers decrease, whose location shifts towards the lower advance coefficient J. The alteration of α leads to making the trend more direct and apparent for the decelerating and accelerating ducts. The high f is advantageous for the cavitation resistance of inside components, like rotor blades and stator blades. The impacts of changing α on the distribution of pressure in pump-jets with accelerating and decelerating ducts are more prominent than changing f. Moreover, the effects of both variations of f and α on the circumferential distributions of the velocity components are prominent, while there are still significant differences between these changes. Additionally, the velocity distribution at the inlet of pump-jets with decelerating ducts is higher than that at the outlet, and the velocity distribution of pump-jets with accelerating ducts presents the opposite pattern.},
keywords = {Duct profile parameters, Flow characteristics, Hydrodynamic performance, Numerical simulation, Pump-jet},
pubstate = {published},
tppubtype = {article}
}
The aim of this study is to investigate the effects of duct profile parameters cambers and angles of attack that distinguish accelerating and decelerating ducts on the flow characteristics of pump-jet. A detailed numerical analysis is carried out to compare the properties of pump-jets with different cambers and attack angles, and to explore the mutual interaction between the duct and components of pump-jet. Beforehand, the numerical methodology is validated by comparing the experiment and simulation results of the pump-jet under mooring conditions and propeller VP1304. Five cambers (f = 0.5t, 0.25t, 0, −0.25t, −0.5t) and three attack angles (α = 4°, 0°, −4°) of duct profile are considered carefully to distinguish accelerating and decelerating ducts, focusing on the propulsion performance and flow field information. The results show that the flow velocity at the outlet of the accelerating ducts is significantly higher compared to the inlet velocity, as opposed to the phenomenon produced by decelerating ducts. The variation of camber makes the internal evolution of the flow field more intuitive compared with the change of angles of attack. Further results indicate that the maximum efficiency of pump-jet drops after the modest growth as the cambers decrease, whose location shifts towards the lower advance coefficient J. The alteration of α leads to making the trend more direct and apparent for the decelerating and accelerating ducts. The high f is advantageous for the cavitation resistance of inside components, like rotor blades and stator blades. The impacts of changing α on the distribution of pressure in pump-jets with accelerating and decelerating ducts are more prominent than changing f. Moreover, the effects of both variations of f and α on the circumferential distributions of the velocity components are prominent, while there are still significant differences between these changes. Additionally, the velocity distribution at the inlet of pump-jets with decelerating ducts is higher than that at the outlet, and the velocity distribution of pump-jets with accelerating ducts presents the opposite pattern.
Zhou, Yunkai; Pavesi, Giorgio; Cavazzini, Giovanna; Yuan, Jianping; Fu, Yanxia; Gao, Quanlin
Comparative numerical investigation on flow characteristics of pump-jets with accelerating duct and decelerating duct Technical Report
2023.
Abstract | Links | BibTeX | Tags: Flow field, Hydrodynamic performance, Numerical simulation, Pump-jet
@techreport{Zhou2023b,
title = {Comparative numerical investigation on flow characteristics of pump-jets with accelerating duct and decelerating duct},
author = {Yunkai Zhou and Giorgio Pavesi and Giovanna Cavazzini and Jianping Yuan and Yanxia Fu and Quanlin Gao},
url = {https://ssrn.com/abstract=4374636},
year = {2023},
date = {2023-01-01},
abstract = {The mutual interaction between the duct and components of pump-jet can induce significant effects on the overall flow properties and inner flow field. In order to compare the properties of pump-jets with accelerating and decelerating ducts and investigate the effects of duct profiles parameters of two different ducts on the flow characteristics, a detailed numerical analysis is implemented on the flow characteristics and interaction of the pump-jet with different duct profile parameters. Beforehand, the comparison of experiment and simulation of propeller VP1304 and the pump-jet under mooring conditions are adopted to validate numerical methodology. In this paper, five cambers f (f=0.5t, 0.25t, 0,-0.25t,-0.5t) and three angles of attack α (α= 4°, 0°,-4°) of duct profile, employed to distinguish accelerating and decelerating ducts, are considered carefully, focusing on the flow field information and propulsion performance. The results, including the comparison of single ducts with different f and α, and comparison of pump-jet with 2 types of ducts distinguished by different f and α, are exhibited. It shows that the flow velocity at the outlet of the accelerating ducts is significantly higher compared to the inlet velocity, as opposed to the phenomenon produced by decelerating ducts. Compared with the change of α, the variation of f makes the internal evolution of the flow field more intuitive. Further results indicate that the maximum efficiency of pump-jet drops after the modest growth as the cambers decrease, whose location shift towards the lower advance coefficient J. The alteration of α leads to making the trend more direct and apparent for the decelerating and accelerating ducts. It is advantageous for the high f to the cavitation resistance of inside components, like rotor blades and stator blades. The impacts of changing α on the distribution of pressure in pump-jets with accelerating and decelerating ducts are more prominent than changing f. Moreover, the effects of both variations of f and α on the circumferential distributions of the velocity components are prominent, while there are still significant differences between these changes. Additionally, the velocity distribution at the inlet of pump-jets with decelerating ducts is higher than that at the outlet, and the velocity distribution of pump-jets with accelerating ducts presents the opposite pattern.},
keywords = {Flow field, Hydrodynamic performance, Numerical simulation, Pump-jet},
pubstate = {published},
tppubtype = {techreport}
}
The mutual interaction between the duct and components of pump-jet can induce significant effects on the overall flow properties and inner flow field. In order to compare the properties of pump-jets with accelerating and decelerating ducts and investigate the effects of duct profiles parameters of two different ducts on the flow characteristics, a detailed numerical analysis is implemented on the flow characteristics and interaction of the pump-jet with different duct profile parameters. Beforehand, the comparison of experiment and simulation of propeller VP1304 and the pump-jet under mooring conditions are adopted to validate numerical methodology. In this paper, five cambers f (f=0.5t, 0.25t, 0,-0.25t,-0.5t) and three angles of attack α (α= 4°, 0°,-4°) of duct profile, employed to distinguish accelerating and decelerating ducts, are considered carefully, focusing on the flow field information and propulsion performance. The results, including the comparison of single ducts with different f and α, and comparison of pump-jet with 2 types of ducts distinguished by different f and α, are exhibited. It shows that the flow velocity at the outlet of the accelerating ducts is significantly higher compared to the inlet velocity, as opposed to the phenomenon produced by decelerating ducts. Compared with the change of α, the variation of f makes the internal evolution of the flow field more intuitive. Further results indicate that the maximum efficiency of pump-jet drops after the modest growth as the cambers decrease, whose location shift towards the lower advance coefficient J. The alteration of α leads to making the trend more direct and apparent for the decelerating and accelerating ducts. It is advantageous for the high f to the cavitation resistance of inside components, like rotor blades and stator blades. The impacts of changing α on the distribution of pressure in pump-jets with accelerating and decelerating ducts are more prominent than changing f. Moreover, the effects of both variations of f and α on the circumferential distributions of the velocity components are prominent, while there are still significant differences between these changes. Additionally, the velocity distribution at the inlet of pump-jets with decelerating ducts is higher than that at the outlet, and the velocity distribution of pump-jets with accelerating ducts presents the opposite pattern.
2010
Castelli, Marco Raciti; Pavesi, Giorgio; Battisti, Lorenzo; Benini, Ernesto; Ardizzon, Guido
Modeling Strategy and Numerical Validation for a Darrieus Vertical Axis Micro-Wind Turbine Proceedings Article
In: International Mechanical Engineering Congress & Exposition (IMECE2010), pp. pp. 409 - 418, American Society of Mechanical Engineers (ASME), 2010, ISBN: 9780791844441.
Abstract | Links | BibTeX | Tags: Darrieus, mesh, Numerical simulation, RANS
@inproceedings{Castelli2010,
title = {Modeling Strategy and Numerical Validation for a Darrieus Vertical Axis Micro-Wind Turbine},
author = {Marco Raciti Castelli and Giorgio Pavesi and Lorenzo Battisti and Ernesto Benini and Guido Ardizzon},
url = {https://doi.org/10.1115/IMECE2010-39548},
doi = {10.1115/IMECE2010-39548},
isbn = {9780791844441},
year = {2010},
date = {2010-01-01},
booktitle = {International Mechanical Engineering Congress & Exposition (IMECE2010)},
volume = {Vol. 7},
issue = {IMECE2010-39548},
pages = {pp. 409 - 418},
publisher = {American Society of Mechanical Engineers (ASME)},
abstract = {This paper presents a model for the evaluation of optimal spatialŋrid node distribution in the CFD analysis of a Darrieus verticalnaxis micro wind turbine, by analyzing the trends over a 360� rotationnof some indicators of near-blade mesh quality. To this purpose, ancomplete validation campaign has been conducted through a systematicncomparison of numerical simulations with wind tunnel experimentalndata. Both two-dimensional and three-dimensional grids, characterizednby average y+ values of 30 and 1, have been tested by applying somenstatistical techniques as a guidance in selecting the appropriateŋrid configuration and corresponding turbulence model. Finally, thentip downstream recirculation zone due to the finite blade extensionnand the influence of spokes have been analyzed, achieving a numericalnquantification of the influence of induced drag and spokes drag onnoverall rotor performance.},
keywords = {Darrieus, mesh, Numerical simulation, RANS},
pubstate = {published},
tppubtype = {inproceedings}
}
This paper presents a model for the evaluation of optimal spatialŋrid node distribution in the CFD analysis of a Darrieus verticalnaxis micro wind turbine, by analyzing the trends over a 360� rotationnof some indicators of near-blade mesh quality. To this purpose, ancomplete validation campaign has been conducted through a systematicncomparison of numerical simulations with wind tunnel experimentalndata. Both two-dimensional and three-dimensional grids, characterizednby average y+ values of 30 and 1, have been tested by applying somenstatistical techniques as a guidance in selecting the appropriateŋrid configuration and corresponding turbulence model. Finally, thentip downstream recirculation zone due to the finite blade extensionnand the influence of spokes have been analyzed, achieving a numericalnquantification of the influence of induced drag and spokes drag onnoverall rotor performance.
2006
Caignaert, Guy; Ardizzon, Guido; Pavesi, Giorgio
Analysis of rotor-stator interactions effects within the vaned diffuser of a radial flow pump Proceedings Article
In: 23rd IAHR Symposium - Yokohama, pp. 1-10, 2006.
Abstract | BibTeX | Tags: Numerical simulation, particle image velocimetry, radial flow pump, Vaned diffuser
@inproceedings{Caignaert2006,
title = {Analysis of rotor-stator interactions effects within the vaned diffuser of a radial flow pump},
author = {Guy Caignaert and Guido Ardizzon and Giorgio Pavesi},
year = {2006},
date = {2006-01-01},
urldate = {2006-01-01},
booktitle = {23rd IAHR Symposium - Yokohama},
volume = {1},
issue = {October},
pages = {1-10},
abstract = {The paper refers to the analysis of interactions between the impeller and the vaned diffuser of a radial flow pump. It mainly focuses on the flow within one blade passage of a vaned dif- fuser in various operating conditions. 2D/2C PIV results within one blade passage of a dif- fuser, in various measuring planes in the hub to shroud direction, for various relative positions of the impeller in the diffuser frame, and for one operating condition, are compared to numeri- cal results obtained with help of CFX computer code.},
keywords = {Numerical simulation, particle image velocimetry, radial flow pump, Vaned diffuser},
pubstate = {published},
tppubtype = {inproceedings}
}
The paper refers to the analysis of interactions between the impeller and the vaned diffuser of a radial flow pump. It mainly focuses on the flow within one blade passage of a vaned dif- fuser in various operating conditions. 2D/2C PIV results within one blade passage of a dif- fuser, in various measuring planes in the hub to shroud direction, for various relative positions of the impeller in the diffuser frame, and for one operating condition, are compared to numeri- cal results obtained with help of CFX computer code.
