Results 211 to 220 of about 184,150 (234)

Cavitating vortex rope in a diffuser at different operation conditions

Physics of Fluids
A self-induced instability known as vortex rope enhanced by cavitation usually occurs at part load operation conditions in the draft tube and negatively affects the normal operation of Francis turbines. In the present study, the Francis turbine draft tube was simplified and modeled as a diffuser with swirling flow to analyze and understand the flow ...
Diana Puga, Chen Geng, Ziyang Wang, Xianwu Luo   +3 more
openaire   +1 more source

Optimal Control of Part Load Vortex Rope in Francis Turbines

Journal of Fluids Engineering, 2019
The mitigation of the precessing vortex core developing in the draft tube of Francis turbines operating under part load conditions is crucial to increase the operation flexibility of these hydraulic machines to balance the massive power production of intermittent energy sources.
Pasche, Simon, Avellan, Francois, Gallaire, Francois   +2 more
openaire   +2 more sources

Study of Pressure Shock Caused by a Vortex Ring Separated From a Vortex Rope in a Draft Tube Model

Journal of Fluids Engineering, 2017
Operating hydraulic turbines under part- or over-load conditions leads to the development of the precessing vortex rope downstream of the turbine runner. In a regime close to the best efficiency point (BEP), the vortex rope is very unstable because of the low residual swirl of the flow.
S. G. Skripkin, M. A. Tsoy, P. A. Kuibin, S. I. Shtork   +3 more
openaire   +1 more source

Measurement of the Self-Oscillating Vortex Rope Dynamics for Hydroacoustic Stability Analysis

Journal of Fluids Engineering, 2015
Flow instabilities in hydraulic machines often feature oscillating cavitation volumes, which locally introduce compliance and mass flow gain effects. These unsteady characteristics play a crucial role in one-dimensional stability models and can be determined through the definition of transfer functions for the state variables, where the cavitation ...
Andres Müller, Keita Yamamoto, Sébastien Alligné, Koichi Yonezawa, Yoshinobu Tsujimoto, François Avellan   +5 more
openaire   +2 more sources

Two-Dimensional Numerical Simulation of Vortex Shedding of Multiple Stranded Ropes

Volume 9: Rodney Eatock Taylor Honoring Symposium on Marine and Offshore Hydrodynamics; Takeshi Kinoshita Honoring Symposium on Offshore Technology, 2019
Abstract The stranded rope is one of the important components of the fishery aquaculture equipment. We investigate the fluid flow through two-dimensional stranded rope by direct simulation of the Navier-Stokes equations. We show that for different kinds of stranded rope structures, there are significant differences in hydrodynamic ...
Xinxin Wang, Liuyi Huang, Yanli Tang, Fenfang Zhao, Peng Sun   +4 more
openaire   +1 more source

Numerical simulation of pressure pulsations caused by a precessing vortex rope

Izvestiya vysshikh uchebnykh zavedenii. Fizika
For numerical simulation of a vortex rope, the Reynolds-averaged Navier-Stokes equations closed by a two-parameter model of turbulent viscosity are considered. To approximate inviscid flows on cell faces, a Roe scheme with 3rd-order MUSCL-reconstruction and 5th-order WENO-reconstruction is used.
Alena R. Kocharina, Denis V. Chirkov, Vladimir A. Skorospelov, Polina A. Turuk   +3 more
openaire   +1 more source

Numerical Analysis of Pulsating Water Jet Method for Mitigating the Vortex Rope

2019 International Conference on ENERGY and ENVIRONMENT (CIEM), 2019
Hydraulic machines, that operate at part load can suffer severe pressure fluctuations. These fluctuations vary in frequency and amplitude depending on the operating point. The cause of these changes in fluctuations, such as a 70% flow rate regime, is the appearance of the rotating vortex (vortex rope). Removing the rotating vortex is a problem that has
Constantin Tanasa, Adrian Stuparu, Alin Bosioc, Romeo Susan-Resiga   +3 more
openaire   +1 more source

Flow-Feedback Method for Mitigating the Vortex Rope in Decelerated Swirling Flows

Journal of Fluids Engineering, 2013
When reaction hydraulic turbines are operated far from the design operating regime, particularly at partial discharge, swirling flow instability is developed downstream of the runner, in the discharge cone, with a precessing helical vortex and its associated severe pressure fluctuations. Bosioc et al.
Constantin Tănasă, Romeo Susan-Resiga, Sebastian Muntean, Alin Ilie Bosioc   +3 more
openaire   +1 more source

Experimental investigation of vortex rope mitigation in a 10 MW axial turbine

Renewable Energy
Validerad;2024;Nivå 2;2024-12-09 (signyg);Fulltext license: CC BYThis article has previously appeared as a manuscript in a thesis.
Michel Cervantes, Joel Sundstrom
exaly   +3 more sources

Identification on Vortex Rope in Francis Turbine Draft Tube Based on Convkurgram

IEEE Transactions on Instrumentation and Measurement, 2022
Huan Wang, Yaochun Hou, Guangfei Ma, Guangkuan Wu, Da Wang, Bin Huang 0003, Peng Wu 0018, Dazhuan Wu   +7 more
openaire   +1 more source