scholarly journals Flow in a Pelton Turbine Bucket: Numerical and Experimental Investigations

2005 ◽  
Vol 128 (2) ◽  
pp. 350-358 ◽  
Author(s):  
Alexandre Perrig ◽  
François Avellan ◽  
Jean-Louis Kueny ◽  
Mohamed Farhat ◽  
Etienne Parkinson
Keyword(s):  
Homogeneous Model ◽  
Free Surface Flow ◽  
Flow Patterns ◽  
Surface Flow ◽  
Experimental Investigations ◽  
Pressure Measurements ◽  
Two Phase ◽  
Pelton Turbine ◽  
Flow Visualizations ◽  
Turbine Bucket

The aim of the paper is to present the results of investigations conducted on the free surface flow in a Pelton turbine model bucket. Unsteady numerical simulations, based on the two-phase homogeneous model, are performed together with wall pressure measurements and flow visualizations. The results obtained allow defining five distinct zones in the bucket from the flow patterns and the pressure signal shapes. The results provided by the numerical simulation are compared for each zone. The flow patterns in the buckets are analyzed from the results. An investigation of the momentum transfer between the water particles and the bucket is performed, showing the regions of the bucket surface that contribute the most to the torque. The study is also conducted for the backside of the bucket, evidencing a probable Coanda interaction between the bucket cutout area and the water jet.

Flow Field Study and Structure Optimization of Pelton Tubine Bucket

2013 ◽  
Vol 655-657 ◽  
pp. 144-148
Author(s):  
Xia Ma ◽  
Wu Gui Hua ◽  
Jie Li ◽  
Gang Li
Keyword(s):  
Free Surface ◽  
Homogeneous Model ◽  
Structure Optimization ◽  
Free Surface Flow ◽  
Flow Patterns ◽  
Surface Flow ◽  
Two Phase ◽  
Pelton Turbine ◽  
Flow Visualizations ◽  
Turbine Model

The aim of the paper is to present the results of investigations conducted on the free surface flow in a Pelton turbine model bucket. Unsteady numerical simulations, based on the two-phase homogeneous model, are performed together with flow visualizations. The results obtained allow defining five distinct zones in the bucket from the flow patterns. The flow patterns in the buckets are analyzed from the results. An investigation of the momentum transfer between the water particles and the bucket is performed, showing the regions of the bucket surface that contribute the most to the torque. The study is also conducted for the backside of the bucket, evidencing a probable Coanda interaction between the bucket cutout area and the Water jet.

Flow dynamics of the free surface flow in the rotating buckets of a Pelton turbine

2009 ◽  
Vol 223 (5) ◽  
pp. 609-623 ◽  
Author(s):  
Zh Zhang
Keyword(s):  
Free Surface Flow ◽  
Surface Flow ◽  
Experimental Investigations ◽  
Hydraulic Efficiency ◽  
Pelton Turbine ◽  
Impact Forces ◽  
Invariance Equation ◽  
Power Exchange ◽  
The Impact ◽  
Rotating Bucket

The relative flow in the rotating buckets of a Pelton turbine was calculated with respect to the influences of centrifugal, Coriolis, and impact forces. Based on the assumption of frictionless flows, the so-called invariance equation was presented, which enables the changeable flow velocity in a rotating bucket to be calculated. The introduced jet layer method relying on the invariance equation significantly simplifies the computation of the entire jet expansion in the rotating bucket. For purely radial flows, contributions of centrifugal, Coriolis, and impact forces to the power exchange and the corresponding effectiveness relations were quantified. In general, the centrifugal force only performs the negligible work, if compared with the effectiveness of the Coriolis and the impact forces. Various calculation examples were presented to show the flow development and the effectiveness of all active forces in the rotating bucket and to explain the application of the invariance equation. The results presented in the article for frictionless flows can be applied as the reference for further computational and experimental investigations with respect to the flow friction effects on the hydraulic efficiency of a Pelton turbine.

scholarly journals High Speed Flow Visualisation of an Impinging Jet on a Pelton Turbine Bucket

2007 ◽  
Author(s):  
Alexandre Perrig ◽  
Mohamed Farhat ◽  
Franc¸ois Avellan
Keyword(s):  
High Speed ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Flow Visualisation ◽  
Pelton Turbine ◽  
Flow Development ◽  
Speed Flow ◽  
Turbine Bucket ◽  
Reduced Scale ◽  
Development And Evolution

This paper deals with flow investigations using endoscopes in a single-injector reduced scale Pelton turbine performed with a CMOS high-speed camera. Both onboard and external visualizations techniques of the flow in a bucket are presented. The flow observations evidence the unsteadiness of the successive steps of jet/bucket interaction, free surface flow development and evolution throughout the bucket duty cycle.

scholarly journals Time-resolved PIV measurements of a deflected submerged jet interacting with liquid-gas and liquid-liquid interfaces

2021 ◽  
Author(s):  
Stefan Puttinger ◽  
Mahdi Saeedipour
Keyword(s):  
Liquid Layer ◽  
Large Scale ◽  
Free Surface Flow ◽  
Industrial Applications ◽  
Liquid Pool ◽  
Surface Flow ◽  
Two Phase ◽  
Time Resolved ◽  
Submerged Jet ◽  
Major Interest

AbstractThis paper presents an experimental investigation on the interactions of a deflected submerged jet into a liquid pool with its above interface in the absence and presence of an additional lighter liquid. Whereas the former is a free surface flow, the latter mimics a situation of two stratified liquids where the liquid-liquid interface is disturbed by large-scale motions in the liquid pool. Such configurations are encountered in various industrial applications and, in most cases, it is of major interest to avoid the entrainment of droplets from the lighter liquid into the main flow. Therefore, it is important to understand the fluid dynamics in such configurations and to analyze the differences between the cases with and without the additional liquid layer. To study this problem, we applied time-resolved particle image velocimetry experiments with high spatial resolution. A detailed data analysis of a small layer beneath the interface shows that although the presence of an additional liquid layer stabilizes the oscillations of the submerged jet significantly, the amount of kinetic energy, enstrophy, and velocity fluctuations concentrated in the proximity of the interface is higher when the oil layer is present. In addition, we analyze the energy distribution across the eigenmodes of a proper orthogonal distribution and the distribution of strain and vortex dominated regions. As the main objective of this study, these high-resolution time-resolved experimental data provide a validation platform for the development of new models in the context of the volume of fluid-based large eddy simulation of turbulent two-phase flows.

scholarly journals The Finite Element Numerical Investigation of Free Surface Newtonian and Non-Newtonian Fluid Flows in the Rectangular Tanks

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Puyang Gao
Keyword(s):  
Finite Element ◽  
Free Surface ◽  
Level Set ◽  
Newtonian Fluid ◽  
Mass Conservation ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Two Phase ◽  
Navier Stokes Equation ◽  
Correction Technique

In this paper, we develop a new computational framework to investigate the sloshing free surface flow of Newtonian and non-Newtonian fluids in the rectangular tanks. We simulate the flow via a two-phase model and employ the fixed unstructured mesh in the computation to avoid the mesh distortion and reconstruction. As for the solution of Navier–Stokes equation, we utilize the SUPG finite element method based on the splitting scheme. The same order interpolation functions are then used for velocity and pressure. Moreover, the moving interface is captured via the concise level set method. We take advantage of the implicit discontinuous Galerkin method to handle the solution of level set and its reinitialization equations. A mass correction technique is also added to ensure the mass conservation property. The dam break-free surface flow is simulated firstly to demonstrate the validity of our mathematical model. In addition, the sloshing Newtonian fluid in the tank with flat and rough bottoms is considered to illustrate the feasibility and robustness of our computational scheme. Finally, the development of free surface for non-Newtonian fluid is also studied in the two tanks, and the influence of power-law index on the sloshing fluid flow is analyzed.

scholarly journals CFD Code Validation against Stratified Air-Water Flow Experimental Data

2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
F. Terzuoli ◽  
M. C. Galassi ◽  
D. Mazzini ◽  
F. D'Auria
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Water Flow ◽  
Nuclear Reactor ◽  
Cold Water ◽  
Three Dimensional ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Two Phase ◽  
Code Validation

Pressurized thermal shock (PTS) modelling has been identified as one of the most important industrial needs related to nuclear reactor safety. A severe PTS scenario limiting the reactor pressure vessel (RPV) lifetime is the cold water emergency core cooling (ECC) injection into the cold leg during a loss of coolant accident (LOCA). Since it represents a big challenge for numerical simulations, this scenario was selected within the European Platform for Nuclear Reactor Simulations (NURESIM) Integrated Project as a reference two-phase problem for computational fluid dynamics (CFDs) code validation. This paper presents a CFD analysis of a stratified air-water flow experimental investigation performed at the Institut de Mécanique des Fluides de Toulouse in 1985, which shares some common physical features with the ECC injection in PWR cold leg. Numerical simulations have been carried out with two commercial codes (Fluent and Ansys CFX), and a research code (NEPTUNE CFD). The aim of this work, carried out at the University of Pisa within the NURESIM IP, is to validate the free surface flow model implemented in the codes against experimental data, and to perform code-to-code benchmarking. Obtained results suggest the relevance of three-dimensional effects and stress the importance of a suitable interface drag modelling.

A Two-Phase Flow Model with VOF for Free Surface Flow Problems

2012 ◽  
Vol 232 ◽  
pp. 279-283 ◽  
Author(s):  
Wei Zhang ◽  
You Hong Tang ◽  
Cheng Bi Zhao ◽  
Cheng Zhang
Keyword(s):  
Free Surface ◽  
Flow Model ◽  
Two Phase Flow ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Phase Model ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Problems ◽  
Fluid Sloshing

A numerical model based on the two-phase flow model for incompressible viscous fluid with a complex free surface has been developed in this study. The two-step projection method is employed to solve the Navier–Stokes equations in the numerical solutions, and finite difference method on a staggered grid is used throughout the computation. The two-order accurate volume of fluid (VOF) method is used to track the distorted and broken free surfaces. The two-phase model is first validated by simulating the dam break over a dry bed, in which the numerical results and experimental data agree well. Then 2-D fluid sloshing in a horizontally excited rectangular tank at different excitation frequencies is simulated using this two-phase model. The results of this study show that the two-phase flow model with VOF method is a potential tool for the simulation of nonlinear fluid sloshing. These studies demonstrate the capability of the two-phase model to simulate free surface flow problems with considering air movement effects.

scholarly journals Finite Element Simulation of a Taylor Bubble in Two-Phase Gas-Liquid Slug Flows using Petrov-Galerkin Formulation

2021 ◽  
Vol 18 (3) ◽  
pp. 229-237
Author(s):  
H.A. Abubakar ◽  
A. Yusuf ◽  
Y. Sanusi ◽  
H.A. Dandajeh
Keyword(s):  
Finite Element ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Two Phase ◽  
Systematic Analysis ◽  
Taylor Bubble ◽  
Galerkin Finite Element ◽  
Flow Problems ◽  
Element Simulation ◽  
Good Agreement

Petrov-Galerkin finite element scheme for systematic analysis of the dynamics of a rising Taylor bubble and general free surface flow problems is derived and implemented. The validity of the scheme is confirmed by simulating the buoyancy-driven motion of a Taylor bubble through a stagnant Newtonian liquid in a vertical pipe characterised by dimensionless inverse viscosity number and Eötvös number of magnitude 111 and 189, respectively. Comparison of the numerical results for the steady state features defining the nose, film, and bottom regions around the bubble with the experiment shows a good agreement between the numerical simulation and the experiment. The percentage deviation of the numerical computed rise velocity, equilibrium film thickness, and stabilisation length ahead of the bubble from the experimental determined values are 8.4%, 2.3%, and 9.5%, respectively.

0522 Analysis of Free Surface Flow Patterns of Undershot Cross-Flow Water Turbines Used by Advanced Equipment

2015 ◽  
Vol 2015 (0) ◽  
pp. _0522-1_-_0522-4_
Author(s):  
Yuichiro YAHAGI ◽  
Yasuyuki NISHI ◽  
Terumi INAGAKI ◽  
Yanrong LI ◽  
Kentaro HATANO ◽  
...  
Keyword(s):  
Free Surface ◽  
Cross Flow ◽  
Free Surface Flow ◽  
Flow Patterns ◽  
Surface Flow ◽  
Water Turbines
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