scholarly journals Capability of Advanced Ultrasonic Inspection Technologies for Hydraulic Turbine Runners

2021 ◽  
Vol 11 (10) ◽  
pp. 4681
Author(s):  
Mohammad Ebrahim Bajgholi ◽  
Gilles Rousseau ◽  
Martin Viens ◽  
Denis Thibault
Keyword(s):  
Ultrasonic Inspection ◽  
High Stress ◽  
Welding Process ◽  
Hydraulic Turbine ◽  
Francis Turbine ◽  
Detection Rates ◽  
Critical Range ◽  
Area Of Interest ◽  
Ambitious Program ◽  
Pulse Echo

This paper presents the results of a project aimed at evaluating the performance of ultrasonic techniques for detecting flaws in Francis turbine runners. This work is the first phase of a more ambitious program aimed at improving the reliability of inspection of critical areas in turbine runners. Francis runners may be utilized to supply power during peak periods, which means that they experience additional load stress associated with start and stop sequences. Inspection during manufacturing is then of paramount importance to remove as much as feasible all flaw initiation sites before the heat treatment. This phase one objective is to collect initial data on a simplified mock-up and then to compare the experimental ultrasonic data with the results of simulations performed by CIVA, a computer simulation package. The area of interest is the region with the highest stress between the blade and the web. A welded T-joint coupon made of UNS S41500 was manufactured to represent this high-stress area. During the FCAW welding process, ceramic beads were embedded in the weld to create discontinuities whose size is in the critical range to initiate a crack. Inspection of the material was carried out by various nondestructive testing (NDT) methods namely conventional pulse-echo, phased array, total focusing method (TFM). With these results, detection rates were obtained in order to compare the effectiveness of each method.

Numerical Prediction of Critical Cavitation Performance in Hydraulic Turbines

2003 ◽  
Author(s):  
Sadao Kurosawa ◽  
Kiyoshi Matsumoto
Keyword(s):  
Flow Model ◽  
Flow Analysis ◽  
Prediction Method ◽  
Hydraulic Turbine ◽  
Francis Turbine ◽  
Two Phase ◽  
Cavitation Performance ◽  
Hydraulic Turbines ◽  
Critical Cavitation ◽  
Good Agreement

In this paper, numerical method for predicting critical cavitation performance in a hydraulic turbine is presented. The prediction method is based on unsteady cavitation flow analysis to use bubble two-phase flow model. The prediction of the critical cavitation performance was carried out for the aixal hydraulic turbine and the francis turbine as a typical examples. Results compared to the experiment showed a good agreement for the volume of cavity and the performance drop off and it was recognized that this method could be used as an engineering tool of a hydraulic turbine development.

Optimization of a Weld Overlay on a Plate Structure

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
John Goldak ◽  
Mahyar Asadi ◽  
Jianguo Zhou ◽  
Stanislav Tchernov ◽  
Dan Downey
Keyword(s):  
Welding Process ◽  
Francis Turbine ◽  
Transient Temperature ◽  
Weld Repair ◽  
Weld Overlay ◽  
Hydroelectric Project ◽  
Repair Procedure ◽  
Strain Stress ◽  
Welding Direction ◽  
Interpass Temperature

An overlay weld repair procedure on a 1066.8×1066.8 mm2 square plate 25.4 mm thick was simulated to compute the 3D transient temperature, microstructure, strain, stress, and displacement of the overlay weld repair procedure. The application for the overlay was the repair of cavitation erosion damage on a large Francis turbine used in a hydroelectric project. The overlay weld consisted of a 4×6 pattern of 100×100 mm2 squares. Each square was covered by 15 weld passes. Each weld pass was 100 mm long. The total length of weld in the six squares was 36 m. The welds in each square were oriented either front-to-back or left-to-right. The welding process was shielded metal arc. The analysis shows that alternating the welding direction in each square produces the least distortion. A delay time of 950 s between the end of one weld pass and the start of the next weld pass was imposed to meet the requirement of a maximum interpass temperature to 50°C.

scholarly journals Derivation of Global Parametric Performance of Mixed Flow Hydraulic Turbine Using CFD

1970 ◽  
Vol 7 ◽  
pp. 60-64 ◽  
Author(s):  
Ruchi Khare ◽  
Vishnu Prasad Prasad ◽  
Sushil Kumar
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Solutions ◽  
Guide Vane ◽  
Hydraulic Turbine ◽  
Francis Turbine ◽  
Mixed Flow ◽  
Flow Equations ◽  
Laboratory Setup ◽  
Wide Range

The testing of physical turbine models is costly, time consuming and subject to limitations of laboratory setup to meet International Electro technical Commission (IEC) standards. Computational fluid dynamics (CFD) has emerged as a powerful tool for funding numerical solutions of wide range of flow equations whose analytical solutions are not feasible. CFD also minimizes the requirement of model testing. The present work deals with simulation of 3D flow in mixed flow (Francis) turbine passage; i.e., stay vane, guide vane, runner and draft tube using ANSYS CFX 10 software for study of flow pattern within turbine space and computation of various losses and efficiency at different operating regimes. The computed values and variation of performance parameters are found to bear close comparison with experimental results.Key words: Hydraulic turbine; Performance; Computational fluid dynamics; Efficiency; LossesDOI: 10.3126/hn.v7i0.4239Hydro Nepal Journal of Water, Energy and EnvironmentVol. 7, July, 2010Page: 60-64Uploaded date: 31 January, 2011

scholarly journals Optimisation of process parameters for M.A.G welding of API X70m material to predict tensile strength using Taguchi method

2021 ◽  
Vol 39 (4) ◽  
pp. 1100-1107
Author(s):  
N.S. Akonyi ◽  
O.A. Olugboji ◽  
E.A.P. Egbe ◽  
O. Adedipe ◽  
S.A. Lawal
Keyword(s):  
Tensile Strength ◽  
Process Parameters ◽  
Welding Process ◽  
Statistical Technique ◽  
Engineering Software ◽  
Area Of Interest ◽  
Girth Welding ◽  
Welding Processes ◽  
Selection Of ◽  
Welding Technique

Girth welded replica of API X70M material have been produced on NG-GMAW welding technique. The particular area of interest is to develop suitable girth welding process parameter using NGGMAW. The major aim of the work was to replicate welds having tensile strength between 650 and 680 MPa. Design of Experiment (DoE) method by Taguchi design, using some selected welding processes was adopted. Two process parameters (factors) – arc voltage and wire feed rate, (the variables), and three levels were used. The resultant joint property on tensile strength of X70M pipeline was examined. The targeted mechanical property was achieved by selecting the best process parameters. Their effects on ultimate tensile strength – UTS was analysed using statistical technique – analysis of variance - ANOVA and Signal to Noise - S/N ratio with ‘thebigger-the–better’ value. Validation was done using MIDAS NFX (an FEA) mechanical engineering software. In conclusion, process parameters that affects or influences the girth welded properties of API X70M under field conditions were identified. Guidance for the specifications and selection of processes that could be used in field-welding for optimum performance has been recommended. Keywords: Optimization, Girth-Weld, Process Parameters, Tensile Strength, NG-GMAW

scholarly journals Numerical Study of Sediment Erosion Analysis in Francis Turbine

2019 ◽  
Vol 11 (5) ◽  
pp. 1423 ◽  
Author(s):  
Md Rakibuzzaman ◽  
Hyoung-Ho Kim ◽  
Kyungwuk Kim ◽  
Sang-Ho Suh ◽  
Kyung Kim
Keyword(s):  
Erosion Rate ◽  
Cavitation Erosion ◽  
Numerical Study ◽  
Leading Edge ◽  
Suction Side ◽  
Hydraulic Turbine ◽  
Francis Turbine ◽  
Trailing Edge ◽  
Sand Erosion ◽  
Turbine Design

Effective hydraulic turbine design prevents sediment and cavitation erosion from impacting the performance and reliability of the machine. Using computational fluid dynamics (CFD) techniques, this study investigated the performance characteristics of sediment and cavitation erosion on a hydraulic Francis turbine by ANSYS-CFX software. For the erosion rate calculation, the particle trajectory Tabakoff–Grant erosion model was used. To predict the cavitation characteristics, the study’s source term for interphase mass transfer was the Rayleigh–Plesset cavitation model. The experimental data acquired by this study were used to validate the existing evaluations of the Francis turbine. Hydraulic results revealed that the maximum difference was only 0.958% compared with the CFD data, and 0.547% compared with the experiment (Korea Institute of Machinery and Materials (KIMM)). The turbine blade region was affected by the erosion rate at the trailing edge because of their high velocity. Furthermore, in the cavitation–erosion simulation, it was observed that abrasion propagation began from the pressure side of the leading edge and continued along to the trailing edge of the runner. Additionally, as sediment flow rates grew within the area of the attached cavitation, they increased from the trailing edge at the suction side, and efficiency was reduced. Cavitation–sand erosion results then revealed a higher erosion rate than of those of the sand erosion condition.

scholarly journals Manipulation of the swirling flow instability in hydraulic turbine diffuser by different methods of water injection

2018 ◽  
Vol 180 ◽  
pp. 02090 ◽  
Author(s):  
Pavel Rudolf ◽  
Jiří Litera ◽  
Germán Alejandro Ibarra Bolanos ◽  
David Štefan
Keyword(s):  
Swirling Flow ◽  
Flow Instability ◽  
Draft Tube ◽  
Water Injection ◽  
Hydraulic Turbine ◽  
Operating Conditions ◽  
Francis Turbine ◽  
Necessary Condition ◽  
Vortex Rope ◽  
Wide Range

Vortex rope, which induces substantial pressure pulsations, arises in the draft tube (diffuser) of Francis turbine for off-design operating conditions. Present paper focuses on mitigation of those pulsations using active water jet injection control. Several modifications of the original Susan-Resiga’s idea were proposed. All modifications are driven by manipulation of the shear layer region, which is believed to play important role in swirling flow instability. While some of the methods provide results close to the original one, none of them works in such a wide range. Series of numerical experiments support the idea that the necessary condition for vortex rope pulsation mitigation is increasing the fluid momentum along the draft tube axis.

Design of a Francis Turbine for a Small Hydro Power Project in Turkey

2010 ◽  
Author(s):  
Kutay Celebioglu ◽  
Gizem Okyay ◽  
Mehmet Yildiz
Keyword(s):  
Power Plants ◽  
Parametric Design ◽  
Optimization Procedure ◽  
Hydraulic Turbine ◽  
Francis Turbine ◽  
Design Parameters ◽  
Hydro Power ◽  
Total Potential ◽  
Computational Fluid Dynamics Analysis ◽  
Hydro Power Plants

Many hydro power plants, both in small and large scales, are being constructed in Turkey. The total potential of these projects reach to 216 billion kWh of feasible energy. However a method was not yet developed for the design of hydraulic machinery equipment in Turkey. In order to accomplish the hydraulic turbine design without any prior information than the design parameters of the hydraulic project, a methodology is developed. This methodology involves the use of computational tools and it is applied for small hydro projects. This methodology is a parametric design-optimization procedure which consists of parametric geometry modeling, computational fluid dynamics analysis and structural verification.

scholarly journals CFD Investigation of a High Head Francis Turbine at Speed No-Load Using Advanced URANS Models

2018 ◽  
Vol 8 (12) ◽  
pp. 2505 ◽  
Author(s):  
Jean Decaix ◽  
Vlad Hasmatuchi ◽  
Maximilian Titzschkau ◽  
Cécile Münch-Alligné
Keyword(s):  
Power Plants ◽  
Turbulence Modeling ◽  
Suction Side ◽  
Hydraulic Turbine ◽  
Operating Conditions ◽  
Francis Turbine ◽  
Hydroelectric Power ◽  
Electrical Grid ◽  
Runner Blade ◽  
Pumped Storage

Due to the integration of new renewable energies, the electrical grid undergoes instabilities. Hydroelectric power plants are key players for grid control thanks to pumped storage power plants. However, this objective requires extending the operating range of the machines and increasing the number of start-up, stand-by, and shut-down procedures, which reduces the lifespan of the machines. CFD based on standard URANS turbulence modeling is currently able to predict accurately the performances of the hydraulic turbines for operating points close to the Best Efficiency Point (BEP). However, far from the BEP, the standard URANS approach is less efficient to capture the dynamics of 3D flows. The current study focuses on a hydraulic turbine, which has been investigated at the BEP and at the Speed-No-Load (SNL) operating conditions. Several “advanced” URANS models such as the Scale-Adaptive Simulation (SAS) SST k - ω and the BSL- EARSM have been considered and compared with the SST k - ω model. The main conclusion of this study is that, at the SNL operating condition, the prediction of the topology and the dynamics of the flow on the suction side of the runner blade channels close to the trailing edge are influenced by the turbulence model.

An Impact Analysis of Turbine Guide Bearing Stiffness on Rotating Parts’ Transverse Vibration Characteristics

2011 ◽  
Vol 117-119 ◽  
pp. 222-230
Author(s):  
Yi Zhu ◽  
Xi De Lai ◽  
Li Fa Wang
Keyword(s):  
Large Scale ◽  
Impact Analysis ◽  
Hydraulic Turbine ◽  
Calculation Model ◽  
Vibration Characteristics ◽  
Francis Turbine ◽  
Lateral Vibration ◽  
The Finite Element Method ◽  
Bearing Stiffness ◽  
The Impact

A vibration calculation model for a large-scale hydraulic turbine group is built to act on the unbalanced force between the rotor and the runner. Take the Francis turbine group for example. Using the finite element method, the units lateral vibration characteristics of rotating components were calculated and analyzed. The paper discusses the impact of location and the guide bearing stiffness on the lateral vibration characteristics of the unit. Based on the elastic supporting models, the paper also compares the results of the guide bearing stiffness modified simultaneously and respectively. Results show that the guide bearing stiffness has a significant impact on the lateral vibration characteristics of the location of the unit, which provides a reference for the reduction of vibration and the optimization of the supporting structure of the turbine unit.

scholarly journals A robot for non-destructive testing weld inspection of offshore mooring chains

2018 ◽  
Vol 15 (3) ◽  
pp. 172988141877053
Author(s):  
A Hernandez ◽  
O Altuzarra ◽  
V Petuya ◽  
Ch Pinto ◽  
E Amezua
Keyword(s):  
Visual Information ◽  
Ultrasonic Inspection ◽  
Flaw Detection ◽  
Destructive Testing ◽  
Usual Practice ◽  
Butt Welding ◽  
Steel Bar ◽  
Subsystem Design ◽  
Weld Area ◽  
Pulse Echo

Welding flaw detection is a key step in manufacturing many components. In offshore chains, every link is manufactured from a steel bar that is bent and the ends joined by flash butt welding. Ultrasonic inspection of the welded area is required for classification. Defects, if any, are parallel to the welded area, which do not favour detection by manual inspection with 45° beams, as per usual practice . This article reports on CIRUS, a robot developed for automatic inspection of the weld area using a combination of pulse-echo and pitch-catch ultrasonic testing. The robot kinematic structure includes global positioning, local positioning and inspection subsystems, and each subsystem design is described in detail. A data acquisition system processes ultrasonic inspection results and provides visual information for the inspector as well as traceability for quality manufacturing.

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