A Synthetical Numerical Model for Evaluating the Reliability of Turbine Blade

2002 ◽  
Author(s):  
Yonghui Xie ◽  
Di Zhang
Keyword(s):  
Fatigue Life ◽  
Numerical Model ◽  
Steam Turbine ◽  
Turbine Blade ◽  
Power Plants ◽  
Dynamic Stress ◽  
Turbine Blades ◽  
Dynamic Stress Analysis ◽  
Steam Turbine Blades ◽  
Blade Failure

Reliability of turbines is very important for power plants, and the most common blade failure normally result from forced vibration which lead to fatigue failure of blades. In this study, a synthetical numerical model has been developed to obtain more precise evaluation of the reliability of blades. At first, the model used to analyze the dynamic stress of steam turbine blades is investigated, base on the results of dynamic stress analysis, a model to evaluate the fatigue life of turbine blade has been developed, many factors such as manufacturing technology of blades and erosion operating environment are considered to get more accurate results for the fatigue life prediction of blades. At last, a 323 mm blade in a 75MW steam turbine is analyzed by the model developed in this paper, it is shown clearly that the model can provide some significant data to evaluate the reliability of blade.

Study on Service Life of Last Stage Blade with Damped Structure in Large Power Steam Turbine

2008 ◽  
Vol 44-46 ◽  
pp. 803-808
Author(s):  
Di Zhang ◽  
Yong Hui Xie
Keyword(s):  
Numerical Model ◽  
Service Life ◽  
Steam Turbine ◽  
Turbine Blade ◽  
Dynamic Stress ◽  
Aerodynamic Load ◽  
Operating Environment ◽  
Large Power ◽  
Last Stage ◽  
Blade Failure

Blade which transfers thermal energy of steam into power, is a basic component in steam turbine. The reliability of blade is heavily influenced by the operating environment. The rotating blade experiences large inertial load and the wake of nozzle flow impose large variations of aerodynamic load on blade, in addition, the last stage blade is also affected by corrosion, so accidents of blade happen from time to time. Preventing blade failure has become one of the major objectives of turbine design and in-service maintenance. It is said that the reason for most of blade failure is fatigue fracture. In this study, a synthetical numerical model has been developed to evaluate service life of blade. At first, a numerical model to analyze the excitation force, dynamic frequency and dynamic stress of steam turbine blade has been developed, based on the results of dynamic stress analysis, a model to evaluate the service life of turbine blade has been developed. Many factors such as manufacturing technology of blade and erosion operating environment are considered to get more accurate results for service life of blade. At last, a last stage blade group of a large power steam turbine is analyzed in detail. It is shown clearly that the numerical model can give some rational quantitative results, and it is suitable for its engineering application to the improvement of the blade reliability.

Torsional stiffness of long steam-turbine blades

1970 ◽  
Vol 5 (4) ◽  
pp. 242-248 ◽  
Author(s):  
A Scholes ◽  
D J Slater
Keyword(s):  
Steam Turbine ◽  
Turbine Blade ◽  
Torsional Vibration ◽  
Natural Frequencies ◽  
Turbine Blades ◽  
Torsional Stiffness ◽  
Steam Turbine Blades ◽  
Shear Centre

In order to obtain accurate values of the natural frequencies of torsional vibration of long steam-turbine blades it is necessary to determine the torsional stiffnesses of the blade accurately. Various empirical formulae are at present available for the calculation of the torsion constant for sections such as those of a turbine blade; to determine which is the best, a range of sections has been tested including prismatic bars as well as an actual blade. One particular formula is suggested for use. Additionally the positions of shear-centre and centre-of-twist of some of the bars were found.

Evaluation and Application of Hard Coatings for Steam Turbine

2017 ◽  
Author(s):  
Liang Yan ◽  
Yujiro Nakatani ◽  
Masayuki Yamada ◽  
Toru Abe ◽  
Koichi Kitaguchi ◽  
...  
Keyword(s):  
High Temperature ◽  
Steam Turbine ◽  
Power Plants ◽  
Turbine Blades ◽  
Temperature Stability ◽  
Hard Coatings ◽  
High Temperature Stability ◽  
Creep Tests ◽  
Tialn Coating ◽  
Steam Turbine Blades

In order to improve solid particle erosion (SPE) resistance for steam turbine blades and nozzles, in corporation with Kobe Steel, Ltd., evaluation of hard coatings of TiN and TiAlN deposited by the Arc Ion Plating (AIP®) process was performed to verify applicability to an actual steam turbine. The results of high-temperature steam oxidation tests and room-temperature sand erosion tests showed that the TiAlN coating had high-temperature stability superior to that of the TiN coating, and erosion resistance far superior to that in the case of the conventional CrC thermal spray coating and boronizing treatment. High-temperature fatigue and creep tests showed that the characteristic strength of the blade material with the TiAlN coating was equal or superior to that of the base blade material. On the basis of the results of comprehensive evaluation, it was confirmed that the TiAlN hard coating has excellent applicability to an actual steam turbine and it was successfully applied to steam turbine blades of power plants in Japan.

scholarly journals BTT & RFLB - THE OPTIMUM SET FOR STEAM TURBINE BLADES MONITORING

2018 ◽  
Vol 20 ◽  
pp. 5-9
Author(s):  
Miroslav Balda
Keyword(s):  
Fatigue Life ◽  
Steam Turbine ◽  
Turbine Blades ◽  
Residual Fatigue Life ◽  
Timing System ◽  
Blade Tip ◽  
Steam Turbine Blades ◽  
Residual Fatigue ◽  
Blade Tips

BTT, Blade Tip Timing system, is a commercially available system generating files of precise times of blade tips when passing sensors attached in a machine stator. RFLB, Residual Fatigue Life of Blades, is a postprocessor of those files evaluating estimates of fatigue lives of all blades fitted to the wheel. The set reduces a danger of unexpected blade failures.

Optimization of Induction Brazing Parameters for Stellite Strip of Steam Turbine Blade Using Taguchi-Neural Network

2013 ◽  
Vol 545 ◽  
pp. 225-229 ◽  
Author(s):  
Nattachai Muangsong ◽  
Wong Sa Sarawan ◽  
Isaratat Phung On
Keyword(s):  
Neural Network ◽  
Steam Turbine ◽  
Turbine Blade ◽  
Induction Heating ◽  
Turbine Blades ◽  
Electrical Power ◽  
Leading Edge ◽  
Temperature Deviation ◽  
Induction Brazing ◽  
Steam Turbine Blades

To repair the damaged of steam turbine blades, the method of increasing wear resistance of the blade leading edge with brazing of stellite plates by induction heating has been addressed in this work. Induction brazing of a Cobalt-based alloy to SUS410Cb steam turbine blades in an electrical power plant has been carried out. Ag-Cu-Zn based material was chosen to be the filler metal sandwiched between the stellite strip and the turbine blade. In order to cope with the large size of blades, an automatic brazing process which used moving induction coils has been developed. In the proposed brazing process, there are three parameters that significantly affect the quality of the brazing joints including coil distance, moving coil speed, and power of induction heating. In this work, the optimum choice of brazing parameters is obtained by using a Taguchi-neural network technique. According to the results of our previous work, it is recommended to attain the temperature distribution at around 750°C for maximum strength and good quality brazing in the brazed components. The objective for the evaluation of brazing quality is therefore a function of this temperature and defined as the temperature deviation from the best brazing temperature. The design is verified and confirmed by the manufacturing of brazed joint applying suggested parameters. The experimental results showed that the Taguchi-Neural network method resulted in a better brazed quality than when using only the Taguchi method.

Diagnostics and monitoring of the operating condition of steam-turbine blades

2007 ◽  
Vol 41 (5) ◽  
pp. 295-301
Author(s):  
A. I. Danilin ◽  
S. I. Adamov ◽  
A. Zh. Chernyavskii ◽  
M. I. Serpokrylov
Keyword(s):  
Steam Turbine ◽  
Turbine Blades ◽  
Operating Condition ◽  
Steam Turbine Blades

Studies on Determination of Natural Frequencies of Industrial Turbine Blades

1995 ◽  
Author(s):  
Mahesh M. Bhat ◽  
V. Ramamurti ◽  
C. Sujatha
Keyword(s):  
Steam Turbine ◽  
Dynamic Behavior ◽  
Turbine Blade ◽  
Natural Frequencies ◽  
Complex Structure ◽  
Turbine Blades ◽  
Blade Root ◽  
Steam Turbine Blade ◽  
Manufacturing Tolerances

Abstract Steam turbine blade is a very complex structure. It has geometric complexities like variation of twist, taper, width and thickness along its length. Most of the time these variations are not uniform. Apart from these geometric complexities, the blades are coupled by means of lacing wire, lacing rod or shroud. Blades are attached to a flexible disc which contributes to the dynamic behavior of the blade. Root fixity also plays an important role in this behavior. There is a considerable variation in the frequencies of blades of newly assembled turbine and frequencies after some hours of running. Again because of manufacturing tolerances there can be some variation in the blade to blade frequencies. Determination of natural frequencies of the blade is therefore a very critical job. Problems associated with typical industrial turbine bladed discs of a 235 MW steam turbine are highlighted in this paper.

Water-droplet erosion behavior of high-velocity oxygen-fuel-sprayed coatings for steam turbine blades

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Dingjun Li ◽  
Peng Jiang ◽  
Fan Sun ◽  
Xiaohu Yuan ◽  
Jianpu Zhang ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Water Droplet ◽  
Erosion Resistance ◽  
Turbine Blades ◽  
Impingement Angle ◽  
Erosion Behavior ◽  
Water Droplet Erosion ◽  
Steam Turbine Blades ◽  
Oxygen Fuel ◽  
Sprayed Coatings

Abstract The water-droplet erosion of low-pressure steam turbine blades under wet steam environments can alter the vibration characteristics of the blade, and lead to its premature failure. Using high-velocity oxygen-fuel (HVOF) sprayed water-droplet erosion resistant coating is beneficial in preventing the erosion failure, while the erosion behavior of such coatings is still not revealed so far. Here, we examined the water-droplet erosion resistance of Cr3C2–25NiCr and WC–10Co–4Cr HVOF sprayed coatings using a pulsed water jet device with different impingement angles. Combined with microscopic characterization, indentation, and adhesion tests, we found that: (1) both of the coatings exhibited a similar three-stage erosion behavior, from the formation of discrete erosion surface cavities and continuous grooves to the broadening and deepening of the groove, (2) the erosion rate accelerates with the increasing impingement angle of the water jet; besides, the impingement angle had a nonlinear effect on the cumulative mass loss, and 30° sample exhibited the smallest mass loss per unit area (3) an improvement in the interfacial adhesion strength, fracture toughness, and hardness of the coating enhanced the water-droplet erosion resistance. These results provide guidance pertaining to the engineering application of water erosion protective coatings on steam turbine blades.

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