scholarly journals Finite Element Study of the Effect of Internal Cracks on Surface Profile Change due to Low Loading of Turbine Blade

2020 ◽  
Vol 10 (14) ◽  
pp. 4883
Author(s):  
Junji Sakamoto ◽  
Naoya Tada ◽  
Takeshi Uemori ◽  
Hayato Kuniyasu
Keyword(s):  
Finite Element ◽  
Surface Properties ◽  
Strain Distribution ◽  
Power Plants ◽  
Thermal Power ◽  
Turbine Blades ◽  
Surface Profile ◽  
Height Distribution ◽  
Small Load ◽  
The Difference

Turbine blades for thermal power plants are exposed to severe environments, making it necessary to ensure safety against damage, such as crack formation. A previous method detected internal cracks by applying a small load to a target member. Changes in the surface properties of the material were detected before and after the load using a digital holographic microscope and a digital height correlation method. In this study, this technique was applied in combination with finite element analysis using a 2D and 3D model simulating the turbine blades. Analysis clarified that the change in the surface properties under a small load varied according to the presence or absence of a crack, and elucidated the strain distribution that caused the difference in the change. In addition, analyses of the 2D model considering the material anisotropy and thermal barrier coating were conducted. The difference in the change in the surface properties and strain distribution according to the presence or absence of cracks was elucidated. The difference in the change in the top surface height distribution of the materials with and without a crack was directly proportional to the crack length. As the value was large with respect to the vertical resolution of 0.2 nm of the digital holographic microscope, the change could be detected by the microscope.

Effect of Cenosphere Addition on Mechanical Properties of Bamboo and E-Glass Fiber Reinforced Epoxy Hybrid Composites

2020 ◽  
Vol 12 (4) ◽  
Author(s):  
B.K. Venkatesh ◽  
R. Saravanan
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Glass Fiber ◽  
Hybrid Composite ◽  
Power Plants ◽  
Hybrid Composites ◽  
Thermal Power ◽  
Element Analysis ◽  
Weight Percentage ◽  
Experimental Values

Cenosphere is a ceramic-rich industrial waste produced during burning of coal in the thermal power plants. This study deals with the effect of cenosphere as particulate filler on mechanical behaviour of woven bamboo-glass hybrid composites. The hybrid composite consists of bamboo and E-glass fiber as reinforcement and epoxy as matrix. Cenosphere of different weight percentage (0.5, 1, 1.5 and 2 %) was added to the hybrid composite. The samples were tested as per ASTM standards for their mechanical properties to establish the effect of filler content. It is found that the mechanical properties are significantly influenced by addition of waste ceramic filler cenosphere up to 2 wt.% and increases the tensile, flexural and inter-laminar shear strength in comparison to unfilled composite. Finite element analysis is also done using Midas NFX and the simulation results are compared with experimental results. From the results, it has been found that the experimental values obtained from tensile testing and flexure testing nearly matches with finite element values.

Detection of Machinery Failure Signs From Big Time-Series Data Obtained by Flow Simulation of Intermediate-Pressure Steam Turbines

2021 ◽  
Author(s):  
Kazuhiko Komatsu ◽  
Hironori Miyazawa ◽  
Cheng Yiran ◽  
Masayuki Sato ◽  
Takashi Furusawa ◽  
...  
Keyword(s):  
Time Series ◽  
Power Plants ◽  
Time Series Data ◽  
Thermal Power ◽  
Turbine Blades ◽  
Series Data ◽  
Thermal Power Plants ◽  
Steam Turbines ◽  
Pressure Steam ◽  
The Status

Abstract The periodic maintenance, repair, and overhaul (MRO) of turbine blades in thermal power plants are essential to maintain a stable power supply. During MRO, older and less-efficient power plants are put into operation, which results in wastage of additional fuels. Such a situation forces thermal power plants to work under off-design conditions. Moreover, such an operation accelerates blade deterioration, which may lead to sudden failure. Therefore, a method for avoiding unexpected failures needs to be developed. To detect the signs of machinery failures, the analysis of time-series data is required. However, data for various blade conditions must be collected from actual operating steam turbines. Further, obtaining abnormal or failure data is difficult. Thus, this paper proposes a classification approach to analyze big time-series data alternatively collected from numerical results. The time-series data from various normal and abnormal cases of actual intermediate-pressure steam-turbine operation were obtained through numerical simulation. Thereafter, useful features were extracted and classified using K-means clustering to judge whether the turbine is operating normally or abnormally. The experimental results indicate that the status of the blade can be appropriately classified. By checking data from real turbine blades using our classification results, the status of these blades can be estimated. Thus, this approach can help decide on the appropriate timing for MRO.

Detection of Machinery Failure Signs From Big Time-Series Data Obtained by Flow Simulation of Intermediate-Pressure Steam Turbines

2021 ◽  
Author(s):  
Kazuhiko Komatsu ◽  
Hironori Miyazawa ◽  
Cheng Yiran ◽  
Masayuki Sato ◽  
Takashi Furusawa ◽  
...  
Keyword(s):  
Time Series ◽  
Power Plants ◽  
Time Series Data ◽  
Thermal Power ◽  
Turbine Blades ◽  
Series Data ◽  
Thermal Power Plants ◽  
Steam Turbines ◽  
Pressure Steam ◽  
The Status

Abstract The periodic maintenance, repair, and overhaul (MRO) of turbine blades in thermal power plants are essential to maintain a stable power supply. During MRO, older and less-efficient power plants are put into operation, which results in wastage of additional fuels. Such a situation forces thermal power plants to work under off-design conditions. Moreover, such an operation accelerates blade deterioration, which may lead to sudden failure. Therefore, a method for avoiding unexpected failures needs to be developed. To detect the signs of machinery failures, the analysis of time-series data is required. However, data for various blade conditions must be collected from actual operating steam turbines. Further, obtaining abnormal or failure data is difficult. Thus, this paper proposes a classification approach to analyze big time-series data alternatively collected from numerical results. The time-series data from various normal and abnormal cases of actual intermediate-pressure steam-turbine operation were obtained through numerical simulation. Thereafter, useful features were extracted and classified using K-means clustering to judge whether the turbine is operating normally or abnormally. The experimental results indicate that the status of the blade can be appropriately classified. By checking data from real turbine blades using our classification results, the status of these blades can be estimated. Thus, this approach can help decide on the appropriate timing for MRO.

Regulation Right Trading Considering DSM in Shanghai Power Grid

2014 ◽  
Vol 1065-1069 ◽  
pp. 3410-3413
Author(s):  
Dun Nan Liu ◽  
Yan Zhao ◽  
Lei Li ◽  
Rui Zhi Liu ◽  
Yu Jie Xu
Keyword(s):  
Power Generation ◽  
Power Plants ◽  
Power Grid ◽  
Thermal Power ◽  
Demand Characteristic ◽  
High Quality ◽  
Load Demand ◽  
Power Peak ◽  
The Difference ◽  
Virtuous Cycle

With the implementation of energy-conservation power generation dispatching, power grid will lose some peak regulation capacity, and changes of load demand characteristic will further increase the difference between peak and valley load of power grid, especially in the Shanghai grid, primarily thermal power units. Its peak regulation capacity will be obviously insufficient, and the problem will become increasingly prominent. This presents a new topic for Shanghai power grid in the power generation market: Under the premise of meeting the customers’ need, how to provide a fair competitive environment that encourage power plants to participate in power peak regulation actively, and then lead the grid to safe, high quality and fairly competitive virtuous cycle.

Estimation of Damping for Turbine Blades in Non-Stationary Working Conditions

2015 ◽  
Author(s):  
Luigi Carassale ◽  
Michela Marrè-Brunenghi ◽  
Stefano Patrone
Keyword(s):  
Power Plants ◽  
Rotation Speed ◽  
Thermal Power ◽  
Turbine Blades ◽  
Experimental Tests ◽  
Strain Gauges ◽  
Identification Procedure ◽  
Time Frequency ◽  
Run Up ◽  
Critical Components

Turbine blades are critical components in thermal power plants and their design process usually includes experimental tests in order to tune or confirm numerical analyses. These tests are generally carried out on full-scale rotors having some blades instrumented with strain gauges and usually involve a run-up and/or a run-down phase. The quantification of damping in these conditions is rather complicated, since the finite sweep velocity produces a distortion of the vibration amplitude in contrast to the Frequency-Response Function that would be expected for an infinitely slow crossing of the resonance. In this work, we show through a numerical simulation that the usual identification procedures lead to a systematic overestimation of damping due both to the finite sweep velocity, as well as to the variation of the blade natural frequency with the rotation speed. An identification procedure based on the time-frequency analysis is proposed and validated through numerical simulations.

scholarly journals Monitoring the difference in liquid levels in adjacent tanks

Radiotekhnika ◽  
2021 ◽  
pp. 115-119
Author(s):  
B.V. Zhukov ◽  
A.V. Odnovo
Keyword(s):  
Power Plants ◽  
Block Diagram ◽  
Thermal Power ◽  
Pulse Signal ◽  
Signal Propagation ◽  
Level Gauge ◽  
Operating Range ◽  
Before And After ◽  
The Difference ◽  
Adjacent Channels

The possibility of synchronous monitoring of coolant levels in the cooling systems of nuclear and thermal power plants before and after the barrier mesh using a specialized level gauge is considered. The block diagram of a level gauge providing current synchronous control of liquid levels in two adjacent channels (reservoirs), as well as the difference in liquid levels in them, is presented. A feature of the structural diagram of a specialized acoustic level gauge is the use of a radiation source common to both channels and a device for dividing the common waveguide path into two channels. An algorithm for the functioning of a specialized level gauge has been developed, in which, based on time diagrams, it is shown how the level is controlled in each channel and the difference in liquid levels before and after the barrier grid is calculated. The description of the algorithm is accompanied by calculated expressions for determining the levels and the difference in liquid levels. For a level gauge made in the acoustic wavelength range, a condition is given that is necessary for the creation of a device that provides matching when dividing a common channel into two independent channels of pulse signal propagation. This condition made it possible to establish the relationship between the inner diameters of cylindrical pipes used as waveguide paths of an acoustic wave.  Variants of the implementation of a specialized level gauge based on two modifications of the ZOND-3M level gauge are proposed, in which cylindrical pipes are used as waveguiding systems. It is shown that when using the AP-7VT transceiver, the level gauge will have an operating range of up to 10m with a level resolution of ± 1mm, and when using the AP-70T transceiver, it will have an operating range of up to 20m with a level resolution of ± 1cm.

scholarly journals Did an Ultra-Low Emissions Policy on Coal-Fueled Thermal Power Reduce the Harmful Emissions? Evidence from Three Typical Air Pollutants Abatement in China

2020 ◽  
Vol 17 (22) ◽  
pp. 8555
Author(s):  
Penghao Ye ◽  
Senmao Xia ◽  
Yu Xiong ◽  
Chaoyang Liu ◽  
Fei Li ◽  
...  
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Central China ◽  
Western China ◽  
Emissions Reduction ◽  
High Carbon ◽  
Harmful Emissions ◽  
Production Techniques ◽  
The Difference ◽  
Reduction Effect

Thermal power generation based on coal-fired power plants has the advantages of stability and controllability and has been the largest source of electricity supply in China. Coal-fired power plants, however, are also accompanied by high carbon emissions and the release of harmful substances (mainly including sulfur dioxide, nitrogen oxides, and smoke dust), and are even regarded as the “chief criminal” in terms of air pollution. However, thermal power is also a pioneering industry involved in several environmental regulations and cleaner production techniques before other industries. Evidence of this is China’s ultra-low emissions (ULE) policy on coal-fired power plants, implemented in 2015. To verify this policy’s effect, this study treats ULE as an exogenous impact variable, examining its emissions reduction effect on SO2, NOx, and smoke dust in Eastern and Central China using the difference-in-difference method (DID). The results show that the total emissions of the three pollutants were abated by 0.133%, 0.057% and 0.036% in Eastern, and by 0.120%, 0.035% and 0.043% in Central China at every 1% rise of thermal power generated after ULE. In addition, several other factors can also argue for the promotion of thermal power. Other industries, such as steel or chemical, have proven that they can contribute significant SO2 and NOx emissions. Based on these results, we provide suggestions on synergistic emissions reduction among multiple industries, as well as a discussion on the necessity of implementing ULE in Western China.

Evolution of the structure and phase state of the heat-resistant intermetallic coating of operating turbine blades

2019 ◽  
pp. 94-100
Author(s):  
I. N. Tsareva ◽  
O. B. Berdnik ◽  
M. V. Maksimov ◽  
E. N. Razov
Keyword(s):  
Gas Turbine ◽  
Phase Structure ◽  
Power Plants ◽  
Thermal Power ◽  
Turbine Blades ◽  
Intermetallic Phase ◽  
High Energy ◽  
Laboratory Research ◽  
Term Operation ◽  
Heat Resistant

The paper treats important problems of domestic engineering, namely, the urgent necessity to increase service life of large-sized turbine blades of the power gas-turbine stations operated on thermal power plants. The heat-resistant coating of the Ni–Co–Cr–Al–Y system with intermetallic phase structure β-(Ni, Me)Al + γ′-(Ni, Me)3Al has been developed. It was made by high-energy plasma powder spraying and intended for protection of blade surface against high-temperature and erosive gas flow. The article studies microstructure, phase structure and physicomechanical properties of a coating given in an initial state, and after laboratory research of heat resistance and a post-operational state at ~29 000 hours (time of real operation of the gas-turbine engine of the GTE-45-3 power station on thermal power plant). After long-term operation, a decrease in the content of the intermetallic phase of β-(Ni, Ме)Al in the phase composition, an increase in the pore size and a decrease in the hardness of the coating have been established. At the same time, erosion resistance and heat-resistant properties of the coating remain, and, consequently, there is a sufficient resource.

Microscopic Analysis of the Initiation of High-Temperature Damage of Ni-Based Heat-Resistant Alloy

2016 ◽  
Author(s):  
Takuya Murakoshi ◽  
Ken Suzuki ◽  
Isamu Nonaka ◽  
Hideo Miura
Keyword(s):  
Co2 Emissions ◽  
Power Plants ◽  
High Efficiency ◽  
Coefficient Of Thermal Expansion ◽  
Thermal Power ◽  
Fatigue Loading ◽  
Thermal Power Plants ◽  
Loading Conditions ◽  
Creep Fatigue ◽  
The Difference

It is imperative to reduce greenhouse-effect gas such as CO2. Since the emission of CO2 from fossil fuel combustion to generate electricity is a critical quantity, accounting for 42% of global CO2 emissions in 2013 [1], high efficiency of thermal power plants is indispensable for reducing the CO2 emissions. In order to further improve thermal efficiency of thermal power plants, various R&D projects have been conducted (such as Thermie 700 in the EU and DOE-Vision 21 in the US) to develop A-USC (advanced ultra-supercritical) power plants of the 700°C-class. Alloy 617 is a candidate alloy for boiler tubes and pipes. Since it has higher coefficient of thermal expansion than conventional ferritic steels, however, the increase in the thermal stress is of concern in the power plant components. In addition, it is important to consider the effect of creep-fatigue loading on the lifetime of the components in the design and maintenance of the components. This is because frequent output change is inevitable for assuring the stable and reliable supply of electricity under the combination with renewable energies. Conventionally, the creep-fatigue damage has been evaluated by linear cumulative damage rule. However, it has been found that there are a lot of loading conditions and materials to which the rule can’t be applied [2–3]. Therefore, it is indispensable to establish the method for evaluating the total damage of materials under creep-fatigue loading conditions. Thus, the authors conducted fatigue and creep-fatigue tests and observed the change of the micro texture to elucidate the damage evolution of the alloy from the viewpoint of the change of the order of atom arrangement using EBSD (Electron Back-Scatter Diffraction) analysis. As a result, it was found that the difference of damage accumulation under fatigue and creep-fatigue loadings appeared in the change of the GROD (Grain Reference Orientation Deviation) value in the inelastic strain range. Therefore, the difference in the damage mode between fatigue and creep loads can be analyzed by using these KAM and GROD values.

scholarly journals Study on water erosion and preventive measures of last stage blade of steam turbine

2021 ◽  
Vol 2076 (1) ◽  
pp. 012071
Author(s):  
Zhengxian Wang ◽  
Tong Liu ◽  
Renda Luo
Keyword(s):  
Steam Turbine ◽  
Power Plants ◽  
Preventive Measures ◽  
Dynamic Performance ◽  
Thermal Power ◽  
Turbine Blades ◽  
Water Erosion ◽  
Low Load ◽  
New Energy ◽  
Last Stage

Abstract In the background of carbon peak and carbon neutralization, most thermal power plants are more involved in peak regulation and even in-depth peak regulation in order to absorb new energy such as wind power and Solar power. When the turbine is running under low load, the exhaust pressure decreases, which leads to the increase of exhaust humidity. More and more turbine blades have water erosion. The erosion of the last stage blades will worsen the dynamic performance of the turbine, increase the risk of the last stage blade fracture, and threaten the safe operation of the turbine. This paper studies the mechanism of the last stage blade erosion of steam turbine, and analyzes the main factors which influence the erosion with examples. Combined with the mechanism of water erosion, the relevant preventive measures are made for reference of power supply plant.

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