Effects of emergency and fired shut down on transient thermal fatigue life of a gas turbine casing

Poursaeidi, Esmaeil; Bazvandi, H.

doi:10.1016/j.applthermaleng.2016.02.049

Cited by 22 publications

(4 citation statements)

References 10 publications

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“…Fuel flow schedule is in the gradually decreasing trend with respect to time in order to reduce the generation level up to minimum power output. During shutdown several low cycle fatigue phenomenon, i.e., thermal fatigue stresses in the turbine casing, are developed that are caused by the time variant temperature gradients during turbine operating cycles [ 94 ]. These kind of temperature gradients can cause various vibrational problems that can lead to component failure.…”

Section: Classifications Of Transient Regimes In Igtmentioning

confidence: 99%

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Transient Behavior in Variable Geometry Industrial Gas Turbines: A Comprehensive Overview of Pertinent Modeling Techniques

Hashmi

Lemma

Ahsan

et al. 2021

Entropy

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Generally, industrial gas turbines (IGT) face transient behavior during start-up, load change, shutdown and variations in ambient conditions. These transient conditions shift engine thermal equilibrium from one steady state to another steady state. In turn, various aero-thermal and mechanical stresses are developed that are adverse for engine’s reliability, availability, and overall health. The transient behavior needs to be accurately predicted since it is highly related to low cycle fatigue and early failures, especially in the hot regions of the gas turbine. In the present paper, several critical aspects related to transient behavior and its modeling are reviewed and studied from the point of view of identifying potential research gaps within the context of fault detection and diagnostics (FDD) under dynamic conditions. Among the considered topics are, (i) general transient regimes and pertinent model formulation techniques, (ii) control mechanism for part-load operation, (iii) developing a database of variable geometry inlet guide vanes (VIGVs) and variable bleed valves (VBVs) schedules along with selection framework, and (iv) data compilation of shaft’s polar moment of inertia for different types of engine’s configurations. This comprehensive literature document, considering all the aspects of transient behavior and its associated modeling techniques will serve as an anchor point for the future researchers, gas turbine operators and design engineers for effective prognostics, FDD and predictive condition monitoring for variable geometry IGT.

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Section: Classifications Of Transient Regimes In Igtmentioning

confidence: 99%

“…The effect of temperature fluctuation during startup and shutdown transients is shown in Figure 5. [94].…”

Section: Shutdownmentioning

confidence: 99%

Transient Behavior in Variable Geometry Industrial Gas Turbines: A Comprehensive Overview of Pertinent Modeling Techniques

Hashmi

Lemma

Ahsan

et al. 2021

Entropy

View full text Add to dashboard Cite

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“…A study was conducted to suggest a method for calculating the lifetime of components through thermal stress change [27,28]. Changes in thermal stress during start-up and shut-down of a GT were analyzed [29,30]. Kim et al [31] tried to inject compressed air to prevent the rapid rise of TIT while increasing the ramp-rate.…”

Section: Increase Of Gt Ramp-rate For Operational Flexibilitymentioning

confidence: 99%

Advanced Control to Improve the Ramp-Rate of a Gas Turbine: Optimization of Control Schedule

2021

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As the proportion of power generation using renewable energy increases, it is important to improve the operational flexibility of gas turbines (GTs) for the stability of power grids. Increasing the ramp-rate of GTs is a general solution. However, a higher ramp-rate increases the turbine inlet temperature (TIT), its rate of change, and the fluctuation of the frequency of produced electricity, which are negative side effects. This study proposes a method to optimize the set-point schedule for a PID controller to improve the ramp-rate while decreasing the negative impacts. The set-point schedule was optimized for a 170-MW class GT using a genetic algorithm to minimize the difference between the value of the process variable and the set-point value of the conventional control. The advanced control reduced the fluctuation of the rotation speed by 20% at the reference ramp-rates (12 MW/min and 15 MW/min). The maximum TIT decreased by 6.3 °C, and its maximum rate of change decreased from 0.7 °C/s to 0.4 °C/s. The advantage of the advanced control becomes more marked as the ramp-rate increases. Even at a much higher ramp-rate (50 MW/min), the advanced control decreased the rotation speed fluctuation by 40% in comparison to the conventional control at the reference ramp-rate.

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“…Bazvandi studied fatigue life of casing for developed crack on eccentric hole. They used ABAQUS software for the analysis and concluded that different crack propagation occur with material behaviour [19]. W. Choi et al, studied thermal fatigue stresses development and its effect in turbine casing of power plants.…”

Section: Introductionmentioning

confidence: 99%

Thermo-mechanical Analysis of Gas Turbine Casing to Enhance Fatigue Life

Sirajuddin¹,

Afzal²

2017

MMC_B

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The vulnerability of gas turbine casings is the area which are found to be the geometries featuring sudden or abrupt changes, such as holes and cross sections. Thermal and mechanical fatigue, which is being exerted on the casing by virtue of factors such as mechanical vibration, thermal cyclic loads and mechanical loads, the fatigue life cycle of the casing is on stake. At the same time, fatigue life of casing is also influenced by the tension exerted by the bolt during assembly called "bolt pre-tension". This work is aimed to address the effect of bolt pre-tension on fatigue life of gas turbine casing taking accountability of its impact. The existing casing is analysed for impact of parameters such as pressure, bolt pre-tension and deformation and is being coupled with thermal boundary conditions and the model is analysed in ANSYS workbench. Based on the results of existing design, casing had to be modified geometrically so that its fatigue life is enhanced. From the analysis, it was found that the fatigue life of modified casing was 16533 cycles more than the fatigue life of existing casing for the same boundary conditions of bolt pre-tension of 1000 N and pressure of 3 MPa.

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Effects of emergency and fired shut down on transient thermal fatigue life of a gas turbine casing

Cited by 22 publications

References 10 publications

Transient Behavior in Variable Geometry Industrial Gas Turbines: A Comprehensive Overview of Pertinent Modeling Techniques

Transient Behavior in Variable Geometry Industrial Gas Turbines: A Comprehensive Overview of Pertinent Modeling Techniques

Advanced Control to Improve the Ramp-Rate of a Gas Turbine: Optimization of Control Schedule

Thermo-mechanical Analysis of Gas Turbine Casing to Enhance Fatigue Life

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