A Method to Evaluate the Impact of Power Demand on HPT Blade Creep Life

Mohamed, Walid; Eshati, S.; Pilidis, Pericles; Ogaji, Stephen; Laskaridis, Panagiotis; Nasir, Adnan

doi:10.1115/gt2011-45092

Cited by 3 publications

(2 citation statements)

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“…They investigated the effect of High-Pressure Turbine (HPT) deterioration on the Turbine Entry Temperature (TET) and creep strain at the first stage (stg1) blade of the Low-Pressure Turbine (LPT). Mohamed et al [16] correlated power demand with HPT blade creep life through the effect of TET on the Creep Factor. Eshati et al [17] studied the effect of humidity on the remaining creep life of HPT blades under a range of TETs by considering the change in heat transfer to the blade due to the water presence in the flow and they identified that a higher Water to Air Ratio (WAR) is beneficial to creep life.…”

Section: Performance-based Gas Turbine Lifing Studiesmentioning

confidence: 99%

Hot Corrosion Damage Modelling in Aero Engines based on Performance and Flight Mission Analysis

Pontika

Laskaridis

Nikolaidis

et al. 2023

AIAA SCITECH 2023 Forum

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Lifing models for aircraft engines are mainly focused on creep, fatigue and oxidation, while hot corrosion remains one of the least explored areas. Hot corrosion is a form of chemical damage that causes surface degradation, sound material loss and reduced component life. A lifing analysis for aircraft engines without considering hot corrosion can lead to unexpected and unexplained hot corrosion findings by aircraft engine operators and Maintenance, Repair and Overhaul (MRO) providers during inspections. Although hot corrosion does not cause failure on its own, the interaction with other damage mechanisms can reduce component life significantly. Consequently, there is a necessity for including hot corrosion in the damage prediction process of aircraft engines. This paper presents a new methodology to estimate hot corrosion damage based on aero-engine performance and flight mission analysis while taking into account environmental exposure, fuel quality and material factors. The analysis in the present paper focuses on the hot corrosion progress over the course of the flight mission, while varying the major contamination factors and thrust derate, and the hot corrosion rate over flight time is then used to calculate the damage at the end of the mission. The participating mechanisms, from salt and sulfur impurity ingestion to deposition rate and hot corrosion attack, are analytically presented to explain the progress of the phenomenon in aero-engine components. In the investigated type of engine, the first stage of the low-pressure turbine is found to be the most affected. It is concluded that hot corrosion is favored by a combination of high pressure, high sulfur oxide concentration, and high salt deposition rate within an intermediate temperature range while the gas conditions near the component surface remain below the sodium sulfate saturation point, and these conditions are linked with aero-engine operation. The presented hot corrosion framework captures the effect of mission requirements, component operating conditions, environmental exposure, fuel quality and material on the hot corrosion damage of hot section components. It can be used to inform aero-engine maintenance planning, lifecycle analysis and MRO contract-costing, and can benefit digital twins for predictive maintenance.

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Section: Performance-based Gas Turbine Lifing Studiesmentioning

confidence: 99%

Hot Corrosion Damage Modelling in Aero Engines based on Performance and Flight Mission Analysis

Pontika

Laskaridis

Nikolaidis

et al. 2023

AIAA SCITECH 2023 Forum

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“…Studies were conducted to analyze the effect of rapid temperature rise on the hot section of GT components [24]. The effect of the temperature rise of the blades on the creep life was analyzed, and various methods to predict the creep life were studied [25,26]. A study was conducted to suggest a method for calculating the lifetime of components through thermal stress change [27,28].…”

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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