A full engine cycle analysis of a turbofan engine for optimum scheduling of variable guide vanes

Kim, Sangjo; Kim, Dong-Hyun; Son, Changmin; Kim, Kui-Soon; Min, Seongki

doi:10.1016/j.ast.2015.09.007

Cited by 44 publications

(7 citation statements)

References 16 publications

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“…Modern gas turbines have increased flexibility and sophisticated control strategies to maximize efficiency, reduce fuel burn, protect engine life and ensure operating stability and safety. Apart from the fuel flow injection control system, some of the most well-documented control features of advanced gas turbines include the variable stator vane (VSV) angle [1,2] and handling bleed-offs to ensure compressor stability [3] at all power settings, the take-off derate to improve life consumption and climb thrust derate settings (with an option for slow and fast washout) to trade-off fuel burn and engine life [4,5]. In the most recent engines, active tip clearance control [6,7] is also used to improve engine efficiency by minimizing the gap between the tip and the casing while avoiding blade rubs under the variable disk and blade thermal and mechanical expansion over the mission.…”

Section: A State Of the Artmentioning

confidence: 99%

Mapping the Effect of Variable HPT Blade Cooling on Fuel Burn, Engine Life and Emissions for Fleet Optimization using Active Control

Pontika

Laskaridis

Gonzalez

et al. 2023

AIAA SCITECH 2023 Forum

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Modern aero engines have increasingly sophisticated control systems. The aim for nextgeneration aircraft is to have even more adaptive and flexible control systems to enable the optimization of economic aspects, operational aspects and fleet management. Among others, an engine control variable that has the potential to offer various life and fuel burn benefits at different flight phases is the High-Pressure Turbine (HPT) blade cooling air. The HPT blades have demanding cooling requirements to protect their life and decelerate HPT efficiency degradation. However, any engine bleed has a penalty in efficiency and results in increased fuel consumption. Previous generation aircraft have a fixed relative blade cooling flow based on a design choice for a trade-off between life and efficiency. However, with adaptive control systems, there is an opportunity to extract the maximum potential benefit under different flight phases and scenarios. With this opportunity comes the challenge of increased complexity in engine behavior necessitating detailed modeling to quantify effects on lifing, fuel burn and safety. This paper focuses on modeling the performance, lifing and emission effects of variable HPT blade cooling air at take-off, climb and cruise. First, the effect of variable cooling on the Turbine Entry Temperature (TET), Exhaust Gas Temperature (EGT), fuel flow, lifing and NOx emissions are modeled at operating point level while the thrust requirement is achieved. Subsequently, a Design of Experiment is performed at mission level with the relative cooling flow at take-off, climb and cruise as the independent variables to train surrogate, analytical models. The analytical models are applied in the probabilistic modeling of system failure rates under different cooling flows. Optimization of engine control variables, in this case, the HPT blade cooling, requires analytical expressions that can be used in objective functions. These analytical models will inform fleet optimizers and active control systems to facilitate the implementation of fleet decisions such as reducing direct operating costs (fuel cost, maintenance reserves, NOx taxation), meeting NOx requirements of airports and extending Time-on-Wing (TOW). The findings indicate that take-off offers an opportunity to protect HPT life with increased cooling, but caution should be exercised in regard to the damage increase at the downstream non-cooled hot gas path components. A decrease in cooling flow at cruise, which is less detrimental to engine life, can offer significant fuel savings and climb

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Section: A State Of the Artmentioning

confidence: 99%

Mapping the Effect of Variable HPT Blade Cooling on Fuel Burn, Engine Life and Emissions for Fleet Optimization using Active Control

Pontika

Laskaridis

Gonzalez

et al. 2023

AIAA SCITECH 2023 Forum

View full text Add to dashboard Cite

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“…However, at higher speeds the operation is converse of the low speed, i.e., at high speed the front stages are choked while the rear stages are surged. In this scenario, to avoid choking, the VIGV angle is re-staggered in order to increase the mass flow and pressure ratio by increasing the sectional flow area of the compressor and hence increase the surge margin [ 182 , 183 , 184 , 185 ].…”

Section: Control Strategies For Dynamic Operationsmentioning

confidence: 99%

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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“…Such a coupling allows insights into certain relationships that the individual tools do not provide. For example, Kim et al (2015), who also coupled a mean-line tool with a performance tool, showed that the settings for variable guide vanes (VGVs) can only be set meaningfully related to engine overall performance. Using a 2-D through flow tool, Reitenbach et al (2015) had also confirmed this.…”

Section: Coupled Model Simulationmentioning

confidence: 99%

Application of a Global Sensitivity Screening Method for Design Space Exploration of Coupled Turbofan Engine Performance and Preliminary Design

Schmeink¹,

Görtz²,

Häßy³

2020

Proceedings of Global Power &Amp; Propulsion Society

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Multidisciplinary preliminary engine design involves a large number of tools and participants. The highly iterative and multidisciplinary workflows make it difficult to evaluate the influence of individual design parameters on the final result. With high-dimensional parameter studies the design space of the system can be investigated. However, the evaluation of the results can rapidly become very challenging. The screening method of elementary effects according to Morris as a method of global sensitivity analysis (GSA) can provide useful insights from even a small number of evaluations. Especially a reduction of the dimensionality due to factor fixing of input parameters with low influence on the problem and factor prioritization of important parameters are addressed by GSA. The purpose of the paper is to demonstrate the application of the method by means of a coupled process which includes performance calculations of the entire engine system and preliminary design of a high-pressure compressor. The variation of input parameters of the different disciplines will be investigated and it will be shown that the Morris screening characteristics allow the evaluation of parameters within the design space in particular with regard to a classification of the significance for the result variables. This shows in the application example that in the comparison parameters with a clear influence emerge from both disciplines. This work is licensed under a Creative Commons Attribution-NonCommercia 4.0 International License CC-BY-NC 4.0.

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A full engine cycle analysis of a turbofan engine for optimum scheduling of variable guide vanes

Cited by 44 publications

References 16 publications

Mapping the Effect of Variable HPT Blade Cooling on Fuel Burn, Engine Life and Emissions for Fleet Optimization using Active Control

Mapping the Effect of Variable HPT Blade Cooling on Fuel Burn, Engine Life and Emissions for Fleet Optimization using Active Control

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

Application of a Global Sensitivity Screening Method for Design Space Exploration of Coupled Turbofan Engine Performance and Preliminary Design

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