Future Aero Engine Designs: An Evolving Vision

Konstantinos, G.

doi:10.5772/19689

Cited by 7 publications

(3 citation statements)

References 24 publications

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“…Thermal barrier coatings (TBCs) are highly engineered coating systems that enable aeroengines to operate at temperatures higher than the melting point of their structural materials [1,2]. TBCs provide the thermal insulation that, combined with a sophisticated internal air-cooling system to extract the heat [3,4], enable a thermal gradient of about 1 °C/µm between the coating surface and the nickel superalloy blade of the high-pressure, high-temperature turbine under a high energy flux of ~ 1 MW/m [5]. The required thermal gradient keeps increasing as the industry improves engine efficiency, in the drive to reduce carbon emissions, both of which demand higher operational temperatures [5].…”

Section: Introductionmentioning

confidence: 99%

Non-destructive thickness measurement of thermal barrier coatings using terahertz radiation

et al. 2021

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A non-destructive thickness measurement technique based on terahertz (THz) reflectivity was successfully deployed to interrogate 7 wt.% yttria-stabilised zirconia thermal barrier coatings (TBCs) produced by electron-beam physical vapour deposition (EB-PVD). The THz technique was shown to produce accurate thickness maps for different samples with a resolution of 1 × 1 mm over a surface of 65 × 20 mm that were compared with direct examination of key cross-sections. All thickness measurements on different samples were calculated using a single value of refractive index. Small defects characteristic of EB-PVD, such as “carrot growths” and variations on column inclination, were evaluated and did not produce significant variations in the refractive index of the TBC. Moreover, the thickness maps correctly display thickness variations that are a consequence of the point-source nature of EB-PVD evaporation. In summary, this paper demonstrates the technique can be successfully deployed on large surfaces, and across different coatings of the same material produced under the same deposition conditions. It is shown that a single n value is required to map the thickness distribution for all samples. This combination of qualities indicates the potential of the technique for in-line control of TBC manufacture.

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Section: Introductionmentioning

confidence: 99%

Non-destructive thickness measurement of thermal barrier coatings using terahertz radiation

et al. 2021

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“…TAY 651 has been in service since 1990 [25] hence when hybridization will be applied, more efficient gas turbines will be available for the same thrust class. The next step would be to analyse the impact of hybridization for a modern UHBR geared turbofan engine with polytropic efficiency estimates for EIS 2035 [35]. In this section, hybrid engine cycle design is performed and presented for an entry into service 2035 turbofan engine.…”

Section: Heps Eis 2035 Engine Cycle Designmentioning

confidence: 99%

Design Methodology and Mission Assessment of Parallel Hybrid Electric Propulsion Systems

Ghelani

Roumeliotis

Saias

et al. 2022

Journal of Engineering for Gas Turbines and Power

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An integrated engine cycle design methodology and mission assessment for parallel hybrid electric propulsion architectures are presented in this paper. The aircraft case study considered is inspired by Fokker 100, boosted by an electric motor on the low-pressure shaft of the gas turbine. The fuel burn benefits arising from boosting the low-pressure shaft are discussed for two different baseline engine technologies. A three-point engine cycle design method is developed to redesign the engine cycle according to the degree of hybridization. The integrated cycle design and power management optimization method is employed to identify potential fuel burn benefits from hybridization for multiple mission ranges. The sensitivity of these mission results has also been analyzed for different assumptions on the electric powertrain. With 1 MW motor power and a battery pack of 2307 kg, a 3% fuel burn benefit can be obtained by retrofitting the gas turbine for 400 nm range. Optimizing the power management strategy improves this fuel burn benefit by 0.2-0.3%. Redesigning the gas turbine and optimizing the power management strategy, provides a 4.2% fuel benefit on 400 nm. The results suggest that a high hybridization by power, low hybridization by energy, and ranges below 700 nm are the only cases where the redesigned hybrid electric aircraft has benefits in fuel burn and energy consumption relative to the baseline aircraft. Finally, it is found that the percentage of fuel burn benefits from the hybrid electric configuration increases with the improvement in engine technology.

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“…The drive for increasing engine efficiency and decreasing fuel consumption are two of the biggest challenges for the aerospace industry. These had been addressed to some degree through the application of thermal barrier coatings (TBCs) and labyrinthine internal air cooling passages [1,2]; in combination, these two features enable high pressure, high temperature (HPHT) turbine blades to operate at surface temperatures above their melting point [3]. However, additional challenges arise at even higher operating temperatures including degradation induced by ingestion of airborne particulates, known as CMAS, that melt and flux the ceramic topcoat.…”

Section: Introductionmentioning

confidence: 99%

Modelling evaporation in electron-beam physical vapour deposition of thermal barrier coatings

et al. 2021

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This work presents computational models of ingot evaporation for electron-beam physical vapour deposition (EB-PVD) that can be applied to the deposition and development of thermal barrier coatings (TBCs). TBCs are insulating coatings that protect aero-engine components from high temperatures, which can be above the component’s melting point. The development of advanced TBCs is fuelled by the need to improve engine efficiency by increasing the engine operating temperature. Rare-earth zirconates (REZ) have been proposed as the next-generation TBCs due to their low coefficient of thermal conductivity and resistance to molten calcium-magnesium alumina-silicates (CMAS). However, the evaporation of REZ has proven to be challenging, with some coatings displaying compositional segregation across their thickness. The computational models form part of a larger analytical model that spans the whole EB-PVD process. The computational models focus on ingot evaporation, have been implemented in MATLAB and include data from 6 oxides: ZrO2, Y2O3, Gd2O3, Er2O3, La2O3 and Yb2O3. Two models (2D and 3D) successfully evaluate the evaporation rates of constituent oxides from multiple-REZ ingots, which can be used to highlight incompatibilities and preferential evaporation of some of these oxides. A third model (local composition activated, LCA) successfully predicts the evaporation rate of the whole ingot and replicates the cyclic change in composition of the evaporated plume, which is manifested as changes in compositional segregation across the coating’s thickness. The models have been validated with experimental data from Cranfield University’s EB-PVD coaters, published vapour pressure calculations and evaporation rate formulas described in the literature.

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Future Aero Engine Designs: An Evolving Vision

Cited by 7 publications

References 24 publications

Non-destructive thickness measurement of thermal barrier coatings using terahertz radiation

Non-destructive thickness measurement of thermal barrier coatings using terahertz radiation

Design Methodology and Mission Assessment of Parallel Hybrid Electric Propulsion Systems

Modelling evaporation in electron-beam physical vapour deposition of thermal barrier coatings

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