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118 results on '"Grönstedt, Tomas"'

9. Assessment of an Open-Source Aircraft Noise Prediction Model Using Approach Phase Measurements.

Author

Thoma, Evangelia Maria, Grönstedt, Tomas, Sola, Evelyn Otero, and Xin Zhao

Abstract

An open-source simulation model for aircraft noise prediction is presented and validated using backpropagated noise measurements for a state-of-the-art engine and aircraft. The validation is focused on approach procedures and was performed using ground-based noise measurements that were taken at 17 recording stations for a total of 18 consecutive flights carried out during the morning of 8 April 2021. The flights were performed using two A321neo aircraft with LEAP-1A engines. It is demonstrated that the presented noise model provides a satisfactory estimation of the source noise for varying approach configurations and flight conditions. Configurations using a greater number of high-lift devices are particularly well predicted in the mid- and high-frequency regions, whereas the lower configuration settings show greater spectral deviations, which are partly attributed to measurement uncertainties caused by the increased aircraft-microphone distance. The model can predict the overall mean total sound intensity level within a 2 dB accuracy for all configurations, while the average predicted level at each microphone differs by less than 3 dB from the measurement average, for all cases except one. Variation in aircraft speed showed to have a strong impact on the predicted total noise, which matches the well-recognized sixth-power Mach number far-field sound intensity scaling law for airframe noise models, while the measurements indicated a less significant dependency. This is mainly due to installation effects and noise reduction measures that are not included in the models. Nevertheless, the variations in the spectra of the predicted and measured noise showed similar patterns. [ABSTRACT FROM AUTHOR]

Published
2024
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25. Preliminary Analysis of Compression System Integrated Heat Management Concepts Using LH 2 -Based Parametric Gas Turbine Model.

Author

Abedi, Hamidreza, Xisto, Carlos, Jonsson, Isak, Grönstedt, Tomas, and Rolt, Andrew

Subjects
HEAT exchangers, HYDROGEN as fuel, ENERGY consumption, FUEL systems, GAS turbine blades, GAS turbines
Abstract

The investigation of the various heat management concepts using LH2 requires the development of a modeling environment coupling the cryogenic hydrogen fuel system with turbofan performance. This paper presents a numerical framework to model hydrogen-fueled gas turbine engines with a dedicated heat-management system, complemented by an introductory analysis of the impact of using LH2 to precool and intercool in the compression system. The propulsion installations comprise Brayton cycle-based turbofans and first assessments are made on how to use the hydrogen as a heat sink integrated into the compression system. Conceptual tubular compact heat exchanger designs are explored to either precool or intercool the compression system and preheat the fuel to improve the installed performance of the propulsion cycles. The precooler and the intercooler show up to 0.3% improved specific fuel consumption for heat exchanger effectiveness in the range 0.5–0.6, but higher effectiveness designs incur disproportionately higher pressure losses that cancel-out the benefits. [ABSTRACT FROM AUTHOR]

Published
2022
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26. Proof of Concept Study for Fuselage Boundary Layer Ingesting Propulsion

Author

Seitz, Arne, primary, Habermann, Anaïs Luisa, additional, Peter, Fabian, additional, Troeltsch, Florian, additional, Castillo Pardo, Alejandro, additional, Della Corte, Biagio, additional, van Sluis, Martijn, additional, Goraj, Zdobyslaw, additional, Kowalski, Mariusz, additional, Zhao, Xin, additional, Grönstedt, Tomas, additional, Bijewitz, Julian, additional, and Wortmann, Guido, additional

Published
2021
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30. Concetual design of ultra-efficient cores for mid-century aircraft turbine engines

Author

Grönstedt, Tomas, Xisto, Carlos, Sethi, V., Rolt, Andrew M., Rosa, Nicolás García, Missirlis, D., Whurr, J., Tantot, Nicholas, Dietz, Martin, and Lundbladh, Anders

Subjects
composite cycle, Boxprop, ACARE 2050 targets, open rotor, Aerospace Engineering, Energy Engineering, Other Mechanical Engineering, pulse detonation topping, turbofan, tube-and-wing aircraft, Constant volume combustion, slotted nacelle, nutating-disc topping
Abstract

For today’s best turbofans propulsive efficiencies are now higher than 80% whereas thermal efficiencies only reach values around 50%. The introduction of the geared engine architecture gives some hope for continued improvement in propulsive efficiency. On the other hand, for the thermal efficiency the progress pace is fairly modest despite the much larger room for improvement. Further rapid progress is primarily challenged by small turbomachinery size and efficiency, high pressure compressor exit and turbine entry temperatures and losses associated with cooling. Fundamental thermodynamics also make progress more difficult than it used to be, e.g. for the ideal Brayton cycle an increase in overall pressure ratio from 50 to 70 will only yield a 3% unit improvement. In 2015, the EU launched a research project, the ULTIMATE project, investigating new core engine architectures. In particular, it was argued that cycle synergy could be a way forward and that the combination of several radical concepts could potentially lead to ultra-efficient cores with less technical challenges than power plants involving single radical concepts. After an initial extensive screening and down-selection, the project developed the most promising propulsion systems to TRL 2. To evaluate the environmental improvement potential the new radical propulsion systems were integrated onto advanced tube-and-wing aircraft and evaluated against the EU SRIA 2050 targets. The paper reviews key findings from the research activities, describing design choices and the architectural evolutions that the different concepts underwent. As a first, the paper also collects the top-level achievements on CO2 emissions to draw conclusions on radical core engine cycle selection. The most notable observation on core engine down-selection is that all concepts integrating pressure rise combustion achieved very large improvements, in particular when synergies with intercooling were explored. Large cuts in CO2 emissions were retained even when compared to year 2050 reference technology.

Published
2019

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