SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Kyprianidis Konstantinos) ;pers:(Kavvalos Mavroudis)"

Sökning: WFRF:(Kyprianidis Konstantinos) > Kavvalos Mavroudis

  • Resultat 1-10 av 13
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Bermperis, Dimitios, et al. (författare)
  • Synergies and Trade-Offs in Hybrid Propulsion Systems Through Physics-Based Electrical Component Modeling
  • 2024
  • Ingår i: Journal of engineering for gas turbines and power. - : American Society of Mechanical Engineers (ASME). - 0742-4795 .- 1528-8919. ; 146:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Hybrid-electric propulsion is recognized as an enabling technology for reducing aviation’s environmental impact. In this work, a serial/parallel hybrid configuration of a 19-passenger commuter aircraft is investigated. Two underwing-mounted turboprop engines are connected to electrical branches via generators. One rear fuselage-mounted electrically driven ducted fan is coupled with an electric motor and respective electrical branch. A battery system completes the selected architecture. Consistency in modeling accuracy of propulsion systems is aimed for by development of an integrated framework. A multipoint synthesis scheme for the gas turbine and electric fan is combined with physics-based analytical modeling for electrical components. Influence of turbomachinery and electrical power system design points on the integrated power system is examined. An opposing trend between electrical and conventional powertrain mass is driven by electric fan design power. Power system efficiency improvements in the order of 2% favor high-power electric fan designs. A trade-off in electrical power system mass and performance arises from oversizing of electrical components for load manipulation. Branch efficiency improvements of up to 3% imply potential to achieve battery mass reduction due to fewer transmission losses. A threshold system voltage of 1 kV, yielding 32% mass reduction of electrical branches and performance improvements of 1–2%, is identified. This work sets the foundation for interpreting mission-level electrification outcomes that are driven by interactions on the integrated power system. Areas of conflicting interests and synergistic opportunities are highlighted for optimal conceptual design of hybrid powertrains.
  •  
2.
  • Bermperis, Dimitios, et al. (författare)
  • SYNERGIES AND TRADE-OFFS IN HYBRID PROPULSION SYSTEMS THROUGH PHYSICS-BASED ELECTRICAL COMPONENT MODELLING
  • 2023
  • Ingår i: Proc. ASME Turbo Expo. - : American Society of Mechanical Engineers (ASME). - 9780791886939
  • Konferensbidrag (refereegranskat)abstract
    • Hybrid-electric propulsion is recognized as one of the enabling technologies for reducing aviation’s environmental impact. In this work a serial/parallel hybrid configuration of a 19-passenger commuter aircraft is investigated. Two underwing-mounted turboprop engines are connected to electrical branches via generators. One rear fuselage-mounted electrically driven ducted fan is coupled with an electric motor and respective electrical branch. A battery system completes the selected architecture. Consistency in modelling accuracy of propulsion systems is aimed for by development of an integrated framework. A multi-point synthesis scheme for the gas turbine and electric fan is combined with physics-based analytical modelling for electrical components. Influence of turbomachinery and electrical power system design points on the integrated power system is examined. An opposing trend between electrical and conventional powertrain mass is driven by electric fan design power. Power system efficiency improvements in the order of 2% favor high-power electric fan designs. A trade-off in electrical power system mass and performance arises from oversizing of electrical components for load manipulation. Branch efficiency improvements of up to 3% imply potential to achieve battery mass reduction due to fewer transmission losses in mission-significant segments. A threshold system voltage of 1kV, yielding 32% mass reduction of electrical branches and performance improvements of 1-2%, is defined. Above the indicated threshold, benefits are limited, and system design complexity increases unfavorably. This work sets the foundation for interpreting mission-level electrification outcomes that are driven by interactions on the integrated power system. Areas of conflicting interests and synergistic opportunities are highlighted for optimal conceptual design of hybrid powertrains.
  •  
3.
  • Gkoutzamanis, V. G., et al. (författare)
  • Conceptual design and energy storage positioning aspects for a hybrid-electric light aircraft
  • 2020
  • Ingår i: Proceedings of the ASME Turbo Expo. - : American Society of Mechanical Engineers (ASME). - 9780791884140
  • Konferensbidrag (refereegranskat)abstract
    • This work focuses on the feasibility of a 19-passenger hybrid-electric aircraft, to serve the short-haul segment within the 200-600 nautical miles. Its ambition is to answer some dominating research questions, during the evaluation and design of aircraft based on electric propulsion architectures. The potential entry into service of such aircraft is foreseen in 2030. A literature review is performed, to identify similar concepts that are under research and development. After the requirements definition, the first level of conceptual design is employed. Based on a set of assumptions, a methodology for the sizing of the hybrid-electric aircraft is described to explore the basis of the design space. Additionally, a methodology for the energy storage positioning is provided, to highlight the multidisciplinary aspects between the sizing of an aircraft, the selected architecture (series/parallel partial hybrid) and the energy storage operational characteristics. The design choices are driven by the aim to reduce CO2 emissions and accommodate boundary layer ingestion engines, with aircraft electrification. The results show that it is not possible to fulfill the initial design requirements (600 nmi) with a fully-electric aircraft configuration, due to the farfetched battery necessities. It is also highlighted that compliance with airworthiness certifications is favored by switching to hybrid-electric aircraft configurations and relaxing the design requirements (targeted range, payload, battery technology). Finally, the lower degree of hybridization (40%) is observed to have a higher energy efficiency (12% lower energy consumption and larger CO2 reduction), compared to the higher degree of hybridization (50%), with respect to the conventional configuration.
  •  
4.
  • Gkoutzamanis, Vasilis G., et al. (författare)
  • Conceptual Design and Energy Storage Positioning Aspects for a Hybrid-Electric Light Aircraft
  • 2021
  • Ingår i: Journal of engineering for gas turbines and power. - : ASME International. - 0742-4795 .- 1528-8919. ; 143:9
  • Tidskriftsartikel (refereegranskat)abstract
    • This work is a feasibility study of a 19-passenger hybrid-electric aircraft, to serve the short-haul segment within the 200-600 nautical miles. Its ambition is to answer some dominating research questions, during the evaluation and design of aircraft based on alternative propulsion architectures. The potential entry into service (EIS) is foreseen beyond 2030. A literature review is performed to identify similar concepts under research and development. After the requirements' definition, the first level of conceptual design is employed. The objective of design selections is driven by the need to reduce CO2 emissions and accommodate aircraft electrification with boundary layer ingestion engines. Based on a set of assumptions, a methodology for the sizing of the hybrid-electric aircraft is described to explore the basis of the design space, incorporating a parametric analysis for the consideration of boundary layer ingestion effects. Additionally, a methodology for the energy storage positioning is provided to highlight the multidisciplinary aspects between the sizing of an aircraft, the selected architecture (series/ parallel partial hybrid), and the storage characteristics. The results show that it is not possible to fulfill the initial design requirements (600 nmi) with a fully-electric aircraft configuration, due to the farfetched battery necessities. It is also highlighted that compliance with airworthiness standards is favored by switching to hybrid-electric aircraft configurations and relaxing the design requirements (targeted range, payload, battery technology). Finally, the lower degree of hybridization (40%) is observed to have a higher energy efficiency (-12% energy consumption) compared to the higher degree of hybridization (50%) and greater CO2 reduction, with respect to the conventional configuration.
  •  
5.
  • Kavvalos, Mavroudis, et al. (författare)
  • A Modelling Approach of Variable Geometry for Low Pressure Ratio Fans
  • 2019
  • Ingår i: International Symposium on Air Breathing Engines, ISABE 2019, Canberra, Australia, 23 - 27 September 2019 Paper No. ISABE-2019-24382.
  • Konferensbidrag (refereegranskat)abstract
    • This paper presents the development and application of a modelling approach of variable geometry conceptsfor low pressure ratio fans; namely Variable Area Nozzle and Variable Pitch Fan. An enhanced approachfor Outlet Guide Vane pressure loss predictions and an aerothermodynamic analysis of variable pitchconcept are developed and integrated into a multi-disciplinary conceptual engine design framework. Astreamline curvature algorithm is deployed for the derivation of the off-design fan performance map,alleviating scaling issues from higher pressure ratio fan designs. Correction deltas are derived through thevariable pitch analysis for calculating the re-shaped off-design fan performance map. The aforementionedvariable geometry concepts are evaluated in terms of surge margin at engine and aircraft level for a lowpressure ratio aft-fan of a hybrid-electric configuration. Performance assessments carried out suggest thata +8° closing of fan blade cascades leads to a 33% surge margin improvement (with reference being thesurge margin without variable geometry) compared to a 25% improvement achieved by +20% opening thenozzle area at end of runway take-off conditions. Although weight and complexity implications of variablegeometry are not considered, the integrated modelling approach is shown to be able to assess and comparesuch novel engine technologies for low pressure ratio fans in terms of operability.
  •  
6.
  • Kavvalos, Mavroudis, et al. (författare)
  • Compressor Characteristics for Transient and Part-load Performance Simulation
  • 2019
  • Ingår i: Proceedings of the ASME Turbo Expo, American Society of Mechanical Engineers (ASME), 2019. - : American Society of Mechanical Engineers (ASME). - 9780791858608
  • Konferensbidrag (refereegranskat)abstract
    • Compressor performance tests are mainly focused on the typical range of operation, resulting in limited knowledge of compressor behavior in the low-speed region. The main target of this work comprises the generation of compressor characteristics at low part-load by giving particular insight into the physical aspect of this operating condition. It is necessary for running transient and part-load performance simulation and can be considered as the first crucial step toward an optimal engine starting schedule. Modelling the low part-load operating regime requires accurate component performance maps extended to the low-speed area, where engine starting and altitude relight occur. In this work, a robust methodology for generating compressor maps in the low part-load operating regime is developed. Compressor geometry and typical operation range compressor map are required as inputs. Two different modelling processes are incorporated within this methodology. Extrapolation based on the principle of similarity laws with modified law exponents constitutes the first modelling process, which seems inaccurate when predicting compressor performance at fixed-rotor conditions. Interpolation based on the fixed-rotor characteristic constitutes the second modelling process, which can be either linear or adaptive. The adaptive interpolation scheme was developed by the authors and generates low-speed characteristics using the same allocation trend as the one obtained from given performance data. It is observed that performance data points of each β-line follow an exponential trend in mass flow differences while increasing rotational speed, with a calculated average relativized Root Mean Square (RMS) error of less than 5%. Adapting the same trend in mass flow to the low-speed region, a compressor performance map with continuous exponential trend in all characteristics (for part- and full-load conditions) can be achieved. Implementing the developed methodology on the High Pressure Compressor (HPC) of the Energy Efficient Engine (E3) project is also presented, showcasing its applicability and the merit of it being incorporated into any conventional performance prediction tool. Furthermore, a sensitivity analysis for input variables, namely compressor exit effective area and pressure loss model coefficients is carried out, demonstrating the significant impact of the former on the shape of the low part-load characteristics. Generation of compressor characteristics at low-speeds with this methodology can be viewed as an enabler for running credible transient starting simulation and transient diagnostics, thereby defining an optimal starting schedule, applicable to both power generation and aerospace industry.
  •  
7.
  • Kavvalos, Mavroudis, et al. (författare)
  • Exploring Design Trade-Offs for Installed Parallel Hybrid Powertrain Systems
  • 2021
  • Ingår i: 2021 AIAA/IEEE Electric Aircraft Technologies Symposium, EATS 2021. - Reston, Virginia : Institute of Electrical and Electronics Engineers Inc.. - 9781624106118
  • Konferensbidrag (refereegranskat)abstract
    • The parallel hybrid (or boosted) turbofan engine alleviates the system complexity of radical electrified powertrain architectures, while also demonstrates substantial benefits in reducing specific fuel consumption. This conservative, yet promising, electrified configuration incorporates an electrical drive coupled with the engine low-pressure or gearbox fan spool. Sophisticated models for the gas turbine and the electrical drive system are developed. The former deploys a multi-point design matching scheme coupled with an installed engine performance approach, as well as an engine sizing and weight estimation tool. The latter incorporates an analytical electrical machine sizing and performance methodology. The objective of this paper is to shed light on the optimal parallel hybrid engine design, considering installed cycle performance and tight coupling of engine and electrical drive systems. The impact of installation drag components on the integrated powertrain system performance is analyzed and design trade-offs are explored. Electrical machine efficiency, propulsion system weight and installed specificfuelconsumptiondemonstrateopposingtrendswithvaryingspecificthrustfordifferent electrical drive installation positions and mechanical connections. It is shown that fan spinner-mounted electrical machine which is mechanically coupled to the low-pressure spool presents the greatest potential in terms of electrical machine efficiency and propulsion system installed performance. A 11.23% and 15.11% increase in installed specific fuel consumption at Top of Climb and Cruise, respectively, is observed for the Cruise-based optimal specific thrust variant, rendering installation effects and electrical drive considerations critical for future low-specific thrust hybrid-electric aero-engine concepts. 
  •  
8.
  • Papagianni, Andromachi, et al. (författare)
  • Conceptual Design of a Hybrid Gas Turbine - Solid Oxide Fuel Cell System for Civil Aviation
  • 2019
  • Konferensbidrag (refereegranskat)abstract
    • A conceptual design of a hybrid Gas Turbine - Solid Oxide Fuel Cell (SOFC) system is presented for civil aviation applications. The system operates using hydrogen as fuel, for the aircraft’s propulsion, while at the same time produces electrical energy in the fuel cell. Hydrogen is produced during flight by reformation of methane. The motivation of the study is to investigate hydrogen’s use for aviation purposes, so the hybrid system’s operation characteristics need to be examined. A configuration is designed, where a SOFC and the burner is modeled as one and simulated, in a modern multidisciplinary programming environment, in order to analyze the thermodynamic characteristics of the hybrid system. The fuel cell sets into motion when the aircraft reaches top of climb. During operation, liquefied natural gas is converted to hydrogen in the fuel cell and part of it is used to produce electrical energy while the rest for combustion. To determine the efficiency of the system, its performance was simulated using two scenarios, one for longhaul flights and one for short-haul flights. Comparing the results, for long-haul flights, the hybrid system presents a reduction in fuel consumption and an increase in thermal efficiency. For flights of a short range, the existing conditions in the fuel cell inlet were found to be prohibitive for it’s operation and the use of the hybrid system ineffective. For the system’s efficiency, the larger the pressure in the SOFC’s inlet the better. However, SOFC’s pressure limits restrict the pressure range and the cell’s use only during flight. Concluding, according to the study’s results, the hybrid system can operate in flight conditions, making the use of hydrogen in civil aviation possible. As a result, a 12% and 35% benefit is achieved, in fuel saving and thermal efficiency respectively.
  •  
9.
  • Sahoo, Smruti, et al. (författare)
  • System-level assessment of a partially distributed hybrid electric propulsion system
  • 2022
  • Ingår i: Proceedings of the ASME Turbo Expo. - : American Society of Mechanical Engineers (ASME). - 9780791885970
  • Konferensbidrag (refereegranskat)abstract
    • Hybrid electric propulsion system based aircraft designs are paving the path towards a future greener aviation sector and thus, have been the major focus of the aeronautical community. The fuel efficiency improvements of such propulsion system configurations are realized at the aircraft level. In order to assess such benefits, a radical shift in the sub-system modeling requirements and an integrated conceptual aircraft design environment is necessary. This work highlights performance model development work pertaining to different hybrid electric propulsion system components and development of a design platform which facilitates tighter integration of different novel propulsion system disciplines at aircraft level. Furthermore, a serial/parallel partially distributed hybrid electric propulsion system is chosen as the candidate configuration to assess the potential benefits and associated trade-offs by conducting multidisciplinary design space exploration studies. It is established that the distributed hybrid electric configurations pose the potential for aircraft structural weight reduction benefits. The study further illustrates the impacts from onboard charging during the low thrust requirement segments, quantitatively. It is highlighted that the amount of off-take power extraction for onboard charging of the battery is limited due to engine operability and higher specific fuel consumption issues. Though provisioning of onboard charging lowers the potential for block fuel savings, improvement in battery specific energy can make it more promising, which is also dependent on the hybridization power level. It is established that distributed propulsion system configurations particularly benefit from a high aspect ratio wing structure, which manifests for high hybridization power levels. A high voltage level transmission system with more efficient electrical components, enhances opportunities for achieving block fuel saving benefits.
  •  
10.
  • Sahoo, Smruti, et al. (författare)
  • System-Level Assessment of a Partially Distributed Hybrid Electric Propulsion System
  • 2023
  • Ingår i: Journal of engineering for gas turbines and power. - : American Society of Mechanical Engineers (ASME). - 0742-4795 .- 1528-8919. ; 145:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Hybrid electric propulsion system-based aircraft designs are paving the path toward a future greener aviation sector and thus, have been the major focus of the aeronautical community. The fuel efficiency improvement associated to such propulsion system configurations are realized at the aircraft level. In order to assess such benefits, a radical shift in the subsystem modeling requirements and of a conceptual-level aircraft design environment are necessary. This work highlights performance model development work pertaining to different hybrid electric propulsion system components and the development of a design platform that facilitates tighter integration of different novel propulsion system disciplines at the aircraft level. Furthermore, a serial/parallel partially distributed hybrid electric propulsion system is chosen as the candidate configuration to assess the potential benefits and associated tradeoffs by conducting multidisciplinary design space exploration studies. It is established that the distributed hybrid electric configurations pose the potential for aircraft structural weight reduction benefits. The study further illustrates the impacts of onboard charging during the low thrust requirement segments, quantitatively. The provision of onboard charging lowers the potential for block fuel savings, and improvement in battery specific energy can make it more promising, which is also dependent on the hybridization power level. It is established that distributed propulsion system configurations particularly benefit from a high aspect ratio wing structure, which manifests in high hybridization power levels. A high voltage level transmission system with more efficient electrical components enhances opportunities for achieving block fuel saving benefits.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 13

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy