Browsing by Author "Kang, Sangkeun"

Now showing 1 - 4 of 4
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    Assessment of engine operability and overall performance for parallel hybrid electric propulsion systems for a single-aisle aircraft
    (American Society of Mechanical Engineers, 2021-09-16) Kang, Sangkeun; Roumeliotis, Ioannis; Zhang, Jinning; Pachidis, Vassilios; Broca, Olivier
    This paper aims to assess the gas turbine operability and overall hybrid electric propulsion system performance for a parallel configuration applied to a 150 passenger single-aisle aircraft. Two arrangements are considered: one where the low pressure shaft is boosted and one where the high pressure shaft is boosted. For identifying limits in the hybridization strategy steady state and transient operation are considered and the hybridization effect on compressor operability is determined. Having established the electric power on-take limits with respect to gas turbine operation the systems performance at aircraft level is quantified for the relevant cases. Different power management strategies are applied for the two arrangements and for different power degrees of hybridization. The results indicate that despite the fact that pollutant emission and fuel consumption may improved for hybrid propulsion, this comes at the cost of reduced payload and operability margins. Boosting the low pressure shaft may give the highest engine performance benefits but with a significant weight penalty, while the low pressure compressor system operability is negatively affected. On the other hand boosting the high pressure shaft provides lower engine performance benefits but with smaller weight penalty and with less operability concerns.
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    ItemOpen Access
    Assessment of engine operability and overall performance for parallel hybrid electric propulsion systems for a single-aisle aircraft
    (American Society of Mechanical Engineers, 2022-01-04) Kang, Sangkeun; Roumeliotis, Ioannis; Zhang, Jinning; Broca, Olivier; Pachidis, Vassilios
    This paper aims to assess the gas turbine operability and overall hybrid electric propulsion system (HEPS) performance for a parallel configuration applied to a 150 passenger single-aisle aircraft. Two arrangements are considered: one where the low-pressure (LP) shaft is boosted and one where the high-pressure (HP) shaft is boosted. For identifying limits in the hybridization strategy, steady-state and transient operation are considered, and the hybridization effect on compressor operability is determined. Having established the electric power on-take limits with respect to gas turbine operation, the systems performance at aircraft level is quantified for the relevant cases. Different power management strategies (PMS) are applied for the two arrangements and for different power degrees of hybridization. The results indicate that despite the fact that pollutant emission and fuel consumption may improve for hybrid propulsion, this comes at the cost of reduced payload and operability margins. Boosting the LP shaft may give the highest engine performance benefits but with a significant weight penalty, while the LP compressor system operability is negatively affected. On the other hand, boosting the HP shaft provides lower engine performance benefits but with smaller weight penalty and with less operability concerns.
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    Design and simulation of eVTOL aircraft Thermal Management System
    (ASME, 2025-06) Kang, Sangkeun; Saias, Chana Anna; Roumeliotis, Ioannis; Broca, Olivier
    Vertical Take-off and Landing (VTOL) aircraft with hybrid or fully-electric propulsion systems are becoming popular for Urban Air Mobility (UAM) applications. However, they face challenges such as limited power and energy density, stringent operating temperature constraints, and the generation of low-grade waste heat. These issues emphasize the need for effective Thermal Management Systems (TMS) design. In light of the above, this paper aims to design the TMS for a parallel hybrid electric XV-15 aircraft, a widely known civil tiltrotor concept. The TMS is integrated into the aircraft system to assess its impact on energy efficiency and emissions at both aircraft and mission levels. This study considers current state of the art technology and expected advancements over the next two decades to identify the benefits of electrification. In the designed TMS, liquid cooling cold plates serve as the main heat acquisition and cooling system for each electric component. An air-coolant heat exchanger is also incorporated to dissipate the accumulated heat load. The study conducts a comparative analysis to determine the optimal TMS design point. It involves a comparison between two design scenarios: one focused on the cruise condition, which constitutes a significant portion of the flight mission, and another designed specifically for peak heat load conditions. This ensures a holistic evaluation of the TMS's performance across various flight phases, balancing efficiency and resilience to peak demands. Finally, the energy efficiency and emission penalty associated with the TMS integration are quantified and discussed in the study.
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    On the design of integrated thermal management systems for eVTOL aircraft
    (American Society of Mechanical Engineers (ASME), 2023-09-28) Kang, Sangkeun; Saias, Chana Anna; Roumeliotis, Ioannis; Broca, Olivier
    Vertical take-off and landing aircraft equipped with hybrid or fully electric propulsion systems have gained interest for urban air mobility applications. Besides the low energy density of state of art electric systems, their strict operating temperature requirement and low-grade heat highlight the importance of effective thermal management system design. This paper aims to establish a design process for the thermal management system for a parallel hybrid electric tiltrotor and showcase it for a system consisting of direct ram-air cooling cold plate and phase change materials. The cold plate is designed for cruise conditions and used as heat acquisition and cooling system, whereas the phase change materials is used as a heat storage system when ram air is limited. Three sizing conditions are considered comprising the baseline design mission, a certification condition for One Engine Inoperative (OEI) and an off-design mission. The effects of thermal management system integration on overall performance are quantified and discussed. The results indicate that designing the system for the baseline sizing mission results in a 5% increase in fuel burn per payload relative to the equivalent counterpart without thermal management consideration. This penalty increases to 14% when certification requirements are accounted. It is highlighted that tor shorter mission thermal management is the limiting factor for battery utilization, hence the expected benefits are significantly reduced. As electric components technology increases thermal management becomes less sensitive to the sizing conditions.