Design Exploration and Performance Assessment of Advanced Recuperated Hybrid-Electric UAM Rotorcraft

2021 ◽  
Author(s):  
Chana Anna Saias ◽  
Ioannis Roumeliotis ◽  
Ioannis Goulos ◽  
Vassilios Pachidis ◽  
Marko Bacic
Keyword(s):  
Environmental Impact ◽  
Electric Propulsion ◽  
Simulation Framework ◽  
Design Exploration ◽  
Rotor Aerodynamics ◽  
Fuel Burn ◽  
Trade Offs ◽  
Parallel Hybrid ◽  
Hybrid Electric ◽  
And Performance

Abstract The design of efficient, environmentally friendly and quiet powerplant for rotorcraft architectures constitutes a key enabler for Urban Air Mobility application. This work focuses on the development and application of a generic methodology for the design, performance and environmental impact assessment of a parallel hybrid-electric propulsion system, utilizing simple and advanced recuperated engine cycles. A simulation framework for rotorcraft analysis comprising models for rotor aerodynamics, flight dynamics and hybrid-electric powerplant performance is deployed for the design exploration and optimization of a hybrid-electric rotorcraft, modelled after the NASA XV-15, adapted for civil applications. Optimally designed powerplants for payload-range capacity, energy efficiency and environmental impact have been obtained. A comparative evaluation has been performed for the optimum designs. The respective trade-offs between engine, heat exchanger weight, thermal efficiency, as well as mission fuel burn and environmental impact have been quantified. It has been demonstrated that a recuperated gas turbine based hybrid-electric architecture may provide improvements of up to 6% in mission range capability without sacrificing useful load. At the same time, analyses performed for a representative 100 km mission suggest reductions in fuel burn and NOX emissions of up to 12.9% and 5.2% respectively. Analyses are carried at aircraft and mission level using realistic UAM mission scenarios.

Operating Characteristics of an Electrically Assisted Turbofan Engine

2020 ◽  
Author(s):  
Merijn Rembrandt van Holsteijn ◽  
Arvind Gangoli Rao ◽  
Feijia Yin
Keyword(s):  
Electric Propulsion ◽  
Propulsion System ◽  
Operating Characteristics ◽  
Turbofan Engine ◽  
Electric Propulsion System ◽  
Fuel Burn ◽  
Parallel Hybrid ◽  
Electrical Propulsion ◽  
Hybrid Electric ◽  
Cruise Flight

Abstract With the growing pressure to reduce the environmental footprint of aviation, new and efficient propulsion systems must be investigated. The current research looks at the operating characteristics of a turbofan engine in a parallel hybrid-electric propulsion system. Electric motors are used to supply power in the most demanding take-off and climb phases to achieve the required thrust, which allows the turbofan to be redesigned to maximize the cruise performance (to some extent). It was found that the turbofan’s cruise efficiency can be improved by 1.0% by relaxing the constraints of take-off and climb. It was found that the surge margins of compressors limit the amount of power that could be electrically supplied. On a short-range mission, the hybrid-electric propulsion system showed a potential to reduce around 7% of fuel burn on an A320 class aircraft. Most of these savings are however achieved due to fully electric taxiing. The weight of the electrical propulsion system largely offsets the efficiency improvements of the gas turbine during cruise flight. A system dedicated for fully electric taxiing system could provide similar savings, at less effort and costs. Given the optimistic technology levels used in the current analysis, parallel hybrid-electric propulsion is not likely to be used in the next-generation short to medium range aircraft.

Preliminary Design of Hybrid-Electric Propulsion Systems for Emerging UAM Rotorcraft Architectures

2021 ◽  
Author(s):  
Chana Anna Saias ◽  
Ioannis Goulos ◽  
Ioannis Roumeliotis ◽  
Vassilios Pachidis ◽  
Marko Bacic
Keyword(s):  
Electric Propulsion ◽  
Flight Test ◽  
Preliminary Design ◽  
Propulsion Systems ◽  
Rotor Aerodynamics ◽  
Tilt Rotor ◽  
Integrated Methodology ◽  
Hybrid Electric ◽  
Battery Energy ◽  
Optimal Implementation

Abstract The increasing demands for air-taxi operations together with the ambitious targets for reduced environmental impact have driven significant interest in alternative rotorcraft architectures and propulsion systems. The design of Hybrid-Electric Propulsion Systems (HEPSs) for rotorcraft is seen as being able to contribute to those goals. This work aims to conduct a comprehensive design and trade-off analysis of hybrid powerplants for rotorcraft, targeting enhanced payload-range capability and fuel economy. An integrated methodology for the design, performance assessment and optimal implementation of HEPSs for conceptual rotorcraft has been developed. A multi-disciplinary approach is devised comprising models for rotor aerodynamics, flight dynamics, HEPS performance and weight estimation. All models are validated using experimental or flight test data. The methodology is deployed for the assessment of a hybrid-electric tilt-rotor, modelled after the NASA XV-15. This work targets to provide new insight in the preliminary design and sizing of optimally designed HEPSs for novel tilt-rotor aircraft. The paper demonstrates that at present, current battery energy densities (250Wh/kg) severely limit the degree of hybridization if a fixed useful payload and range are to be achieved. However, it is also shown that if advancements in battery energy density to 500Wh/kg are realized, a significant increase in the level of hybridization and hence reduction of fuel burned and carbon output relative to the conventional configuration can be attained. The methodology presented is flexible enough to be applied to alternative rotorcraft configurations and propulsion systems.

scholarly journals Integrated Systems Simulation for Assessing Fuel Thermal Management Capabilities for Hybrid-Electric Rotorcraft

2020 ◽  
Author(s):  
Ioannis Roumeliotis ◽  
Lorenzo Castro ◽  
Soheil Jafari ◽  
Vassilios Pachidis ◽  
Louis De Riberolles ◽  
...  
Keyword(s):  
Thermal Management ◽  
Electric Propulsion ◽  
Cooling Capacity ◽  
Propulsion System ◽  
Fuel Tank ◽  
Thermal Loads ◽  
Simulation Framework ◽  
Propulsion Systems ◽  
Integrated Simulation ◽  
Hybrid Electric

Abstract Future aircraft and rotorcraft propulsion systems should be able to meet ambitious targets and severe limitations set by governments and organizations. These targets cannot be achieved through marginal improvements in turbine technology or vehicle design. Hybrid-electric propulsion is being widely considered as a revolutionary concept to further improve the environmental impact of air travel. One of the most important challenges and barriers in the development phase of hybrid-electric propulsion systems is the Thermal Management System (TMS) design, sizing and optimization for addressing the increased thermal loads due to the electric power train. The aim of this paper is to establish an integrated simulation framework including the vehicle, the propulsion system and the fuel-oil system (FOS) for assessing the cooling capability of the FOS for the more electric era of rotorcrafts. The framework consists of a helicopter model, propulsion system models, both conventional and hybrid-electric, and a FOS model. The test case is a twin-engine medium (TEM) helicopter flying a representative Passenger Air Transport (PAT) mission. The conventional power plant heat loads are calculated and the cooling capacity of the FOS is quantified for different operating conditions. Having established the baseline, three different Power Management Strategies (PMS) are considered and the integrated simulation framework is utilized for evaluating FOS temperatures. The results highlight the limitations of existing rotorcraft FOS to cope with the high values of thermal loads associated with hybridization for the cases examined. Hence, new ideas and embodiments should be identified and assessed. The case of exploiting the fuel tank as a heat sink is investigated and the results indicate that recirculating fuel to the fuel tank can enhance the cooling capacity of conventional FOS.

Parallel Hybrid Electric Propulsion Demonstrator Concept

2021 ◽  
Author(s):  
Rebecca Salter ◽  
James M. Falcone ◽  
John Bonet
Keyword(s):  
Electric Propulsion ◽  
Parallel Hybrid ◽  
Hybrid Electric

Development of a Suite of Hybrid Electric Propulsion Modeling Elements Using NPSS

2014 ◽  
Author(s):  
Christopher A. Perullo ◽  
David Trawick ◽  
William Clifton ◽  
Jimmy C. M. Tai ◽  
Dimitri N. Mavris
Keyword(s):  
Fuel Cell ◽  
Distribution System ◽  
Electric Propulsion ◽  
Degrees Of Freedom ◽  
Modeling Tools ◽  
Power Sources ◽  
Fuel Burn ◽  
Hybrid Electric ◽  
Unconventional Aircraft ◽  
Electric Engine

NASA is actively funding research into advanced, unconventional aircraft and engine architectures to achieve drastic reductions in vehicle fuel burn, noise, and emissions. One such concept is being explored by Boeing, General Electric, Virginia Tech, and Georgia Tech under the Subsonic Ultra Green Aircraft Research (SUGAR) project [1]. A major cornerstone of this research is evaluating the potential performance benefits that can be attributed to using hybrid electric propulsion. Hybrid electric propulsion in this context involves a non-Brayton power generation or storage source, such as a battery or a fuel cell, which can be used to provide additional propulsive energy to a conventional Brayton cycle powered turbofan engine. Employing additional power sources for thrust production increases the number of degrees of freedom both from a design and configuration standpoint and from an operational one. In order to assess and understand the myriad number of potential new configurations a modeling and simulation tool is needed; however, current state of the art propulsion modeling tools such as the Numerical Propulsion System Simulation (NPSS) are not natively capable of assessing novel hybrid electric configurations. This research addresses the gap between hybrid electric propulsion and conventional cycle analysis tools by developing a suite of native NPSS elements suitable for hybrid electric engine cycle design and analysis. Elements have been developed for a fuel cell, battery, motor, generator, and electrical distribution system. Both room temperature and cryogenically cooled superconducting variants are developed. The elements are designed such that they can be seamlessly integrated into existing NPSS cycle models to assess any system configuration or architecture the designer can envision.

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