scholarly journals Conceptual design and comparison of hybrid electric propulsion systems for small aircraft

2021 ◽  
Author(s):  
Jo Köhler ◽  
Peter Jeschke
Keyword(s):  
Conceptual Design ◽  
Electric Propulsion ◽  
Design Method ◽  
Propulsion System ◽  
Design Parameters ◽  
Propulsion Systems ◽  
Design Algorithm ◽  
Parallel Hybrid ◽  
Hybrid Electric ◽  
Small Aircraft

AbstractThis paper presents a novel conceptual design method for electric and hybrid electric propulsion systems in small aircraft. The effects of key design parameters on the propulsion system performance are analyzed and the advantages and drawbacks of the investigated propulsion systems are discussed on the basis of two sets of thrust requirements. First, the general conceptual design algorithm is outlined. This is followed by a description of the three propulsion systems investigated: the fully electric; the parallel hybrid; and the conventional internal combustion engine. Scalable models of all required propulsion system components are presented, including weight estimation and operating characteristics. Afterwards, the conceptual design algorithm is exemplified for a reference two-seater motorized glider with a cruising speed of 140 kt and a maximum take-off mass of 1000 kg. Key design parameters are identified and their impact on propulsion system mass and cruise efficiency discussed. This study suggests that the parallel hybrid propulsion system is advantageous for high power ratios between take-off and cruise. For a power ratio of 4.5, either a relative cruise efficiency advantage of 12% or a maximum system mass advantage of 10% can be expected, depending on the propeller design. For the chosen cruise range of 300 km, the system mass of the fully electric propulsion system is at least 2.37 times higher when compared to the conventional propulsion system. In summary, a design method for hybrid electric propulsion systems is presented here which may be used for conceptual design. Furthermore, the suitability of the propulsion systems under investigation for different sets of thrust requirements is assessed, which may be helpful for aircraft designers.

scholarly journals Conceptual design of small aircraft with hybrid-electric propulsion systems

Energy ◽  
2020 ◽  
Vol 204 ◽  
pp. 117937 ◽  
Author(s):  
David Sziroczak ◽  
Istvan Jankovics ◽  
Istvan Gal ◽  
Daniel Rohacs
Keyword(s):  
Conceptual Design ◽  
Electric Propulsion ◽  
Propulsion Systems ◽  
Hybrid Electric ◽  
Small Aircraft

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.

scholarly journals Comparison of Diesel-Electric with Hybrid-Electric Propulsion System Safety Using System-Theoretic Process Analysis

2019 ◽  
Author(s):  
V Bolbot ◽  
G Theotokatos ◽  
E Boulougouris ◽  
D Vassalos
Keyword(s):  
Electric Propulsion ◽  
Process Analysis ◽  
Hazard Analysis ◽  
Propulsion System ◽  
Cruise Ship ◽  
Propulsion Systems ◽  
Electric Propulsion System ◽  
Automation And Control ◽  
Hybrid Electric ◽  
And Control

Cruise ship industry is rapidly developing, with both the vessels size and number constantly growing up, which renders ensuring passengers, crew and ship safety a paramount necessity. Collision, grounding and fire are among the most frequent accidents on cruise ships with high consequences. In this study, a hazard analysis of diesel-electric and hybrid-electric propulsion system is undertaken using System-Theoretic Process Analysis (STPA). The results demonstrate significant increase in potential hazardous scenarios due to failures in automation and control systems, leading to fire and a higher number of scenarios leading to propulsion and power loss in hybrid-electric propulsion systems than on a conventional cruise-ship propulsion system. Results also demonstrate that STPA enhancement is required to compare the risk of two propulsion systems.

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.

Life Cycle Analysis for a Powertrain in a Concept for Electric Power Generation in a Hybrid Electric Aircraft

2020 ◽  
Author(s):  
Michael Schneider ◽  
Jens Dickhoff ◽  
Karsten Kusterer ◽  
Wilfried Visser
Keyword(s):  
Life Cycle ◽  
Gas Turbine ◽  
Electric Propulsion ◽  
Aircraft Engine ◽  
Propulsion System ◽  
Civil Aviation ◽  
Propulsion Systems ◽  
Hybrid Propulsion ◽  
Hybrid Electric ◽  
The Impact

Abstract In the recent decades, civil aviation was growing 4.7% per annum. In order to reduce emissions promoting the global warming process, alternative propulsion systems are needed. Full-electric propulsion systems in aviation might have the potential for emission-free flights using renewable energy. However, several research efforts indicate electric propulsion only seems feasible for small aircraft. Especially due to the low energy density of batteries compared to fossil fuels. For this reason, hybrid propulsion systems came into focus, combining the benefits of all-electric and conventional propulsion system concepts. It is also considered as bridging technology, system test and basis for component development — and therewith paves the way towards CO2 free aviation. In the ‘HyFly’ project (supported by the German Luftfahrtforschungsprogramm LuFo V-3), the potential of a hybrid electric concept for a short/mid-range 19 PAX aircraft is assessed — not only on system but also on single component basis. In a recent study, the propulsion architecture and the operating mode of the gas turbine and the electric components have been defined [1]. In this paper, the advantages of the hybrid propulsion architecture and a qualitative assessment of component life are presented. Methods for life time prediction for the aircraft engine, the electric motor, the reluctance generator and the battery are discussed. The impact of turbine inlet temperature on life consumption is analyzed. The life cycle of the aircraft engine and the electric components including gradual component deterioration and consequent performance degradation is simulated by using an in-house gas turbine simulation tool (GTPsim). Therefore, various effects on electric propulsion system can be predicted for the entire drivetrain system in less than one hour.

Performance Assessment of an Integrated Parallel Hybrid-Electric Propulsion System Aircraft

2019 ◽  
Author(s):  
Smruti Sahoo ◽  
Xin Zhao ◽  
Konstantinos G. Kyprianidis ◽  
Anestis Kalfas
Keyword(s):  
Performance Assessment ◽  
Electric Propulsion ◽  
Electrical Power ◽  
Propulsion System ◽  
System Level ◽  
Electric Propulsion System ◽  
The Core ◽  
Parallel Hybrid ◽  
Overall Efficiency ◽  
Hybrid Electric

Abstract Hybrid-electric propulsion system promises avenues for a greener aviation sector. Ground research work was performed in the past for the feasibility assessment, at the system level, for such novel concepts and the results showed were promising. Such designs, however, possess unique challenges from an operational point of view, and for sizing of the sub-system components; necessitating further design space exploration for associating with an optimal operational strategy. In light of the above, the paper aims at presenting an operational analysis and performance assessment study, for a conceptualised parallel hybrid design of an advanced geared turbofan engine, based on 2035 timeframe technology level. It is identified that the hybrid power operation of the engine is constrained with respect to the requirement of maintaining an adequate surge margin for the low pressure side components; however, a core re-optimised engine design with consideration of electrical power add-in for the design condition, relieves such limit. Therefore such a design, makes it suitable for implementation of higher degree of hybridisation. Furthermore, performance assessment is made both at engine and engine-aircraft integrated level for both scenarios of hybrid operation and the benefits are established relative to the baseline engine. The performance at engine level engine specific fuel consumption (SFC), thrust specific power consumption (TSPC), and overall efficiency, shows improvement in both hybridised scenarios. Improvement in SFC is achieved due to supply of the electrical power, whereas, the boost in TSPC, and overall efficiency is attributed to the use of higher efficiency electrical drive system. Furthermore, it is observed that while the hybridised scenario performs better at engine level, the core re-optimised design exhibits a better saving for block fuel/energy consumption, due to the considerable weight savings in the core components.

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