Electrically driven, Compact, Transonic Mixed-Flow Compressor for Active High-Lift Systems in Future Aircraft

This paper gives an overview of the interdisciplinary design process of an electrically-powered high-lift system for future commercial aircraft, with a focus on the mixed-flow compressor performance. Based on the requirements of the high-lift system, a multi-objective optimization is used for the aero-mechanical design of the compressor stage. The demand for high pressure ratio and efficiency, together with the constrained installation space yields an unconventional mixed-flow compressor design with a transonic flow regime. To supply the required pressurized air for the high-lift system, rotational speeds of up to60,000rpm are necessary according to CFD analysis. A very compact integrated prototype of the compressor system is designed, including electrical machine and power electronics with high power-to-mass ratios. Performance predictions are validated at part load. To integrate the compressor stage into the prototype, some adjustments to the geometry become necessary. Additional CFD simulations reveal a big impact of the new inlet duct on the compressor performance due to inlet flow distortion. It is assumed that a fully-integrated design process, which includes all relevant interdependencies of the different components, would yield a better overall system design

Challenges and Opportunities of Very Light High-Performance Electric Drives for Aviation

The demand for alternative fueling methods to reduce the need for fossil fuels is not limited to the electrification of ground vehicles. More-electric and all-electric aircraft pose challenges, with extensive requirements in terms of power density, efficiency, safety, and environmental sustainability. This paper focuses on electrical machines and their components, especially for high-power applications like the main propulsion. The electrical machine is evaluated from different aspects, followed by a closer look at the components and materials to determine the suitability of the current standard materials and advanced technologies. Furthermore, the mechanical and thermal aspects are reviewed, including new and innovative concepts for the cooling of windings and for the use of additive manufacturing. Aircraft have special demands regarding weight and installation space. Following recent developments and looking ahead to the future, the need and the possibilities for light and efficient electrical machines are addressed. All of the approaches and developments presented lead to a better understanding of the challenges to be expected and highlight the upcoming opportunities in electrical machine design for the use of electric motors and generators in future aircraft. Several prototypes of electrical machines for smaller aircraft already exist, such as the electric drive of the Siemens powered Extra 330LE. The focus of this paper is to provide an overview of current technical possibilities and technical interrelations of high performance electric drives for aviation. A 1 MW drive is exemplified to present the possibilities for future drives for airplanes carrying a larger number of passengers. All presented techniques can also be applied to other drive power classes

Progress in Efficient Active High-Lift

This paper presents some of the progress in research on efficient high-lift systems for future civil aircraft achieved by the Coordinated Research Centre CRC 880 sponsored by the German Research Foundation. Several new approaches to increasing the lift are applied as part of the design of a reference aircraft with short take-off and landing capability: The numerically predicted positive effect of Coanda jet blowing at the trailing edge flap is validated in water tunnel experiments. Robust miniature pressure and hot-fi�lm sensors are developed for the closed-loop control of a piezo-actuated blowing lip. A flexible leading-edge device utilizes composite materials, for which new structural designs are developed. Additionally, a potential de-icing system, as well as a lightning-strike protection are presented. A high power-density electrically driven compressor with a broad operating range is designed to provide the blowing air ow. Different propulsion systems for the reference aircraft are evaluated. An ultra-high bypass ratio engine is considered to be most promising, and thus a preliminary fan stage design process is established. The rotor dynamic influences of the engine on the aircraft structure are investigated through a hybrid approach using a multibody model and modal reduction