A holistic system approach for short range passenger aircraft with cryogenic propulsion system

Abstract

Currently, hybrid-electric aircraft are under investigation as one possible solution to reduce the emissions of the aviation industry according to Flightpath 2050 of the European Union. To meet the drive train's requirements on low mass while aiming for highest efficiency, superconducting technologies are regarded as a key enabling technology for drive train powers of several tens of megawatts. Within the German nationally funded project TELOS an exemplary mission profile and the physical measures of a 220-passenger aircraft are used to derive the requirements for a cryogenic-cooled serial hybrid-electric propulsion system. To optimize the total system performance, we subsequently evaluated the superconducting and cryogenic-cooled components by using computationally fast, analytical models. This approach allows quantifying the system performance by using component technologies being available today. In particular, the system performance of geared drive to direct drive propulsion units are compared and the influence of the DC bus voltage and the electric frequencies of the AC circuits on the mass and the efficiency of the drive trains are analysed.

Comparative Analysis and Optimization of Technical and Weight Parameters of Turbo-Electric Propulsion Systems

“…Comparing the results for a fully cryogenic turbo-electric power train from [8] and a non-cryogenic turbo-electric power train, as presented in this paper, we can draw the following conclusions:…”

“…All electric machines and inverters are connected to corresponding heat exchangers for cooling. For comparison: The cryogenic drivetrain system architecture that was analyzed in [8] consisted of similar electric components (and a gearbox); however instead of heat exchangers liquid hydrogen (and the corresponding tanks) were considered for cryogenic cooling.…”

“…These comparisons revealed an accuracy of 2% to 5% for our analytical models depending on component and power level. As the modeling is similar to some of our previous work, text parts from [8,15] were re-used for the following description. Figure 3.…”

“…Thus, it was investigated in detail what masses and efficiencies are achievable with fully cryogenic turbo-electric drivetrain architecture [8]. In [8] and consequently in this publication, a turbo-electric propulsion system instead of a hybrid-electric configuration (i.e., a turbo-electric configuration including batteries) was chosen, in order to focus on the electric components whose design is mainly affected by the cryogenic temperature, i.e., electric machines, inverters and cables. The study was based on a hypothetically hybridized 220 PAX aircraft with a mission range of 2500 nm.…”

“…As the details for the CEPS study were already published previously [8], this paper focuses on a system design study for a TEPS with identical top-level requirements. The paper follows a similar methodological approach as [8], i.e., physics-driven analytical models are used to describe each component precisely, so that many parameter combinations can be studied to find the best system configuration for the given requirements. Also, the paper's structure is similar, where first the requirements and methodological approach are presented.…”