In this thesis, a novel turbofan concept is investigated. This concept is similar to a two-spool direct drive turbofan, except that the booster is not connected to the low-pressure spool but to a summation gearbox whereby it is powered by both the low- and high-pressure turbine. Additionally, the booster rotational speed is higher than the low-pressure spool speed but less than the high-pressure spool speed. At first, the concept is investigated analytically. It is shown that the arrangement of the epicyclic gear train as used in the concept is best suitable for the intended application. Furthermore, it is shown that the gear ratio of the gearbox is an important design parameter that affects the design and off-design operation of the engine. Guidelines for choosing the gear ratio are given. The analytical expression for the operating lines of the booster and the high-pressure compressor indicate that the booster operational characteristics are significantly different from conventional turbofan configurations. In order to further assess the concept, a preliminary engine design study is conducted in which an engine for the Airbus A320neo is designed. The engine is then benchmarked against a two-spool direct drive and a geared turbofan. It is shown that in part-load operations, the booster surge margin decreases considerably, which is identified as a significant disadvantage of the novel concept. Countermeasures to mitigate this problem are presented. Through a preliminary component design, it is found that the core compressors in the novel concept are similar to a geared turbofan while the turbines are similar to a two-spool direct drive turbofan. Take-off, climb, and cruise performance of the novel concept was found to be very similar to the compared concepts. The new concept was found to be an excellent basis for a more-electric or hybrid engine because high levels of power offtake and input at the booster spool unsettle the engine far less than the same power transfers in competing concepts. At the same time, the turbomachinery used in the engine is shown to be conventional, which facilitates market introduction.
Assessment of the dual drive booster turbofan concepte
Untersuchung des Dual Drive Booster Turbofan Konzeptes
2021-01-01
1 Online-Ressource : Illustrationen, Diagramme pages
Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2020; Aachen : RWTH Aachen University 1 Online-Ressource : Illustrationen, Diagramme (2021). = Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2020
Miscellaneous
Electronic Resource
English
VITAL HIGHLY LOADED DIRECT DRIVE TURBOFAN LOW PRESSURE BOOSTER
British Library Conference Proceedings | 2009
|Dual drive booster for a two-spool turbofan: performance effects and mechanical feasibility
Online Contents | 2016
|AIAA | 1987
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