Abstract Radical aircraft propulsion concepts based on a Composite Cycle Engine architecture are presented to improve significantly the core efficiency of aero engines. Therefore, three different piston engine modes and configurations (a two-stroke and a four-stroke reciprocating piston configuration, as well as a Wankel-type rotary engine) are evaluated to identify the most promising piston engine concept in a Composite Cycle Engine application. The qualitative and quantitative assessment of the piston systems considers thermodynamic performance, weight and $ NO_{x} $ emissions, as well as cooling, lubrication and integration aspects. To compare the performance of the different piston systems, models for the non-stationary thermodynamic cycle of the piston engines are presented and integrated in a turbo engine performance simulation framework. A turboshaft platform with 22-MW shaft power at typical take-off conditions and unified state-of-the-art turbo component characteristics are used for the evaluation of the piston configurations. Further, approaches for the prediction of piston engine weights, cooling fin design and $ NO_{x} $ emissions are introduced. The four-stroke reciprocation piston engine configuration is identified as most promising option due to the best combination of thermal material requirements, $ NO_{x} $ emissions and specific fuel consumption. It is found that the high scavenging efficiency and the lower temperature level compared to the two-stroke engine compensate the additional scavenging cycle. A preliminary geometric design of the four-stroke piston engines is illustrated for the investigated application case.
Evaluation of piston engine modes and configurations in composite cycle engine architectures
CEAS Aeronautical Journal ; 11 , 2
2019
Article (Journal)
English
Evaluation of piston engine modes and configurations in composite cycle engine architectures
Springer Verlag | 2020
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