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 NOx 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 NOx 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, NOx 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 Aeronaut J
CEAS Aeronautical Journal ; 11 , 2 ; 391-400
2020-06-01
10 pages
Article (Journal)
Electronic Resource
English
Evaluation of piston engine modes and configurations in composite cycle engine architectures
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