IMPACT OF AN OPTIMIZED POWER TURBINE DISKS CAVITY ON GEARED OPEN ROTOR PERFORMANCE – A MULTIDISCIPLINARY APPROACH IN THE PRELIMINARY DESIGN

A constantly growing number of studies have been oriented to Green Aircraft and Green Engine concepts during last years in order to reduce pollutants and carbon-dioxide production by 2020. Ultra high by-pass engines are recently getting the highest interest by academia, research centers and industries. Among the most recent research activities, many studies are focused on geared architectures, the Geared Turbofan (GTF) and the Geared Open Rotor (GOR). The GOR architecture seems to be the most promising radical architecture for short-range aircraft as climbing and landing phases interest the major part of the whole mission. Our work takes place in the most recent research activities regarding a GOR-like engine, and can fit its preliminary design phase. A multidisciplinary modular simulation environment was developed to let researchers the chance to directly relate the considered disciplines. Introductory trade-off studies were carried on to effectively show GOR capabilities amongst the most innovative engines. A reference military core engine was used for the considered GOR engine, as previously done by General Electric for its original open rotor engine. GOR performance were predicted on-design and off-design, by relating to corporate inputs. Optimization studies of the GOR high-speed power turbine disks cavity were performed to reduce disks weight and cooling flows, complying with several engineering constraints provided by the industry. Finally the optimization outcomes were linked to the performance code to capture their impact on the overall engine efficiency and specific fuel consumption. Results show that it is possible to get an improvement in the specific fuel consumption by minimizing the required cooling flows of the GOR power turbine. Moreover, for a required thrust level, engine weight may be reduced.