This paper aims to develop an advanced three-shaft turbofan engine with ultra-high BPR for entry-into-service (EIS) 2050. The boundary approaching method is utilized to obtain the optimal engine for a series of engines with different fan diameters. Furthermore, the flight mission analysis was carried out to fully consider the engine performance and weight penalty. The optimum engine employs a 3.26m fan diameter with ultra-high BPR reaching 21.39. The corresponding SFC is 11.42 ((g/s)/kN) which is 3.88% lower than the 2.95m fan diameter engine. However, the weight penalty has offset part of the benefits and the block fuel reduction is 2.5%. Sensitivity analysis results reveal that the LPT efficiency plays a dominant role in engine performance. Afterwards, the effects of variable geometry are investigated including the blow-off valve (BOV), variable inlet guide vane (VIGV) and bypass variable area nozzle (VAN). Results show that combining the three measures would boost engine performance and save fuel. The designed schedule for the combination of VIGV, BOV and VAN has generated a reduction in block fuel, NOx, CO2 and H2O reaching 3.36%, 5.55%, 2.47% and 2.53 % respectively.

This paper aims to develop a robust design process by approaching the performance boundaries and evaluating the operability of the pursued geared turbofan engine with low specific thrust for EIS 2025. A two-spool direct-drive turbofan (DDTF) engine of EIS 2000 was improved according to aircraft specifications and technology boundaries in 2025. A series of optimized engines with consecutive fan diameters were established to seek the ideal engine by balancing SFC, weight and mission fuel burn. The fan diameter was proved to be a decisive factor for lowering SFC and energy usage. The cycle design optimization process achieved a thermal efficiency of approximately 52%, and a propulsive efficiency of 79.5%, which is 8.19% increase in propulsive efficiency by enlarging fan diameter from 1.6m to 1.9m. Meanwhile, the 1.9m-fan diameter engine achieved a reduction in SFC and fuel burn of 7.47% and 6.58% respectively which offers an overall reduction of 30.82% in block fuel burnt and CO2 emission compared to the DDTF engine. A feasibility check verified the viability of the designed optimum engine in terms of fan tip speed, stage loading and AN2. Dynamic simulation offered a deep understanding of transient behaviour and fundamental mechanism of the geared turbofan engine. An important aspect of this paper is the use of advanced CMC materials, which led to an improvement of 4.92% in block fuel burn and 2.93% in engine weight.

More electric engines (MEEs) and more electric aircraft (MEA) are mainly implemented to address the global warming issue and make engines more fuel efficient. Developing technology has made them applicable. This paper presents a detailed introduction to the MEE for civil aircraft, including its architecture, characteristics and performance, as well as the potential benefits of fuel consumption and emissions reduction. It is obvious that the adoption of electric components, such as active magnet bearings, electric starters and generators and electric fuel pumps, is beneficial. It is especially

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