The conceptual design of a civil turbofan aero-engine was studied. Three subsystems were integrated and analyzed in detail including: overall performance (analysis of thermodynamic cycle

assessment of mass

noise

oxynitride emissions)

fan (analysis of aerodynamics and strength)

low pressure turbine (analysis of aerodynamics and strength). Multidisciplinary design optimization (MDO) of the engine conceptual design was carried out with different optimization strategies but for the same optimization objects

i.e.: specific fuel consumption

overall mass

overflight noise power level

approaching noise power level

and oxynitride emissions of the combustor. Optimization strategies including individual discipline feasible (IDF) optimization

collaborative optimization (CO) and asymmetric subspace optimization (ASO)

were adopted in the MDO study of aero-engine. The modeling method of the MDO engine system

the data transmission and the decoupling method of the subsystems were discussed. Finally

the following conclusions were drawn: the efficiencies of the three optimization strategies were approximately equal

and the difference of the maximum time consumption between every two of them was 742s. Moreover

CO and ASO strategies had better optimization results in the MDO of aero-engine conceptual design

and their comprehensive evaluation index were reduced by 0.82% and 0.86% respectively.