Design of High-Performance Fans Using Advanced Aerodynamics Codes

In the recent past, the performance of transonic fans has been significantly improved. In addition, through the extensive use of advanced aerodynamic computation codes, the development time required has been considerably reduced. Methods used range from the definition of airfoils in quasi-three-dimensional flow with boundary layer optimization to the analysis of three-dimensional inviscid flow for stage operation at the design point and in off-design conditions. Such a set of methods was used to design the fan blade of the CFM56-5 engine to a very high performance level. This paper will discuss the optimization of rotor and stator airfoils, the assessment of off-design performance, and the operational stability of this fan. A detailed comparison of full-size component test data with computation results shows the validity of these methods and also identifies those areas where research is still required.