A Procedure for Axial Blade Optimization

This paper proposes a method to modify the geometry of an axial blade to obtain a better stress distribution without compromising the aerodynamic design. The method is applied to an axial blade and is most relevant to those blades with a high degree of twist, such as for instance fan blades. The behavior of such blades is described by a finite element shell model. The initial aerodynamic definition of the axial blade is taken as the basic geometry. Variations of geometry are now considered, which maintain the essential aerodynamic characteristics, and the stresses are calculated. The stresses are expressed as a linear function of the geometric variations. A simple search technique is utilized to find the optimum combination of geometric variations. An example of a representative model shows that a quick convergence towards the final geometry is achieved.