Flutter free design technology of a two stages fan was investigated. During fan rotor blades design

appropriate aspect ratio was selected by considering aerodynamic performance

weight and flutter stability. Energy method was used to analyze the flutter stability for both rotor blades of the fan. Blade thickness

three dimensional blade shape and tip to hub chord ratio were modified to eliminate the flutter risk. The investigation showed that the aspect ratio was not the only parameter of concern for flutter free design in conceptual design phase. The near stall points at the rotational speed when blade tip flow was transonic were more prone to flutter. Strong shock waves could enhance the coupling effect between fluid and structure

and induce complex construction of aerodynamic work distribution. Blade thickness and tip to hub chord ratio were effective parameters to improve flutter risk.