Design of high Reynolds number compressor airfoil with early transition for heavy-duty gas turbine

A type of compressor airfoil, characterized by lower losses and wider operating range than conventional controlled diffusion airfoil (CDA), was developed for use in heavy-duty gas turbines, which considered the early boundary layer transition on blade surface induced by high Reynolds number. Direct design process was adopted, in which the parameterization of airfoil geometry and the blade to blade flow solver were integrated into genetic algorithm to facilitate automatic optimization of airfoil. The optimization object was considered as a compromise of airfoil loss and operating range of incidence, and a special airfoil geometry model correlating the thickness distribution with camber line was applied to reduce optimzation variables. The main characteristics of early transition airfoil by optimization are as follows: the suction side velocity maximum moves forward to around 10% of chord, and the velocity distribution in the rear portion is flat. Finally, the design strategy of this type of early transition airfoil was summarized according to the optimization results.