Abstract
Turbine vanes and blades are important components in steam turbines and gas turbines to convert thermal energy into mechanical energy. Since the turbine operates for a long period of time under a harsh environment, the turbine performance tends to deteriorate in a gradual manner due to increase in surface roughness or deformation due to wear, dent, chipping or thermal expansion. It is preferable from a viewpoint of developing a new type of real-time health monitoring technique of the turbine if one could detect any change in surface condition or shape of turbine vanes and blades from the information of the turbine performance deterioration. As one of the representative geometrical changes in turbine, the study focuses on the size of the trailing edge diameter of upstream turbine nozzle, emulating possible change in shape of trailing edge due to wear, chipping or deposition of foreign object or scale on the nozzle surface. A low-speed wind tunnel in Iwate University is used to investigate how and to what extent the change in trailing edge size affects the aerodynamic performance of the subsequent turbine blade.
