Forming a flow directing element for a turbine

摘要

A flow directing element for the turbine section of a rotary machine includes various construction details which are developed which increase the aerodynamic efficiency of the flow directing element. In one embodiment, the flow directing element is a rotor blade having a roughened surface which approximates the critical roughness characteristic of the airfoil. In one particular embodiment, the roughness average of the surface lies between 120 to 200 AA microinches.