Numerical Investigation of the Effect of Blade Manufacturing Tolerances on Axial Turbine Performance

Even though designs are carried out for prescribed dimensions, every part has tolerances either small or large because of manufacturing processes. Therefore, designers not only have to design parts with optimum shapes, but also need to consider the effects of the manufacturing variability. Designers may want to tighten up these tolerances but when these tolerances are too tight, one may need to change the manufacturing process to a more controlled and probably an expensive one or accept more scrap parts. This is also valid for gas turbine engine parts, particularly for the axial turbine blades of this study. In the context of this paper, different possible manufacturing variations will be investigated on Aachen turbine geometry using Computational Fluid Dynamics (CFD). The possible deviations that are considered in this study include; variation in stagger angle, variation in chord lengths and variation in maximum thickness.