Beschreibung
The effectiveness of gas turbines can be improved significantly by decreasing the friction losses. Compared to smooth surfaces riblet-structures have been proven to reduce skin friction in turbulent flow up to 10 %. For the technical application on compressor blades in turbo machines, micro riblet structures with a riblet width between 20 and 120 lm and a depth of the half width are required. Furthermore, the structuring process must be able to generate micro patterns, which are orientated in stream direction, on free formed surfaces. So far, riblet structures have been ground on single curved NACA6510. In order to grind riblet structures a 5–axes-grinding process is required. However, the complex motion of the grinding wheel results in defects on the ground geometries. This paper presents the effect of the 5-axes-kinematics on the riblet aspect ratio and, as a consequence, General conditions, which enable a grinding process without defects on the ground riblets.
