REDUCING THE FRICTION LOSS OF ROTOR DISKS IN TURBOMACHINERY

In turbomachinery the skin friction of the rotor disk and the opposite stationary wall contributes to the hydraulic losses affecting the ove rall efficiency. For machines with low specific speed this is one majo r source of energy loss. Usually, the disk surface is machined as smoo th as possible whenever the skin friction has to be minimized. However , in this contribution it is shown that, in order to reduce the skin f riction, V shape riblets machined into the surface can be applied. Thi s results in drag reduction due to an effect which was examined earlie r by investigators in fluid dynamics research.