抄録
This paper shows the effect of local surface roughness on the
aerodynamic loss behavior of a turbine blade. Non-contact measurements
of the surface roughness of turbine blades of a jet engine
are conducted. The roughness is quantitatively characterised using
a shape and density parameter to parametrise the topology and
the average roughness height. An experimental investigation in a
linear cascade wind tunnel is conducted in order to identify the contributions
of pressure- and friction-losses of the measured surfaces
to the overall profile loss increase due to local surface roughness.
The results show that the change of profile losses due to local surface
roughness is significant. The change in losses is dependent on
the roughness height, as well as of the position on the blade of the
roughness and the condition of the boundary layer behind. The local
pressure gradient at and downstream of the surface roughness is
identified as the main influencing parameter besides the roughness
height.
