The effects of surface roughness on the aerodynamic performance and boundary layer condition of low pressure turbine blade PACKD-A were investigated experimentally under steady state and unsteady state. The upstream wakes were simulated by the rotating bars

thus

an unsteady environment state was formed. To produce the roughness blades

the sandpaper was stuck into the slot

which was incised on the smooth blade. The profile loss and the loading of the suction side were measured by aerodynamic probes and static pressure holes associated with the pressure transducer. And the details of the boundary layer were measured with a single hotwire probe. Result shows that the roughness strips covering 5.2% suction surface length (starting at 44.3% suction surface length

stopping at 49.5% suction surface length) and with 8.82μm roughness height have a better performance than others in the unsteady state. The profile loss is reduced with this roughness strip with the whole tested Reynolds number(3×104~12×104). In addition

the roughness strips covering 19.5% suction surface length (starting at 30% suction surface length

stopping at 49.5% suction surface length) and with 20.91μm roughness height reduce the profile loss and extended the operating margin of the turbine blade with low Reynolds number(less than 8×104) under steady state. However

some additional profile loss is produced with this type of roughness with high Reynolds number(more than 8×104).