LDV Measurements of Unsteady Flow within a Turbine Rotor at Low Reynolds Numbers

The unsteady flow field within an annular axial-flow turbine rotor at low Reynolds numbers was investigated experimentally using an LDV system. Detailed measurements of the time-averaged and time-dependent distributions of the velocity, the flow angle, and the turbulence intensity were carried out at the design operating condition. The obtained data was analyzed in terms of both absolute (stationary) frame of reference and relative (rotating) frame of reference. The effect of the turbine stator wake on the flow field inside the rotor passage was captured qualitatively and quantitatively. The unsteady flow was also analyzed using animations to visualize flow and thus clarify the unsteady phenomenon in a turbine rotor.