Application of a laser-Doppler anemometry for the study of unsteady flow structure in a model micro-hydro turbine

Current work deals with an LDA characterization of the velocity distributions and pressure pulsation maps in an axisymmetric draft tube for the flow conditions corresponding to wide range of the operating regimes of the micro-hydro turbine unit. For the detailed analysis of the velocity profiles, three characteristic regimes corresponding to part-load regime with precessing vortex core formation, best efficiency regime and overload regime of hydro turbine operation were selected. To capture spatial characteristics of the unsteady flow for part-load regime a phase averaging procedure for the LDA data has been employed. (paper)