EXPERIMENTAL INVESTIGATION ON THE PERFORMANCE OF AN ANNULAR NOZZLE CASCADE of A HIGHLY-LOADED TRANSONIC TURBINE-STAGAE

An annular nozzle cascade of a highly-loaded transonic turbine-stage has been tested in annular cascade wind tunnel,and its two plane cascades at the hub-and mid-sections—in a plane cascade wind tunnel.Their loss performance,exit flow angle,exit flow velocity as well as the flow velocity distribution on the blade-profile surfaces obtained in both cases are analyzed comparatively.It is proven that the experimantal results of the annular nozzle cascade are comprable with those of the plane cascades,particularlly,in quite good agreement at the mid-section.But at the hub-section a obvious difference between the experimental of both results occurs because of the local flow complexity in the annular nozzle cascade.