Hot-wire measurements in a Direct Driven high speed Turbo Fan (DDTF) rig

Kurzfassung

The German Aerospace Center (DLR) has measured and analyzed the unsteady flow field of a representative Direct Driven Turbo Fan (DDTF) stage by using hot-wire anemometry. Measurements were conducted together with the partner Rolls-Royce at the fan test bed of AneCom AeroTest. The averaged mean vectors as well as the fluctuating components of the velocity in the wake of each individual rotor blade were determined and the local turbulence distribution was calculated for various axial and radial positions downstream of the rotor. The calculated local turbulence distribution of the flow downstream of the rotating blades shows an increase of the turbulence intensity from 4.5% up to 12 % in the wake depending on the operating point. The variation of the axial position downstream of the rotor describes the mixing process of the rotor blade wakes. With increasing distance from the trailing edge of the rotor the turbulence intensities levels are getting more equalized.