Development and assessment of volume resolving velocimetry for turbomachinery test facilities

Kurzfassung

The present thesis assesses the applicability of volume resolving velocimetry for turbo machinery test facilities. Tomographic particle image velocimetry has been implemented in a transonic cascade wind tunnel. Assessment is based on 3D-3C measurements of the passage vortex in an axial compressor cascade at subsonic inflow (Ma1=0.6). Results show broad consistency with stereoscopic PIV with improved depth resolution. A novel Fast Multiplicative Algebraic Reconstruction Technique (FMART) enables signicantly faster computations of particle reconstructions in comparison to a state-of-the-art procedure (simultaneous MART) while maintaining similar accuracies. The second part describes the development of tomographic shadowgraphy for 3-D measurements of spatial fuel spray distributions and droplet velocities. This novel approach is based on simultaneous imaging from different directions with pulsed LED inline illumination. Assessment is based on 3D-3C measurements of the airblast atomization of a single kerosene jet in a swirl flow at air pressures between 4-7 bar and air temperatures between 440-570 K inside a spray test facility. The minimum resolvable droplet diameter is 10 µm under the given experimental conditions. Validation against PDA data revealed consistency at size classes d = 10µm and 15µm.