Dr. Ing Ullrich Doll
Defense: 12.08.2016
Title “Filtered Rayleigh scattering for simultaneous determination of pressure, temperature and velocity fields in gas flows“
Promotionsfeier Dr. Ing. Ullrich Doll
Chairman: Prof. D. Plettemeier, TU Dresden
Referee: Prof. J. Czarske, TU Dresden
Prof. I. Röhle, Beuth Hochschule für Technik Berlin
Examiner: Prof. J. Czarske, TU Dresden
Prof. I. Röhle, Beuth Hochschule für Technik Berlin
Prof. U. Hampel, TU Dresden
Abstract:
The characterization of gas flows is of great importance both in aerospace as well as power engineering. Laser-optical methods are capable of spatially and temporally resolved measurements with minimal influence on the investigated phenomenon. The aim of this work is to provide a measuring system based on spectrally filtered Rayleigh scattering (FRS), which allows for a simultaneous determination of time-averaged pressure, temperature and velocity fields under the challenging conditions of modern gas turbine test benches.
The FRS technique utilizes the absorption bands of atomic or molecular gases to filter laser stray light from surfaces or large particles from the measured signal. Previous implementations of the technique are based on pulsed laser light sources. Despite their general usability under test rig conditions has to be discussed, many of these systems suffer from spectral broadening mechanisms which lead to an insufficient suppression of laser stray light. In contrast, the employed solid-state continuous-wave laser of this contribution benefits from its high spectral quality as well as robust and compact design.