Aero-thermal flow characterization downstream of an NGV cascade by five-hole probe and filtered Rayleigh scattering measurements

Abstract

The characterization of pressure, temperature and velocity fields in turbomachinery flows typically relies on well-proven probe-based technology such as pneumatic probes, hot-wire sensors or thermocouples. These devices have to be introduced into narrow flow channels and by that obstruct part of the duct at the actual measuring position, which can significantly alter the aerodynamic performance of the components under investigation. In this contribution, measurement results of a commercially available five-hole probe with mounted temperature sensor and laser-optical filtered Rayleigh scattering diagnostics are acquired downstream of a nozzle guide vane cascade with lean-burn combustion representative inlet flow distortions. Pressure results obtained by both methods are found to be on a

Auto-Processing of Filtered Rayleigh Scattering Images Including Mie and Background Scattering Contributions

“…This specific wavelength is typical for frequency-doubled, diode-pumped lasers using gain media such as Nd:YVO 4 or Nd:YAG lasers. Doll et al use similar techniques [1][2][3]. The addition of Mie and background scattering into the theoretical model has been covered extensively by [4][5][6] and [7].…”

“…Items three through five yield the measurement principles, namely that direct measurements of static pressure (3) and static temperature (4) can be used to get static density from the state equation, while the mean Doppler shifted signal yields flow velocity. These effects are all observed through the use of a molecular absorption filter, in this case, an iodine vapor cell is used.…”

Time-resolved temperature profile measurements in the exhaust of a single sector gas turbine combustor at realistic operating conditions

“…Ihme (2017); Morgans and Duran (2016); Bake et al (2009); Bauerheim et al (2016); Hield et al (2009). Beyond the noise generation through spatio-temporal variation of temperature, knowledge of the unsteady temperature distribution at the exit of the combustion chamber is of high value for reliable design of cooling strategies of NGVs and the performance of the downstream high-pressure turbine stages (Doll et al 2018).…”

Resolving nonuniform temperature distributions with single-beam absorption spectroscopy. Part I: Theoretical capabilities and limitations

“…In gas turbine engines, for example, so-called 'hot streaks' across the combustor exit force operation of engines at sub-optimal operating conditions in order to keep engine components well below material limitations [1,2]. To improve system efficiencies, several studies have probed the magnitude of this exhaust temperature nonuniformity [2][3][4][5][6]. Nonuniformities also impair industrial combustion processes; for instance, temperature nonuniformities introduce unwanted material variability into temperature-dependent flame treatments [7].…”

“…Nonuniformities also impair industrial combustion processes; for instance, temperature nonuniformities introduce unwanted material variability into temperature-dependent flame treatments [7]. Real-time control [1,8,9] and design of nextgeneration combustors [5,6] would benefit from a technique capable of recovering spatial nonuniformities within these industrial power and manufacturing systems.…”