An approach to measure total-head in wakes and near end walls at high fogging conditions
Publication date
2021-09-16
Document type
Konferenzbeitrag
Author
Organisational unit
Conference
ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition ; Online ; June 7-11, 2021
Publisher
The American Society of Mechanical Engineers
Book title
Proceedings of ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition
Volume (part of multivolume book)
8
Article ID
V008T20A008
Part of the university bibliography
✅
Language
English
Abstract
Evaporation cooling increases gas turbine power output. Experimental results suggest an 8% increase of power when 1% of the overall mass flow is added via water droplets injected upstream of the compressor. However, water injection has an impact on the flow field, which requires experimental research involving probe measurements in the droplet-laden flow as well as reliable monitoring during operation, as the volumetric flow rate throughout the stages changes notably and deviates from (dry) design parameters. Measuring with a conventional pressure probe in two-phase flows is challenging because the droplet-laden flow can clog the pressure taps, thus effectively separating the sensor from the measurement location. This paper presents a consistent approach to measure stagnation pressure in a droplet-laden flow field. The probe was purged constantly to prevent droplets from clogging the tubing. The recorded pressure is then corrected using a transfer function to account for the purging pressure offset. A detailed description of how to obtain this function is given within the paper. With this setup, the flow field downstream of a blade cascade was measured at several water mass fractions and spray characteristics. The pressure measurements are compared with the usual LDA/PDA measurements in the wake of the cascade. Based on the test results, an evaluation of the change of total-head loss due to water injection and evaporation compared to dry operation can be performed.
Version
Published version
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