Measurement with a Split-fiber Probe in Unsteady and Reverting Periodic Flows

0507251 - ÚT 2020 PL eng A - Abstract
Lepičovský, Jan
Measurement with a Split-fiber Probe in Unsteady and Reverting Periodic Flows.
Book of Abstract ISAIF 14th. Gdaňsk, 2019. s. 73-74.
[International Symposium on Experimental and Computational Aerothermodynamics of Internal Flows /14./. 08.07.2019-11.07.2019, Gdańsk]
R&D Projects: GA TA ČR TH02020057
Institutional support: RVO:61388998
Keywords : experimental methodology * flow velocity and direction measurement * thermo-anemometry * split-fiber probe * turbomachinery * rotating stall
OECD category: Mechanical engineering

The topic of this paper is to assess suitability of thermo-anemometric split-fiber probes for reliable measurement of velocity direction variations in unsteady and reverting periodic flows. A split-fiber probe has two heated thin films deposited along the axis of a thin quartz cylinder. Consequently, probe characterisrics depend on both an instant flow velocity as well as the immediate flow direction. The probe directional characteristics are linear within the incidence angle range of 40 deg. For larger range of incdences and reverting flows the measurements must be repeated for several probe angle settings, and the acquired sets of data must be segmented into portions where for each probe setting angle the detected angle deviations are within the band of 40 deg. After that the individual segments of repeated data sets are patched together into a single data set. However, such a procedure can be applied only to periodoc flow patterns. Flows in rotating components of turbomachines satisfy this condition. A presented flow pattern measured behind the first rotor of an axial compressor operated in the rotating stall regime was acquired using this newly proposed measurement methdology.
Permanent Link: http://hdl.handle.net/11104/0299151