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Four spot laser anemometer and optical access techniques for turbine applicationsA time-of-flight anemometer (TOFA) system, utilizing a spatial lead-lag filter for bipolar pulse generation was constructed and tested. This system, called a Four Spot Laser Anemometer, was specifically designed for use in high speed, turbulent flows in the presence of walls or surfaces. The TOFA system uses elliptical spots to increase the flow acceptance angle to be comparable with that of a fringe type anemometer. The tightly focused spots used in the Four Spot yield excellent flare light rejection capabilities. Good results were obtained to 75 microns normal to a surface, with a f/2.5 collecting lens. This system is being evaluated for use in a warm turbine facility. Results from both a particle lag velocity experiment and boundary layer profiles will be discussed. In addition, an analysis of the use of curved windows in a turbine casing will be presented. Curved windows, matching the inner radius of the turbine casing, preserve the flow conditions, but introduce astigmatic aberrations. A correction optic was designed that virtually eliminates these astigmatic aberrations throughout the intrablade survey region for normal incidence.
Document ID
19870008624
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Wernet, Mark P.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 5, 2013
Publication Date
January 1, 1987
Subject Category
Instrumentation And Photography
Report/Patent Number
NASA-TM-88972
NAS 1.15:88972
E-3440
Accession Number
87N18057
Funding Number(s)
PROJECT: RTOP 533-04-11
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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