Optical Techniques for Flow Visualization and Flow Field Measurements in Aircraft Turbomachinery.
Final rept. May 69-Apr 70 on Item 1,
PRATT AND WHITNEY AIRCRAFT GROUP EAST HARTFORD CT
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The objective of the work is the development of optical methods for visualizing and measuring gas flow in turbomachinery. The work in flow visualization concentrated on an investigation of the methods of holographic interferometry using small scale flow rigs. It was found that flowno flow holograms can be analyzed to yield three-dimensional gas density distributions. Because of stability requirements, however, single-exposure double-pulse holograms are more easily applied to turbomachinery. These permit the visualization, in three dimensions, of density gradients in motion such as shocks, turbulent wakes and acoustic phenomena. The measurement of gas velocity at a point using laser doppler velocimetry LDV was also investigated. A dual beam optical configuration was developed which, because of its insensitivity to vibration and its good light collection efficiency, is especially useful for application to turbomachinery. In general, it is concluded that both holography and optical doppler velocimetry offer many potential advantages for measurement of gas flow. Forms of the apparatus most suitable for use in turbomachinery are described. Author
- Lasers and Masers
- Fluid Mechanics
- Jet and Gas Turbine Engines