Accession Number : AD0870186

Title :   Optical Techniques for Flow Visualization and Flow Field Measurements in Aircraft Turbomachinery.

Descriptive Note : Final rept. May 69-Apr 70 on Item 1,

Corporate Author : PRATT AND WHITNEY AIRCRAFT GROUP EAST HARTFORD CT

Personal Author(s) : Alwang, Walter G. ; Cavanaugh, Lawrence A. ; Burr, Ronald J. ; Hauer, Allan

Report Date : JUN 1970

Pagination or Media Count : 107

Abstract : 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 flow/no 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)

Descriptors :   *LASERS), (*AIRCRAFT ENGINES, GAS FLOW), (*FLOW VISUALIZATION, INTERFEROMETERS, GAS TURBINES, VELOCITY, THREE DIMENSIONAL FLOW, DENSITY.

Subject Categories : Lasers and Masers
      Fluid Mechanics
      Jet and Gas Turbine Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE